Anesthesia for Cesarean Section

A practical evidence based approach

Preetham Suresh MD December 17, 2008

What are the indications for C/S?Should we give IVF prior to neuraxial?Should we use O2 during routine C/S?Is a spinal more effective than an epidural?

What is the ideal dose of epidural or IT narcotics?

What do I do if my epidural doesn’t work for C/S?

What induction agent should I use for GA?

Indications for Cesarean Preoperative preparation Intraoperative managment Consider the options

Neuraxial▪ Spinal▪ Epidural▪ Continuous Spinal ▪ Dealing with complications

GA

Sweha et al. Interpretation of the Electronic Fetal Heart Rate During Labor. American Family Physician. 1999. Gabbe: Obstetrics. Churchill Livingstone. 2007.

www.childbirthconnection.org

Maternal Labor contraindicated LUS Obstruction Herpes

Fetal Nonreassuring FHR Abnormal lie Congenital abnormalities

Maternal-fetal Abnormal placentation Cephalopelvic disproportion



GA

Preop AssessmentConsentVerbal anxiolysis

BZD rarely necessary Early low dose midaz/fent probably ok

Explain potential downsides and document

Be clear about who you are treating

Frolich et al. A single dose of fentanyl and midazolam prior to Cesarean section have no adverse neontal effects. CJA 2006.

Aspiration prophylaxis 30 cc sodium citrate – lasts 40-60 min▪ Quickly and reliably raises pH▪ Increased gastric volume?

20 mg famotidine 1-2 hr before procedure

10 mg metoclopramide diluted over 10 min

Cochrane review of 75 RCT (n>4600) Crystalloids > no fluids Colloids > crystalloids Ephedrine > crystalloids Phenylephrine = ephedrine

Techniques for preventing hypotension during spinal anaesthesia for caesarean section. Cochrane Database of Systematic Reviews 2006.



GA

Equipment check Suction!

Monitors Assess FHR in OR

LUDEvaluate IV access

100% O2 UmV PO2: 28 47 mmHg

40% O2 Increases Fetal SpO2 43.5% 48.5%

Effect greatest with lowest starting fSpO2

60% O2 UmV PO2: 30 36 mmHg Higher maternal and fetal free radicals

Hughes et al. Shnider and Levinson’s Anesthesia for Obstetrics. Lippincott 2002.Khaw et al. Effects of high FiO2 during elective C-Section under spinal on maternal and fetal oxygenation and lipid peroxidation. Br J Anaesth 2002.Haydon et al. The effect of maternal O2 administration on FSPO2 during labor in fetuses with nonreassuring FHR patterns. Am J OB Gyn 2006.

Uterine Artery

Umbilical Arteries

Uterine Vein

Umbilical Vein

Placenta

Diagram adopted from Berkeley Bio-Engineering Inc.



GA

Spinal versus epidural anaesthesia for caesarean section. Cochrane Database of Systematic Reviews 2004.Morgan et al. Comparison of maternal satisfaction between epidural and spinal anesthesia for elective C-section. Can J Anesth, 2000.Regional versus general anaesthesia for caesarean section. Cochrane Database of Systematic Reviews 2006.

Spinal CSE Epidural

CSA GA

Fast Onset ✚ ✚ ✚✚ ✚✚✚

Adjustable duration

✜ ✚ ✚ ✚

Low maternal M&M ✚ ✚ ✚ ✜

Fetal wellbeing ✚ ✚ ✚ ✚

Maternal satisfaction

✚ ✚✚ ✚ ✚✚ ✚✚

Maternal Hemodynamics

✚ ✚ ✚ ✚✚

LA toxicity unlikely

✚ ✚ ✚ ✚

Reliable ✚✚ ✚✚ ✚ ✚✚ ✚✚✚

Low risk of PDPH ✚ ✚ ✚ ✚✚

Spinal CSE Epidural

CSA

Fast Onset ✚ ✚ ✚✚

Adjustable duration

✜ ✚ ✚

Low maternal M&M ✚ ✚ ✚ ✜

Fetal wellbeing ✚ ✚ ✚ ✚


✚ ✚✚ ✚ ✚✚


✚ ✚ ✚


✚ ✚ ✚

Reliable ✚✚ ✚✚ ✚ ✚✚

Low risk of PDPH ✚ ✚ ✚

Spinal CSE Epidural

Fast Onset ✚ ✚

Adjustable duration

✜ ✚

Low maternal M&M ✚ ✚ ✚

Fetal wellbeing ✚ ✚ ✚


✚ ✚✚ ✚


✚ ✚


✚ ✚

Reliable ✚✚ ✚✚ ✚

Low risk of PDPH ✚ ✚ ✚

Spinal CSE

Fast Onset ✚ ✚

Adjustable duration

✜

Low maternal M&M ✚ ✚

Fetal wellbeing ✚ ✚


✚ ✚✚


✚


✚ ✚

Reliable ✚✚ ✚✚

Low risk of PDPH ✚ ✚

Spinal

Fast Onset ✚

Adjustable duration

Low maternal M&M ✚

Fetal wellbeing ✚


✚



✚

Reliable ✚✚

Low risk of PDPH ✚

Spinal anesthesia (11 mg Bupiv) is NOT contraindicated in severe preeclampsia Prospective randomized multicenter study

Hypotension with spinal (51%) vs epidural (23%)

No difference in APGAR or UA blood gases

Spinal versus epidural anaesthesia for caesarean section. Cochrane Database of Systematic Reviews 2004.Visalyaputra et al. Spinal Versus Epidural Anesthesia for Cesarean Delivery in Severe Preeclampsia: A Prospective Randomized, Multicenter Study. A&A 2005.

Regional General

Maternal blood loss

Intraoperative pain

Postoperative pain

Maternal Satisfaction

Shivering

N/V

UA/UV pH

NNAS/APGAR

Need for neonatal O2 resuscitation

Regional versus general anaesthesia for caesarean section. Cochrane Database of Systematic Reviews 2006.

Hawkins et al. Anesthesia-related deaths during obstetric delivery in the United States. Anesthesiology 1997.



GA

Bupivicaine Good duration for C/S Low neuro toxicity

When dosed w/ 0.2mg M 10mcg F ED50 = 8 mg ED95 = 11 mg

Need higher doses if no narcotic

0.75 %

cc mg

1 7.5

1.2 9

1.4 10.5

1.5 11.25

1.6 12

1.8 13.5

2 15

Ginosar et al. ED50 and ED95 of IT Hyperbaric Bupivacaine Coadministered with Opioids for Cesarean Delivery. Anesthesiology 2004

Success with lower doses (3.75 -7.5 mg) Less hypotension and nausea Faster recovery Slower onset Higher incidence of intraoperative discomfort

Requires backup epidural

Balestrieri et al. CSE Anesthesia for Cesarean Delivery: The Dose-Dependent Effects of Hyperbaric Bupivacaine on Maternal Hemodynamics. Anesth. Analg. 2007

Spread likely independent of patient factors Taller use more Obese use less

Dose matters Impact of baricity depends on patient position

Solution Density (g/ml)

CSF 1.00030 ± 0.00004

0.75% Bupivicaine + 8.25% dextrose

1.0252 ± 0.0001

0.5% Bupivicaine Plain 0.9994 ± 0.0001

PF Morphine 1.0001 ± 0.0001

Fentanyl 0.9936 ± 0.0001

Hare et al. Density determination of local anaesthetic opioid mixtures for spinal anaesthesia. Can J Anaesth 1998.

D CSF

D opioid

D Bupiv

Hare et al. Density determination of local anaesthetic opioid mixtures for spinal anaesthesia. Can J Anaesth 1998.

Hyperbaric

Hypobaric

Hallworth et al. The Effect of Posture and Baricity on the Spread of IT Bupivacaine for Elective Cesarean Delivery. Anesth Analg 2005.Center for Simulation, Safety, Advanced Learning and Technology. University of Florida. http://vam.anest.ufl.edu/Bret Harx. Back and Bed: Ergonomic aspects of sleeping. CRC Press.

Girgin et al. Intrathecal morphine in anesthesia for cesarean delivery: dose-response relationship for combinations of low-dose intrathecal morphine and spinal bupivacaine. Journal of Clinical Anesthesia 2008.

0.1 mg IT PF morphine Decreased PCA useage by 32 mg Increased time to 1st PCA by 10 hrs No additional N/V

Higher doses No effect on postop PCA use Linear increase in pruritis severity

Palmer et al. Dose-Response Relationship of Intrathecal Morphine for Postcesarean Analgesia. Anesthesiology 1999.

20% less intraop supplementationReduces intraop and postop N/V for 4 hrs

Improves postop analgesia for 4 hrs

May have no effect or may increase narcotic requirements from 6-24hrs

More pruritis at higher doses

Hunt et al. Perioperative Analgesia with Subarachnoid Fentanyl-Bupivicaine for Cesarean Delivery. Anesthesiology 1989.



GA

2% Lidocaine Add 5 mcg/cc Epi Add 1 cc bicarb/10 cc Lidocaine

▪ Increases onset from 9.7 min to 5.2 min

▪ More hypotension

Lam et al. Extension of epidural blockade in labour for emergency Caesarean section using 2% lidocaine with epinephrine and fentanyl, with or without alkalinisation* Anaesthesia 2001.

3% Chloroprocaine Rapidly cleared in plasma

Interferes with the action of subsequent epidural narcotic

Previous preparation neurotoxic

Consider to avoid LA toxicity

Onset similar to Lido+epiBjornestad et al. Similar onset time of 2-chloroprocaine an lidocaine + epi for epidural anesthesia for elective C-section. Acta Anaesthesiol

Scand 2006.

Dose 50-100 mcg Better efficacy in vol >10 cc

Benefits Potentiates intraop analgesia Decreases need for IV supplementation Decreases N/V Pain control for 4 hrs post op

No adverse maternal or neonatal effect

Naulty et al. Epidural Fentanyl for post-cesarean delivery pain management. Anesthesiology 1985.

Dose = 3.75 mg 60 women for elective CS

Prospective randomized double blinded

0, 1.25, 2.5, 3.75, 5 mg doses diluted to 10 cc

Side effects and PCA usage monitored

Side effects not dose relatedPalmer et al. Postcesarean Epidural Morphine: A Dose-Response Study. Anesthesia and Analgesia 2000.



GA

May be making a comebackTake it if you get itRisk of PDPH

~80% with touhy and no CSA < 15% with CSA and catheter d/c after 12-24hr

Dose CSA based on desired goal 1 cc 0.25% isobaric bupivicaine in incremental doses

Supplement with 10 mcg IT fentanyl



GA

Respiratory depressionInadequate blockHigh blockLocal anesthetic toxicityIntraoperative pain

Lipophilic opioid respiratory depression rare < 30 min

Hydrophilic opioid respiratory depression 0-0.9% 30-90 min (epidural) 6-18 hrs (IT or epidural)

Carvalho et al. Respiratory Depression After Neuraxial Opioids in the Obstetric Setting. Anesth & Analg 2008.

Risk factors: Obesity OSA (worse on Mg) Cardiopulmonary disease Opioid tolerance Monitor for 24hrs

▪ Q1hr 0-12 hr▪ Q2hr 12-24 hr

Carvalho et al. Respiratory Depression After Neuraxial Opioids in the Obstetric Setting. Anesth & Analg 2008.

Limit initial epidural dose to 10 cc 2% Lido/HCO3/Epi/Fentanyl

Test block carefully before preppingIf no block after 5-10 min, go to plan B Spinal New epidural CSE CSA GA

Gaiser, R. Cesarean Section and the Failed Epidural: What Next? OB Anesthesia Mtng 2004.

Place 4 cm of catheter into epidural space

Replace problematic labor epidurals early

Need for >2 ‘top-ups’ predicts epidural failure for C/S

If >20cc bolus, replace with new 3% Chloroprocaine epidural

If <20cc bolus, consider reduced dose CSE

Watch for early signs Weak hands Trouble speaking or swallowing Trouble breathing Bradycardia

Prepare to manage airway May still need SCh to relax the jaw musculature

Treat hypotension

Test dose catheter in ORUse fractionated dosesWatch for early signsTreat cardiotoxicity with 20% Intralipid 1.5 cc/kg bolus 1-3x 0.25-0.5 cc/kg/min x 30-60min

Explain what to expectWait for epidural to workKetamine 10-20 mgFentanyl 50-100 mcg

If prior to cord clamp, mention to peds

N2O Keep patient conscious! Not the place for deep sedation

Convert to GA if needed



GA

Contraindication to neuraxial Coagulopathy Localized infection Severe hypovolemia Stenotic valvular lesions? Maternal refusal

Fetal distress confirmed in the OR

Anticipated intraoperative hemorrhage?

Adequate preoxygenation PaO2: 30 sec 4 VC = 3 min preO2 Faster desaturation after 4 VC 1 min 8 VC = 3 min preO2 Time to desaturation depends on EtO2

Norris et al. Preoxygenation for cesarean section: A comparison of two techniques. Anesthesiology 1985. Gambee et al. Preoxygenation techniques: Comparison of three minutes and four breaths. Anesth Analg 1987.

Chiron et al. Standard preoxygenation technique versus two rapid techniques in pregnant patients. Int’l Journal of OB Anesthesia 2004.

8x higher incidence of difficult intubations

Progressive progesterone induced airway edema

Higher VO2, low FRC and rushed preO2

Full stomach, CP may compromise view

Be ready for plan BKodali et al. Airway Changes during Labor and Delivery. Anesthesiology 2008.

Vasdev et al. Management of the difficult and failed airway in obstetric anesthesia. J Anesthesia 2008.

Sodium Thiopental 5-7 mg/kg Well established use in OB Quick onset No pain on injection No neonatal depression up to doses of 7 mg/kg

Capogna et al. The effects of anaesthetic agents on the newborn. Effects on the Baby of Maternal Analgesia and Anaesthesia 1993.

Ketamine 1-1.5 mg/kg Sympathomimetic Oxytocic if >2mg/kg Less postop morphine required Psychomimetic side effects unlikely

May increase secretions

Baraka et al. Maternal awareness and neonatal outcome after ketamine induction of anaesthesia for Caesarean section. Can J Anaes 1990.

Etomidate 0.3 mg/kg Cardiac stable Pain on injection Documented neonatal adrenal suppression▪ Reduction in plasma cortisol levels at 2h post delivery

▪ No effect on neonatal plasma glucose

Crozier et al. Effects of etomidate on the adrenocortical and metabolic adaptation of the neonate. Br J of Anaesth 1993.

Propofol 2.5 mg/kg Off label use in obstetrics Maternal bradycardia when used with SCh

Fetal depression greater than with STP

Russel R. Opposer: Propofol should be the agent of choice for caesarean section under general anaesthesia. Intl J of OB Anaesth 2003.

90 women at term

90 women at term

Pentothal5 mg/kgPentothal5 mg/kg

Midazolam 0.3 mg/kgMidazolam 0.3 mg/kg

Propofol 2.4 mg/kgPropofol 2.4 mg/kg

1 min APGAR >7

1 min APGAR >7

89%89% 51%*51%*46%*46%*

Celleno et al. Which induction drug for cesarean section? A comparison of thiopental sodium, propofol, and midazolam. J Clin Anesth 1993.

90 women at term

90 women at term

Pentothal5 mg/kgPentothal5 mg/kg

Midazolam 0.3 mg/kgMidazolam 0.3 mg/kg

Propofol 2.4 mg/kgPropofol 2.4 mg/kg

EEG / clinical

findings of light

anesthesia

EEG / clinical

findings of light

anesthesia

10% / 0%10% / 0% 43% / 43%*43% / 43%*50% / 50%*50% / 50%*

Celleno et al. Which induction drug for cesarean section? A comparison of thiopental sodium, propofol, and midazolam. J Clin Anesth 1993.

Decreased MAC by 30%Highest incidence of awareness is prior to delivery

100% O2 with 1-2 MAC vapor Consider 50% N2O

50%N2O with ½ MAC vapor post delivery

What are the indications for C/S?Should we give IVF prior to neuraxial?Should we use O2 during routine C/S?Is a spinal more effective than an epidural?

What is the ideal dose of epidural or IT narcotics?

What do I do if my epidural doesn’t work for C/S?

What induction agent should I use for GA?

Documents

Anesthesia for Cesarean Section