Cost Effectiveness of Intrathecal Morphine for Postoperative Analgesia after Caesarean Section: a Randomised Controlled Trial

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Yu S C¹, Chu K L¹, Kwan A S K¹, Ho L M²
1 Department of Anaesthesiology and Pain Medicine, United Christian Hospital, Hong Kong
2 Department of Community Medicine, University of Hong Kong

Purpose of Study

Caesarean section is of public health importance and costs of providing acute postoperative analgesia are of economic interest.1 Decision makers require data on costs and effectiveness of treatments under conditions of normal clinical practice, but little economic data exists for intrathecal morphine in caesarean section. This randomised controlled trial aimed to compare costs and clinical effectiveness of intrathecal morphine against the standard of care, intravenous patient controlled analgesia (PCA), after caesarean section from a hospital budget holder perspective.

Method

After research ethics committee approval and informed consent, 140 ASA I or II term patients scheduled for elective caesarean section under spinal anaesthesia were recruited. Patients were randomly allocated to receive either intrathecal morphine 200mcg or intravenous PCA (1mg bolus, lockout 6 minutes) for postoperative analgesia. Postoperative care and management followed routine ward practices. Postoperative outcomes included pain scores, adverse effects and also first times to walking, carrying the neonate and breast feeding. Costs were calculated using micro-costing and nursing time estimates of specific events matched to individual patient episodes over a 24 hour timeframe with subsequent bootstrapping.2

Result

The intrathecal morphine group had lower mean (±2SD) 24 hour cumulative pain scores, 2.4 (7.0) versus 5.2 (8.6), p<0.05. Adverse effects were more frequent in the intrathecal morphine group (Table 1). There were no differences in first times to breast feeding, walking or carrying the neonate. Mean costs (95% reference interval) were less in the intrathecal morphine group, HK$43.81 (5.67 - 105.77) versus HK$171.94 (65.3 - 290.50).

Conclusion

Intrathecal morphine was more cost effective than intravenous PCA for postoperative analgesia after caesarean section (NHMRC Level II evidence).

Table 1. Incidence of postoperative adverse effects

References

1. Australian and New Zealand College of Anaesthetists and Faculty of Pain Medicine. Acute Pain Management: Scientific Evidence. 2nd edition 2005, Appendix B
2. Briggs A, Gray A. The distribution of health care costs and their statistical analysis for economic evaluation. J Health Serv Res Policy (1998); 3: 233-245

Time of Presentation
0830