1: Anesthesiology 1996 Nov;85(5):1055-62

Omission of nitrous oxide during anesthesia reduces the incidence of
postoperative nausea and vomiting. A meta-analysis.

Divatia JV, Vaidya JS, Badwe RA, Hawaldar RW

Department of Anesthesiology, Tata Memorial Hospital, Bombay, India.
root@tmc.ernet.in

BACKGROUND: Postoperative nausea and vomiting are important causes of morbidity
after general anesthesia. Nitrous oxide has been implicated as an emetogenic
agent in many studies. However, several other trials have failed to sustain this
claim. The authors tried to resolve this issue through a meta-analysis of
randomized controlled trials comparing the incidence of postoperative nausea and
vomiting after anesthesia with or without nitrous oxide. METHODS: Of 37
published studies retrieved by a search of articles indexed on the MEDLINE
database from 1966 to 1994, 24 studies (26 trials) with distinct nitrous-oxide
and non-nitrous oxide groups were eligible for the meta-analysis. The pooled
odds ratio and relative risk were calculated. Post boc subgroup analysis was
also performed to qualify the result. RESULTS: The pooled odds ratio was 0.63
(0.53 to 0.75). Omission of nitrous oxide reduced the risk for postoperative
nausea and vomiting by 28% (18% to 37%). In the subgroup analysis, the maximal
effect of omission of nitrous oxide was seen in female patients. In patients
undergoing abdominal surgery and general surgical procedures, the effect of
omission of nitrous oxide, although in the same direction, was not significant.
CONCLUSION: Omission of nitrous oxide reduced the odds of postoperative nausea
and vomiting by 37%, a reduction in risk of 28%.

Publication Types:
Meta-analysis

PMID: 8916823, UI: 97074396