Evaluation of the effect of halothane on postoperative vomiting.

Observations on the frequency and severity of postanaesthetic nausea and vomiting were made in 252 women undergoing minor gynaecological operations under general anaesthesia consisting of thiopentone, nitrous oxide and oxygen. Anaesthesia lasted for 10 minutes in all patients. One per cent halothane in oxygen was given for 5 minutes at the end of anaesthesia to two groups of cases, one with and one without atropine premedication. This did not lead to a statistically significant reduction of the incidence and severity of sickness as compared with the unpremedicated control group. The administration of halodiane in this way did, however, lead to a significant reduction in emergence vomiting in atropine-premedicated patients. The incidence and severity of sickness after chlorpromazine premedication was significantly lower than in the control group. Trichloroethylene supplementation of nitrous oxide and oxygen anaesthesia did not materially influence sickness as compared with the control group. The major part of postoperative sickness occurred in the first postoperative hour in patients without effective anti-emetic premedication.