A total of 84 studies involving 6,069 patients, 3,098 treated with propofol, were included.
Propofol used as a maintenance regimen reduced early (<6 hours) postoperative nausea and vomiting. NNTs for the 3 types of early emetic event were as follows:
Propofol used for induction of anaesthesia: nausea: 5 (95% CI, 2.7 to 35); vomiting: 7 (95% CI, 4.4 to 17); any emetic event: 14 (95% CI, 5 to (). Propofol for anaesthesia maintenance: nausea 4.7 (95% CI, 3.8 to 6.3); vomiting 4.9 (95% CI, 4 to 6.1); any emetic event: 4.9 (95% CI, 3.7 to 7.1).
Analysis of early and late outcomes after propofol as an induction agent, or late outcomes after propofol maintenance, produced NNTs greater than 9 in every case. Late outcomes showed that although propofol maintenance led to significantly less nausea and vomiting (reported as separate events) than control anaesthetics (NNTs 6.1, 95% CI, 3.9 to 15, and 8.3, 95% CI, 4.9 to 28, respectively) there were no other significant differences between propofol and controls. Subgroup analyses revealed that the advantage of propofol was greater with major gynaecological surgery than with minor surgery, with NNTs for prevention of early vomiting of 4.2 (95% CI, 3 to 8) and 16 (95% CI, 11 to 32), respectively. These subgroups had different control rates of vomiting: 32% with major surgery, 10% with minor.