Background: There is increasing need to perform invasive surgical procedures in intensive care units (ICUs). Traditional ICUs differ from operating rooms (ORs) in several ways including air changes per hour (ACH) and pressurization. Increased ACH and positive pressurization of ORs intend to provide more aseptic environments for surgery. Development of procedure ready ICUs that transition through unoccupied, occupied, and procedure modes is one solution to improve environmental quality when performing surgery in ICUs. This study assessed the efficacy of two airflow control systems, variable air volume (VAV) and Venturi control, in preventing contaminants from entering ICU from adjacent corridors.
Study design: Controlled contaminants, sulfur hexafluoride (SF6) and baker's yeast (CFU/m3), were released in the corridor adjacent to the ICU. SF6 and CFU/m3 were detected inside the ICU at the patient bed during a dynamic simulation of code blue event. VAV and Venturi were compared as they cycled the room through unoccupied, occupied, and procedure modes.
Results: VAV and Venturi showed significantly fewer CFU/m3 at the patient bed than corridor point of release (p < .05). Although not significant, Venturi cultured 14% fewer CFU/m3 than VAV at the patient bed. There was less SF6 detected at the patient bed with VAV and Venturi (p < .05). There was less SF6 detected at the patient bed with Venturi compared to VAV (p < .05). Venturi transitioned between modes faster than VAV (p < .05).
Conclusion: Using efficient mode transitioning systems in ICUs may be effective in creating a more aseptic environment that mimics that of the OR.
Keywords: ACH; American Society of Heating; Refrigeration and Air Conditioning Engineers; Venturi valve; and air conditioning; environmental quality indicators (EQI); heating; procedure ready ICU room; room pressure; variable air volume (VAV); ventilation.