Evaluation of the analgesic efficacy of a low dose of intrathecal morphine in laparoscopic abdominal surgery: A randomised control trial

Introduction: Intrathecal opioid is an analgesic option in laparoscopic surgery. We assessed primarily the intraoperative opioid requirement amongst patients receiving intrathecal morphine (ITM) (Group M) versus standard care (Group C) for abdominal surgery. The secondary outcomes were intraoperative haemodynamic changes, extubation on table and pain scores in the intensive care unit (ICU) at 6 th hourly intervals for 24 h postoperatively.

Patients and methods: Patients undergoing laparoscopic abdominal surgery were randomised into Group M ( n = 30) that received ITM at 2 μg/kg while Group C ( n = 30) was control. A rise in mean arterial pressure > 20% from baseline was treated sequentially with 0.3 mg /kg propofol and 0.5 μg/kg fentanyl intravenously (IV). Pain management in the ICU included paracetamol 1G IV 8 th hourly for all patients, while nefopam 20 mg and fentanyl 0.5 μg/kg IV were the second and third tiers of pain management.

Results: Intraoperatively, 10 patients in Group M versus 26 in Group C needed additional fentanyl ( P < 0.001) and 15 versus 26 patients needed additional propofol ( P = 0.0024). Pain scores were superior in Group M at all time points in the ICU and at ambulation and during incentive spirometry. Thirteen patients in Group C versus 3 in Group M needed nefopam at the time of shifting to the ICU ( P = 0.004) and 10 patients versus 1 at 8 h in the ICU ( P = 0.003) while pain management at 16 h and 24 h was comparable.

Conclusion: Pre-operative ITM at 2 μg/kg reduces intraoperative opioid requirement and improves analgesia 24 h postoperatively amongst patients undergoing major laparoscopic abdominal surgery without delay in extubation or changes in haemodynamics.