METAANALYTIC COMPARISON OF PROPHYLACTIC ANTIEMETIC EFFICACY FOR POSTOPERATIVE NAUSEA AND VOMITING - PROPOFOL ANESTHESIA VS OMITTING NITROUS-OXIDE VS TOTAL IV ANESTHESIA WITH PROPOFOL

Data from two published and one new metaanalysis were reviewed to comp are the antiemetic efficacy of three different anaesthetic regimens: ( i) propofol anaesthesia compared with another anaesthetic (control); ( ii) anaesthesia without nitrous oxide compared with the same anaesthet ic with nitrous oxide (control); (iii) propofol anaesthesia without ni trous oxide (TIVA) compared with another anaesthetic with nitrous oxid e (control). Efficacy (prevention of postoperative nausea and vomiting compared with control) was estimated using odds ratio and number-need ed-to-treat methods, and compared within a range of 20-60% control eve nt rates for early efficacy (0-6 h) and 40-80% for late efficacy (0-48 h). Propofol anaesthesia or omitting nitrous oxide had similar effect s on vomiting, both early and late. Propofol (but not omitting nitrous oxide) decreased the incidence of nausea. TIVA studies were documente d poorly; appropriate comparisons with other interventions were not po ssible. Efficacy of treatments should be compared within a setting-spe cific range of control event rates. There is insufficient evidence tha t TIVA with propofol is an anaesthetic technique with a low emetogenic potency.