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Labour Analgesia Dr Ajay Dr Nishtha Dr Pooja Sikka

Labour analgesia - ajay

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An overview of Labor Analgesia

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  • 1.Dr Ajay Dr NishthaDr Pooja Sikka

2. THE LABOUR IS REPORTED TO BE ONE OFTHE MOST PAINFUL EXPERIENCES IN AWOMANS LIFE. 3. Pain Pathways- First stage of labour- uterine contraction + cervicaldilatation. Afferent- visceral afferent from uterus (symathetic)T 10, 11, 12, L 1 posterior segments. Second stage- distension of pelvic floor, vagina andperineum by descending head Afferent- sensory fibres of S 2, 3, 4 (pudendal nerve) 4. EFFECTS OF PAIN AND STRESS release of adrenocorticotropic hormone, cortisol,catecholamines, and b-endorphins. b-adrenergic agents have uterine relaxant effects andhigher epinephrine levels are associated with anxietyand prolonged labour. animal studies indicate that both epinephrine andnor-epinephrine can decrease uterine blood flow inthe absence of maternal heart rate and blood pressurechanges, contributing to occult fetal asphyxia. 5. Maternal psychological stress (induced by bright lightsor toe clamp) can detrimentally affect uterine bloodflow and fetal acid-base status (animal studies) Postpartum women suffer objective deficits incognitive and memory function when compared withnonpregnant women. 6. Analgesia for Labor and Delivery Always controversial! Birth is a natural process Women should suffer!! Concerns for mothers safety Concerns for baby Concerns for effects on labor 7. Analgesia for Vaginal Delivery Psychoanalgesic techniques Acupuncture TENS (transcutaneous electric nerve stimulation) Systemic narcotics Tranquilizers / hypnotics Inhalation analgesia 8. ANALGESIA FOR LABOURPsychoprophylaxis- nonpharmacologic method Relaxation, concentration onbreathing, acupuncture, gentle massage, and partnerparticipation. may be used alone, or in conjunction with parenteralor regional techniques. efficacy of these techniques is largely unprovenbecause of a lack of randomized clinical trials. there are no serious safety concerns with any of thesetechniques. 9. Acupuncture Acupuncture alleviates labour pain and reduces use ofboth epidural analgesia and parenteral opioids. Arranging to have a qualified provider available at thetime of delivery may be challenging. 10. Under Water Delivery No advantage in labour outcome or in reducing theneed for analgesia. The request for epidural analgesia was delayed byabout 30 minutes. Lack of trials demonstrating safety and the rare butreported unusual complications such as fetal infectionor asphyxia. 11. Others- Intracutaneous sterile water injections- similar gatingmechanism as acupuncture. transcutaneous electrical nerve stimulation duringlabour- made the pain less disturbing, doesnt decreaseit. 12. Placental Transfer of Drugs:Maternal, Drug, Placental and Fetal Factors Lipid solubility Molecular size Total dose of drug Concentration gradient Maternal metabolism and excretion Degree of ionization pKa of drug, maternal and fetal pH Protein binding - mother and fetus Uterine blood flow 13. Sedatives Do not possess analgesic qualities. Used early in labour to relieve anxiety or to aid insleep. Cross the placenta freely. Barbiturates, Phenothiazines, and Benzodiazepines. Barbiturate and benzodiazepines are not usedroutinely in obstetrics. 14. Phenothiazines Promethazine (Phenargan) Dose- 25 mg Antagonists are not available. Weak antiemetic. Routine use of promethazine is unnecessary. 15. Systemic Opioid Analgesia Morphine-like pharmacological activity. Natural- morphine and codeine Semisynthetic- hydromorphone and heroine Synthetic- meperidine and fentanyl Provide sedation and a sense of euphoria. Analgesic effect in labour is limited. Primary mechanism of action is sedation. 16. Advantages- Easy administration. Inexpensive. Avoids complications of regional block. Does not require skilled personnel. Few serious maternal complications. 17. Disadvantages- All drugs easily cross placenta. Pain relief inadequate in most cases Maternal sedation Nausea, vomiting, gastric stasis Fetal heart rate effects: Loss of beat-to-beat variability Sinusoidal rhythm Dose-related maternal / neonatal depression Newborn neurobehavioral depression 18. Treatment of respiratory depression- ventilation, oxygenation, gentle stimulation, naloxone. 19. Tramadol Centrally acting opioid analgesic used in treating severepain. Route- IV or IM Dose- 50 mg Emetic. Should be given with antiemetic. Maximum respiratory depression and low apgar scoreoccur in newborns that are delivered within- 3 hours after an IM administration 2 hours after an IV administration. 20. Meperidine Meperidine 100 mg is roughly equi-analgesic tomorphine 10 mg. Side effects- tachycardia, nausea and vomiting, and adelay in gastric emptying. Normeperidine - active metabolite ofmeperidine, potentiating meperidines depressanteffects in the newborn. Concentrations increaseslowly, therefore, exerts its effect on the newbornduring the second hour after administration. Multiple doses of meperidine = greater accumulationof both meperidine and normeperidine in fetal tissues. 21. Fentanyl Fast-onset, short-acting synthetic opioid. Requires frequent redosing or the use of a patient-controlled intravenous infusion pump. Fewer neonatal effects and less maternal sedation andnausea. Other opioids are nalbuphine, pentazocine, buprenorphine and butorphanol 22. Inhalational analgesia Easy to administer (no needles) Nitrous oxide is administered in subanaestheticconcentrations. (N2O 30-50%) Analgesia without loss of consciousness. Crosses the placenta but is eliminated efficiently, nountoward neonatal effects. No effects on uterine contractions. Most effective for short term (1-2 hrs) pain relief Most beneficial in late first stage of labour. 23. Local and regional techniques Local infiltration Pudendal block Paracervical block Paravertebral (lumbar sympathetic block) Epidural - lumbar (caudal) Spinal Combined spinal-epidural (CSE) 24. Perineal Infiltration Direct infiltration of 1% lignocaine is used for perinealand lower vaginal lacerations. Advance the needle and inject and aspirate to avoidintravascular injection. Dose of lignocaine is 3-4 mg/kg plain solution, and 7-8mg/kg with added epinephrine. 1% solution = 10 mg/ml For 6O kg woman total dose should not exceed 200 mgor 20 ml. After local infiltration one should wait 3 minutesbefore proceeding. 25. Paracervical block 5 to 6 ml of a dilute solution of local anestheticwithout epinephrine (e.g., 1 percent lidocaine or 1 or 2percent 2-chloroprocaine) is injected into the mucosaof the cervix at the 3- and 9-oclock positions fetal bradycardia that follows in 2 to 70 percent ofapplications fetal acidosis and death have been reported Paracervical block should be used cautiously at alltimes and should not be used at all in mothers withfetuses in either acute or chronic distress. 26. mechanism of postparacervical block bradycardia- local anesthetic injected close to the uterine arterypassed to the fetus uterine artery vasoconstriction secondary to a directeffect of the local anesthetic on the uterine artery local anesthetic injected directly into the uterinemusculature increases uterine tone 27. Pudendal nerve block minor regional block, effective and very safe. Using a 20-gauge needle, inject 5 to 10 ml of localanesthetic just below the ischial spine. Because the hemorrhoidal nerve may be aberrant in 50percent of patients, some prefer to inject a portion ofthe local anesthetic somewhat posterior to the spine. Although a transperineal approach to the ischial spineis possible, most prefer the transvaginal approach.One-percent lidocaine or 2-percent 2-chloroprocainecan be used 28. satisfactory for all spontaneous vaginal deliveries andepisiotomies, and for some outlet or low operativevaginal deliveries. The potential for local anesthetic toxicity is higherwith pudendal block compared with perinealinfiltration because of large vessels proximal to theinjection site. Aspiration before injection isparticularly important. 29. Regional Analgesia for Labor Epidural (LA or opioids) Spinal (LA opioids) CSE- combined spinal epidural (opioids LA) 30. Fetal / Neonatal Effects of RegionalAnalgesia in Labor Uterine perfusion maintained. Profound hypotension & possible fetal compromise. LA toxicity - extremely rare. FHR changes: baseline variability periodic decelerations (due to maternalcatecholamine) Neurobehavioral effects absent with current agents. 31. Epidural Analgesia Epidural block is the most effective and leastdepressant (pharmacologic option) allowing for analert, participating mother.(guidelines American College of Obs & gynae) Primary indication is the patients desire for painrelief. Medical indications during labor- selected forms ofcardiovascular and respiratory disease, and preventionor treatment of autonomic hyperreflexia in parturientswith a high spinal cord lesion. 32. Epidural analgesia prevents increases in both cortisol and 11-hydroxycorticosteroid levels during labor, but systemically administered opioids do not. Epidural analgesia also attenuates elevations of epinephrine, norepinephrine, and endorphin levels. 33. Contraindications- Coagulopathy Sepsis Patients refusal Fixed cardiac output disease History of allergy to local anaesthetics Thrombocytopenia Hypovolemia 34. Types- Lumbar- routinely done Caudal- not favoured 35. Lumbar- Low concentrations of local anesthetic are injected atL2-L5. Affecting the small easily blocked sympathetic nervesthat mediate early labour pain. Sparing the sensation of pressure and motor functionof the perineum and lower extremities. Dose can be adjusted according to patients response. 36. Choice of epidural local anaestheticLignocaine- rapid onset, dense motor block, risk ofcumulative toxicity with repeated doses.Bupivacaine- good sensory block with minimal motoreffect. No adverse effect on labour with 0.0625%concentration Highly protein bound, fetal blood concentrations arelower than with other local anaesthetics. 37. Epidural Opioids in Labour Inadequate analgesics used alone Synergistic with local anesthetics Speedy onset of analgesia Improves quality of analgesia Permits use of very dilute LA solutions Help relieve persistent perineal pain and unblocked segments 38. Fentanyl and Sufentanil Rapid onset, few side effects Sufentanil slightly more effective No significant fetal drug accumulation No serious adverse neonatal effects with either 39. Side effects of epidural- hypotension local anesthetic toxicity allergic reaction high or total spinal anesthesia neurologic injury spinal headache. Fetal bradycardia 40. The effect of epidural analgesia on labourprogression, fetal position, and risk of cesareandelivery is controversial. Randomized studies support the conclusion thatepidural analgesia results in a modest prolongation ofboth the first and second stages of labour. Significant increase in the use of oxytocin for labouraugmentation. 41. Increased rate of instrumental delivery. Several well-designed randomized studies suggest that, in settings with baseline low rates of caesarean delivery, epidural analgesia does not increase the risk of caesarean delivery. 42. Epidural analgesia during labor is associated with anincrease in maternal temperature. Dependent on the duration of exposure. Possible mechanisms- noninfectious inflammatoryactivation, changes in thermoregulation, and acquiredintrapartum infection. 43. Combined spinal epidural Opioids LA Rapid onset of intense analgesia. Ideal in late or rapidly progressing labour. Very low failure rate. Less need for supplemental boluses. Minimal motor block (walking epidural) Walking epidural- Use of opioid only to allowparturients to ambulate during labour because there islittle or no interference with motor function. 44. Early intrathecal opioids followed by continuous epidural infusion in active labour may be a good option for women desiring regional analgesia, offering superior pain control until active labour has been achieved. 45. One randomized study found that use of intrathecalopioids increased speed of cervical dilatation anddecreased length of labour when compared withconventional epidural. The use of intrathecal opioids improved pain control inearly labor without increasing the risk of caesareandelivery. avoids maternal sedation , decreases nausea and vomiting. comparisons of intrathecal opioid analgesia versus epiduralor parenteral opioids in labour found the use of intrathecalopioids significantly increases the risk of fetal bradycardia . 46. Fetal heart rate should be monitored during and afterthe administration of either epidural or intrathecalmedications to allow for timely intrauterineresuscitation. No increase in emergency caesarean delivery. 47. Conclusions Individualize technique to patients goals and stage oflabour. Optimize management for spontaneous delivery. Provide safe, cost-effective analgesia. 48. Thank you