RESUMEN
Background: Morphine Patient-Controlled Analgesia (PCA) increases the frequency of postoperative nausea and vomiting (PONV) and the effectiveness adding haloperidol is unknown. Methods: 145 women scheduled to undergo short-stay surgery under general anaesthesia were randomly assigned in two groups: One group received 2 mg i.v. of haloperidol 30 minutes before the end of surgery plus 2 mg mixed with 50 mg of morphine for administration via PCA (Group H); the other group received the same analgesic scheme for pain management using two comparable i.v. boluses of saline (Group P). Furthermore, both groups received dexamethasone 4 mg during anaesthesia induction. Ondansetron (4 mg i.v.) was used for antiemetic rescue. significa Participants and outcomes assessors were blinded to group assignment. The primary endpoints were incidence of nausea, vomiting and antiemetic requirements during the first 24 hours after surgery. Secondary endpoints included sedation and morphine requirement. Results: Cumulative data at 24 hours showed that the group H had less nausea (71.2% vs. 20.6%; RR 0.29 [95% CI: 0.17-0.46]) and vomiting (47% vs. 11.8%; RR 0.25; [95% CI: 0.12-0.49]), and required less ondansetron (66.7% vs. 17.7%), but had an increased incidence of sedation (NNH: 3.5; 95% CI, 2.3-6.7). The NNT for Total response (no nausea, no vomiting/retching) was 2.5 (0-2 hours) and 2 (2-24 hours). Conclusion: A bolus of haloperidol 2 mg prior to the end of surgery followed by 2 mg mixed with 50 mg of Morphine for PCA administration can significantly reduce the frequency of PONV but at a cost of increased sedation.