Incidence and aetiology of postoperative nausea and vomiting.

The reported incidence of emetic symptoms in surgical patients varies from 8-92%. Intractable postoperative nausea and vomiting remains one of the most unpleasant side-effects experienced by patients postoperatively, both in ambulatory and non-ambulatory care, and has potential risks for severe postoperative complications. Multiple factors are associated with an increased risk of developing postoperative nausea and vomiting: age, gender, pre-existing disease, premedication, operative procedure, anaesthetic and analgesic drugs, anaesthetic procedure, and postoperative symptoms. Prophylactic use of anti-emetic premedication is not currently routine practice because not all patients are at serious risk of postoperative nausea and vomiting, and currently available anti-emetics carry undesirable side-effects. However, anti-emetic prophylaxis is very valuable for patients at increased risk. If symptoms do develop in the recovery room, several factors need to be considered in order for anti-emetic treatment to be successful. Adequate hydration and pain control should be ensured, tight-fitting oxygen masks avoided, and patients should be encouraged to take slow, deep breaths to decrease the sensation of nausea. To avoid side-effects, anti-emetics should be administered in minimally effective doses. If the administration of anti-emetics is initially unsuccessful, it may be useful to try a combination of anti-emetic drugs with different mechanisms of action.