title: Microbiological safety and cost-effectiveness of weekly breathing circuit changes in combination with heat moisture exchange filters: a prospective longitudinal clinical survey.
abstract: OBJECTIVE
  To assess the safety and cost effectiveness of a usage for seven days of breathing circuit systems (BCSs) in combination with heat moisture exchanger filters (HMEF) in operation room anesthesia.
  
  
  METHODS
  In a prospective longitudinal clinical study, the contamination on high-risk surfaces (HMEF together with inner and outer surface of BCS) was monitored over 1, 2, 5, and 7 days. RESULTS of endogenous respiratory patient flora and contamination flora of BCS, HMEF and bag were compared. Costs of prolonged use of BCS together with HMEF up to 7 days were calculated.
  
  
  RESULTS
  Neither physiological respiratory flora nor colonizing pathogens of the oropharynx of the ventilated patients were transmitted through the filters at any time. None of the included patients developed a postoperative pneumonia. Using the BCS for 24 hours provides a cost savings of up to 40% versus single use. Extending the change interval from 24 hours to 48 hours saved over 50% compared to change after each patient, and an additional 19% compared to change after 24 hours. In combination with a HMEF BCS can be used up to 7 days without clinical risk on multiple patients in operation room settings.
  
  
  CONCLUSIONS
  Expanding the usage of berating in combination with usage of moist exchange filters is feasible, microbiologically safe and cost effective, as 41% of material costs per ventilation may be saved. Further research is needed to confirm these results.
authors.affiliation: Institute of Hygiene and Environmental Medicine, University Medicine Greifswald, Greifswald, Germany.
authors.forename: Nils-Olaf
authors.initials: NO
authors.lastname: Hübner
authors.forename: Georg
authors.initials: G
authors.lastname: Daeschlein
authors.forename: Christian
authors.initials: C
authors.lastname: Lehmann
authors.forename: Sergei
authors.initials: S
authors.lastname: Musatkin
authors.forename: Ute
authors.initials: U
authors.lastname: Kohlheim
authors.forename: Andreas
authors.initials: A
authors.lastname: Gibb
authors.forename: Ojan
authors.initials: O
authors.lastname: Assadian
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Kobayashi