Aim: 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.

Method: 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.

Conclusion: 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.