Female>male (x3). Incidence increases during menstruation and decreases after the menopause. after 70 years of age,both sexes are equally affected. Obese (has been suggested, although there is currently insufficient evidence to conclude an association). Young. Risk of PONV is almost twice that for adults. Equal distribution between boys and girls until puberty. Previous history of PONV/motion sickness Early ambulation, early postoperative eating and drinking.
Surgery Intra-abdominal-laparoscopic Intracranial, middle ear Squint surgery (highest incidence of PONV in children) Gynaecological, especially ovarian Head and neck, especially tonsillectomy and adenoidectomy (suggested due to blood in upper gastrointestinal tract (GIT), stimulation of trigeminal nerve afferents and peroperative opioids). Prolonged surgery Painful
Anaesthesia/drugs Opioids (NB untreated pain is also emetogenic) Sympathomimetics Inhalational agents (Isoflurane++) Etomidate, ketamine, methohexitone (compared with propofol and thiopentone) Neostigmine (recent work suggests that this is not associated with PONV) Nitrous oxide (GIT distension/expansion of middle ear cavities). Prolonged anaesthesia Spinal anaesthesia (blocks above T5), hypotension. Intraoperative dehydration Inexperienced bag and mask ventilation (gastric dilatation).
Intercurrent Disease Intestinal obstruction Metabolic, e.g. hypoglycaemia, uraemia Hypoxia
Tramèr MR . A rational approach to the control of postoperative nausea and vomiting: evidence from systematic reviews. Part I. Efficacy and harm of antiemetic interventions, and methodological issues. Acta Anaesthesiol Scand. 2001 Jan;45(1):4-13.
Tramèr MR . A rational approach to the control of postoperative nausea and vomiting: evidence from systematic reviews. Part II. Recommendations for prevention and treatment, and research agenda. Acta Anaesthesiol Scand. 2001 Jan;45(1):14-9 .
Tramèr MR. (Editorial) Rational control of PONV – the rule of three/Le contrôle rationnel des NVPO – la règle de trios. Canadian Journal of Anesthesia. 2004 51:283-285
1. Reduce the baseline risk by such measures as reducing nitrous oxide use, avoiding neostigmine, using local anaesthetics wherever possible instead of opiates and using propofol for induction and maintenance of anaesthesia.
2. Do not use routine preventative treatment as it does not work well, is less cost effective and unnecessarily exposes patients to the drugs.
3. Identify the high risk patients and then use an effective drug combination.
Apfel CC, Läärä E, Koivuranta M, Greim CA, Roewer N. A simplified risk score for predicting postoperative nausea and vomiting: conclusions from cross-validations between two centers. Anesthesiology. 1990; 91:693-700.
Koivuranta M, Läärä E, Snare L, Alahunta S. A survey of postoperative nausea and vomiting.
It has been shown that both dexamethasone and droperidol increase the efficacy of “setrons” and it is more effective to give a “cocktail” of prophylaxis.
For example: steroid (dexamethasone 8mg) at induction and a 5-HT3 antagonist, good for treating vomiting, (ondansetron 4mg) with a D2 antagonist, good for treating nausea, (droperidol 0.75mg) at the end of the procedure .
There is no evidence for an effect greater than placebo for metoclopramide.
Prospective randomized, double-blind comparative study of dexamethasone, ondansetron, and ondansetron plus dexamethasone as prophylactic antiemetic therapy in patients undergoing day-case gynaecological surgery. Thomas R, Jones N. Br J Anaesth 2001; 87(4): 588-92 .
Prevention of vomiting after strabismus surgery in children: dexamethasone alone versus dexamethasone plus low-dose ondansetron. Splinter WM. Paediatr Anaesth 2001; 11(5): 591-5 .