Advances in Labor Analgesia

1. Advances in Labor Analgesia Luis Lahud, M.D. Norman Bolden, M.D. Department of Anesthesiology MetroHealth Medical Center May 3rd, 2005 Cleveland, OH

2. Contents • Introduction • PCEA • CSE • Pros • Cons • Review article • Protocols and Cocktails • Discussion

3. INTRODUCTION

4. From 1985 to present use of epidural analgesia for labor has increased from 10% to over 50% of laboring women in the U.S. • Advances include low dose epidurals, “walking” epidurals, PCEA, and CSE • Early: increased doses of LA = increased SE • PDPH 7-10% • OB/GYN perspective

5. Adding opioids < MB • “Walking” epidurals: < MB meant better outcomes • No evidence of improved labor pattern/outcome with ambulation • Women don’t walk even if they can • Monitoring problems • Techniques that allow “walking” may be “better” whether or not patient ambulates

6. Effect of Low-Dose Mobile vs. Traditional Epidural Techniques on Mode of Delivery: A Randomized Controlled TrialCOMET Study, Lancet 2001 • 1054 nulliparous women were randomized into 3 groups to receive either a traditional epid (0.25% BUP), a low-dose CSE, or a low-dose infusion epid • Increased rate of normal vaginal delivery with CSE and low-dose infusion • Decreased rate of instrumental vaginal delivery • Increased rate of CS with traditional epidural

7. PCEA

8. Introduced in 1988 • Small basal dose • PCEA less med overall

9. PCEA VS. CONTINUOUSGambling et al., Can J Anaesth 1988 Epidural initiated: 8 ml 0.25% BUP 0.125% BUP CIEA: 12 ml/hr infusion PCA: 4 ml basal, 4 ml bolus, Lockout 20 min, 16 ml/hr max

10. PCEA VS. CONTINUOUSGambling et al., Can J Anaesth 1988 PCEA (n=14) CIEA (n=11) ______________________________________________________________ Duration (h) 7.0 ± 0.6 5.8 ± 0.6 # demands/hr 1.9 ± 0.4 1.2 ± 0.2 Dose of BUP/hr 11.2 ± 0.85 15.2 ± 0.5

11. PCEA + CI vs. PCEA only • Both groups provide good analgesia • Both use less than continuous • No benefit with basal rate over demand only

12. Ferrante et al. 1994 • Background infusion increases drug use by 30% • No obvious benefit in pain relief • Background infusion decreases physician “top-ups” • Only physician administer “top-ups” associated with hypotension

13. BACKGROUND VS. DEMAND ONLY?Ferrante et al. 1994 • Bupivacaine 0.125% with 2 mcg/ml fentanyl • Loading dose: 0.5% bupivacaine for S5 – T10 level

14. PCEA compared to CEI in an ultra-low-dose regimen for labor pain relief : a randomized studyEriksson, Gentele and Olofsson Acta Anaesthesiologica Scandinavica 2003 • 80 parturients (40 per group) • Ropivacaine 0.1% + SUF 0.5mcg/ml • Test dose + 5ml loading dose • PCEA: 4ml doses, 20min lockout • CEI: 6ml/hr • Rescue: 5ml if VAS > 5

15. CONCLUSIONS: • PCEA group used less drug ( 5.2 v 6.9ml/hr) • PCEA group had shorter labor (296min v 357min, p< 0.001) • Pts titrated themselves to VAS ~ 3

16. PCEA at MH • Test dose • Loading dose: 6 -10cc of 0.125% BUP with 2mcg/cc of fentanyl • Basal infusion: 8 – 12cc of 0.11% BUP with 2mcg/cc of fentanyl • Demand dose: 5cc with 15 min lockout max 30cc/hr

17. Issues with PCEA • Patient/Nurse education • Treat pain early • Emphasize that we are available • Call us if 2 PCEA attempts don’t work • ONLY patient pushes button • Equipment • Record keeping • Maintain patient contact

18. PCEA CONCLUSIONS • Easy modification of existing practice • Fewer MD visits required • May allow lower concentration of drugs with better analgesia • Lower drug usage • Very popular with patients

19. CSE

20. The ideal labor analgesic: • Rapid onset • Long duration • Easy to administer • No side effects on mother • No side effects on baby • Allow ambulation, unrestricted expulsive efforts • No effect on length of labor or mode of delivery • Is CSE the ideal labor analgesic?

21. Advantages of CSE • Rapid onset of analgesia • Reliable, fewer failed, or patchy blocks • Effective sacral analgesia in advanced labor • Less motor block

22. Better patient satisfaction • Aids epidural localization in difficult backs • Faster cervical dilation in early nulliparas • Side effects are acceptably low

23. Rapid Onset of Analgesia • Most dramatic feature; analgesia is often nearly complete before the epidural cath is taped up and the tray discarded • Van de Velde randomized 110 parturients to epid. BUP 0.125% w sufentanil and epinephrine or IT sufentanil. The time to effective analgesia was significantly shorter in the CSE group (326 ± 22 vs. 766 ± 79sec).

24. Nickells randomized women to epid. or SA BUP and fentanyl. The time to first painless contraction was shorter in the CSE group ( 10 ± 5.7 vs. 12.1 ± 6.5min) • Hepner randomized women to receive 10ml of 0.0625% BUP + fentanyl 2mcg/ml + epinephrine + bicarbonate epidurally or 25mcg fentanyl and 2.5mg BUP IT • 26/26 patients had a VAS < 3 within 5min in CSE group, only 17/24 in the epidural group • Does a few minutes advantage in analgesic onset matter?

25. Better Blocks • Quality of analgesia is improved by CSE • Norris retrospectively compared epid. and CSE techniques in 1661 women who received either technique and found a lower incidence of failed blocks and a greater incidence of bilateral symmetrical analgesia w CSE

26. A retrospective analysis in a large academic medical center involving near 20 thousand patients found incidences of overall failure, IV epid cath, wet tap, inadequate epid analgesia and cath replacement were all lower in patients receiving CSE • Sacral analgesia is difficult to obtain with conventional epidural, CSE is good at providing it • CSE is an obvious choice in advanced labor

27. A number of mechanisms may explain this advantage: • One cannot obtain CSF using the needle-through-needle technique unless the epid needle is positioned near the mid line of the actual epid space • There may be passage of LA from the epidural space into the IT space via the dural hole • There may be synergism between epid and spinal blocks, such that one enhances the other

28. Less Motor Block • CSE associated with less total LA use for a given degree of analgesia • In a randomized trial, Collis found 12/98 patients in the CSE group, compared to 32/99 in the epid group had leg weakness at 20min • The difference widened to 10% vs. 80% at 5hr • MB may be minimized or made equivalent to CSE with use of low dose and/or PCEA for epid analgesia • Requirements for anesthesiologist intervention are lower w CSE regardless of technique

29. Better Patient Satisfaction • Several studies have found better patient satisfaction scores with CSE vs. conventional epid. Others have found no difference, but none have found better satisfaction with conventional epid analgesia

30. Better in Difficult Backs • No randomized trial has yet appeared • CSE has been associated with improved chances of adequate analgesia in parturients with scoliosis or other causes of a difficult back

31. Progress of Labor • Patients progress rapidly through labor • One explanation for an apparent increase in FHR abnormalities occurring after CSE is this rapid progress • 2 large randomized trials have confirmed an increase in the spontaneous vaginal delivery rate with CSE vs. conventional epid analgesia • As is the case with epidural analgesia, the CS rate is not increased with CSE

32. Side Effects • PDPH • Fetal bradycardia/FHR changes • Pruritus • Infection • Neurotrauma • Other side effects

33. PDPH • Rate ~ 1% • CSE technique might actually decrease the incidence of dural puncture with the epid needle by allowing the anesthesiologist to confirm an equivocal loss of resistance by passage of a pencil point spinal needle rather than advancing the large bore epid needle futher

34. Fetal bradycardia/ FHR changes • Incidence of 11-30% • Meta - analysis of 24 randomized trials including over 3,500 patients comparing CSE to conventional epid analgesia found no difference in the rate of FHR changes but an increase in the risk of bradycardia • Usually a reduction in uterine activity (decreasing or interrupting oxytocin administration, or short acting tocolytic administration), raising maternal BP, position change, or simply patience will resolve the problem

35. The meta – analysis showed no difference in the rate of CS due to bradycardia or for all indications, and neonatal Apgar scores were equivalent • Pruritus • 3-95% of patients • Effect is time limited, peak at 30min and largely resolved within 1hr • Prophylactic Ondansetron • Patient satisfaction remains high

36. Other side effects • Hypotension • Subarachnoid migration • Respiratory depression

37. On the other hand….. • How fast do we need a block to be? • Nickells et al. noted that the time to first painless contraction with CSE was 10± 5.7 vs. 12.1 ± 6.5min with the epid technique. With a mean difference of 2min, how clinically significant is this? • In the study by Hepner mentioned before at 5min the VAS was < 3 in 26/26 with a CSE vs. 17/24 with an epid; However, no difference in maternal satisfaction, motor blockade or number of times the anesthesiologist was called to intervene. • Why pay more for CSE?

38. Walking and CSE vs. Epidural • No data to suggest a real difference in labor outcome • More maternal satisfaction with being mobile but outcome is the same • Instrumental delivery rate and CS rates are virtually the same • Epid can be used to allow mobility if that is your goal

39. Side Effects of CSE • Collis et al. (1994) found the failure rate of the IT portion as high as 10%. Duration of the spinal portion 90min (mean) and highly variable • Norris et al. noted the spinal part failed in 4.9% • Expected side effects include pruritus, mild decrease in maternal BP, PDPH • Best and worst of both worlds

40. Causes of Failure for CSE Technique

42. Infection • Meningitis and epid abscess have been reported • There are least 8 cases of spinal meningitis related to a CSE • There is also a case of epid abscess after a CSE for labor • Conversely spinal anesthesia for elective CS does not carry these risks

43. Neurotrauma • Cord trauma has been reported with the CSE technique in at least 5 cases • In a report of 7 cases with damage to the conus medullaris following spinal anesthesia by Reynolds of Saint Thomas Hospital in London, 4 were patients who had received a CSE and 3 after a single shot spinal (6 in total were obstetric patients) • In all cases, an atraumatic needle was used, 25 or 27 gauge Whitacre and the anesthesiologist believed to be at L2-3

44. Epid has proven to be relatively safe over many years. If placed in error at T12-L1, for example, there is little concern in good hands • A CSE at that level is a disaster, with penetration of the cord likely • In 43% of women the cord extends to L2 • Numerous studies have shown that we are often 1-2 spaces off, which can cause cord trauma with a CSE

45. Van Gessel et al. demonstrated that 59% of dural punctures were performed 1 or 2 spaces higher than assumed • Broadbent et al. demonstrated in a group of experienced anesthesiologists that when they believed they were at L3-L4, in 85% of the cases the space was 1 to as many as 4 segments higher

47. FHR Changes • Numerous studies of varying quality • Bradycardia more frequent • Management: LUD, fluids, oxygen, treat BP if applicable, IV or SL NTG has been shown to be effective in treating fetal bradycardia associated with uterine hyperactivity • However, there is no data demonstrating an increased risk of CS due to CSE

48. The Risk of Cesarean Delivery with Neuraxial Analgesia Given Early vs. Late in LaborWong et al, NEJM, February 17, 2005 • Epid analgesia initiated early in labor (cervix < 4cm dilated) has been associated with an increased risk of CS. It is unclear whether this is due to the analgesia or to other factors • Women who request analgesia early in labor frequently receive systemic opioid analgesia • Hypothesis: Initiating and maintaining neuraxial analgesia early in labor with IT opioid as part of a low dose LA technique would not increase the risk of CS when compared with systemic opioid analgesia

49. 884 Consented Systemic opioid Intrathecal opioid First request for analgesia; Cervical examination performed 134 Not eligible (cervix≥4.0cm) 750 Randomly assigned (cervix <4.0cm) 13 Excluded 9 Excluded Standard care 362 Assigned to hydromorphone (1mg intravenously + 1mg intramuscularly) And included in analysis; 353 received intervention 366 Assigned to fentanyl (25mcg intrathecally and epid test dose) and included in analysis; 360 received intervention 6 delivered before second request for analgesia 2 delivered before second request for analgesia 720 second request for analgesia; cervical examination performed 215 Cervix ≥4.0 cm or no cervical examination 226 Cervix ≥4.0 cm or no cervical examination 141 cervix <4.0cm 138 Cervix <4.0 cm Hydromorphone (1mg Intravenously + 1 mg intramusculary) Epidural bolus: 15 ml (bupivacaine, 0.625 mg/ml with fentanyl, 2mcg/ml); PCEA begun Third request for analgesia Epidural test dose Epidural bolus: 15 ml (bupivacaine, 1.25 mg/ml); patient-controled Analgesia begun Standard care

50. Results • 728 subjects were included in the analysis • The groups were similar at baseline, except that the systemic analgesia group had a greater % of subjects with dilation ≤ 1.5cm at first request for analgesia (42 vs. 30.9%) • The rate of CS was not significantly different between the groups (IT 17.8 vs. 20.7% SA)