Aerobiology in the operating room and its implications for working standards

Area of Science:

• Healthcare Engineering
• Infection Control
• Environmental Microbiology

Background:

• Operating room (OR) ventilation is critical for maintaining sterile environments.
• Novel ventilation systems aim to improve air quality and reduce surgical site infections.
• Evaluating bacteriological performance of new OR ventilation is essential.

Purpose of the Study:

• To compare the bacteriological efficacy of two novel OR ventilation systems against conventional methods.
• To assess thermal convection and exponential laminar air flow (LAF) systems.
• To determine their impact on airborne and surface bacterial contamination.

Main Methods:

• Bacteriological evaluation of thermal convection (17 air changes/h) versus conventional ventilation (16 air changes/h).
• Comparison of exponential LAF (no extra walls) with vertical and horizontal LAF (with extra walls).
• Standardized simulated operations conducted in the same OR to minimize variables.

Main Results:

• The thermal convection system showed a 2-3 fold increase in bacterial counts compared to conventional ventilation (p < 0.05-0.0001).
• Exponential LAF systems demonstrated equal bacteriological efficiency to traditional LAF units, meeting ultra-clean air criteria (<10 bacteria/m³).
• Turbulent systems showed a significant correlation between air and surface contamination (p < 0.02-0.0006), unlike LAF systems.

Conclusions:

• The thermal convection system is less effective than conventional ventilation for bacterial control in ORs.
• Exponential LAF systems offer an effective ultra-clean air solution without requiring additional OR walls.
• LAF technology minimizes the correlation between air and surface contamination, enhancing surgical asepsis.