A systematic approach to the management of postoperative nausea and vomiting.

Postoperative nausea and vomiting (PONV), a common complication after anesthesia and surgery, often results in delayed discharge with the patient's unpleasant symptoms continuing at home. To effectively prevent and treat PONV, it is important to understand the factors implicated in PONV, the mechanisms of PONV, the pharmacology of the antiemetic agents, and the nonpharmacologic measures that have been shown to be effective. The cause of PONV is likely to be multifactorial, with important predictors being female gender, history of PONV, and history of motion sickness. The vomiting center can be triggered by activation of dopamine, serotonin (type 3), histamine (type 1), and muscarinic cholingergic receptors in the chemoreceptor trigger zone and the nucleus tractus solitarus, as well as acetylcholine receptors in the vestibular apparatus, vagal afferents from the periphery, and the endocrine environment. Antiemetic agents such as the serotonin antagonists (eg, ondansetron, dolasetron), droperidol, antihistamines (eg, diphenhydramine, dimenhydrinate), and promethazine can prevent and treat PONV effectively. Transdermal scopolamine and dexamethasone have a role in the prevention of PONV, particularly for certain high-risk patients. Nonpharmacologic measures and alternative treatments such as hydration, maintaining blood pressure, acupressure techniques, trancutaneous acupoint stimulation, and isopropyl alcohol must not be overlooked. Finally, an evidence-based algorithm for the prevention and treatment of PONV in adults is presented.