Nausea and vomiting in the postoperative patient-controlled analgesia environment.

Despite common clinical opinion that patient-controlled analgesia should be renamed 'patient-controlled nausea', there is little evidence in support of the notion that postoperative nausea and vomiting are exacerbated by the method. Indeed, data indicate that opioid-sparing techniques are not associated with less postoperative nausea and vomiting. Although some evidence suggests that certain opioids are less emetogenic than others, this too does not stand scrutiny when compared across patients, although research is still required to find whether individual patients are better treated with a particular opioid. Similarly, the emerging practice of combining anti-emetics with patient-controlled analgesia needs wider study before it can be supported.