title: Changing patterns in anesthetic fresh gas flow rates over 5 years in a teaching hospital.
abstract: BACKGROUND
  Reducing anesthetic fresh gas flows can reduce volatile anesthetic consumption without affecting drug delivery to the patient. Delivery systems with electronic flow transducers permit the simple and accurate collection of fresh gas flow information. In a 2001 audit of fresh gas flow, we found little response to interventions designed to foster more efficient use of fresh gas. We compared current practice with our earlier results.
  
  
  METHODS
  Flow data were collected in areas with a mix of general and acute surgery in March and November 2001, and again during 2006, by recording directly from the Datex ADU to a computer every 10 s. We extracted the distribution of flow rates when a volatile anesthetic was being administered. Data collection in March 2001 and 2006 was not advertised.
  
  
  RESULTS
  In 2001, the mean flow rates were 1.95 and 2.1 L/min with a median flow of 1.5 L/min. In 2006, the mean was 1.27 and the median in the range 0.5-1.0 L/min. Isoflurane use decreased from 47% in 2001 to 4% in 2006.
  
  
  CONCLUSIONS
  Fresh gas flows used in our department have decreased by 35% over 4 years. Although the absolute change in flow rate is not large, this represents potential annual savings of more than $US130,000. This occurred without specific initiatives, suggesting an evolution in practice towards lower fresh gas flow. Improvements in equipment and monitoring, including a locally developed system, which displays forward predictions of end-tidal and effect-site vapor concentrations, may be factors in this change.
authors.affiliation: Department of Anaesthesia, Christchurch Hospital and University of Otago, Christchurch, Rolleston Ave., Christchurch, New Zealand. ross.kennedy@chmeds.ac.nz
authors.forename: R Ross
authors.initials: RR
authors.lastname: Kennedy
authors.forename: Richard A
authors.initials: RA
authors.lastname: French
mesh_terms: D000761:Anesthesia Department, Hospital / Q000191:economics / Q000706:statistics & numerical data*; D000764:Anesthesia, Closed-Circuit / Q000191:economics / Q000295:instrumentation / Q000639:trends*; D018685:Anesthetics, Inhalation / Q000191:economics; D017046:Cost Savings; D016527:Drug Costs; D004867:Equipment Design; D006784:Hospitals, Teaching / Q000191:economics / Q000706:statistics & numerical data*; D006801:Humans; D008485:Medical Audit; D009520:New Zealand; D010818:Practice Patterns, Physicians' / Q000639:trends*; D012815:Signal Processing, Computer-Assisted; D013997:Time Factors; D014159:Transducers
chemical_list: D018685:Anesthetics, Inhalation