A survey of the choice of general anaesthetic agents in Australia and New Zealand

Strategies to reduce the adverse environmental costs of anaesthesia include choice of agent and fresh gas flows. The current preferences of Australian and New Zealand anaesthetists are unknown. We conducted a survey of Australian and New Zealand anaesthetists to determine the use of volatiles, nitrous oxide and intravenous anaesthesia, lowest fresh gas flow rates, automated end-tidal volatile control, and the rationales for these choices. The survey was answered by 359/1000 (36%), although not all questions and multiple responses within single questions were answered by all respondents. Sevoflurane was preferred by 246/342 (72%, 95% confidence interval (CI) 67%-77%), followed by propofol, 54/340 (16%, 95% CI 12%-20%), desflurane 39/339 (12%, 95% CI 8%-16%) and isoflurane 3/338(1%, 95% CI 0-3%). When asked about all anaesthetics, low-risk clinical profile was the most common reason given for using sevoflurane (129/301 (43%, 95% CI 37%-49%)), reduced postoperative nausea for propofol (297/318 (93%, 95% CI 90%-96%)) and faster induction/awakening times for desflurane (46/313 (79%, 95% CI 74%-83%)). Two-thirds (226/340 (66%, 95% CI 61%-71%)) of respondents used nitrous oxide in 0-20% of general anaesthetics. Low fresh gas flow rates for sevoflurane were used by 310/333 (93%, 95% CI 90%-95%) and for 262/268 (98%, 95% CI 95%-99%) for desflurane. Automated endtidal control was used by 196/333 (59%, 95% CI 53%-64%). The majority of respondents (>70%) preferred sevoflurane at low flows. These data allow anaesthetists to consider further whether changes are required to the choices of anaesthetic agents for environmental, financial, or any other reasons.