The Gerard W. Ostheimer LectureWhat’s New in Obstetric Anesthesia?

2009Jill Mhyre M.D.

Assistant Professor of AnesthesiologyThe University of Michigan Health System

Ann Arbor, Michigan

Objective: Upon completion of this presentation, participants will be able to identify novel concepts, themes, and areas of research relevant to the understanding and management of major pregnancy-related disorders, labor and delivery, obstetric anesthesia, and perinatal complications.

Summary: This presentation will outline the methods used to identify 150 of the most important articles for obstetric anesthesiologists published in 2009. Discussion of selected articles will illustrate salient themes, and suggest future directions for the science and practice of obstetric anesthesia.

Methods: Article ascertainment relied primarily on a monthly review of the tables of contents of major journals published in the English language from January – December 2009 covering anesthesiology, obstetrics, pediatrics, and general medicine. Ascertainment was augmented through a variety of electronic and print media including: MDLinx, Faculty of 1000 Medicine, Doctor’s Guide, ISI Web of Knowledge, LexisNexis, PubMed and Google searches of keywords, Obstetric Anesthesia Digest, Obstetric and Gynecological Survey, and the Journal of Women’s Health: Hot Papers in the Literature.

In total, 1,323 potentially relevant items were retrieved, including articles, reports, news releases, and other media. Of these, 894 were excluded based on initial review. The remaining items were evaluated for the following criteria:

1. Relevance to the practice of obstetric anesthesia2. Importance of the hypothesis or study purpose, considering whether the study addressed a fundamental question, or a particularly severe or

frequent problem3. Clinical implications for anesthetic management of pregnant or recently delivered women4. Clinical implications for obstetric or medical management of pregnant or recently delivered women, or clinical implications for perinatal care5. Research implications, including novel methods, design, questions, or areas of concern that should compel further research by members of the

Society of Obstetric Anesthesia and Perinatology (SOAP)6. Novelty 7. Validity, considering the degree to which study methods were meticulously planned, executed, and analyzed in order to minimize bias to the

maximal degree for a given research question and design. Sources of residual bias were identifi ed and implications were addressed8. Defi nitiveness, considering not only the level of evidence, but also the magnitude of the established effect size, the precision of the estimate,

and the relationship with previously published results9. Educational value or clinical pearls

10. Overall assessment, including my general impression of the article, the degree to which I was compelled to read in detail, the strength of the graphics, a connection to emerging topical themes, and timeliness in the current sociopolitical environment

Additional metrics included the journal impact factor, the Faculty of 1000 Medicine score, and any relevant quality scores, including the Chalmers score for the quality of randomized controlled trials (RCTs).

Articles were sorted by topic area. At the end of the year, topic areas were reviewed to identify not only the strongest individual articles, but also the most important themes that emerged in 2009. In order to more fully illustrate themes and to direct readers to accompanying editorials, supplementary references have been inserted.

Study design is reported below each citation. Randomized controlled trials were evaluated using the Chalmers quality assessment tool. Quality scores over 75% are reported as “high quality,” scores between 50% and 75% as “moderate quality,” and scores less than 50% as “limited quality.” Refer to Anesthesia & Analgesia (2009; 108:1916-1921) for a description of this scoring method.

List of Journals

Anesthesia JournalsActa Anaesthesiologica ScandinavicaAnaesthesiaAnaesthesia and Intensive CareAnesthesia & AnalgesiaAnesthesiologyAnesthesiology Clinics of North AmericaBritish Journal of AnaesthesiaCanadian Journal of AnaesthesiaCurrent Opinion in AnesthesiologyEuropean Journal of AnesthesiologyEuropean Journal of Pain

International Anesthesiology ClinicsInternational Journal of Obstetric AnesthesiaJournal of Clinical AnesthesiaJournal of PainObstetric Anesthesia DigestPainRegional Anesthesia and Pain Medicine

General Medical JournalsAmerican Journal of EpidemiologyAnnals of Internal MedicineBritish Medical JournalBritish Journal of HaemotologyChest

CirculationCritical Care MedicineEuropean Heart JournalHealth AffairsHealth Services ResearchHeartJournal of the American Medical AssociationJournal of American College of CardiologyJournal of Clinical EpidemiologyJournal of Patient SafetyLancet Morbidity and Mortality Weekly ReportNatureNew England Journal of MedicineQuality and Safety in Health CareResuscitationScience

Obstetric and Gynecology JournalsActa Obstetrica et Gynecologica ScandinavicaAmerican Journal of Maternal/Child NursingAmerican Journal of Obstetrics & GynecologyThe Australian and New Zealand Journal of Obstetrics & GynecologyBirth: Issues in Perinatal CareBritish Journal of Obstetrics and Gynaecology Clinical Obstetrics and GynecologyObstetrics, Gynaecology & Reproductive MedicineCurrent Opinion in Obstetrics and GynecologyEuropean Journal of Obstetrics & Gynecology and Reproductive BiologyFertility and SterilityGynecologic and Obstetric InvestigationInternational Journal of Gynecology & ObstetricsJournal of PerinatologyJournal of Maternal-Fetal & Neonatal MedicineJournal of Midwifery & Women’s Health Journal of Women’s HealthMidwiferyObstetrical & Gynecological SurveyObstetrics & GynecologyObstetrics & Gynecology Clinics of North AmericaObstetric Medicine: The Medicine of Pregnancy

Pediatrics JournalsBMC PediatricsJournal of Paediatrics and Child HealthJournal of PediatricsPediatrics

Table of ContentsAnesthesia and Analgesia

Non-pharmacologic Analgesia #1-5AcupuncturePhysiology and Psychology of Non-pharmacologic Analgesia

Intravenous Analgesia #6Remifentanil

Neuraxial Block Placement, Equipment, and Technique #7-13Physical ExaminationUltrasonographyCatheter Design Catheter Insertion TechniqueEpidural Catheter Testing

Neuraxial Labor Analgesia #14-20Combined Spinal Epidural versus Epidural AnalgesiaPharmacologic AdjuvantsPatient-controlled Epidural Anesthesia

Neuraxial Analgesia and the Progress of Labor #21-23

Neuraxial Anesthesia for Cesarean Delivery #24-35Spinal HypotensionMaternal Oxygen SupplementationCombined Spinal Epidural versus Single Shot SpinalPharmacologic AdjuvantsThermoregulation

General Anesthesia for Cesarean Delivery #36-37Pharmacologic Adjuvants

Post-delivery Analgesia #38-45Analgesia following Vaginal DeliveryAnalgesia following Cesarean DeliverySide Effect Management

Complications of Anesthesia #46-57General Risk FactorsAspiration: Risk, Prophylaxis, and TreatmentThe Diffi cult Airway: Risk, Prophylaxis, and TreatmentLipid Rescue for Local Anesthetic ToxicityComplications of Neuraxial AnesthesiaMedicolegal Issues in Obstetric Anesthesia

ObstetricsMaternal Coexisting Disease #58-81

Cardiac DiseaseHypertensive Disorders including PreeclampsiaDiabetesHematologic DiseaseInfectionObesitySubstance Abuse

Obstetric Management #82-105The First TrimesterPreterm Labor Breech PresentationTrial of Labor after Cesarean (TOLAC) and Vaginal Birth after Cesarean (VBAC)Induction of LaborPeripartum Fluids, Electrolytes, and FeedingTechnology to Monitor Progress of Labor Intrapartum Fetal Monitoring

Obstetric Complications #106-118HemorrhageUterine RuptureNeurologic ComplicationsGeneral Obstetric Complications

PerinatologyNeonatal Outcomes #119-131

Anesthetic Technique and Neonatal OutcomesEarly PrematurityLate PrematurityTerm BirthNeurologic Morbidity and Mortality

Other TopicsBreastfeeding #132-133Education #134-135

CommunicationThe Health Care Delivery System #136-149

Home BirthOrganization of Anesthetic ServicesPatient Safety

Books #150

References:

Non-pharmacologic Analgesia

Acupuncture

1. Wang SM, DeZinno P, Lin EC, et al: Auricular acupuncture as a treatment for pregnant women who have low back and posterior pelvic pain: a pilot study. Am J Obstet Gynecol 2009; 201: 271 e1-9Study Design: High quality RCT (n=159 comprising 3 groups of n=58 [acupuncture] vs. n=54 [sham acupuncture] vs. n=47 [control])Conclusion: One week of continuous auricular acupuncture decreases the pain and disability experienced by women with pregnancy-related low back and posterior pelvic pain.

Physiology and Psychology of Non-pharmacologic Analgesia

2. Eippert F, Bingel U, Schoell ED, et al: Activation of the opioidergic descending pain control system underlies placebo analgesia. Neuron 2009; 63: 533-43Study Design: Randomized controlled healthy volunteer experiment (n= 40 men comprising 2 groups of n=19 [naloxone] vs. n=21 [saline])Conclusion: By combining a robust procedure to generate placebo analgesia, a randomized naloxone infusion, and functional MRI, this study provides functional evidence of the endogenous opioid-mediated interactions between the hypothalamus, the periaqueductal gray, and the rostral ventromedial medulla, in effecting placebo analgesia.

See also: Eippert F, Finsterbusch F, Bingel U, Büchel C: Direct evidence for spinal cord involvement in placebo analgesia. Science 2009; 326: 404Study Design: Healthy volunteer cross-over experiment (n=13 men)Conclusion: Further work by the same group illustrates the contribution of the dorsal horn of the spinal cord to placebo analgesia.

3. McGowan N, Sharpe L, Refshauge K, Nicholas MK: The effect of attentional re-training and threat expectancy in response to acute pain. Pain 2009; 142: 101-7Study Design: Randomized controlled healthy volunteer experiment (n=104 men and women comprising 2 groups of n=51[threat condition] vs. n=53 [non-threat condition]Conclusion: In this experimental task (arm immersion in 5° C water), both description of the task in threatening terms (‘risk of frostbite’), and training attention towards pain-related stimuli, independently lowered the threshold for pain and initial pain ratings, but did not change tolerance (time to arm withdrawal) or pain ratings at tolerance.

4. Colloca L, Benedetti F: Placebo analgesia induced by social observational learning. Pain 2009; 144: 28-34Study Design: Randomized controlled healthy volunteer experiment (n=48, comprising 3 groups of women, n=16 [social observation] vs. n=16 [conditioning] vs. n=16 [verbal suggestion])Conclusion: The participants who observed a benefi cial effect of the intervention in an actor (simulating benefi t) experienced a marked placebo effect, which correlated with scores for empathy. The group who received verbal instruction to expect a benefi t experienced signifi cantly smaller placebo effects.

Two accompanying editorials:Porro CA: Open your mind to placebo conditioning. Pain 2009; 145: 2-3

Robinson ME, Price DD: Placebo analgesia: widening the scope of measured infl uences. Pain 2009; 144: 5-6

5. Stephens R, Atkins J, Kingston A: Swearing as a response to pain. Neuroreport 2009; 20: 1056-60Study Design: Healthy volunteer cross-over experiment (n=67, including 38 men and 29 women)Conclusion: In this experimental model, swearing increased pain tolerance, increased heart rate, and decreased perceived pain compared with not swearing. The effect was more dramatic in women than men.

Intravenous Analgesia

Remifentanil

6. Angst MS, Chu LF, Tingle MS, Shafer SL, Clark JD, Drover DR: No evidence for the development of acute tolerance to analgesic, respiratory depressant and sedative opioid effects in humans. Pain 2009; 142: 17-26Study Design: Randomized controlled healthy volunteer cross-over experiment including men and women (n=36 comprising 12 groups of n=4 [allocation illustrated in Fig 1])Conclusion: Short-term administration of clinically useful doses of remifentanil is not associated with the development of signifi cant tolerance to analgesic, respiratory depressant, or sedative opioid effects.

Accompanying editorial:Simonnet G: Acute tolerance to opioids: methodological, theoretical and clinical implications. Pain 2009; 142: 3-4

Neuraxial Block Placement, Equipment, and Technique

Physical Examination

7. Ellinas EH, Eastwood DC, Patel SN, Maitra-D’Cruze AM, Ebert TJ: The effect of obesity on neuraxial technique diffi culty in pregnant patients: a prospective, observational study. Anesth Analg 2009; 109: 1225-31Study Design: Prospective cohort (n=427 women with BMI 20-62 [mean BMI=33] kg/m2)Conclusion: Two factors predicted neuraxial technique diffi culty: 1) the practitioner’s ability to palpate the patient’s bony landmarks, and 2) the patient’s ability to fl ex her back. Body mass index was not an independent predictor. Obesity did, however, strongly predict both the ability to palpate landmarks and fl ex the back.

Ultrasonography

8. Balki M, Lee Y, Halpern S, Carvalho JC: Ultrasound imaging of the lumbar spine in the transverse plane: the correlation between estimated and actual depth to the epidural space in obese parturients. Anesth Analg 2009; 108: 1876-81Study Design: Exploratory cohort to evaluate a diagnostic test with a reliable gold standard (actual needle depth) (n=46 women with BMI 30-79 [median 36] kg/m2) Conclusion: Depth measured by ultrasonography correlated with actual needle depth. Taken together, results from Ellinas (#7 above) and Balki suggest that prepuncture lumbar ultrasonography may be a useful guide to facilitate the placement of epidural needles in obese parturients when black fl exion is limited, spinous processes are not palpable, or initial placement attempts fail.

Catheter Design

9. Spiegel JE, Vasudevan A, Li Y, Hess PE: A randomized prospective study comparing two fl exible epidural catheters for labour analgesia. Br J Anaesth 2009; 103: 400-5Study Design: Moderate quality RCT (n=486 comprising 2 groups of n=246 [end-holed] vs. n=240 [three-holed]) Conclusion: There were no differences in the initial analgesia success rate, complications, or labor analgesia between end-hole versus multi-hole fl exible epidural catheters.

Catheter Insertion Technique

10. Grondin LS, Nelson K, Ross V, Aponte O, Lee S, Pan PH: Success of spinal and epidural labor analgesia: comparison of loss of resistance technique using air versus saline in combined spinal-epidural labor analgesia technique. Anesthesiology 2009; 111: 165-72Study Design: Moderate quality RCT (n=345 comprised of 2 groups of n=173 [air] vs. n=172 [saline])Conclusion: This study did not identify a difference in either spinal or epidural analgesic effi cacy whether air or saline was used for LOR during CSE placement. The aspiration for fl uid after observing initial passive fl uid return from the hub of the spinal needle may be unnecessary–neither spinal nor epidural analgesic success rates differed whether spinal fl uid could be aspirated or not. However, in CSE procedures where fl uid did not return spontaneously from the hub of the spinal needle, the corresponding epidural catheter was less likely to provide effective analgesia for the duration of labor.

11. Schier R, Guerra D, Aguilar J, et al: Epidural space identifi cation: a meta-analysis of complications after air versus liquid as the medium for loss of resistance. Anesth Analg 2009; 109: 2012-21Study Design: Meta-analysis of 5 RCTs of primarily limited to moderate quality Conclusion: The risk differences for adverse outcome between loss of resistance to air versus saline were not statistically different for obstetric patients. However, given the rarity of signifi cant outcomes, the available studies do not have suffi cient power to demonstrate any differences.

12. Mhyre JM, Greenfi eld ML, Tsen LC, Polley LS: A systematic review of randomized controlled trials that evaluate strategies to avoid epidural vein cannulation during obstetric epidural catheter placement. Anesth Analg 2009; 108: 1232-42Study Design: Meta-analysis of 30 RCTs of primarily limited to moderate quality Conclusion: The risk of intravascular placement of a lumbar epidural catheter during pregnancy may be reduced with the lateral patient position, fl uid predistension, a single orifi ce catheter, a wire-embedded polyurethane epidural catheter, and limiting the depth of catheter insertion to 6 cm or less. Limited trial quality weakens the strength of these recommendations.

Epidural Catheter Testing

13. Servin MN, Mhyre JM, Greenfi eld ML, Polley LS: An observational cohort study of the meniscus test to detect intravascular epidural catheters in pregnant women. Int J Obstet Anesth 2009; 18: 215-20Study Design: Exploratory cohort study to evaluate a diagnostic test with a weak reference standard (tachycardia in response to epinephrine) (n=419 of which 24 are cases)Conclusion: For obstetric patients in the sitting position, the meniscus test does not improve diagnostic accuracy of aspiration for detecting intravascular multiorifi ce epidural catheter placement.

Neuraxial Labor Analgesia

Combined Spinal Epidural versus Epidural Analgesia

14. Abrao KC, Francisco RPV, Miyadahira S, Cicarelli DD, Zugaib M: Elevation of uterine basal tone and fetal heart rate abnormalities after labor analgesia: a randomized controlled trial. Obstet Gynecol 2009; 113: 41-7Study Design: High quality RCT (n=77 comprising 2 groups of n=41 [CSE] vs. n=36 [epidural])Conclusion: In the fi rst 15 minutes after block placement, CSE analgesia was associated with a signifi cantly greater incidence of transient FHR abnormalities and uterine hypertonus compared with standard epidural analgesia. Speed of analgesic onset correlated with uterine hypertonus and FHR changes.

Letter to the editor: Landau R, Carvalho B, Wong C, Smiley R, Tsen L, Van de Velde M: Elevation of uterine basal tone and fetal heart rate abnormalities after labor analgesia: a randomized controlled trial. Obstet Gynecol 2009; 113: 1374-5The authors question the design and conclusions of Abrao et al, and recommends research to identify patients at risk for uterine hyperactivity, and to evaluate clinical maneuvers to decrease risk.

15. Goodman SR, Smiley RM, Negron MA, Freedman PA, Landau R: A randomized trial of breakthrough pain during combined spinal-epidural versus epidural labor analgesia in parous women. Anesth Analg 2009; 108: 246-51Study Design: Moderate quality RCT (n= 84 comprising 2 groups of n= 43 [CSE] vs. n=41 [epidural])Conclusion: This study did not demonstrate a difference in requirement for top-up doses between CSE and standard epidural analgesia in parous patients, but may have been underpowered to detect a difference. CSE provided better analgesia in the fi rst 30 min compared with standard epidural analgesia.

Pharmacologic Adjuvants

16. Ross VH, Pan PH, Owen MD, et al: Neostigmine decreases bupivacaine use by patient-controlled epidural analgesia during labor: a randomized controlled study. Anesth Analg 2009; 109: 524-31Study Design: Pilot safety assessment (n=12). High quality RCT (n=40) comprising 2 groups of n=20 [bupivacaine] vs. n=20 [bupivacaine+neostigmine])Conclusion: Epidural neostigmine 4 mcg/mL reduced the hourly bupivacaine requirement by 19%-25% in women receiving labor PCEA. The authors noted an increased rate of mild sedation. Note: Larger studies are needed to evaluate for other side effects.

Three accompanying editorials: Eisenach JC: Epidural neostigmine: will it replace lipid soluble opioids for postoperative and labor analgesia? Anesth Analg 2009; 109: 293-5

Wong CA: Labor analgesia: is there an ideal technique? Anesth Analg 2009; 109: 296-8

Schultheis LW, Nikhar BM, Mellon RD, et al: Clinical investigation of neuraxially administered drugs: a regulatory perspective. Anesth Analg 2009; 109: 299-300

17. Van de Velde M, Berends N, Kumar A, et al: Effects of epidural clonidine and neostigmine following intrathecal labour analgesia: a randomised, double-blind, placebo-controlled trial. Int J Obstet Anesth 2009; 18: 207-14Study Design: Moderate quality RCT (n=70 comprising 2 groups of n=35 [epidural neostigmine/clonidine] vs. n=35 [epidural saline])Conclusion: A bolus dose of epidural neostigmine 500 mcg and clonidine 75 mcg, following the intrathecal injection of ropivacaine and sufentanil, prolonged analgesia and reduced subsequent hourly ropivacaine consumption. Note: The study was not powered to detect differences in side effects (hypotension or nausea).

Accompanying editorial: Paech M, Pan P: New recipes for neuraxial labor analgesia: simple fare or gourmet combos? Int J Obstet Anesth 2009; 18: 201-203

See also: #39 Horlocker Anesethesiology 2009;110:218-30

Patient-controlled Epidural Anesthesia

18. Sng BL, Sia AT, Lim Y, Woo D, Ocampo C: Comparison of computer-integrated patient-controlled epidural analgesia and patient-controlled epidural analgesia with a basal infusion for labour and delivery. Anaesth Intensive Care 2009; 37: 46-53Study Design: Moderate quality RCT (n=60 comprising 2 groups of n=30 [“CIPCEA” = PCEA with computer adjusted basal infusion] vs. n=30 [PCEA with constant basal infusion at 5 mL/hr]) Conclusion: CIPCEA improved maternal satisfaction in conjunction with an increased infusion rate during the second stage of labor. Note: Larger studies are needed to confi rm an absence of effect on the duration of the second stage and other side effects.

19. Wilson MJ, MacArthur C, Cooper GM, Shennan A: Ambulation in labour and delivery mode: a randomised controlled trial of high-dose vs mobile epidural analgesia. Anaesthesia 2009; 64: 266-72Study Design: Secondary analysis of data from the Comparative Obstetric Mobile Epidural Trial (COMET) RCT (n=353 [Control] vs. n=351 [CSE] vs. n=350 [LDI])Conclusion: This observational analysis did not demonstrate an association between the level of ambulation a woman actually achieved after epidural placement and mode of delivery.

20. Wilson MJ, MacArthur C, Shennan A: Urinary catheterization in labour with high-dose vs mobile epidural analgesia: a randomized controlled trial. Br J Anaesth 2009; 102: 97-103Study Design: Secondary analysis of data from the COMET RCT (n=353 [Control] vs. n=351 [CSE] vs. n=350 [LDI])Conclusion: Relative to conventional high-dose block, mobile epidural techniques encourage the retention of normal bladder function. Routine bladder catheterization may not be necessary.

Neuraxial Analgesia and the Progress of Labor

21. Wang F, Shen X, Guo X, Peng Y, Gu X: Epidural analgesia in the latent phase of labor and the risk of Cesarean delivery: a fi ve-year randomized controlled trial. Anesthesiology 2009; 111: 871-80Study Design: High quality RCT (n=12,793 comprising n=6,394 [latent phase epidural analgesia] vs. 6,399 [active phase epidural analgesia])Conclusion: Standard epidural analgesia in the latent phase of labor (cervical dilation 1-3 cm) does not prolong the duration of labor and does not increase the rate of cesarean delivery in nulliparous women compared with a strategy of systemic opiates (meperidine 25 mg IM boluses) used to delay neuraxial analgesia until cervical dilation of at least 4 cm. Mean duration was 11.3 vs. 11.8 hours, P=0.9. Cesarean delivery rates were 23.2% vs. 22.8%, P=0.51. The group with early neuraxial analgesia reported increased satisfaction scores (median 84 vs. 62, P=0.01), but decreased rates of breastfeeding at 6 weeks (70.1% vs. 77.8%, P<0.0001).

Accompanying editorial: Flood PMD: Primary versus secondary outcomes in gargantuan studies. Anesthesiology 2009; 111: 704-705This editorial suggests that the effect of breastfeeding success rates may be a consequence of multiple comparisons and excessive statistical power, and recommends that breastfeeding success should be followed-up as a primary endpoint in a future trial.

22. Wong CA, McCarthy RJ, Sullivan JT, Scavone BM, Gerber SE, Yaghmour EA: Early compared with late neuraxial analgesia in nulliparous labor induction: a randomized controlled trial. Obstet Gynecol 2009; 113: 1066-74Study Design: High quality RCT (n=806 comprising 2 groups of n=406 [early intervention] vs. n=400 [late intervention])Conclusion: In this population of nulliparas admitted for induction of labor, early labor intrathecal fentanyl followed by epidural analgesia did not increase the cesarean delivery rate compared with a strategy of systemic opiates (hydromorphone 1 mg IM and 1 mg IV) used to delay the initiation of standard epidural analgesia until cervical dilation of at least 4 cm (32.7% vs. 31.5%, P=0.65). The original design was powered for 1600 participants.

23. Beilin Y, Mungall D, Hossain S, Bodian CA: Labor pain at the time of epidural analgesia and mode of delivery in nulliparous women presenting for an induction of labor. Obstet Gynecol 2009; 114: 764-9 Study Design: Case control (n=555 comprising 3 groups of n=185 [pain score 0-3] vs. n=185 [pain score 4-6] vs. n=185 [pain score 7-10])Conclusion: This case control analysis did not demonstrate an association between the degree of labor pain at initiation of epidural analgesia and mode of delivery or duration of labor.

Neuraxial Anesthesia for Cesarean Delivery

Spinal Hypotension

24. Ngan Kee WD, Khaw KS, Tan PE, Ng FF, Karmakar MK: Placental transfer and fetal metabolic effects of phenylephrine and ephedrine during spinal anesthesia for cesarean delivery. Anesthesiology 2009; 111: 506-12Study Design: Moderate quality RCT (n=104 comprising 2 groups of n=52 [phenylephrine infusion starting at 100 mcg/min] vs. n=52 [ephedrine infusion starting at 8 mg/min] with both infusions titrated to maintain baseline maternal SBP)Conclusion: Ephedrine crosses the placenta to a greater extent and undergoes less early metabolism and/or redistribution in the fetus compared with phenylephrine. The associated increased fetal concentrations of lactate (UA lactate 4.2 vs. 2.2 mmol/L P<0.001), glucose, and catecholamines support the hypothesis that depression of fetal pH and base excess with ephedrine is related to metabolic effects secondary to stimulation of fetal beta-adrenergic receptors. The overall effect of the vasopressors on fetal oxygen supply and demand balance appears to favor phenylephrine.

Accompanying editorial: Smiley RM: Burden of proof. Anesthesiology 2009; 111: 470-2This editorial recommends that titrated phenylephrine infusions (25-100 mcg/min) have become the standard of care for spinal hypotension prophylaxis and treatment.

25. Dyer R, Reed A, van Dyk D, et al: Hemodynamic effects of ephedrine, phenylephrine, and the coadministration of phenylephrine with oxytocin during spinal anesthesia for elective cesarean delivery. Anesthesiology 2009; 111: 753-765Study Design: High quality RCT (n=38 comprising 2 groups of n=20 [phenylephrine 80 mcg] vs. n=18 [ephedrine 10 mg])Conclusion: First, when administered as a bolus to treat maternal hypotension following spinal anesthesia for elective cesarean delivery, phenylephrine reduced maternal CO back towards baseline values, when compared with ephedrine, which increased CO further. Second,

changes in CO correlated with heart rate changes after vasopressor administration, suggesting that heart rate may be a useful surrogate indicator of CO. Third, in an adjunctive pilot RCT (n=20 comprising 2 groups of n=10 [oxytocin 2.5 IU] vs. 10 [oxytocin 2.5 IU + phenylephrine 80 mcg], a coadministered phenylephrine bolus attenuated hemodynamic responses to an oxytocin bolus.

26. Teoh WH, Sia AT: Colloid preload versus coload for spinal anesthesia for cesarean delivery: the effects on maternal cardiac output. Anesth Analg 2009; 108: 1592-8

Study Design: High quality RCT (n=40 comprising 2 groups of n=20 [preload] vs. n=20 [coload])Conclusion: Intravascular volume expansion with 15 mL/kg HES 130/0.4 given as a preload, but not coload, signifi cantly increased maternal CO for the fi rst 5 min after spinal anesthesia for cesarean delivery. Maternal and neonatal outcomes were not different.

27. Tamilselvan P, Fernando R, Bray J, Sodhi M, Columb M: The effects of crystalloid and colloid preload on cardiac output in the parturient undergoing planned cesarean delivery under spinal anesthesia: a randomized trial. Anesth Analg 2009; 109: 1916-21Study Design: High quality RCT (n=60 comprising 3 groups of n=20 [1.5L crystalloid] vs. n=20 [0.5L HES] vs. n=20 [1.0L HES])Conclusion: CO and corrected fl ow time (FTc) increase after fl uid preload, particularly with HES 1.0 L. There were no differences among groups in the incidence of hypotension or mean ephedrine dose—in all three groups, regardless of CO, a signifi cant proportion of patients experienced hypotension that required treatment with ephedrine.

28. Siddik-Sayyid SM, Nasr VG, Taha SK, et al: A randomized trial comparing colloid preload to coload during spinal anesthesia for elective cesarean delivery. Anesth Analg 2009; 109: 1219-24Study Design: High quality RCT (n=178 comprising 2 groups of n=90 [preload] vs. n=88 [coload])Conclusion: There was no difference in the incidence of hypotension in women who received colloid preload compared with coload. A 500 mL colloid bolus is ineffi cient as a single intervention to prevent hypotension, regardless of the timing of administration.

29. Carvalho B, Mercier FJ, Riley ET, Brummel C, Cohen SE: Hetastarch co-loading is as effective as pre-loading for the prevention of hypotension following spinal anesthesia for cesarean delivery. Int J Obstet Anesth 2009; 18: 150-5Study Design: Moderate quality RCT (n=46 comprising 2 groups of n=23 [pre-load] vs. n=23 [co-load])Conclusion: There was no difference in the incidence of hypotension or requirement for vasopressor rescue in women who received colloid preload compared with coload.

30. Leo S, Sng BL, Lim Y, Sia AT: A randomized comparison of low doses of hyperbaric bupivacaine in combined spinal-epidural anesthesia for cesarean delivery. Anesth Analg 2009; 109: 1600-5Study Design: High quality RCT (n=60 patients comprising 3 groups of n=20 [7mg intrathecal bupivacaine] vs. n=20 [8mg] vs. n=20 [9mg])Conclusion: The lowest dose of hyperbaric bupivacaine (7 mg) provided equally rapid onset and effective anesthesia for cesarean delivery while reducing the incidence of hypotension compared with 8 and 9 mg doses. However, because of its shorter duration of anesthesia, low dose spinal anesthesia may be feasible only when the block can be reinforced using a functional epidural catheter.

Accompanying editorial: Benhamou D, Wong C: Neuraxial anesthesia for cesarean delivery: what criteria defi ne the “optimal” technique? Anesth Analg 2009; 109: 1370-3This editorial questions the existence of one optimal intrathecal local anesthetic dose for cesarean delivery, given a long list of patient, anesthetic, and surgical covariates.

Maternal Oxygen Supplementation

31. Khaw KS, Wang CC, Ngan Kee WD, et al: Supplementary oxygen for emergency Caesarean section under regional anaesthesia. Br J Anaesth 2009; 102: 90-6Study Design: Moderate quality RCT (n=125 comprising 2 groups of n=64 [air] vs. n=61 [oxygen])Conclusion: Breathing 60% oxygen during emergency cesarean delivery under neuraxial anesthesia increased fetal oxygenation with no associated increase in lipid-peroxidation in the mother or fetus.

Accompanying editorial: Van de Velde M: Emergency Caesarean delivery: is supplementary maternal oxygen necessary? Br J Anaesth 2009; 102: 1-2This editorial recommends supplementary oxygen for women undergoing unplanned cesarean delivery, but room air for elective cesarean delivery.

Combined Spinal Epidural versus Single Shot Spinal

32. Horstman DJ, Riley ET, Carvalho B: A randomized trial of maximum cephalad sensory blockade with single-shot spinal compared with combined spinal-epidural techniques for cesarean delivery. Anesth Analg 2009; 108: 240-5Study Design: Moderate quality RCT (n=28 comprised of 2 groups of n=13 [single shot spinal] vs. n=15 [CSE])Conclusion: The SSS and CSE techniques (1 mL LOR to air, without epidural catheter insertion) inserted with the patient in the lateral decubitus position resulted in similar extent of sensory blockade and CSF pressure.

Pharmacologic Adjuvants

33. Unlugenc H, Ozalevli M, Gunduz M, et al: Comparison of intrathecal magnesium, fentanyl, or placebo combined with bupivacaine 0.5% for parturients undergoing elective cesarean delivery. Acta Anaesthesiol Scand 2009; 53: 346-53Study Design: Moderate quality RCT (n=90 comprising 3 groups of n=30 [magnesium] vs. n=30 [fentanyl] vs. n=30 [saline placebo])Conclusion: In patients undergoing cesarean delivery under spinal anesthesia, the addition of intrathecal magnesium sulfate (50 mg) to spinal bupivacaine 10 mg did not shorten the onset time of sensory and motor blockade or prolong the duration of spinal anesthesia, as seen with fentanyl. Note: Data on the safety of intrathecal magnesium are limited. (See page 352, references #11-13, and #30).

Thermoregulation

34. Woolnough M, Allam J, Hemingway C, Cox M, Yentis SM: Intra-operative fl uid warming in elective caesarean section: a blinded randomised controlled trial. Int J Obstet Anesth 2009; 18: 346-51Study Design: Moderate quality RCT (n=75 comprising 3 groups of n=25 [room temperature] vs. n=25 [cabinet-warmed] vs. n=25 [Hotline®-warmed])Conclusion: Warming intravenous fl uids (either in a cabinet or with a Hotline®) mitigates the decrease in maternal temperature during elective caesarean delivery under combined spinal-epidural anesthesia and improves thermal comfort, but does not affect shivering.

35. Yokoyama K, Suzuki M, Shimada Y, Matsushima T, Bito H, Sakamoto A: Effect of administration of pre-warmed intravenous fl uids on the frequency of hypothermia following spinal anesthesia for Cesarean delivery. J Clin Anesth 2009; 21: 242-8Study Design: Moderate quality RCT (n=30 comprising 2 groups of n=15 [warmed fl uid] vs. n=15 [unwarmed fl uid])Conclusion: Administration of pre-warmed intravenous colloid, followed by crystalloids, maintained core temperature better at the time of cesarean delivery and up to 45 minutes after delivery. Infants born to mothers who received pre-warmed fl uids had higher Apgar scores at one minute and umbilical arterial pH values (7.33±0.05 vs. 7.29±0.03, P=0.023).

Accompanying editorial: Halloran OJ: Warming our Cesarean section patients: why and how? J Clin Anesth 2009; 21: 239-41Warming is recommended, but much larger studies are needed to show an improvement in important but less common clinical outcomes (e.g., blood transfusion, wound infection, neonatal intensive care unit admission).

General Anesthesia for Cesarean Delivery

Pharmacologic Adjuvants

36. Lee DH, Kwon IC: Magnesium sulphate has benefi cial effects as an adjuvant during general anaesthesia for Caesarean section. Br J Anaesth 2009; 6: 861-6Study Design: Moderate quality RCT (n=72 comprising 3 groups of n=24 [saline control] vs. n=23 [magnesium sulfate 30mg] vs. n=25 [magnesium sulfate 45mg])Conclusion: Preoperative IV magnesium sulfate attenuated BIS and arterial pressure increases in the pre-delivery period in patients undergoing cesarean delivery under general anesthesia.

37. Yoo KY, Jeong CW, Park BY, et al: Effects of remifentanil on cardiovascular and bispectral index responses to endotracheal intubation in severe pre-eclamptic patients undergoing Caesarean delivery under general anaesthesia. Br J Anaesth 2009; 102: 812-9Study Design: Moderate quality RCT (n=42 comprising 2 groups of n=21 [saline control) vs. n=21 [remifentanil])Conclusion: A single bolus of remifentanil 1 mcg/kg attenuated hemodynamic but not BIS responses to tracheal intubation in preeclamptic patients undergoing cesarean delivery under general anesthesia. Its use was associated with maternal hypotension and neonatal respiratory depression requiring resuscitation.

Post-delivery Analgesia

Analgesia following Vaginal Delivery

38. Franchi M, Cromi A, Scarperi S, Gaudino F, Siesto G, Ghezzi F: Comparison between lidocaine-prilocaine cream (EMLA®) and mepivacaine infi ltration for pain relief during perineal repair after childbirth: a randomized trial. Am J Obstet Gynecol 2009; 201: 186 e1-5Study Design: High quality RCT (n= 61 comprising 2 groups of n=31 [EMLA® cream] vs. n=30 [mepivacaine]) Conclusion: EMLA® cream applied to the perineum 1 hour before the expected time of birth, and reapplied after delivery for 10 minutes prior to perineal suturing, appears to be a superior alternative to local anesthetic infi ltration for the relief of pain during repair of fi rst and second degree perineal lacerations.

Analgesia following Cesarean Delivery

39. Horlocker TT, Burton AW, Connis RT, et al: Practice guidelines for the prevention, detection, and management of respiratory depression associated with neuraxial opioid administration. Anesthesiology 2009; 110: 218-30Study Design: GuidelinesConclusion: See pages 224-5 for a summary of the recommended monitoring intervals and durations following various neuraxial opioid dosing

regimens. “Increased monitoring (e.g., intensity, duration, or additional methods) may be warranted in patients at increased risk of respiratory depression.”

40. Bamigboye AA, Hofmeyr GJ: Local anaesthetic wound infi ltration and abdominal nerves block during caesarean section for postoperative pain relief. Cochrane Database Syst Rev 2009: CD006954Study Design: Meta-analysis of 20 RCTs of variable quality; only 4 of 28 outcomes were addressed by more than a single study.Conclusion: Local anesthetic infi ltration, peritoneal spraying, and abdominal nerve blocks for cesarean delivery patients reduce postoperative systemic opioid consumption in the 24 hours following delivery. Drug solutions that also contain NSAIDs may confer additional pain relief. These strategies are recommended for patients undergoing general anesthesia. Note: To further defi ne the value for patients receiving neuraxial anesthesia, future studies should test the benefi t of these interventions in the presence and absence of neuraxial morphine.

41. Belavy D, Cowlishaw PJ, Howes M, Phillips F: Ultrasound-guided transversus abdominis plane block for analgesia after Caesarean delivery. Br J Anaesth 2009; 103: 726-30Study Design: Moderate quality RCT (n=47 comprising 2 groups of n=24 [saline block] vs. n=23 [ropivacaine block])Conclusion: The ultrasound-guided TAP block reduced morphine requirements after cesarean delivery when used as a component of a multimodal analgesic regimen, including scheduled acetaminophen and NSAIDS, and morphine PCA.

42. Costello JF, Moore AR, Wieczorek PM, Macarthur AJ, Balki M, Carvalho JC: The transversus abdominis plane block, when used as part of a multimodal regimen inclusive of intrathecal morphine, does not improve analgesia after cesarean delivery. Reg Anesth Pain Med 2009; 34: 586-9Study Design: Moderate quality RCT (n=96 comprising 2 groups of n=49 [saline block] vs. n=47 [ropivacaine block])Conclusion: The TAP block did not improve postoperative visual analogue scale pain or satisfaction scores when used as part of a multimodal regimen that included intrathecal morphine, scheduled acetaminophen and NSAIDs, and morphine 2 mg prn for rescue.

43. Toledo P, McCarthy RJ, Ebarvia MJ, Huser CJ, Wong CA: The interaction between epidural 2-chloroprocaine and morphine: a randomized controlled trial of the effect of drug administration timing on the effi cacy of morphine analgesia. Anesth Analg 2009; 109: 168-73Study Design: High quality RCT (n=87 comprising 3 groups of n=29 [morphine followed by 2-chloroprocaine then saline] vs. n=30 [saline followed by 2-chloroprocaine then morphine] vs. n=28 [saline followed by lidocaine then morphine]) Conclusion: For postpartum tubal ligation patients, the administration of epidural morphine 30 minutes before epidural anesthesia with 2-chloroprocaine achieved a similar duration of postoperative analgesia as epidural morphine administered after epidural anesthesia with lidocaine. In contrast, epidural 2-chloroprocaine administered before epidural morphine reduced the duration of postoperative analgesia. The discussion considers both pharmacodynamic and biologic explanations for the discrepancy introduced by the relative timing of morphine and 2-chloroprocaine administration.

Side Effect Management

44. Tamdee D, Charuluxananan S, Punjasawadwong Y, Tawichasri C, Patumanond J, Sriprajittichai P: A randomized controlled trial of pentazocine versus ondansetron for the treatment of intrathecal morphine-induced pruritus in patients undergoing cesarean delivery. Anesth Analg 2009; 109: 1606-11Study Design: High quality RCT (n=208 comprising 2 groups of n=104 [IV pentazocine] vs. n=104 [IV ondansetron])Conclusion: Pentazocine 15 mg (a κ-opioid receptor agonist and μ-opioid receptor partial agonist) is superior to ondansetron 4 mg for the treatment of intrathecal morphine-induced pruritus and has a lower recurrence rate within 4 hours.

45. George RB, Allen TK, Habib AS: Serotonin receptor antagonists for the prevention and treatment of pruritus, nausea, and vomiting in women undergoing cesarean delivery with intrathecal morphine: a systematic review and meta-analysis. Anesth Analg 2009; 109: 174-82Study Design: Meta-analysis of 9 RCTs of limited to moderate quality Conclusion: Although prophylactic 5-HT(3) receptor antagonists were not effective in reducing the incidence of pruritus, they signifi cantly reduced the severity and the need for treatment of pruritus, the incidence of postoperative nausea and vomiting, and the need for rescue antiemetic therapy in parturients who received intrathecal morphine for cesarean delivery. They were also effective for the treatment of established pruritus.

Complications of Anesthesia

General Risk Factors

46. Cheesman K, Brady JE, Flood P, Li G: Epidemiology of anesthesia-related complications in labor and delivery, New York State, 2002-2005. Anesth Analg 2009; 109: 1174-81Study Design: Cross-sectional study of n=4,438 patients with at least one anesthesia-related complication coded by ICD-9CM in 957,471 deliveries Conclusion: Factors associated with anesthesia-related complications included cesarean delivery, living in rural areas, having preexisting medical conditions, Caucasian race, private insurance, and scheduled admission. Overall, 96 women died, and anesthesia-related complications during labor and delivery were associated with a 22-fold increased risk of maternal mortality. Causal relationships are impossible to infer.

Aspiration: Risk, Prophylaxis, and Treatment

47. Rice MJ, Mancuso AA, Gibbs C, Morey TE, Gravenstein N, Deitte LA: Cricoid pressure results in compression of the postcricoid hypopharynx: the esophageal position is irrelevant. Anesth Analg 2009; 109: 1546-52Study Design: A pre/post test design in healthy volunteers (n=24 comprising 13 men and 11 nonpregnant women)Conclusions: Approximately 2-4 kg of pressure over the cricoid ring effectively compresses the alimentary tract at the level of the postcricoid hypopharynx, not the esophagus. Anatomic compression is evident even when pressure displaces the crico-hypopharyngeal unit laterally from the vertebral body.

Two accompanying editorials: Lerman J: On cricoid pressure: “may the force be with you.” Anesth Analg 2009; 109: 1363-6This editorial questions whether anatomic compression measured on MRI guarantees an effective physiologic barrier to regurgitation.

Ovassapian A, Salem MR: Sellick’s maneuver: to do or not do. Anesth Analg 2009; 109: 1360-2

48. Fenton PM, Reynolds F: Life-saving or ineffective? An observational study of the use of cricoid pressure and maternal outcome in an African setting. Int J Obstet Anesth 2009; 18: 106-10Study Design: Secondary analysis of a prospective cohort in which 45 anesthesia providers completed a uniform data sheet on sequential deliveries under their care between 1998 and 2000 (n=139 cases of vomiting or regurgitation reported among n=4,891 cesarean deliveries under general anesthesia)Conclusion: Thirty cases of regurgitation occurred on induction of anesthesia, in 24 of whom cricoid pressure was applied (per the anesthesia provider’s report). Nine of 11 mothers who died after aspiration had cricoid pressure applied on induction. Cricoid pressure was associated with increased rates of regurgitation on induction and overall maternal death. In settings such as Malawi, where anesthetist training is limited, and patient acuity is high (see Fenton BMJ 2003; 327: b587), preoperative gastric emptying may be a more effective measure than cricoid pressure to prevent aspiration of gastric contents.

Accompanying editorial: Vanner R: Cricoid pressure. Int J Obstet Anesth 2009; 18: 103-5

See also #97 below [O’Sullivan BMJ 2009]

The Diffi cult Airway: Risk, Prophylaxis, and Treatment

49. McClelland SH, Bogod DG, Hardman JG: Pre-oxygenation and apnoea in pregnancy: changes during labour and with obstetric morbidity in a computational simulation. Anaesthesia 2009; 64: 371-7Study Design: Computer simulationConclusion: A series of hypothetical patients were assumed to breathe 100% oxygen for 10 minutes before a period of apnea. The calculations suggest that a laboring woman with a body mass index of 50 kg/m2 would rapidly desaturate after only 98 sec of apnea, compared to 292 sec in a standard pregnant woman in labor. Preeclampsia appears to prolong both pre-oxygenation and tolerance to apnea. Maternal hemorrhage and multiple pregnancy have minor effects.

50. Djabatey EA, Barclay PM: Diffi cult and failed intubation in 3430 obstetric general anaesthetics. Anaesthesia 2009; 64: 1168-71Study Design: Retrospective observational study (n=3,430 obstetric general anesthetics)Conclusion: Of 23 diffi cult intubations, none had a failed intubation, 1 patient had a prolonged desaturation with no evidence of aspiration, and no major sequelae were noted. The authors attribute the low incidence of airway complications to an above average rate of general anesthesia (8.7% of elective and 30.4% of emergency cesarean deliveries), consultant level supervision during the day, paired staffi ng with senior and junior trainees out of hours, and specialized anesthetic operating department assistants.

51. Lee C, Jahr JS, Candiotti KA, Warriner B, Zornow MH, Naguib M: Reversal of profound neuromuscular block by sugammadex administered three minutes after rocuronium: a comparison with spontaneous recovery from succinylcholine. Anesthesiology 2009; 110: 1020-5Study Design: High quality RCT (n=108 comprised of 2 groups of non-obstetric patients, including men and women with n=55 [rocuronium/sugammadex] vs. n=53 [succinylcholine]) Conclusion: Reversal of profound high-dose rocuronium-induced neuromuscular block (1.2 mg/kg) with 16 mg/kg sugammadex was signifi cantly faster than spontaneous recovery from 1 mg/kg succinylcholine. After sugammadex, the mean time to recovery of T1 to 10% was just 1.2 minutes.

Lipid Rescue for Local Anesthetic Toxicity

52. Hiller DB, Gregorio GD, Ripper R, et al: Epinephrine impairs lipid resuscitation from bupivacaine overdose. Anesthesiology 2009; 111: 498-505Study Design: Animal study (n=30 rats comprised of 6 groups of 5 rats each)Conclusion: While epinephrine improves initial return of spontaneous circulation at 5 minutes, lipid alone results in slower but more sustained recovery. Epinephrine over a threshold dose of 10 mcg/kg impairs lipid resuscitation from bupivacaine overdose, increases lactate, worsens acidosis, and worsens recovery at 15 minutes, possibly due to detrimental metabolic consequences of adrenergic stimulation.

Accompanying editorial: Harvey M, Cave G: Bupivacaine-induced cardiac arrest: fat is good. Is epinephrine really bad? Anesthesiology 2009; 111: 467-9

Complications of Neuraxial Anesthesia

53. Fettes PD, Jansson JR, Wildsmith JA: Failed spinal anaesthesia: mechanisms, management and prevention. Br J Anaesth 2009; 102: 739-48Study Design: Review articleConclusion: This review considers the mechanisms of failed spinal anesthesia in a sequential way: problems with lumbar puncture; errors in the preparation and injection of solutions; inadequate spreading of drugs through cerebrospinal fl uid; failure of drug action on nervous tissue; and diffi culties more related to patient management than the actual block. Techniques for minimizing the possibility of failure are discussed, all of them requiring, in essence, close attention to detail.

Accompanying editorial: Drasner K: Spinal anaesthesia: a century of refi nement, and failure is still an option. Br J Anaesth 2009; 102: 729-30

Letters to the editor:Popham PA: Anatomical causes of failed spinal anaesthesia may becommoner than thought. Br J Anaesth 2009; 103: 459

Davis S: Use of Luer connection syringes for spinal anaesthesia. Br J Anaesth 2009; 103: 459-60

54. Cook TM, Counsell D, Wildsmith JA: Major complications of central neuraxial block: report on the Third National Audit Project of the Royal College of Anaesthetists. Br J Anaesth 2009; 102: 179-90Study Design: Prospective surveillance of major neurologic complications attributed to neuraxial block in the United Kingdom between 9/1/2006 and 8/31/2007 (n=an estimated 320,425 central neuraxial blocks in obstetric patients).Conclusion: Of 12 cases reported after CNB in obstetric patients, 6 were wrong route errors in which dilute bupivacaine solutions were infused intravenously with no evidence of patient harm. All but 4 patients recovered completely within 6 months. The remaining 4 (1 abscess, 2 nerve injuries, 1 subdural hematoma) all made at least partial recoveries, but in 3 cases follow-up was incomplete. There were no cases of paraplegia or death after obstetric CNB.

Accompanying editorial: Buggy DJ: Central neuraxial block: defi ning risk more clearly. Br J Anaesth 2009; 102: 151-3

Selected letters to the editor:Moen V, Irestedt L, Dahlgren N: Major complications of central neuraxial block: the Third National Audit Project: some comments and questions. Br J Anaesth 2009; 103: 130-1

Scott M, Stones J, Payne N: Antiseptic solutions for central neuraxial blockade: which concentration of chlorhexidine in alcohol should we use? Br J Anaesth 2009; 103: 456

Online report: National audit of major complications of central neuraxial block in the United Kingdom. The Royal College of Anaesthetists 2009; www.rcoa.ac.uk. Accessed 2/19/10

55. Batai I, Bogar L, Juhasz V, Batai R, Kerenyi M: A comparison of the antimicrobial property of lidocaine / prilocaine cream (EMLA®) and an alcohol-based disinfectant on intact human skin fl ora. Anes Analg 2009; 108: 666-8Study design: Healthy volunteer study (n=20 volunteers each serving as his or her own control)Conclusion: EMLA® cream has a longer bacteriostatic effect after early bactericidal impact compared with skin disinfection with Skinsept Pur®.

Medicolegal Issues in Obstetric Anesthesia

56. Davies JM, Posner KL, Lee LA, Cheney FW, Domino KB: Liability associated with obstetric anesthesia: a closed claims analysis. Anesthesiology 2009; 110: 131-9Study Design: Retrospective review of obstetric anesthesia claims in the American Society of Anesthesiologists Closed Claims database (n=616 claims comprising 2 groups of n=426 [from 1990-2003] vs. n=190 [from before 1990])Conclusion: Among post-1990 claims for maternal death or brain damage, high spinal attributed to unrecognized intrathecal epidural catheters emerged as probably the single most notable anesthesia-related complication in this report. Maternal nerve injury and newborn death/brain damage together accounted for almost 50% of all claims. Possibly preventable anesthetic causes of newborn injury included anesthesia delay and poor communication between the anesthesiologist and obstetrician.

Accompanying editorial: Leighton BL: Why obstetric anesthesiologists get sued. Anesthesiology 2009; 110: 8-9

57. Mihai R, Scott S, Cook TM: Litigation related to inadequate anaesthesia: an analysis of claims against the NHS in England 1995-2007. Anaesthesia 2009; 64: 829-35Study Design: Retrospective review, case series of claims of inadequate anesthesia in the UK (n=159 cases)

Conclusion: Inadequate anesthesia accounts for 19% of anesthesia-related claims in the NHS in England. Of 80 claims in obstetric patients, 50 were for inadequate neuraxial anesthesia, 23 for undesired awareness, and 7 for awake paralysis.

Maternal Coexisting Disease

Cardiac Disease

58. Grewal J, Siu S, Ross H, et al: Pregnancy outcomes in women with dilated cardiomyopathy. J Am Coll Cardiol 2009; 55: A1-A54Study Design: Prospective cohort substudy of 32 consecutive pregnant women with idiopathic DCM (n=32); nonpregnant women with DCM (n=18) matched on age and LV systolic function served as a control cohortConclusion: In pregnant women with DCM the risk of adverse cardiac events was 39%, with increased risk among women with moderate to severe LV dysfunction and NYHA functional class of III or IV. In the subset of women with moderate to severe LV dysfunction, 16-month event-free survival was worse in pregnant women compared with non-pregnant controls.

59. Tzemos N, Silversides CK, Colman JM, et al: Late cardiac outcomes after pregnancy in women with congenital aortic stenosis. Am Heart J 2009; 157: 474-80Study Design: Prospective cohort of 51 consecutive pregnant women with congenital AS experiencing 70 pregnancies leading to live-birth; prospective double cohort comparison (sub-sample of n=26 [pregnant] vs. n=26 [never pregnant])Conclusion: Women with congenital AS who have undergone pregnancy have a higher frequency of late cardiac events (pulmonary edema, cardiac arrhythmia, cardiac death, cardiac interventions >1 year since baseline evaluation) compared with those who have never been pregnant (31% vs. 0%, P=0.02).

60. Yap SC, Drenthen W, Meijboom FJ, et al: Comparison of pregnancy outcomes in women with repaired versus unrepaired atrial septal defect. BJOG 2009; 116: 1593-601Study Design: Retrospective cohort (n=133 [pregnancies in 67 women with unrepaired ASD] vs. n=55 [pregnancies in 31 women with repaired ASD] vs. n=9,667 [population controls])Conclusion: Women with an unrepaired ASD are at increased risk of delivering infants who experience neonatal events in comparison with women with a repaired ASD. Compared with the general population, women with an unrepaired ASD are at increased risk of preeclampsia, small-for-gestational-age births, and fetal mortality.

61. Modi KA, Illum S, Jariatul K, Caldito G, Reddy PC: Poor outcome of indigent patients with peripartum cardiomyopathy in the United States. Am J Obstet Gynecol 2009; 201: 171 e1-5Study Design: Retrospective cohort (n= 44, including 39 African Americans)Conclusion: LV function recovery (35%) and survival rates (84%) of PPCM patients observed in this population recruited at Louisiana State University are worse than prior reports from the United States, and similar to rates reported from Haiti and South Africa.

62. Bedard E, Dimopoulos K, Gatzoulis MA: Has there been any progress made on pregnancy outcomes among women with pulmonary arterial hypertension? Eur Heart J 2009; 30: 256-65Study Design: Systematic review of case series and case reports (n=73 cases reported in 48 articles)Conclusion: Maternal mortality in parturients with PAH remains prohibitively high, at 25%, based on reports published since 1997. General anesthesia was associated with a higher risk of death, but causality cannot be inferred.

Hypertensive Disorders including Preeclampsia

63. Koopmans CM, Bijlenga D, Groen H, et al: Induction of labour versus expectant monitoring for gestational hypertension or mild pre-eclampsia after 36 weeks’ gestation (HYPITAT): a multicentre, open-label randomised controlled trial. Lancet 2009; 374: 979-88Study Design: High quality RCT (n=756 comprising 2 groups of n=377 [induction] vs. 379 [expectant monitoring])Conclusion: Induction of labor was associated with less progression to severe hypertension, and less need for anti-hypertensive medications or anticonvulsants. There were no cases of eclampsia, neonatal death, or maternal death.

Accompanying editorial: Johnson DD: Induced labour for pre-eclampsia and gestational hypertension. Lancet 2009; 374: 951-2

Letter to the editor: Bewley S, Shennan A: HYPITAT and the fallacy of pregnancy interruption. Lancet 2009; 375: 119-20

64. Founds SA, Conley YP, Lyons-Weiler JF, Jeyabalan A, Hogge WA, Conrad KP: Altered global gene expression in fi rst trimester placentas of women destined to develop preeclampsia. Placenta 2009; 30: 15-24Study Design: Prospective enrollment with case control analysis (n=12 comprising 2 groups of n=4 [with preeclampsia] vs. n=8 [controls sampled from 124])Conclusion: Using micro-array analysis and banked chorionic villous samples (CVS), this study identifi ed 36 candidate genes that showed dysregulation in the early placentas of women approximately 6 months before developing preeclampsia. Many were related to infl ammation, immunoregulation, and cell motility. These data support the theory that placentation in preeclampsia is compromised in the fi rst trimester by maternal and fetal immune dysregulation, abnormal decidualization, or both, thereby impairing trophoblast invasion. No evidence was found for alterations in genes regulated by oxidative stress.

65. Purwosunu Y, Sekizawa A, Okazaki S, et al: Prediction of preeclampsia by analysis of cell-free messenger RNA in maternal plasma. Am J Obstet Gynecol 2009; 200: 386 e1-7Study Design: Prospective enrollment with case control analysis (n=372 comprising 2 groups with n=62 [preeclampsia] vs. n=310 [controls sampled from 598])Conclusion: A panel of 7 messenger RNA markers measured in maternal plasma (at 15-20 gestational weeks) is able to predict subjects who will experience preeclampsia, with a detection rate of 84% at a 5% false-positive rate with an AUROC of 0.927. A scaled score combining results across markers correlates with the severity of subsequent disease.

66. Champagne K, Schwartzman K, Opatrny L, et al: Obstructive sleep apnoea and its association with gestational hypertension. Eur Respir J 2009; 33: 559-65Study Design: Case control (n=50 comprising 2 groups of n=17 [pregnant women with gestational hypertension] vs. n=33 [pregnant women without hypertension])Conclusion: Sleep is highly disturbed in pregnancy. The mean apnea-hypopnea index for normotensive pregnant women was 18.2 events per hour compared with 38.6 for those with new-onset of hypertension during pregnancy. Fifteen potential cases and 13 potential controls were excluded because they were unable to sleep for the study. Gestational hypertension appears to be strongly associated with the presence of obstructive sleep apnea.

67. Ginosar Y, Nadjari M, Hoffman A, et al: Antepartum continuous epidural ropivacaine therapy reduces uterine artery vascular resistance in pre-eclampsia: a randomized, dose-ranging, placebo-controlled study. Br J Anaesth 2009; 102: 369-78Study Design: Stage 1: pilot RCT (n=10 comprising 2 groups of n=5 [exposed to ACET across 5 randomized doses administered blindly in random order] vs. n=5 [control]); Stage 2: Sustained ACET therapy until delivery, interrupted once by saline placebo (n=3)Conclusion: In preeclamptic patients remote from term (<32 weeks gestational age) antepartum continuous epidural therapy (ACET) reduces uterine artery resistance in a dose-dependent fashion, with the effect localized to the uterine artery which demonstrated higher baseline resistance. The contralateral uterine artery exhibited either increased vascular resistance or no change. Duration of pregnancy was increased in the ACET group, but further studies are needed to confi rm a causal relationship.

68. Berks D, Steegers EA, Molas M, Visser W: Resolution of hypertension and proteinuria after preeclampsia. Obstet Gynecol 2009; 114: 1307-14Study Design: Prospective cohort study conducted between 1990 and 1992 (n= 205 preeclamptic women)Conclusion: After preeclampsia, it can take up to 2 years for hypertension and proteinuria to resolve. The severity of preeclampsia and the time interval between diagnosis and delivery are associated with postpartum time-to-resolution of hypertension and proteinuria.

69. Wu CS, Nohr EA, Bech BH, Vestergaard M, Catov JM, Olsen J: Health of children born to mothers who had preeclampsia: a population-based cohort study. Am J Obstet Gynecol 2009; 201: 269 1-10Study Design: Retrospective cohort (n=46,384 singletons exposed prenatally to preeclampsia)Conclusion: Controlling for factors such as gestational age at birth, children exposed to preeclampsia in utero had an increased risk of endocrine, nutritional, and metabolic diseases, and diseases of the blood and blood-forming organs. Exposure to preeclampsia was also associated with an increased risk of being hospitalized in childhood.

70. Ehrenstein V, Rothman KJ, Pedersen L, Hatch EE, Sorensen HT: Pregnancy-associated hypertensive disorders and adult cognitive function among Danish conscripts. Am J Epidemiol 2009; 170: 1025-31Study Design: Retrospective cohort (17,457 men of whom n=891 were exposed to any pregnancy-associated hypertensive disorder)Conclusion: Controlling for factors such as gestational age at birth, adult men (median age 19 years) who had been exposed to gestational hypertension in utero demonstrated reduced performance on the mandatory IQ test conducted as part of registration for the Danish draft.

71. Calderon-Margalit R, Friedlander Y, Yanetz R, et al: Preeclampsia and subsequent risk of cancer: update from the Jerusalem Perinatal Study. Am J Obstet Gynecol 2009; 200: 63 e1-5Study Design: Retrospective cohort (n=41,206 women who delivered between 1964 and 1976)Conclusion: The 1,107 women who developed preeclampsia experienced higher rates of subsequent breast cancer and ovarian cancer during the time that this population was followed through 2004.

Diabetes

72. Landon MB, Spong CY, Thom E, et al: A multicenter, randomized trial of treatment for mild gestational diabetes. N Engl J Med 2009; 361: 1339-48Study Design: High quality RCT (n=958 comprising 2 groups of n=485 [treatment of dietary intervention, self-monitoring blood glucose, and insulin therapy] vs. n=473 [usual prenatal care])Conclusion: Although treatment of mild gestational diabetes mellitus did not signifi cantly reduce the frequency of a composite outcome that included stillbirth or perinatal death and several neonatal complications, it did reduce the risks of fetal overgrowth, shoulder dystocia, cesarean delivery, and hypertensive disorders.

Accompanying editorial:Sacks DA: Gestational diabetes—whom do we treat? N Engl J Med 2009; 361: 1339-48

Letters to the editor: Walters BN: Treatment for mild gestational diabetes. N Engl J Med 2009; 362: 365-6Bloomgarden Z, Stell L, Jovanovic L: Treatment for mild gestational diabetes. N Engl J Med 2009; 362: 365-6; author reply 366-7

Hematologic Disease

73. Rey E, Garneau P, David M, et al: Dalteparin for the prevention of recurrence of placental-mediated complications of pregnancy in women without thrombophilia: a pilot randomized controlled trial. J Thromb Haemost 2009; 7: 58-64Study Design: High quality RCT (n=110 comprising 2 groups of n=55 [dalteparin] vs. n=55 [no dalteparin])Conclusion: Dalteparin was effective in decreasing the recurrence of placental-mediated complications (including a composite of severe preeclampsia, IUGR, and/or placental abruption) in women without thrombophilia. These results require confi rmation in future randomized trials.

74. Laskin CA, Spitzer KA, Clark CA, et al: Low molecular weight heparin and aspirin for recurrent pregnancy loss: results from the randomized, controlled HepASA trial. J Rheumatol 2009; 36: 279-87Study Design: High quality RCT (n=88 comprising 2 groups of n=43 [ASA only] vs. n=45 [ASA+LMWH])Conclusion: ASA+LMWH did not confer incremental benefi t compared with ASA alone for women with antiphospholipid antibodies and recurrent pregnancy loss. These fi ndings contribute to a growing body of literature that contests the emerging standard of care comprising LMWH/ASA for women with antiphospholipid antibodies whose only clinical manifestation is recurrent pregnancy loss.

Letter to the editor: Carp HJ: Low molecular weight heparin and aspirin for recurrent pregnancy loss: results from the HepASA trial. J Rheumatol 2009; 37: 202

75. Saha P, Stott D, Atalla R: Haemostatic changes in the puerperium ‘6 weeks postpartum’ (HIP Study) - implication for maternal thromboembolism. BJOG 2009; 116: 1602-12Study Design: Prospective cohort (n=46 deliveries comprising 2 groups of n=24 [cesarean births] vs. n=22 [vaginal births])Conclusion: Coagulation screens as well as thomboelastometry suggest a persistent hypercoagulation that lasts approximately 3-4 weeks after delivery. Comparing by mode of delivery, there were nonsignifi cant increases in thrombotic parameters after cesarean delivery.

76. Kato R, Shinohara A, Sato J: ADAMTS13 defi ciency, an important cause of thrombocytopenia during pregnancy. Int J Obstet Anesth 2009; 18: 73-7Study Design: Case reportConclusion: ADAMTS13 is a protease that cleaves VWF. A defi ciency of ADAMTS13 is a genetic cause of thrombotic thrombocytopenic purpura (TTP) that may manifest only during pregnancy. TTP may be lethal if misdiagnosed, may be confused with either HELLP syndrome, DIC or ITP, and is treatable with fresh frozen plasma (which provides ADAMTS13) and plasma exchange. Therapy should help to restore the platelet count and facilitate neuraxial anesthesia.

See also: Fujimura Y, Matsumoto M, Kokame K, et al: Pregnancy-induced thrombocytopenia and TTP, and the risk of fetal death, in Upshaw-Shulman syndrome: a series of 15 pregnancies in 9 genotyped patients. Br J Haematol 2009; 144: 742-54Study Design: Case series with familial genotypingConclusion: ADAMTS13 activity is important to measure when evaluating thrombocytopenia during childhood and pregnancy.

Infection

77. Jamieson DJ, Honein MA, Rasmussen SA, et al: H1N1 2009 infl uenza virus infection during pregnancy in the USA. Lancet 2009; 374: 451-8Study Design: Population surveillance (n=34 cases reported between April and May 2009, and n=6 deaths reported between April and June, 2009)Conclusion: Pregnant women might be at increased risk for complications from pandemic H1N1 virus infection, and should receive prompt anti-infl uenza therapy upon development of symptoms.

Accompanying editorial: Mangtani P, Mak TK, Pfeifer D: Pandemic H1N1 infection in pregnant women in the USA. Lancet 2009; 374: 429-30

Letter to the editor: Su LL, Chan J, Chong YS, Choolani M, Biswas A, Yong EL. Pregnancy and H1N1 infection. Lancet 2009; 374: 1417-8

See also: Louie JK, Acosta M, Jamieson DJ, Honein MA: Severe 2009 H1N1 infl uenza in pregnant and postpartum women in California. N Engl J Med 2010; 362: 27-35Study Design: Prospective cohort identifi ed through population surveillance between April and August, 2009 (n=219 comprising three groups of n=94 [pregnant] vs. 8 [≤2 wks postpartum] vs. 137 [non-pregnant women of reproductive age])Conclusion: 2009 H1N1 infl uenza can cause severe illness and death in pregnant and postpartum women; regardless of the results of rapid antigen testing, prompt evaluation and antiviral treatment of infl uenza-like illness should be considered in such women. The high cause-specifi c maternal mortality ratio (4.3 per 100,000 live births) suggests that 2009 H1N1 infl uenza will increase the 2009 maternal mortality ratio in the United States.

78. Ho CS, Bhatnagar J, Cohen AL, et al: Undiagnosed cases of fatal clostridium-associated toxic shock in Californian women of childbearing age. Am J Obstet Gynecol 2009; 201: 459 e1-7Study Design: Population surveillance (5 cases identifi ed from 325 candidate deaths)Conclusion: Histologic specimens from the fi ve deceased women tested positive for Clostridium perfringens (n=3), Clostridium sordellii (n=1), or both (n=1). Deaths followed undiagnosed catastrophic sepsis that developed after medical procedures for cervical dysplasia (n=2), surgical abortion (n=1), stillborn delivery (n=1), and term live birth (n=1).

Obesity

See above #7 Ellinas, Anesth Analg 2009; 109: 1225-31 and #8 Balki, Anesth Analg 2009; 108: 1876-81

79. IOM (Institute of Medicine). 2009. Weight gain during pregnancy: reexamining the guidelines. Washington, DC: The National Academies Press.Study Design: GuidelinesConclusion: New recommendations from the Institute of Medicine for total weight gain during pregnancy, by pre-pregnancy body mass index (BMI):

Prepregnancy BMI Total weight gain in poundsUnderweight <18.5 kg/m2 28-40

Normal weight 18.5-24.9 kg/m2 25-35Overweight 25.0-29.9 kg/m2 15-25

Obese ≥30 kg/m2 11-25

80. Oken E, Kleinman KP, Belfort MB, Hammitt JK, Gillman MW: Associations of gestational weight gain with short- and longer-term maternal and child health outcomes. Am J Epidemiol 2009; 170: 173-80Study Design: Retrospective secondary analysis of a longitudinal cohort data (n=2,012 maternal/child dyads)Conclusion: Considering a composite outcome that includes preterm birth, small for gestational age, large for gestational age, child obesity, and postpartum maternal weight retention, for normal-weight women, minimum composite risk occurred with a weight gain of approximately 31 pounds, and for overweight women, approximately 16 pounds. These estimates varied modestly with adjustment for maternal characteristics and with different outcome weightings. For obese women, the lowest-risk weight change was weight loss in all models.

Letter to the editor: Ruiz JR, Barakat R, Lucia A: Associations of gestational weight gain with short- and longer-term maternal and child health outcomes. Am J Epidemiol 2009; 170: 173-80

Substance Abuse

81. Terplan M, Smith EJ, Kozloski MJ, Pollack HA: Methamphetamine use among pregnant women. Obstet Gynecol 2009; 113: 1285-91Study Design: Retrospective trend analysis of surveillance data (n=245,970 pregnant US women admitted for substance treatment between 1994 to 2006)Conclusion: Methamphetamine has become the primary substance compelling inpatient treatment during pregnancy in the US. Admissions remain most prevalent in the Western States, but substantial increases have been noted in the Midwest and the South.

Obstetric Management

The First Trimester

82. Cansino C, Edelman A, Burke A, Jamshidi R: Paracervical block with combined ketorolac and lidocaine in fi rst-trimester surgical abortion: a randomized controlled trial. Obstet Gynecol 2009; 114: 1220-6Study Design: High quality RCT (n=50 comprising 2 groups of n=25 [oral ibuprofen followed by paracervical block with lidocaine] vs. n=25 [oral placebo followed by paracervical block with ketorolac and lidocaine])Conclusion: Paracervical block with combined ketorolac and lidocaine signifi cantly decreased perceived pain associated with cervical dilation during fi rst-trimester surgical abortion.

83. Matok I, Gorodischer R, Koren G, Sheiner E, Wiznitzer A, Levy A: The safety of metoclopramide use in the fi rst trimester of pregnancy. N Engl J Med 2009; 360: 2528-35Study Design: Retrospective cohort (n=81,703 infants comprising 2 groups of n=3,458 [exposed to metoclopramide] vs. 78,245 [not exposed]) Conclusion: In this large cohort of infants, exposure to metoclopramide in the fi rst trimester was not associated with signifi cantly increased risks of major congenital malformations, low birth weight, preterm delivery, or perinatal death.

See also: U.S. Food and Drug Administration. Pregnancy and lactation labeling. http://www.fda.gov/Drugs/DevelopmentApprovalProcess/DevelopmentResources/Labeling/ucm093307.htm. Accessed 2/19/2010The US FDA has proposed to eliminate the current pregnancy categories A, B, C, D, and X. Instead, the pregnancy and lactation subsections of labeling would include a risk summary, which summarizes the risks of the medicine to the developing fetus or breastfeeding infant, and a discussion of data supporting that summary.

84. Meador KJ, Baker GA, Browning N, et al: Cognitive function at 3 years of age after fetal exposure to antiepileptic drugs. N Engl J Med 2009; 360: 1597-605Study Design: Prospective observational multicenter (USA & UK) cohort (n=258 children with fetal exposure to antiepileptic drugs comprised of 4 groups of n=73 [carbamazepine] vs. n= 84 [lamotrigine] vs. n=48 [phenytoin] vs. n=53 [valproate])Conclusion: In utero exposure to valproate, as compared with other commonly used antiepileptic drugs, is associated with an increased risk of impaired cognitive function at 3 years of age. This fi nding supports a recommendation that valproate not be used as a fi rst-choice drug in women of childbearing potential.

Accompanying editorial: Tomson T: Which drug for the pregnant woman with epilepsy? N Engl J Med 2009; 360: 1667-9

Preterm Labor

85. Norman JE, Mackenzie F, Owen P, et al: Progesterone for the prevention of preterm birth in twin pregnancy (STOPPIT): a randomized, double-blind, placebo-controlled study and meta-analysis. Lancet 2009; 373: 2034-40Study Design: Moderate quality RCT (n=494 comprising 2 groups of n=247 [progesterone vaginal gel] vs. n=247 [placebo vaginal gel])Conclusion: Progesterone (90 mg vaginal suppository administered daily from 24 weeks’ gestation) does not prevent preterm birth in women with twin pregnancy.

Accompanying editorial: Doyle LW: Antenatal progesterone to prevent preterm birth. Lancet 2009; 373: 2000-2This editorial stresses the importance of planned long-term follow-up for survivors in randomized controlled trials of perinatal interventions, because “…long-term outcomes for the fetus are the primary endpoints of any study designed to prolong pregnancy.”

See also: U.S Department of Health and Services. The National Children’s Study. http://www.nationalchildrensstudy.gov , Accessed 2/23/2010The National Children’s Study will examine the effects of environmental infl uences on the health and development of 100,000 children across the United States, following them from before birth (even before conception in some cases) until age 21years.

86. Newnham JP, Newnham IA, Ball CM, et al: Treatment of periodontal disease during pregnancy: a randomized controlled trial. Obstet Gynecol 2009; 114: 1239-48Study Design: High quality RCT (n=1,078 comprised of 2 groups of n=538 [antenatal periodontal treatment] vs. n=540 [no antenatal periodontal treatment])Conclusion: The evidence provided by the present study does not support the hypothesis that treatment of periodontal disease during pregnancy in this population prevents preterm birth, fetal growth restriction, or preeclampsia. Periodontal treatment was not hazardous to the women or their pregnancies.

See also: Polyzos NP, Polyzos IP, Mauri D, et al: Effect of periodontal disease treatment during pregnancy on preterm birth incidence: a metaanalysis of randomized trials. Am J Obstet Gynecol 2009; 200: 225-32Study Design: Meta-analysis of 7 RCTs of limited quality Conclusion: Based on this meta-analysis, scaling and root planing decreased preterm birth and low birth weight, but did not reduce spontaneous abortion/stillbirth. Note: Publication bias and heterogeneity limit the strength of these conclusions.

87. Simcox R, Seed PT, Bennett P, Teoh TG, Poston L, Shennan AH: A randomized controlled trial of cervical scanning vs history to determine cerclage in women at high risk of preterm birth (CIRCLE trial). Am J Obstet Gynecol 2009; 200: 623 e1-6Study Design: Moderate quality RCT (n=247 comprised of 2 groups of n=122 [serial ultrasound monitoring] vs. 125 [cerclage based on history])Conclusion: Screening women with a history of spontaneous preterm birth with cervical ultrasonography to determine cerclage placement results in more intervention but similar outcome compared with history-indicated placement.

Letter to the editor: Andrews J: Don’t be fooled by Simcox CIRCLE. Am J Obstet Gynecol 2010; 202: e4; author reply e4-5

88. Owen J, Hankins G, Iams JD, et al: Multicenter randomized trial of cerclage for preterm birth prevention in high-risk women with shortened midtrimester cervical length. Am J Obstet Gynecol 2009; 201: 375 e1-8Study Design: High quality RCT (n=301 comprised of 2 groups of n=153 [no cerclage] vs. n=148 [cerclage])Conclusion: In women with a prior spontaneous preterm birth less than 34 weeks and cervical length less than 25 mm, cerclage reduced previable birth and perinatal mortality but did not prevent birth less than 35 weeks, unless cervical length was less than 15 mm.

89. Garite TJ, Kurtzman J, Maurel K, et al: Impact of a ‘rescue course’ of antenatal corticosteroids: a multicenter randomized placebo-controlled trial. Am J Obstet Gynecol 2009; 200: 248 e1-9Study design: High quality RCT (n=558 neonates (from 437 pregnancies) with known outcome comprising 2 groups of n=276 [rescue course of antenatal corticosteroids] vs. n=282 [placebo control])Conclusion: This study enrolled women with singletons or twins <33 weeks who had completed a single course of antenatal corticosteroids (ACS) before 30 weeks and at least 14 days prior to inclusion, and were judged to have a recurring threat of preterm birth in the coming week. Among this population, a single rescue course of ACS reduced the composite outcome of neonatal morbidity in babies delivering

before 34 weeks (including respiratory distress syndrome, bronchopulmonary dysplasia, severe intraventricular hemorrhage, periventricular leukomalacia, blood culture-proven sepsis, necrotizing enterocolitis, or perinatal death). ACS rescue did not change short-term neonatal risk or anthropomorphic measurements of the neonate (birth weight, rates of IUGR, or head circumference).

Accompanying editorial: Bonanno C, Wapner RJ: To rescue or not to rescue: that is the question. Am J Obstet Gynecol 2009; 200: 248 e1-9

90. Shirangi A, Fritchi L, Holman CO: Associations of unscavenged anesthetic gases and long working hours with preterm delivery in female veterinarians. Obstet Gynecol 2009; 113: 1008-17Study Design: Secondary analysis of a national survey study (n=1,197 [response rate=59%] reporting 744 pregnancies)Conclusion: Self-reported long working hours and performing surgery in the absence of a scavenger system for anesthetic gases appeared to be independent risk factors for preterm birth in female veterinarians.

91. Haas DM, Imperiale TF, Kirkpatrick PR, Klein RW, Zollinger TW, Golichowski AM: Tocolytic therapy: a meta-analysis and decision analysis. Obstet Gynecol 2009; 113: 585-93Study Design: Meta-analysis and decision analysis of 58 RCTs of primarily limited to moderate quality Conclusion: Although all current tocolytic agents were superior to no treatment for delaying delivery beyond 48 hours and also to 7 days, prostaglandin inhibitors were superior to the other agents and may be considered the optimal fi rst-line agent before 32 weeks of gestation to delay delivery. Calcium channel blockers demonstrated the highest proportion of patients tolerating treatment and achieving delay in delivery until 37 weeks’ gestation.

Breech Presentation

92. Sullivan JT, Grobman WA, Bauchat JR, et al: A randomized controlled trial of the effect of combined spinal-epidural analgesia on the success of external cephalic version for breech presentation. Int J Obstet Anesth 2009; 18: 328-34Study Design: Moderate quality RCT (n=95 comprising 2 groups of n=47 [CSE] vs. 48 [systemic fentanyl]); discussion includes a meta-analysis of 5 trials Conclusion: There was no difference in the rate of successful ECV or vaginal delivery with CSE compared with intravenous fentanyl analgesia. Pain scores were lower and satisfaction higher with CSE analgesia. Larger trials are needed to assess safety. Meta-analysis suggests that there may be a dose-dependent relationship between neuraxial analgesia/anesthesia and success of ECV—demonstrating a favorable effect when the studies using neuraxial anesthesia are combined, but not when the studies using analgesia are combined.

Trial of Labor after Cesarean (TOLAC) and Vaginal Birth after Cesarean (VBAC)

93. Hamdan M, Sidhu K, Sabir N, Omar SZ, Tan PC: Serial membrane sweeping at term in planned vaginal birth after cesarean: a randomized controlled trial. Obstet Gynecol 2009; 114: 745-51Study Design: Moderate quality RCT (n=211 comprising 2 groups of n=107 [sweep] vs. n=104 [vaginal exam control])Conclusion: Serial membrane sweeping at term in women who planned VBAC had no signifi cant effect on the onset of labor, pregnancy duration, induction of labor, or repeat cesarean delivery.

94. Grobman WA, Lai Y, Landon MB, et al: Can a prediction model for vaginal birth after cesarean also predict the probability of morbidity related to a trial of labor? Am J Obstet Gynecol 2009; 200: 56 e1-6Study Design: Retrospective cohort (n=13,541 comprising 2 groups of n=7,660 [TOLAC] vs. n=5,881 [elective repeat CD])Conclusion: A prediction model for VBAC provides information regarding the chance of TOL-related morbidity and suggests that maternal morbidity is not greater for those women who undergo TOL compared with those who undergo ERCS if the chance of VBAC is at least 70%.

95. Kamath BD, Todd JK, Glazner JE, Lezotte D, Lynch AM: Neonatal outcomes after elective cesarean delivery. Obstet Gynecol 2009; 113: 1231-8Study Design: Retrospective cohort (n=672 comprising 2 groups of n=329 [TOLAC] vs. n=343 [elective repeat CD]); cost estimation by intended mode of delivery Conclusion: Cost estimation suggests that the median total maternal and neonatal cost for patients managed with planned cesarean delivery is 24% higher than for those managed by planned vaginal birth. However, cesarean delivery after a failed trial of labor was estimated to cost 14% more than planned cesarean delivery, so accurate prediction of VBAC success (see #94 above, Grobman) is important.

Induction of Labor

96. Caughey AB, Sundaram V, Kaimal AJ, et al: Systematic review: elective induction of labor versus expectant management of pregnancy. Ann Intern Med 2009; 151: 252-63, W53-63Study Design: Meta-analysis of 11 fair quality RCTs Conclusion: RCTs suggest that elective induction of labor at 41 weeks’ gestation and beyond is associated with a decreased risk for cesarean delivery and for meconium-stained amniotic fl uid.

Accompanying editorial: Macones GA: Elective induction of labor: waking the sleeping dogma? Ann Intern Med 2009; 151: 281-2Editorial calls for well-designed RCTs of induction versus expectant management at 39 to 41 weeks’gestation.

Peripartum Fluids, Electrolytes, and Feeding

97. O’Sullivan G, Liu B, Hart D, Seed P, Shennan A: Effect of food intake during labour on obstetric outcome: randomised controlled trial. BMJ 2009; 338: b784Study Design: High quality RCT (n=2,426 comprised of 2 groups of n=1,207 [water] vs. n=1,219 [eating])Conclusion: Consumption of a light diet during labor did not infl uence obstetric or neonatal outcomes in participants, nor did it increase the incidence of vomiting. Women who are allowed to eat in labor had similar lengths of labor and operative delivery rates compared with women who were allowed water only during labor.

Accompanying commentary: Downe S: Eating a light diet during labour does not seem to worsen obstetric outcomes. BMJ 2009; 338: b732Note: The title of this commentary as well as extensive press coverage for the article framed the study results in a direction that is not clinically relevant. The point of the study is that eating in labor does not improve delivery outcomes. If these results are accurate, then the sole reason to eat in labor is to enhance maternal comfort. The study was not designed to address the question of whether eating in labor changes the risk for aspiration of gastric contents.

98. Shrivastava VK, Garite TJ, Jenkins SM, et al: A randomized, double-blinded, controlled trial comparing parenteral normal saline with and without dextrose on the course of labor in nulliparas. Am J Obstet Gynecol 2009; 200: 379 1-6Study Design: High quality RCT (n=289 comprised of 3 groups of n=97 [NS] vs. n=94 [D5NS] vs. n= 98 [D10NS])Conclusion: Administration of a dextrose solution, regardless of concentration, was associated with a shortened labor course in term vaginally delivered nulliparae subjects in active labor.

99. Moen V, Brudin L, Rundgren M, Irestedt L: Hyponatremia complicating labour—rare or unrecognised? A prospective observational study. BJOG 2009; 116: 552-61Study Design: Prospective cohort (n=287 women comprised of 4 groups of n=26 [elective cesarean delivery] vs. 113 [received under 1 L of fl uids in labor] vs. 87 [received 1-2.5 L fl uids] vs. 61 [received >2.5 L fl uids])Conclusion: Hyponatremia (Na ≤130 mmol/L) was found in 26% of women who received over 2.5 L of fl uid during labor, with a minimum sodium value of 122. Two-thirds of fl uids were orally ingested. For women in labor, oral fl uids should be recorded, and intravenous administration of hypotonic fl uids should be avoided.

100. Abd-El-Maeboud KH, Ibrahim MI, Shalaby DA, Fikry MF: Gum chewing stimulates early return of bowel motility after caesarean section. BJOG 2009; 116: 1334-9Study Design: Moderate quality RCT (n=200 comprised of 2 groups of n=93 [chewed gum] vs. n=107 [controls])Conclusion: Gum chewing after cesarean delivery is well tolerated, and associated with more rapid resumption of intestinal motility and shorter hospital stay (40.8±10.6 vs. 50.5±8.9 hours, P<0.001).

Letter to the editor: Byrne H: Gum chewing stimulates early return of bowel motility after caesarean section. BJOG 2010; 117: 117; author reply 117-8

Technology to Monitor Progress of Labor

101. Debiec J, Conell-Price J, Evansmith J, Shafer SL, Flood P: Mathematical modeling of the pain and progress of the fi rst stage of nulliparous labor. Anesthesiology 2009; 111: 1093-110Study Design: Retrospective cohort (n=500 patients comprised of 5 groups of n=100 [Asian] vs. n=100 [Black] vs. n=100 [Hispanic] vs. n=100 [White] vs. n=100 [Other])Conclusion: Mathematical models can be used to detect subtle effects of patient covariates on the progress and pain of the fi rst stage of labor. Asian women and heavier women had slower labor and slower onset of labor pain than others. These effects were modest compared with the substantial remaining unexplained subject-to-subject variability in labor progress and labor pain.

Accompanying editorial: Fisher DM, Eisenach JC: Science marches forward: a new tool to study the progress of labor. Anesthesiology 2009; 111: 936-7

102. Euliano TY, Marossero D, Nguyen MT, Euliano NR, Principe J, Edwards RK: Spatiotemporal electrohysterography patterns in normal and arrested labor. Am J Obstet Gynecol 2009; 200: 54 e1-7Study Design: Case control (n=36 comprising 2 groups of n=12 [cesarean deliveries] vs. n=24 [control vaginal deliveries])Conclusion: The center of uterine electrical activity (CUA) was derived from the electrohysterogram during a period of arrest of dilation, or the same dilation in controls. Predominately upward movement of the CUA (longer and/or stronger contraction at the fundus) was more common with normal dilation (P=0.003). Conversely, the CUA was more likely to remain in the lower uterine segment in those who later delivered by cesarean for arrest of dilation.

Accompanying editorial: Buhimschi CS: Spatiotemporal electromyography during human labor to monitor propagation of the uterine contraction wave and diagnose dystocia. Am J Obstet Gynecol 2009; 200: 1-3

103. Nizard J, Haberman S, Paltieli Y, et al: Determination of fetal head station and position during labor: a new technique that combines ultrasound and a position-tracking system. Am J Obstet Gynecol 2009; 200: 404 e1-5Study Design: Exploratory prospective cohort to evaluate a diagnostic test against a weak reference standard (vaginal examination); (n=311

paired measurements in n=166 women)Conclusion: The LaborPro® ultrasound-based system can determine fetal head station and position during labor, when compared with the current standard vaginal examination.

Intrapartum Fetal Monitoring

104. Costa A, Ayres-de-Campos D, Costa F, Santos C, Bernardes J: Prediction of neonatal acidemia by computer analysis of fetal heart rate and ST event signals. Am J Obstet Gynecol 2009; 201: 464 e1-6Study Design: Exploratory prospective cohort (n=148) to evaluate a diagnostic test against a reliable reference standard (UA pH≤7.05)Conclusion: Computer analysis of FHR and ST event signals predicted neonatal acidemia with a sensitivity of 1.0 (95% CI 0.56-1.0), PPV of 0.47 (95% CI 0.22-0.72), NPV of 1.0 (95% CI 0.96-1.0), positive LR 17.6 (95% CI 9.0-34.5).

Article discussion: Pettker CM, Macones GA. Predicting neonatal acidemia by computer analysis: Costa et al. Am J Obstet Gynecol 2009; 201: 543-4

105. Leung TY, Chung PW, Rogers MS, Sahota DS, Lao TT-H, Hung Chung TK: Urgent cesarean delivery for fetal bradycardia. Obstet & Gynecol 2009; 114: 1023-8Study Design: Retrospective cohort (n=235 comprising 3 groups of n=39 [irreversible group] vs. n=22 [potentially reversible group] vs. n=174 [unknown])Conclusion: Cord arterial pH deteriorates with the bradycardia-to-delivery interval when the underlying cause of fetal distress is irreversible (placental abruption, cord prolapse, uterine rupture, preeclampsia, or failed instrumental delivery), but not so otherwise (iatrogenic uterine hyperstimulation, hypotension after epidural anesthesia, cephalic version without abruption, aortocaval compression, or unknown cause for fetal bradycardia).

Obstetric Complications

Hemorrhage

106. WHO Guidelines for the management of postpartum haemorrhage and retained placenta. Geneva, World Health Organization, 2009Study Design: GuidelinesConclusion: These guidelines provide a stepwise algorithm for postpartum hemorrhage, beginning with: 1) uterine massage and oxytocin 2) ergometrine; 3) prostaglandin, and 4) tranexamic acid (if the bleeding is attributed in part to trauma). There is insuffi cient evidence to recommend recombinant factor VIIa. Recommended non-operative and operative maneuvers include: 1) bimanual uterine compression as a temporizing measure in the treatment of PPH due to uterine atony after vaginal delivery, 2) intrauterine balloon tamponade (but not uterine packing), 3) uterine artery embolization, 4) compression sutures, 5) vessel ligation, and 6) subtotal hysterectomy. Isotonic crystalloids should be used in preference to colloids for fl uid resuscitation. Health care facilities should adopt a formal protocol for the management of PPH.

107. Thachil J, Toh CH: Disseminated intravascular coagulation in obstetric disorders and its acute haematological management. Blood Rev 2009; 23: 167-76Study Design: Review articleConclusion: A common theme for pregnancy-associated DIC is the pivotal role played by the placenta. This article reviews how pregnancy-associated DIC can be diagnosed promptly and how treatment should be managed strategically. It also discusses the latest understanding of hemostatic mechanisms within the placenta and how these mechanisms may have relevance to new diagnostic approaches as well as novel therapeutic modalities.

108. Butwick AJ, Aleshi P, Fontaine M, Riley ET, Goodnough LT: Retrospective analysis of transfusion outcomes in pregnant patients at a tertiary obstetric center. Int J Obstet Anesth 2009; 18: 302-8

Study Design: Retrospective case series (n=74 cases)Conclusion: The peripartum transfusion rate was 1.4%. For over one-third of recipients, no documented indication for transfusion could be identifi ed based on chart review.

Accompanying editorial for Butwick and Parker (#109): Clark V, Waters JH: Blood transfusions: more is not necessarily better. Int J Obstet Anesth 2009; 18: 299-301Given the risks of blood transfusion, the enormous cost of banked blood products, and the relative health of the obstetric population, every effort should be made to restrict transfusion policies, and to avoid the need for blood transfusion.

109. Parker J, Thompson J, Stanworth S: A retrospective one-year single-centre survey of obstetric red cell transfusions. Int J Obstet Anesth 2009; 18: 309-13Study Design: Retrospective case series (n=202 cases)Conclusion: The peripartum transfusion rate was 3.1%. Almost one-third of recipients had a pre-transfusion hemoglobin >7 g/dL with no documentation of ongoing bleeding or symptoms of anemia.

110. Vergani P, Ornaghi S, Pozzi I, et al: Placenta previa: distance to internal os and mode of delivery. Am J Obstet Gynecol 2009; 201:266e1-5Study Design: Retrospective cohort (n=95 comprising 3 groups of n=42 [cesarean deliveries for true previa] vs. n=24 [laboring women with placental edge to internal os distance of 1-10 mm] vs. n=29 [laboring women with a distance of 11-20 mm]Conclusion: More than two-thirds of women with a placental edge to cervical os distance of >10 mm deliver vaginally without increased risk of hemorrhage.

Accompanying editorial: Oppenheimer LW, Farine D: A new classifi cation of placenta previa: measuring progress in obstetrics. Am J Obstet Gynecol. 2009; 201: 227-9The term “low-lying placenta” is out of date, and should be replaced with the distance measured from the placental edge to the cervical os.

Uterine Rupture

111. Zwart JJ, Richters JM, Ory F, de Vries JI, Bloemenkamp KW, van Roosmalen J: Uterine rupture in The Netherlands: a nationwide population-based cohort study. BJOG 2009; 116: 1069-78; discussion 1078-80Study Design: Population-based surveillance (n=210 cases in 371,021 deliveries)Conclusion: Although much attention is paid to scar rupture associated with uterotonic agents, 13% of ruptures occurred in unscarred uteri and 72% of ruptures occurred during spontaneous labor.

112. Porreco RP, Clark SL, Belfort MA, Dildy GA, Meyers JA: The changing specter of uterine rupture. Am J Obstet Gynecol 2009; 200: 269 e1-4Study Design: Retrospective case series (n=41 true ruptures [of 69 coded cases] in 226,325 deliveries)Conclusion: Epidemiological data on uterine rupture based on hospital discharge codes without concurrent chart review may be invalid (28 of 69 cases coded by ICD9-CM were actually cases of uterine dehiscence, not true ruptures). In this US health system with a VBAC rate of 6.2%, only 25% of true uterine ruptures occurred during a trial of labor in a patient with a scarred uterus. Prior uterine surgery, induction with oxytocin or prostaglandins, and nulliparity were other factors noted on chart review.

Neurologic Complications

113. Bushnell CD, Jamison M, James AH: Migraines during pregnancy linked to stroke and vascular diseases: US population based case-control study. BMJ 2009; 338: b664Study Design: Cross-sectional study of n=33,956 patients with migraine coded by ICD-9CM in n=18,345,538 pregnancy-related hospital dischargesConclusion: In this large, population-based sample of admissions in pregnant women, active peripartum migraine was strongly associated with both stroke and hypertension. Moderate associations were found between peripartum migraine and other vascular disorders, including myocardial infarction/heart disease, pulmonary embolism/venous thromboembolism, preeclampsia/gestational hypertension, smoking, and diabetes.

114. Coutinho JM, Ferro JM, Canhao P, et al: Cerebral venous and sinus thrombosis in women. Stroke 2009; 40: 2356-61Study Design: Prospective cohort of consecutive patients with symptomatic CVST (n=624, including 77 women who were pregnant or postpartum) Conclusion: Women with symptomatic CVST and a gender-specifi c risk factor (including pregnancy) have a much better prognosis than other patients with symptomatic CVST.

115. Singhal AB, Kimberly WT, Schaefer PW, Hedley-Whyte ET: Case records of the Massachusetts General Hospital. Case 8-2009. A 36-year-old woman with headache, hypertension, and seizure 2 weeks post partum. N Engl J Med 2009; 360: 1126-37Study Design: Case report of reversible cerebral vasoconstriction syndromeConclusion: Characterized by recurrent thunderclap headaches and dynamic segmental arterial vasoconstriction (that may or may not be visualized on serial brain imaging), this syndrome can lead to ischemic strokes, seizures, parenchymal hemorrhage, vasogenic edema, subarachnoid hemorrhage, and death. Treatment is with calcium-channel antagonists, corticosteroids, and blood pressure control.

General Obstetric Complications

116. Kuklina EV, Meikle SF, Jamieson DJ, et al: Severe obstetric morbidity in the United States: 1998-2005. Obstet Gynecol 2009; 113: 293-9Study design: Trend analysis of a cross-sectional study of n=227,333 patients with at least one severe obstetric morbidity coded by ICD-9CM in n=32,276,863 pregnancy-related hospital dischargesConclusion: Rates of overall severe obstetric morbidity in the US increased from 1998-1999 to 2004-2005. Controlling for the increasing rate of cesarean delivery, the rates of renal failure, adult respiratory distress syndrome, shock, and ventilation did not change. Increases in pulmonary embolism and blood transfusion correlated with—but could not be completely explained by—increasing cesarean delivery. Complications of anesthesia decreased over time in all models, regardless of mode of delivery.

117. Berg CJ, Mackay AP, Qin C, Callaghan WM: Overview of maternal morbidity during hospitalization for labor and delivery in the United States: 1993-1997 and 2001-2005. Obstet Gynecol 2009; 113: 1075-81Study Design: Cross-sectional study of approximately n=52,461 patients with at least one obstetric morbidity coded by ICD-9CM in n=183,431 delivery hospitalizations between 2001-2005 Conclusion: Between 1993-1997 and 2001-2005, the rate of intrapartum morbidity associated with obstetric complications in the US was unchanged (at 28.6%) and the rate of pregnancies complicated by preexisting medical conditions (chronic hypertension, cardiac disease, asthma, diabetes and renal disease) increased from 4.1% to 4.9%. Note: Increasingly comprehensive documentation of comorbidities in order to maintain revenue may explain some of this increase.

118. Knight M, Kurinczuk JJ, Spark P, Brocklehurst P: Inequalities in maternal health: national cohort study of ethnic variation in severe maternal morbidities. BMJ 2009; 338: b542Study Design: National surveillance for severe maternal morbidity in the United Kingdom (n=686 cases in an estimated 775,186 maternities between 2005-2006)Conclusion: Severe maternal morbidity (severe fatty liver of pregnancy, amniotic fl uid embolism, antenatal pulmonary embolism, eclampsia, or peripartum hysterectomy) is signifi cantly more common among non-white women than among white women in the UK, particularly in black African and Caribbean ethnic groups. This pattern is very similar to reported ethnic differences in maternal death rates.

Accompanying editorial: Pollock W, King JF: Inequalities in maternal health: routine data collection of more detailed data is key to improving knowledge. BMJ 2009; 338: b357

Neonatal Outcomes

Anesthetic Technique and Neonatal Outcomes

119. Laudenbach V, Mercier FJ, Roze JC, et al: Anaesthesia mode for caesarean section and mortality in very preterm infants: an epidemiologic study in the EPIPAGE cohort. Int J Obstet Anesth 2009; 18: 142-9Study Design: Prospective population-based cohort (n=1,338 infants having cesarean deliveries in France in 1997 comprising 3 groups of n=711 [general anesthesia] vs. n=419 [spinal anesthesia] vs. n=208 [epidural anesthesia])Conclusion: Spinal anesthesia for delivery was associated with an increased risk of neonatal mortality in very preterm infants compared with general anesthesia (and epidural anesthesia), when controlled for gestational age and characteristics of the pregnancies, deliveries, and neonates. A future randomized controlled trial is needed to confi rm or refute this relationship in modern anesthetic practice.

120. Sprung J, Flick RP, Wilder RT, et al: Anesthesia for cesarean delivery and learning disabilities in a population-based birth cohort. Anesthesiology 2009; 111: 302-10Study Design: Retrospective cohort (n=5,320 including 3 groups of n=4,823 [vaginal delivery] vs. n=193 [cesarean under general anesthesia] vs. n=304 [cesarean under neuraxial anesthesia])Conclusion: Children exposed to general anesthesia during cesarean delivery are not more likely to develop learning disabilities compared with children delivered vaginally. The risk of learning disabilities may be lower in children whose mothers received neuraxial anesthesia for cesarean delivery. Note: Unmeasured perinatal hypoxia likely confounds these relationships.

Accompanying editorial: Hansen TG, Flick R: Anesthetic effects on the developing brain: insights from epidemiology. Anesthesiology 2009; 110: 1-3This editorial considers epidemiologic approaches to exploring anesthetic effects on the developing brain. Note: Effective studies will require both detailed obstetric and anesthetic birth records, as well as rigorous follow-up of children’s academic outcomes.

Early Prematurity

121. Conde-Agudelo A, Romero R: Antenatal magnesium sulfate for the prevention of cerebral palsy in preterm infants less than 34 weeks’ gestation: a systematic review and metaanalysis. Am J Obstet Gynecol 2009; 200: 595-609Study design: Meta-analysis of 6 RCTs of primarily moderate to high quality, and cost-effectiveness analysis Conclusion: Magnesium sulfate administered to women at risk of delivery before 34 weeks’ gestation reduces the risk of cerebral palsy. Based on a calculated NNT of 52, the incremental cost of preventing once case of cerebral palsy is estimated at $10,291.

122. The EXPRESS Group: One-year survival of extremely preterm infants after active perinatal care in Sweden. JAMA 2009; 301: 2225-33Study Design: Population-based prospective cohort study (n=707 infants born at less than 26 weeks gestational age among 305,319 births)Conclusion: During 2004 to 2007, 1-year survival of infants born alive at 22 to 26 weeks’ gestation in Sweden was 70% and ranged from 9.8% at 22 weeks to 85% at 26 weeks.

Accompanying editorial: Zylke JW, DeAngelis CD: Health promotion and disease prevention in children: it’s never too early. JAMA 2009; 301: 2270-1

123. Johnson S, Fawke J, Hennessy E, et al: Neurodevelopmental disability through 11 years of age in children born before 26 weeks of gestation. Pediatrics 2009; 124: e249-57Study Design: Population-based prospective cohort study (n=219 children born at less than 26 weeks gestational age); case control analysis (n=219 vs. n=153 classmate controls)Conclusion: Compared with term-birth peers, extremely preterm children remain at high risk for neurodevelopmental disability at 11 years of age, and cognitive defi cits continue to be the most prevalent impairment. The prevalence of disability remained stable between 6 and 11 years of age.

124. Manuck TA: Outcomes of expectantly managed preterm premature rupture of membranes occurring before 24 weeks of gestation. Obstet Gynecol 2009; 114: 29-37Study Design: Retrospective cohort (n=159 pregnancies with PPROM less than 24 weeks gestational age)Conclusion: More than one-half of women with a singleton pregnancy less than 24 weeks’ gestation, who achieved at least 12 hours of latency after preterm PROM, and who elected expectant management, had a surviving infant (56%); nearly 50% of surviving infants had no severe neonatal morbidity. Serious maternal complications were uncommon.

Late Prematurity

125. Reddy UM, Ko CW, Raju TN, Willinger M: Delivery indications at late-preterm gestations and infant mortality rates in the United States. Pediatrics 2009; 124: 234-9Study Design: Retrospective population-based cohort study of NCHS 2001 US birth cohort linked birth/death fi les (n=292,627 late-preterm births of n=3,483,496 singleton births) Conclusion: 23% of late preterm births (delivered between 340/7-366/7 weeks) had no recorded indication for delivery noted on birth certifi cates. Controlling for gestational age at birth, this group (without an indication for late preterm delivery) had higher neonatal and infant mortality rates compared with those born after isolated spontaneous labor.

126. Morse SB, Zheng H, Tang Y, Roth J: Early school-age outcomes of late preterm infants. Pediatrics 2009; 123: e622-9Study Design: Retrospective cohort study of healthy late preterm births vs. healthy term infants (n=159,813 comprised of 2 groups of n=7,152 [healthy late preterm] vs. n=152,661 [term])Conclusion: This study suggests that healthy-appearing late preterm infants (delivered between 340/7-366/7 weeks’gestation) face a greater risk for developmental delay, requirements for supplemental educational services, and adverse early school-age problems through the fi rst 5 years of life when compared with healthy term infants.

Term Birth

127. Tita AT, Landon MB, Spong CY, et al: Timing of elective repeat cesarean delivery at term and neonatal outcomes. N Engl J Med 2009; 360: 111-20Study design: Retrospective cohort study (n=1,262 adverse neonatal events among 13,258 elective cesarean deliveries after 37 weeks gestational age)Conclusion: Elective repeat cesarean delivery before 390/7 weeks’ gestation is common and is associated with preventable increases in neonatal morbidity (including respiratory and other adverse neonatal outcomes) and admissions to the neonatal ICU. Incremental risk was noted even among those infants born between 384/7 and 386/7 weeks’ gestational age. These fi nding support the delay of elective cesarean deliveries until 39 weeks’ gestation.

Accompanying editorial: Greene MF: Making small risks even smaller. N Engl J Med 2009; 360: 183-4

Letter to the editor: Salim R, Zafran N, Shalev E: Timing of elective repeat cesarean delivery at term. N Engl J Med. 2009; 360: 1570 author reply 1570-1

128. Zhang X, Kramer MS: Variations in mortality and morbidity by gestational age among infants born at term. J Pediatr 2009; 154: 358-362 e1Study Design: Retrospective population-based cohort study of NCHS 2001 US birth cohort linked birth/death fi les (n=4,976 neonatal deaths and n=14,776 post-neonatal infant deaths among 12,762,098 births)Conclusion: Neonatal death, low 5-minute Apgar score, and mechanical ventilation show a U-shaped relation across term gestational ages, with minimum risk noted between 390/7 weeks and 406/7 weeks. Rates of meconium aspiration syndrome and birth injury rise with increasing gestational age. Post-neonatal death and postneonatal SIDS decrease with increasing gestational age up to 39 weeks.

Neurologic Morbidity and Mortality

129. Bhat MA, Charoo BA, Bhat JI, Ahmad SM, Ali SW, Mufti MU: Magnesium sulfate in severe perinatal asphyxia: a randomized, placebo-controlled trial. Pediatrics 2009; 123: e764-9Study Design: High quality RCT (n=40 comprising 2 groups of n=20 [magnesium sulfate] vs. n=20 [saline placebo])Conclusion: Postnatal magnesium sulfate treatment improves neurologic outcomes at discharge for term neonates with severe perinatal asphyxia when it is given early (within 6 hours). More studies with larger sample sizes, preferably multicenter trials, are needed to confi rm the results of this study.

130. Odd DE, Lewis G, Whitelaw A, Gunnell D: Resuscitation at birth and cognition at 8 years of age: a cohort study. Lancet 2009; 373: 1615-22Study Design: Population-based longitudinal cohort study (n=11,482 children comprised of 3 groups of n=815 [resuscitated but asymptomatic] vs. n=58 [resuscitated and symptomatic] vs. n=10,609 [not resuscitated and asymptomatic])Conclusion: Infants who were resuscitated at birth had increased risk of a low IQ score at age 8 years, even if they remained healthy during the neonatal period. Resuscitated infants asymptomatic for encephalopathy might result in a larger proportion of adults with low IQs than do those who develop neurological symptoms consistent with encephalopathy.

Accompanying editorial: Hack M, Stork E: Resuscitation at birth and long-term follow-up. Lancet 2009; 373: 1581-2

Letter to the editor: Mercer J, Bewley S: Could early cord clamping harm neonatal stabilisation? Lancet 2009; 374: 377-8

131. Pasupathy D, Wood AM, Pell JP, Fleming M, Smith GC: Rates of and factors associated with delivery-related perinatal death among term infants in Scotland. JAMA 2009; 302: 660-8Study Design: Population-based retrospective cohort study (n=219 intrapartum stillbirths and n=500 neonatal deaths among 1,012,266 births)Conclusion: Rates of intrapartum stillbirth and neonatal death at term decreased in Scotland between 1988 and 2007. This decrease was only signifi cant for deaths ascribed to intrapartum anoxia (defi ned broadly including hypoxia, acidosis, and asphyxia), with a total decrease from 5.7 to 3.0 per 10,000 births (adjusted OR 0.46 [95% CI 0.33-0.65]). The authors correlate this decrease in perinatal death with an increasing cesarean delivery rate (from 8.9% to 21.6%), and question the WHO recommendation to limit cesarean deliveries to no more than 15% of all births.

Breastfeeding

132. Stuebe AM, Michels KB, Willett WC, Manson JE, Rexrode K, Rich-Edwards JW: Duration of lactation and the incidence of myocardial infarction in middle to late adulthood. Am J Obstet Gynecol 2009 200 e1–8Study Design: Retrospective cohort (n=2,540 cases of CAD among 89,326 parous women in the Nurses’ Health Study)Conclusion: Long duration of lactation (life-time total of 2 years or longer) was associated with a reduced risk of coronary heart disease during the 30 years after a woman’s last birth, even when adjusted for age, parity, adiposity, family history, comorbidities, and lifestyle factors.

133. Schwarz EB, Ray RM, Stuebe AM, et al: Duration of lactation and risk factors for maternal cardiovascular disease. Obstet Gynecol 2009; 113: 974-982Study Design: Retrospective cohort (n=139,681 women in the Women’s Health Initiative study)Conclusion: Among postmenopausal women, increased duration of lactation (life-time total of at least 12 months) was associated with a lower prevalence of hypertension, diabetes, hyperlipidemia, and cardiovascular disease. In fully adjusted models stratifi ed by age, the cardiovascular benefi ts of lactation appeared to decrease as women age, with the strongest effects among women 50-59 years of age, and no signifi cant effects among women aged 70-79.

Accompanying editorial: Newton ER: “Whatsoever a [woman] soweth, that shall [she] also reap.” Obstet Gynecol 2009; 113: 972-3

See also: Strathearn L, Mamun AA, Najman JM, O’Callaghan MJ: Does breastfeeding protect against substantiated child abuse and neglect? A 15-year cohort study. Pediatrics 2009; 123: 483-93Study Design: Retrospective analysis of a longitudinal cohort (n=6,621 maternal-child dyads)Conclusion: Among other factors, breastfeeding may help to protect against maternally perpetrated child maltreatment, particularly child neglect. Note: Women invested enough to breastfeed are probably less likely to subsequently neglect their children.

Education

Communication

134. Waisel DB, Lamiani G, Sandrock NJ, Pascucci R, Truog RD, Meyer EC: Anesthesiology trainees face ethical, practical, and relational challenges in obtaining informed consent. Anesthesiology 2009; 110: 480-6Study Design: Qualitative analysis of written narratives (n=39)Conclusion: The ethical, practical, and relational challenges in obtaining informed consent colored trainees’ views of patient care and affected their interactions with patients. Using participant narratives personalizes education and motivates participants. The richness of narratives may help anesthesiologists to appreciate the qualitative aspects of informed consent.

Accompanying editorial: Shafer A: “It blew my mind”: exploring the diffi culties of anesthesia informed consent through narrative. Anesthesiology 2009; 110: 445-6

Selected by the editorial board of Anesthesiology as one of the top 12 articles “…to advance the science and practice of perioperative, critical care, and pain medicine through the promotion of seminal discovery.”

Borgeat A, Brennan TJ, Eisenach JC, et al: 2009 in review: advancing medicine in anesthesiology. Anesthesiology 2009; 111: 1192

Letter to the editor: Edler AA: Paradigm consciousness: a new approach to understanding anesthesia knowledge and education. Anesthesiology 2009; 111: 920

135. Cyna AM, Andrew MI, Tan SG: Communication skills for the anaesthetist. Anaesthesia 2009; 64: 658-665Study Design: Review articleConclusion: Recent evidence suggests that communication practices should include a consideration of conscious and subconscious processes and responses. This model has potential relevance when learning and teaching how to communicate effectively in the stressful environment of anesthetic clinical practice, and includes refl ective listening, observing, acceptance, utilization, and suggestion.

Letters to the editor: Langford RA: Communication and consent. Anaesthesia 2009; 64: 1259

Mercer SJ, Moneypenny MJ, Guha A: Communication and simulation for anaesthetists. Anaesthesia 2009; 64:1259-60; author reply 1260-1

The Health Care Delivery System

Home Birth

136. de Jonge A, van der Goes BY, Ravelli AC, et al: Perinatal mortality and morbidity in a nationwide cohort of 529,688 low-risk planned home and hospital births. BJOG 2009; 116: 1177-84Study Design: Retrospective cohort (n=529,688 comprised of 3 groups of n=321,307 [home birth plan] vs. n=163,261 [hospital birth plan] vs. n=45,120 [unknown plan]) including all women under midwifery care who gave birth in the Netherlands between 2000 and 2006Conclusion: Planning a home birth was not associated with increased risks of perinatal mortality (intrapartum and up to 7 days after birth) or severe perinatal morbidity among low-risk women (normal singleton vertex gestation, 37-42 weeks’ gestation, with no maternal medical or obstetric risk factors), provided the availability of well-trained midwives and a good transportation and referral system.

Letter to the editor:Groenendaal F: Home birth: as safe as in hospital? BJOG 2009; 116: 1684-5; author reply 1685-6

137. Janssen PA, Saxell L, Page LA, Klein MC, Liston RM, Lee SK: Outcomes of planned home birth with registered midwife versus planned hospital birth with midwife or physician. CMAJ 2009; 181: 377-383Study Design: Prospective cohort (n= 12,982 comprising 3 groups of n=2,899 [home birth with midwife] vs. n=4,752 [hospital birth with midwife] compared against a matched control cohort n=5,331 [hospital birth with physician]) Conclusion: Compared with planned hospital births attended by a registered midwife or physician, planned home births attended by a registered midwife were associated with comparable rates of perinatal death (stillbirth after 20 weeks or death in the fi rst 28 days of life) and with reduced rates of obstetric interventions and other adverse perinatal outcomes.

Accompanying editorial: McLachlan H, Forster D: The safety of home birth: is the evidence good enough? CMAJ 2009; 181: 359-60This editorial calls for a multicenter RCT with a composite outcome measure of perinatal mortality and major morbidity to compare planned home versus hospital birth.

Organization of Anesthetic Services

138. Angle P, Kurtz Landy C, Murthy Y, Cino P: Key issues and barriers to obstetrical anesthesia care in Ontario community hospitals with fewer than 2,000 deliveries annually. Can J Anaesth 2009; 56: 667-77Study design: Secondary qualitative analysis of transcripts from 4 focus groups including 18 anesthesia providersConclusion: Physicians in community hospitals face signifi cant barriers in the provision of obstetric anesthesia care. These barriers are greatest among family practitioner/general practitioner anesthetists and in rural hospitals where physician shortages and lack of supports threaten provision of services. Future study of local context-specifi c and systems-level solutions is required.

Accompanying editorial: Douglas J, Preston R: Provision of obstetric anesthesia: throwing down the gauntlet! Can J Anaesth. 2009; 56: 631-5

139. Needleman J, Minnick AF: Anesthesia provider model, hospital resources, and maternal outcomes. Health Services Research 2009; 44: 464-82Study Design: Cross-sectional analysis (of 1,141,641 discharges for delivery) linked to a survey of anesthesia providers in 369 hospitals; study funded by the American Association of Nurse Anesthetists (AANA) Conclusion: This study did not detect a difference in anesthesia-related or obstetric complications billed by ICD-9CM codes between hospitals that use only CRNAs, a combination of CRNAs and anesthesiologists, or anesthesiologist-only models. Note: A future study is needed that clearly describes the characteristics of the populations constructed by propensity scores, accounts for hospital transfers, adjusts for obstetric acuity, and provides specifi cs about the anesthesia-related complications.

See also: The US Center for Medicare and Medicaid Services. Revised Hospital Anesthesia Services Interpretive Guidelines. http://www.cms.hhs.gov/SurveyCertifi cationGenInfo/downloads/SCLetter10_09.pdf , Accessed 2/19/2010

Patient Safety

140. Sherman H, Castro G, Fletcher M, et al: Towards an international classifi cation for patient safety: the conceptual framework. Int J Qual Health Care 2009; 21: 2-8Study Design: Consensus document based on a two-stage web-based modifi ed Delphi survey of over 250 international expertsConclusion: This conceptual framework describes 10 components of a patient safety incident: incident type, patient outcomes, patient characteristics, incident characteristics, contributing factors/hazards, organizational outcomes, detection, mitigating factors, ameliorating actions, and actions taken to reduce risk for future incidents.

See also: The World Health Organization. Patient Safety. http://www.who.int/patientsafety/research/en/index.html , Accessed 2/19/2010

141. Haynes AB, Weiser TG, Berry WR, et al: A surgical safety checklist to reduce morbidity and mortality in a global population. N Engl J Med 2009; 360: 491-9Study Design: International pre/post design (n=7,688 patients in 8 hospitals comprised of 2 groups of n=3,733 [patients before checklist] vs. n=3,955 [patients after checklist])Conclusion: Following implementation of the surgical checklist, the death rate across all 8 institutions decreased from 1.5% to 0.8% (P=0.003); inpatient complications decreased from 11.0% to 7.0% (P<0.001).

Letters to the editor: Multiple letters with numerous authors: A surgical safety checklist. N Engl J Med 2009; 360: 2372-4, author reply 2374-5

142. Haller G, Myles PS, Taffe P, Perneger TV, Wu CL: Rate of undesirable events at beginning of academic year: retrospective cohort study. BMJ 2009; 339: b3974Study Design: Retrospective cohort (n=2,672 undesirable events in 19,560 anesthetics)Conclusion: The rate of undesirable events (central and peripheral nerve injuries, inadequate oxygenation, vomiting/aspiration, technical failures of tracheal tube placement) was greater among trainees at the beginning of the academic year regardless of the trainee’s level of clinical experience. This suggests that several additional factors, such as knowledge of the working environment, teamwork, and communication, may contribute to the increase in undesirable events.

Accompanying editorial: Barach P, Johnson JK: Variation in adverse events during the academic year: trainees need practice and mentorship, and graduated clinical responsibilities. BMJ 2009; 339: b3949

143. Simpson KR, Kortz CC, Knox GE: A comprehensive perinatal patient safety program to reduce preventable adverse outcomes and costs of liability claims. Jt Comm J Qual Patient Saf 2009; 35: 565-74Study Design: Description and evaluation of an ongoing quality improvement program targeting perinatal patient safety in 16 delivery units Conclusion: This perinatal patient safety program (which continues to evolve) produced improved outcomes from 2003 to 2008 including reductions in perinatal harm, a decrease in the number of claims, and a decrease in the costs of claims.

144. Pettker CM, Thung SF, Norwitz ER, et al: Impact of a comprehensive patient safety strategy on obstetric adverse events. Am J Obstet Gynecol 2009; 200: 492 e1-8Study Design: Description and evaluation of a quality improvement program targeting perinatal safety in a major academic centerConclusion: A systematic strategy to improve patient safety included outside expert review, protocol standardization, the creation of a patient safety nurse position and patient safety committee, and training in team skills, and fetal heart rate monitoring interpretation. These interventions signifi cantly reduced the Adverse Outcome Index over time, P=0.01.

145. Siassakos D, Hasafa Z, Sibanda T, et al: Retrospective cohort study of diagnosis-delivery interval with umbilical cord prolapse: the effect of team training. BJOG 2009; 116: 1089-96Study Design: Pre/post design (n=34 [events before team training] compared with n=28 [events post-training])Conclusion: After introduction of annual multidisciplinary simulation training, median diagnosis-delivery intervals for cord prolapse decreased (from 25 to 14.5 minutes, P<0.001) and the rate of cesarean deliveries in which recommended actions had been performed increased (from 35 to 82%, P=0.003). Future RCTs are needed to confi rm these results.

146. Siassakos D, Crofts JF, Winter C, Weiner CP, Draycott TJ: The active components of effective training in obstetric emergencies. BJOG 2009; 116: 1028-32Study Design: Review articleConclusion: This review evaluates obstetric emergency training programs from hospitals that have demonstrated improved outcomes to determine the active components of effective training. Common features identifi ed were institution-level incentives to train, multi-professional training of all staff in their units, teamwork training integrated with clinical teaching, and use of high fi delity simulation models. Local training appeared to facilitate self-directed infrastructural change.

147. Wilkins KK, Greenfi eld ML, Polley LS, Mhyre JM: A survey of obstetric perianesthesia care unit standards. Anesth Analg 2009; 108: 1869-75Study Design: Survey study (n=67 obstetric anesthesia directors in North America; response rate=55%)Conclusion: Results from this survey suggest that the level of care provided for postanesthesia recovery from cesarean delivery in North American academic institutions may not meet the guidelines established by the American Society of PeriAnesthesia Nurses.

148. Swanton RD, Al-Rawi S, Wee MY: A national survey of obstetric early warning systems in the United Kingdom. Int J Obstet Anesth 2009; 18: 253-7Study Design: Survey study (n=158 of UK consultant-led obstetric anesthetic units; response rate=71%)Conclusion: Survey results support the recommendation for a nationally standardized obstetric early warning scoring system (EWS). Using extracts from 9 unit responders, an EWS was devised and has been submitted to OAA for consideration.

149. Sibanda T, Sibanda N, Siassakos D, et al: Prospective evaluation of a continuous monitoring and quality-improvement system for reducing adverse neonatal outcomes. Am J Obstet Gynecol 2009; 201: 480 e1-6Study Design: Description and evaluation of cumulative sum analysis as a tool to monitor rates of Apgar scores <7 and to target quality improvement effortsConclusion: Prospective and continuous monitoring of clinical outcomes using the CUSUM chart method may allow early detection and correction of adverse trends and may help to identify and target quality improvement efforts.

Books

150. Chestnut DH, Polley LS, Tsen LC, Wong CA (eds): Chestnut’s Obstetric Anesthesia Principles and Practice 4th edition. Philadelphia, Mosby, 2009This new edition is an up-to-date comprehensive resource for the practice of obstetric anesthesia.