Reinforcing a "low flow" anaesthesia policy with feedback can produce a sustained reduction in isoflurane consumption

A three-month audit of isoflurane consumption at Palmerston North Hospital in 1994 showed an averaged vapour flow rate of approx 85 ml per minute of anaesthesia, equivalent to 1.4% isoflurane at six litres per minute. After purchasing volatile agent analysers, a program encouraging low flow anaesthesia and providing a report of the previous month's consumption rate was started in July 1996. The isoflurane averaged vapour flow rate was tracked over the following twenty-month period and fell by a sustained 65% to range around 30 +/- 5 ml/min, producing savings of approximately NZ$104,000 over this period.