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Anesthesia for Cesarean Section

A practical evidence based approach. Anesthesia for Cesarean Section. December 17, 2008. Questions to Answer. 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?

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Anesthesia for Cesarean Section

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  1. A practical evidence based approach Anesthesia for Cesarean Section December 17, 2008 Preetham Suresh MD

  2. Questions to Answer • 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?

  3. Anesthesia for Cesarean Section • Indications for Cesarean • Preoperative preparation • Intraoperative managment • Consider the options • Neuraxial • Spinal • Epidural • Continuous Spinal • Dealing with complications • GA

  4. Indications for C/S • Maternal • Labor contraindicated • LUS Obstruction • Herpes • Fetal • Nonreassuring FHR • Abnormal lie • Congenital abnormalities • Maternal-fetal • Abnormal placentation • Cephalopelvic disproportion www.childbirthconnection.org Sweha et al. Interpretation of the Electronic Fetal Heart Rate During Labor. American Family Physician. 1999. Gabbe: Obstetrics. Churchill Livingstone. 2007.

  5. Anesthesia for Cesarean Section • Indications for Cesarean • Preoperative preparation • Intraoperative managment • Consider the options • Neuraxial • Spinal • Epidural • Continuous Spinal • Dealing with complications • GA

  6. Preop Preparation • Preop Assessment • Consent • Verbal 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.

  7. Preop Preparation • 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

  8. Preop Preparation

  9. Fluid loading • 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.

  10. Anesthesia for Cesarean Section • Indications for Cesarean • Preoperative preparation • Intraoperative managment • Consider the options • Neuraxial • Spinal • Epidural • Continuous Spinal • Dealing with complications • GA

  11. Intraop management • Equipment check • Suction! • Monitors • Assess FHR in OR • LUD • Evaluate IV access

  12. Intraoperative O2 Uterine Artery Uterine Vein • 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 Placenta Umbilical Arteries Umbilical Vein Diagram adopted from Berkeley Bio-Engineering Inc. 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.

  13. Anesthesia for Cesarean Section • Indications for Cesarean • Preoperative preparation • Intraoperative managment • Consider the options • Neuraxial • Spinal • Epidural • Continuous Spinal • Dealing with complications • GA

  14. Choosing an Anesthetic Plan 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.

  15. Spinal vs Epidural • 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.

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

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

  18. Anesthesia for Cesarean Section • Indications for Cesarean • Preoperative preparation • Intraoperative managment • Consider the options • Neuraxial • Spinal • Epidural • Continuous Spinal • Dealing with complications • GA

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

  20. Spinal Dosing • 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

  21. Spinal Dosing • Spread likely independent of patient factors • Taller use more • Obese use less • Dose matters • Impact of baricity depends on patient position

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

  23. Effect of baricity D Bupiv D CSF Hypobaric Hyperbaric D opioid Hare et al. Density determination of local anaesthetic opioid mixtures for spinal anaesthesia. Can J Anaesth 1998.

  24. Effect of baricity 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.

  25. Intrathecal Morphine Dosing • 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 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.

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

  27. IntrathecalFentanyl Dosing • 20% less intraop supplementation • Reduces 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

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

  29. Anesthesia for Cesarean Section • Indications for Cesarean • Preoperative preparation • Intraoperative managment • Consider the options • Neuraxial • Spinal • Epidural • Continuous Spinal • Dealing with complications • GA

  30. Epidural Dosing • 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.

  31. Epidural Dosing • 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+epi Bjornestad et al. Similar onset time of 2-chloroprocaine an lidocaine + epi for epidural anesthesia for elective C-section. Acta Anaesthesiol Scand 2006.

  32. Epidural Fentanyl • 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

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

  34. Epidural Morphine • 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 related Palmer et al. Postcesarean Epidural Morphine: A Dose-Response Study. Anesthesia and Analgesia 2000.

  35. Anesthesia for Cesarean Section • Indications for Cesarean • Preoperative preparation • Intraoperative managment • Consider the options • Neuraxial • Spinal • Epidural • Continuous Spinal • Dealing with complications • GA

  36. Continuous Spinal Anesthesia • May be making a comeback • Take it if you get it • Risk 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

  37. Anesthesia for Cesarean Section • Indications for Cesarean • Preoperative preparation • Intraoperative managment • Consider the options • Neuraxial • Spinal • Epidural • Continuous Spinal • Dealing with complications • GA

  38. Dealing with Complications • Respiratory depression • Inadequate block • High block • Local anesthetic toxicity • Intraoperative pain

  39. Respiratory Depression • 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.

  40. Respiratory Depression • 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.

  41. Inadequate Block • Limit initial epidural dose to 10 cc 2% Lido/HCO3/Epi/Fentanyl • Test block carefully before prepping • If no block after 5-10 min, go to plan B • Spinal • New epidural • CSE • CSA • GA

  42. Spinal after failed epidural

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

  44. Avoid problems • 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

  45. High Block • 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

  46. Local anesthetic toxicity • Test dose catheter in OR • Use fractionated doses • Watch for early signs • Treat cardiotoxicity with 20% Intralipid • 1.5 cc/kg bolus 1-3x • 0.25-0.5 cc/kg/min x 30-60min

  47. Intraoperative Pain • Explain what to expect • Wait for epidural to work • Ketamine 10-20 mg • Fentanyl 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

  48. Anesthesia for Cesarean Section • Indications for Cesarean • Preoperative preparation • Intraoperative managment • Consider the options • Neuraxial • Spinal • Epidural • Continuous Spinal • Dealing with complications • GA

  49. Indications for GA • Contraindication to neuraxial • Coagulopathy • Localized infection • Severe hypovolemia • Stenotic valvular lesions? • Maternal refusal • Fetal distress confirmed in the OR • Anticipated intraoperative hemorrhage?

  50. Considerations for GA • 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.

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