Epidural Analgesia Grand Rounds April 2006 Jose Mata, MD Objectives Describe the effects that epidural analgesia may have on: • Labor progress • Rates of assisted vaginal delivery • Rates of cesarean section • Fetal well-being General • Approximately 50-60% of women in labor choose epidural analgesia in the US • Approximately 20% of women in labor choose epidural analgesia in the UK Anim-Somuah et al. Cochrane Review. Pathways of Labor Pain Eltzschig, H. K. et al. N Engl J Med 2003;348:319-332 Types of Epidurals • All include some type of local anesthetic • Most also include an opioid • “Walking epidurals” have a lower concentration of local anesthetic and add an opioid in an attempt to decrease motor blockade • Can combine it with a spinal • Typically a continuous infusion, but may also be patient-controlled or bolused Labor Pain during Different Stages of Labor Eltzschig, H. K. et al. N Engl J Med 2003;348:319-332 Undisputed Benefits of Epidurals • The most effective form of analgesia for labor • Provides good analgesia for vaginal procedures (assisted delivery, manual rotation, manual removal of placenta, etc.) • Can be used for cesarean section Topics to be Covered The effects of epidural analgesia on: • Prolongation of labor • Rates of operative vaginal delivery • Rates of cesarean section • Rates of malposition • Maternal adverse effects • Neonatal adverse effects Prolongation of labor • A review article found an average increase in the first stage of labor by 42 minutes* • The same review found an average increase in the second stage of labor by 14 minutes* • A Cochrane review found no significant difference on the first stage of labor+ • The same Cochrane review found prolongation of the second stage of labor by 15.6 minutes (95% CI: 7.5 to 23.6 minutes)+ *- Eltzschig et al. NEJM Review. +- Anim-Somuah et al. Cochrane Review. Prolongation of Labor: Alexander Study • Participants were nulliparous and had uncomplicated pregnancies • Compared patient-controlled epidural to patient-controlled parenteral opioids • The active phase of labor was prolonged by one hour in the epidural group • Rate of cervical dilation was significantly lower in the epidural group Alexander et al. Rates of instrumental vaginal delivery • Consistently increased rate of vacuum and forceps delivery is observed with epidurals* • Relative risk of instrumental delivery of 1.38 (95% CI: 1.24-1.53)+ • Almost every study reviewed for this presentation found an increased rate of operative vaginal delivery with epidurals *- Eltzschig et al. NEJM Review. +- Anim-Somuah et al. Cochrane Review. Adverse Effects of Operative Vaginal Delivery • Perineal trauma • Urinary incontinence • Fecal incontinence • Sexual dysfunction • Organ prolapse • Chronic pain • Neonatal trauma Management of the Second Stage of Labor • Cochrane review of discontinuation of epidural to reduce the prolongation of the second stage • No significant difference in the length of the second stage or time spent pushing • No significant difference in rate of operative vaginal delivery or c-section • Only significant difference was an increase in inadequate pain relief Torvaldsen et al. Cochrane Review. Management of the Second Stage of Labor • Evaluated the effects of delayed (1hr) versus immediate pushing on the second stage of labor • Significantly longer labor with delayed pushing • No reduction in operative vaginal delivery or cesarean section • Identical fetal outcomes • No differences in anal manometry or neurophysiological studies Fitzpatrick et al. BJOG. Management of the Second Stage of Labor • Compared delayed versus immediate pushing to reduce rates of operative vaginal delivery • Non-significant reduction in the rate of operative vaginal delivery • Statistically significant reduction in rate of rotational forceps • Non-significant reduction in c-section • Longer second stage in the delayed pushing group • Significant reduction the total time pushing in the delayed pushing group Roberts et al. BJOG Meta-Analysis. Management of the Second Stage of Labor • Evaluated immediate pushing versus waiting for a strong urge to push at complete cervical dilation in nulliparous patients • No difference in the rates of operative vaginal delivery or cesarean section • No difference in fetal outcome • Significantly longer second stage in the delayed group • No difference in total time spent pushing Plunkett et al. Obstetrics & Gynecology. Effect of Epidurals on the Rate of Cesarean Section • Many observational studies have found that epidurals increase the rate of cesarean section • None of these studies were prospective, randomized trials Criticisms of Early Studies Suggesting Higher Cesarean Section Rate • Some compared women who chose to get an epidural to women who chose not to • Were not intention-to-treat analyses • Non-randomized, retrospective studies • Often had a small sample size Eltzschig et al. NEJM (1-14). Rates of Cesarean Section • A review found no significant increase in the rate of cesarean section with epidurals* • A Cochrane review also found no significant difference in the rate of cesarean section, but the relative risk was 1.07 (95% CI: 0.93-1.23) *- Eltzschig et al. NEJM Review. +- Anim-Somuah et al. Cochrane Review. Rates of Cesarean section: Sharma Study • Largest contributor to the Cochrane review • Intention-to-treat analysis comparing rates of cesarean section with epidural analgesia with patient-controlled parenteral analgesia • No difference in the rates of cesarean section • Statistically significant increase in low forceps deliveries for the epidural group Sharma et al. Anesthesiology. Rates of Cesarean section: Sharma Study (cont) • Significantly prolonged first stage in the epidural group • No significant difference in the length of the second stage • Significantly more women in the epidural group required oxytocin augmentation • Significantly more women in the epidural group had an intrapartum fever Sharma et al. Anesthesiology. Rates of Cesarean Section: Loughnan Study • Intention-to-treat analysis comparing the rates of cesarean section between epidural analgesia and parenteral opioids using an active management of labor protocol • No statistically significant difference in the rates of cesarean section • Statistically significant difference at initiation of analgesia between the two groups with the parenteral opioids group have a smaller cervical dilation Loughnan et al. BJA. Rates of Cesarean Section: Liu Study • A systematic review evaluating the rate of cesarean section in the setting of low concentration epidurals versus parenteral opioids • No statistically significant difference in rates of cesarean section • Statistically significant increase in operative vaginal delivery • Epidurals prolonged the second stage of labor Liu et al. BMJ. Timing of Epidural • Most observational studies show higher rates of cesarean section if epidurals started at cervical dilation of less than 4cm • No randomized controlled trial to date has supported the above finding Eltzschig et al. NEJM. Rates of Cesarean Section: Wong Study • Evaluated cesarean section rate in the setting of early epidurals compared to parenteral opioids • There was a significant differences of cervical dilation at the initiation of analgesia • There was also a significant difference in the percentage of spontaneous rupture of membranes prior to randomization • No difference in cesarean section or operative vaginal delivery • Parenteral opioid group required significantly more oxytocin Wong et al. NEJM. Rates of Malposition • An association between occiput posterior position and epidurals has been reported* • The relative risk for malposition with an epidural is 1.4 (95% CI: 0.98-1.99) *- Eltzschig et al. NEJM Review. +- Anim-Somuah et al. Cochrane Review. Intrapartum Fever • Epidural analgesia is consistently associated with maternal temperature > 100.4oF about 20% of the time* • No difference in the rates of neonatal sepsis* • Relative risk of intrapartum fever of 3.7 (95% CI: 2.8-4.9) with epidural analgesia+ *- Eltzschig et al. NEJM Review. +- Anim-Somuah et al. Cochrane Review. Maternal Hypotension • The relative risk of maternal hypotension is 20.1 (95% CI: 4.83-83.64) with epidurals • The hypotension is usually transient and typically resolves within one hour • The hypotension is very likely to be associated with a non-reassuring FHT • Can be prevented by IV bolus of at least 500mL of isotonic fluid Anim-Somuah et al. Cochrane Review. Post-Epidural Headache • Thought to be due to puncture of the dura • Incidence of 1% • Blood patch effectively treats the above 60% of the time Anim-Somuah et al. Cochrane Review. Long-term Low Back Pain • A review found no significant association between epidurals and long-term low back pain* • A Cochrane review also failed to find any significant association between epidurals and long-term low back pain+ *- Eltzschig et al. NEJM Review. +- Anim-Somuah et al. Cochrane Review. Long-term Low Back Pain: Howell Study • Follow-up study after a randomized, controlled trial • No significant difference in self reported low back pain after more than 2 years • No significant differences in physical exam after more than 2 years • No significant differences in terms of disability after more than 2 years Howell et al. BMJ. Neonatal Complications • No significant difference in Apgar scores with epidurals • A relative risk of arterial cord pH<7.2 of 0.8 (95% CI: 0.66-0.96) • A relative risk of naloxone administration (when compared to parenteral opioids) of 0.13 (95% CI: 0.08-0.21) Anim-Somuah et al. Cochrane Review. Fetal Heart Rate • Reported rates of abnormal fetal heart tracings after epidural of 11% to 78% • Typically lasts less than 30-40 minutes after initiation of epidural anlagesia • 34% of all patient experienced abnormal fetal heart rate tracings within 40 minutes of epidural initiation • Repetitive late decelerations were rare (<2%) Hill et al. Obtetrics & Gynecology Effects of Epidurals on Fetal Acid-Base Balance • Significant improvement in cord arterial pH with epidurals • An odds ratio of 0.54 (P-value < 0.05) for a 1-minute Apgar <7 • An odds ratio of 0.20 (P-value < 0.01) for naloxone administration Reynolds et al. BJOG. Summary of the Effects of Epidurals • Consistently associated with statistically significant prolongation of labor • Consistently associated with statistically significant increased rates of operative vaginal delivery • May lead to increased rates of cesarean section • May increase the rates of malposition Summary of the Effects of Epidurals (cont) • Increased rate of intrapartum fever • Increased rate of transient maternal hypotension • Increased rate of transient non-reassuring fetal heart tracings • Have no direct adverse affects on the fetus • Do not cause long-term low back pain Conclusion ACOG guidelines from 2002 state that a woman’s request for pain relief during labor alone is sufficient medical justification for the use of epidural analgesia Recommendations • Discuss epidural analgesia with your patients during prenatal visits • Present the data in an unbiased manner and help the patient make the decision that is best for them • Support your patient in whatever decision they make References 1. Anim-Somuah, M. et al. Epidural versus non-epidural or no analgesia in labour. The Cochrane Database of Systematic Reviews 2005. 2. Eltzschig, H.K. et al. Regional Anesthesia and Analgesia for Labor and Delivery. NEJM. Jan 23, 2003. vol 348(4): 319-332. 3. Alexander, J.M. et al Epidural Analgesia Lengthens the Friedman Active Phase of Labor. Obstetrics & Gynecology. July 2002. vol 100(1):46-50. 4. Torvaldsen, S. et al. Discontinuation of epidural analgesia late in labour for reducing the adverse delivery outcomes associated with epidural analgesia. The Cochrane Database of Systematic Reviews 2004. 5. Fitzpatrick, M. et al. A randomised clinical trial comparing the effects of delayed versus immediate pushing with epidural analgesia on mode of delivery and faecal continence. BJOG. December 2002. vol 109: 1359-1365. 6. Roberts, C.L. et al. Delayed versus early pushing in women with epidural analgesia: a systematic review and meta-analysis. BJOG. December 2004. vol 111: 1333-1340. References (cont) 7. Plunkett, B.A. et al. Management of the Second Stage of Labor in Nulliparas With Continuous Epidural Analgesia. Obstetrics & Gynecology. July 2003. vol 102(1): 109-114. 8. Sharma, S.K. et al. Cesarean Delivery: A Randomized Trial of Epidural versus Patient-controlled Meperidine Analgesia during Labor. Anesthesiology. September 1997. vol 87(3): 487-494. 9. Loughnan, B.A. et al. Randomized controlled comparison of epidural bupivacaine versus pethidine for analgesia in labour. British Journal of Anaesthesia. 2000. vol 84(6): 715-719. 10. Liu, E.H.C. et al. Rates of caesarean section and instrumental vaginal delivery in nulliparous women after low dose concentration epidural infusions or opioid analgesia: systematic review. BMJ. June 12, 2004. vol 328(7453): 1410-1415. 11. Wong, C.A. et al. The Risk of Cesarean Delivery with Neuraxial Analgesia Given Early versus Late in Labor. NEJM. February 17, 2005. vol 352(7): 655-665. References (cont) 12. Howell, C.J. et al. Randomised study of long term outcome after epidural versus non-epidural analgesia during labor. BMJ. August 17, 2002. vol 325(7360): 357-360. 13. Hill, J.B. et al. A Comparison of the Effects of Epidural and Meperidine Analgesia During Labor on Fetal Heart Rate. Obstetrics & Gynecology. August 2003. vol 102(2): 333-337. 14. Reynolds, F. et al. Analgesia in labour and fetal acid-base balance: a meta-analysis comparing epidural with systemic opioid analgesia. BJOG. December 2002. vol 109: 1344-1353.
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