Spinal Local Anaesthetics: What’s New?

1. Spinal Local Anaesthetics:What’s New? Kim S Khaw Department of Anaesthesia & Intensive Care The Chinese University of Hong Kong Prince of Wales Hospital Shatin, NT.

2. Local Anaesthetics Karl Koller(1857-1944) • Licked fingers - cocaine • Tongue - numb

3. Spinal Anaesthesia August Karl Gustav Bier (1861 - 1949) • 1898 – Spinal Anaesthesia • Suggested use in Obstetrics

4. Spinal Anaesthesia for Obstetrics Oscar Kreis (1900) • Labour Analgesia • ‘single shot technique’ - 6 parturients • at full dilatation – ‘good analgesia’ • 50% forceps rate Hopkins S (1902) • Caesarean section • Case with a placenta praevia!

5. Spinal Anaesthesia for Obstetrics Post dural puncture headache Hypotension – Supine Hypotensive Syndrome Mortality SA>GA “There is, we fear …. a considerable number of healthy pregnant women who standcondemned to death by spinal anaesthesiafor Caesarean section” Bourne and Williams Recent Advances in Obstetrics and Gynaecology 7th edition (1948)

7. UK Survey: 1992 – 69% 2002 – 87% Prince of Wales: 1999 – 77% 2004 – 93% Spinal Anae for Elective CS

8. Improvements in SA • Pencil-point Spinal Needles • Superior Analgesia • Addition of Opioids • Management of Hypotension • Combined techniques with Epidural (CSE)

9. Ideal Spinal Anaesthesia • Absolute analgesia • Fast onset – comparable to GA • No maternal or fetal adverse effects • Good post operative analgesia • Urinary function maintained

10. What’s New

11. What’s New

16. Ropivacaine (Naropin) • Single Isomer • Equipotent to Bupivacaine • Safer • Motor Sparing

17. Potency of ropivacaine?

18. Potency Bup:Rop – 2:1 McDonald S, Liu SS et al. ‘healthy volunteers’ April 1999

19. ED50 16.7mg and ED95 26.8mg Khaw K, Ngan Kee W, ‘Caesarean Section – dose response’ 2001

20. Gautier P, De Kock M‘CS’ - Rop vs Bup vs Levo - 2003

21. Gautier P, De Kock M‘CS’ - Rop vs Bup vs Levo - 2003 Ropivacaine 12mg vs bupivacaine 8mg…… (Plain with sufentanil 2.5 mcg) • Successful anaesthesia • Ropivacaine - 87% • Bupivacaine - 97% • Duration of motor block • Ropivacaine – 116 min • Bupivacaine – 142 min

22. Öğün C.Ö – ‘CS’ – Ropivacaine (morphine) vs Bupivacaine (morphine) - 2003

23. Öğün C.Ö - Ropivacaine Ropivacaine 15mg vs bupivacaine 15mg (Plain with Morphine 150 mcg) • Successful anaesthesia • Ropivacaine - 100% • Bupivacaine - 100% • Duration of motor block • Ropivacaine – 200 min • Bupivacaine – 220 min Short Operation time ~29min Unusual Motor Block duration

24. Ropivacaine 25mg • Successful anaesthesia: • Plain - 75% • Hyperbaric - 100% Hyperbaric Ropivacaine?

25. Block Height Spinal Ropivacaine for Cesarean Delivery – Khaw K

26. Sensory Block Profile Spinal Ropivacaine for Cesarean Delivery – Khaw K

27. Motor Block Profile Spinal Ropivacaine for Cesarean Delivery – Khaw K

28. Chung C, Choi S – ‘CS’ – Hyperbaric Ropivacaine vs Bupivacaine 2001 Spinal Ropivacaine for Cesarean Delivery – Khaw K

29. Chung C – Ropivacaine • Ropivacaine 18mg vs bupivacaine 12mg • (Hyperbaric) • Successful anaesthesia • Ropivacaine - 100% • Bupivacaine - 100% • Duration of motor block • Ropivacaine – 114 min • Bupivacaine – 159 min • Gautier: (Plain) • 12mg: 116 min • 8mg: 142 min

30. Summary – Spinal Ropivacaine • No report of neurological problems • Less Potent • Shorter duration of action - faster recovery • Shorter duration of clinical anaesthesia • Opioids provides ‘dose-sparing’ effects • Hyperbaric solution better

31. Hyperbaric Ropivacaine • Faster onset • More reliable block • Better spread & Lower incidence of failure • Faster recovery of motor block

32. Levobupivacine

33. Gautier P, De Kock M‘CS’ - Rop vs Bup vs Levo - 2003

34. Gautier P, De Kock M‘CS’ - Rop vs Bup vs Levo - 2003 Levobupivacaine 8mg vs bupivacaine 8mg.. (plain with sufentanil 2.5 mcg) • Successful anaesthesia • Levobupivacine - 80% • Bupivacaine - 97% • Duration of motor block • Levobupivacine - 121 min • Bupivacaine - 142 min

35. Motor Block ED50 • Levobupivacaine – 4.8 mg • Ropivacaine –5.9 mg Camorcia M, Capogna G – ‘CS’ ED50 Motor Block - Levo & Rop - 2004

36. Khaw K, Ngan Kee W. Dose Response Comparison Study - Levo & Bup - ‘CS’OAA & CARO Meeting Versailles 2004 Randomized double blinded study 120 ASA 1-2 term parturients for elective C/S 10 groups (n=12) Combined Spinal-Epidural 5.5mg, 6.5mg, 8mg, 10mg,14mg Hyperbaric (8% glucose) • Levo-bupivacaine • Bupivacaine • Block >T7 (Pin), Surgery Completed • If pain encountered • Fentanyl 25 micrograms Maximum of 2 doses • Epidural top up (failed block)

37. 5.5 mg 6.5 mg 8 mg 10 mg 14 mg Khaw - Levo vs Bupivacaine

38. Successful Anaesthesia – Probit Analysis

39. Successful Anaesthesia-Dose Response Relationship Probability of Success Bupivacaine Levobupivacaine Dose of Drug (mg)

40. Bromage 3 Bromage 2 Bromage 1 6.5mg 8mg 10mg 14mg 5.5mg Characteristics of Motor Block

41. Motor Blockade – Probit Analysis

42. Ratio of ED 50

43. Summary - Levobupivacaine Less potent than Bupivacaine potency ratio ~ 0.7 Similar motor sparing property to bupivacaine Clinical properties similar to bupivacaine For Caesarean Section: 14 mg of Levobupivacaine

44. Personal Reflections • CSE • Spinal Ropivacaine ~ 200 cases • Spinal Levobupivacaine ~ 150 cases • No convincing advantage over bupivacaine • Discomfort & Pain ~ 30% • 99% occurs after delivery - ‘closing’ • Dose & Timerelated phenomena • Low Dose Spinal Anaesthesia • NOT Less than ED 95

45. … What do I want?….. Ultimately….. • Bupivacaine (>10mg) • Levobupivacaine (>14mg) • (Ropivacaine) (>20mg) • Hyperbaric & Fentanyl 15µg • Good BP control strategy • (Warwick Ngan Kee’s regime)

46. Thank You Kim S Khaw Department of Anaesthesia & Intensive Care The Chinese University of Hong Kong Prince of Wales Hospital Shatin, NT.