To the Editor:
There are many good reasons to encourage reduced fresh gas flows during the administration of volatile anesthetic agents. The recent publication by Nair et al.1
outlines these issues and addresses the twin problems of producing and maintaining a change in fresh gas flows across a large group of providers. Their article then goes on to describe an elegant and robust approach to achieve these objectives.
In the introduction to their article, Nair et al.
state that “… providers reverted to original behavior over time,” and cite a number of references to support this. In one of our publications on this topic,2
we found that flow rates continued to decrease over a 5-yr period in the absence of any specific intervention. We have unpublished data showing this trend has continued. We attribute this reduction to a locally developed predictive display system,3
which allows the user to easily see the consequence of any combination of fresh gas flow rate and vaporizer setting, along with an indicator of the vapor cost thus simplifying and incentivizing flow reduction.
Although we agree that most studies show that flow rates return to normal, our observations suggest that decision support tools that guide drug administration can be used to enable and support practice in addition to those tools that provide reminders based on monitoring practice.
R. Ross Kennedy, M.B., Ch.B., Ph.D., F.A.N.Z.C.A.,* Richard A. French, M.B., B.S., F.A.N.Z.C.A.
*University of Washington, Seattle, Washington.firstname.lastname@example.org
1. Nair BG, Peterson GN, Neradilek MB, Newman SF, Huang EY, Schwid HA. Reducing wastage of inhalation anesthetics using real-time decision support to notify of excessive fresh gas flow. ANESTHESIOLOGY. 2013;118:874–84
2. Kennedy RR, French RA. Changing patterns in anesthetic fresh gas flow rates over 5 years in a teaching hospital. Anesth Analg. 2008;106:1487–90
3. Kennedy RR, McKellow MA, French RA. The effect of predictive display on the control of step changes in effect site sevoflurane levels. Anaesthesia. 2010;65:826–30
4. Kennedy RR, French RA. The development of a system to guide volatile anaesthetic administration. Anaesth Intensive Care. 2011;39:182–90
© 2013 American Society of Anesthesiologists, Inc.