Postoperative nausea and vomiting
|Postoperative nausea and vomiting|
|Classification and external resources|
Postoperative nausea and vomiting (PONV) is an unpleasant complication affecting about a third of the 10% of the population undergoing general anaesthesia each year. A 2008 study compared 121 Japanese patients who experienced PONV after being given the general anesthetic propofol to 790 people who were free of post-operative nausea after receiving it. Those with a G at both copies of rs1800497 were 1.6 times more likely to experience PONV within six hours of surgery compared to those with the AG or AA genotypes. But they were not significantly more likely to experience PONV more than six hours after surgery.
On average the incidence of nausea or vomiting after general anesthesia ranges between 25 and 30% [Cohen 1994]. Nausea and vomiting can be extremely distressing for patients and is therefore one of their major concerns [Macario 1999]. Vomiting has been associated with major complications such as pulmonary aspiration of gastric content and might endanger surgical outcomes after certain procedures, for example after maxillofacial surgery with wired jaws. Nausea and vomiting can delay discharge and about 1% of patients scheduled for day surgery require unanticipated overnight admission because of uncontrolled postoperative nausea and vomiting.
Because no currently available antiemetic is especially effective by itself, and successful control is often elusive, experts recommend a multimodal approach. Anaesthetic strategies to prevent vomiting include using regional anaesthesia wherever possible and avoiding emetogenic drugs. Pharmacological treatment and prevention of postoperative nausea and vomiting is limited by both cost and the adverse effects of drugs. Patients with risk factors probably warrant prophylaxis, whereas a "wait and see" strategy is appropriate for those without risk factors.
In conjunction with antiemetic medications, at least one study has found that application to the Pericardium Meridian 6 accupressure point produced a positive effect in relieving postoperative nausea and vomiting. Another study found no statistically significant difference.
Continuous Wound Infiltration may reduce PONV and the need for post-operative pain management drugs.
The introduction of the 5HT3 receptor antagonist, ondansetron, in the early 1990s was a significant breakthrough. Despite the many studies, however, the evidence base to support rational antiemetic treatment remains patchy. Recent research has led to better understanding of some older drugs and has demonstrated that combinations of drugs are often useful. While the efficacy of droperidol is now clear, metoclopramide, a popular antiemetic for decades, was found to have limited efficacy at the lower traditional dosage. Some older drugs, such as haloperidol and hyoscine remain inadequately studied.
Postoperative nausea and vomiting results from anaesthesic, surgical, and patients factors. Gynaecological, urological, strabismus correction and middle ear surgery all have a higher risk of postoperative nausea and vomiting.
Patients that are female or who have a history of postoperative nausea and vomiting are at greater risk. Smokers have a decreased risk, but this would never be recommended by any physician. Older patients suffer less PONV.
- Cohen MM, Duncan PG, DeBoer DP, Tweed WA. The postoperative interview: assessing risk factors for nausea and vomiting. Anesth Analg 1994;78:7-16.
- Macario A, Weininger M, Carney S, Kim A. Which clinical anesthesia outcomes are important to avoid? The perspective of patients. Anesth Analg 1999:89(9):652-8
- Tramèr MR. Treatment of postoperative nausea and vomiting. BMJ 2003;327:762-3. Fulltext. PMID 14525850.
- Gan TJ: Risk factors for postoperative nausea and vomiting. Anesth Analg. 2006 Jun;102(6):1884-98. Review. PMID 16717343