Air Contamination in Operating Theatres: The Key Factors That Can Influence It.

Area of Science:

• Microbiology
• Hospital Infection Control
• Environmental Monitoring

Background:

• Surgical site infections (SSIs) are a significant concern, increasing patient morbidity, mortality, and healthcare costs.
• Adequate ventilation and air filtration in operating theatres are crucial for preventing SSIs.
• Factors beyond ventilation, such as personnel presence and door management, may also impact airborne contamination.

Purpose of the Study:

• To assess the impact of the number of operators and door status on microbiological airborne contamination in operating rooms.
• To investigate the correlation between air changes and airborne microbial load.
• To determine the relationship between environmental factors and bacterial colony counts at different incubation temperatures.

Main Methods:

• Analysis of 105 operational control reports from Siena's Teaching Hospital (2018-2021).
• Spearman correlation analysis to relate colony counts (at 22°C and 36°C) to air changes and operator numbers.
• Mann-Whitney test to compare colony counts with doors open versus closed.

Main Results:

• Colony counts at 22°C correlated only with air changes (Spearman ρ = -0.441, p < 0.001).
• Colony counts at 36°C correlated with air changes (ρ = -0.394, p < 0.001) and operator numbers (ρ = +0.249, p = 0.011).
• Significant differences in colony counts at 36°C were observed between open and closed doors (p = 0.013), and between laminar and turbulent airflow rooms (p < 0.001).

Conclusions:

• Continuous monitoring of airflows, door status, and operator numbers is essential for predicting and controlling airborne contamination.
• Implementing strategies based on these monitored factors can aid in the prevention of surgical site infections.
• Optimizing operating room environmental conditions is key to reducing the risk of hospital-acquired infections.