Prevention and treatment of postoperative vomiting
Postoperative nausea and vomiting emerge during the first 240-48 hours from surgery. Prevalence of postoperative nausea and vomiting is as high as 30% among all patients undergoing surgery, and almost 80% among the patients with high risk of postoperative vomiting. Since postoperative nausea and vomiting create very unpleasant experience and could lead to serious complications, they should be either prevented or treated. There are several perioperative factors which may initiate postoperative vomiting: opioids, inhalation anesthetics, anxiety, adverse drug effects and transporting the patient. More than one neurotransmitter system is involved in regulation of nausea and vomiting: cholinergic, dopaminergic, serotonergic, histaminergic and neurokinin system. Procedures which may decrease prevalence of postoperative vomiting are: use of local or regional anesthesia instead of general one and use of propofol for anesthesia induction (prevalence of vomiting drops for 30%). Ondansetron, dexamethasone and droperidol are equally effective: when administered prophylactically, they decrease risk of posoprative vomiting for 25%. These drugs have additive effect, since their mechanisms of action are different. The patients with extreme risk of postoperative vomiting should receive long-acting antiemetic, like transdermal scopolamine or palonosetron, or combinations of two antiemetics. If a patient who already received antiemetic prophylaxis still develops nausea and vomiting, he or she should be treated by new antiemetic having another mechanism of action.