Emetogenic drugs commonly used in anaesthesia include nitrous oxide, physostigmine, and opioids. The intravenous anaesthetic propofol is currently the least emetogenic general anaesthetic. These medications are thought to stimulate the chemoreceptor trigger zone. This area is on the floor of the fourth ventricle and is effectively outside of the blood-brain barrier, which makes it incredibly sensitive to toxin and pharmacological stimulation. Several neurotransmitters are known, such as histamine, dopamine, serotonin, acetylcholine, and the more recently discovered neurokinin-1 (substance P). Risk factors A 2008 study compared 121 Japanese patients who experienced<unk>  after being given the general anesthetic propofol to 790 people who were free of<unk><unk>  after receiving it. Those with a G at both copies of rs1800497 were 1.6 times more likely to experience<unk>  within six hours of surgery compared to those with the AG or AA genotypes, but they were not significantly more likely to experience<unk>  more than six hours after surgery.<unk>  results from patient, surgical, and anesthetic factors. Surgical factors that confer increased risk for<unk>  include procedures of increased length and gynecological, abdominal, laparoscopic and ENT procedures, and strabismus procedures in children. Anesthetic risk factors include the use of volatile anesthetics, nitrous oxide (N2O), opioids, and longer duration of anesthesia. Patient factors that confer increased risk for<unk>  include female gender, obesity, age less than 16 years, past history of motion sickness or chemotherapy-induced<unk> , high levels of preoperative anxiety, and patients with history of<unk> . Smokers and the elderly often have a decreased risk for<unk> . A risk-stratification method created by Apfel et al has been developed to determine a patient's risk for<unk> . The presence of 0, 1, 2, 3, or 4 of any of the following risk factors corresponds to a<unk>  respective risk of 10, 20, 40, 60, and 80%. - Female gender - Non-smoking - History of<unk>  or motion sickness - Expectant use of<unk>  opioid medications
Postoperative nausea and vomiting
Postoperative fever
Post-vagotomy diarrhea
Postoperative cognitive dysfunction
Abdominal compartment syndrome
Short bowel syndrome
Retroperitoneal bleeding
Acute abdomen