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Updated: Jan 9, 2026
Conducting Respiratory Oscillometry in an Outpatient Setting
Published on: April 8, 2022
Measuring dynamic air quality in clean operating rooms using three methods: a prospective study
Mingyue Fu1, Ying Zhang2, Jin Hu3
1Intensive Care Unit, China-Japan Friendship Hospital, Beijing, China.
Background:
perating rooms (ORs) are critical environments where air quality directly impacts surgical site infection (SSI) rates.
Aim:
To characterise dynamics of airborne contamination and identify risk factors in operating rooms during surgery.
Methods:
A prospective observational study was conducted in three Class III (International Organization for Standardization (ISO) Class 7) clean gastrointestinal (GI) ORs at a tertiary hospital (China-Japan Friendship Hospital, Beijing) between March and April 2025. Thirty consecutive laparoscopic GI surgeries were monitored. Airborne bacteria, settling bacteria, and airborne particle counts were measured at four critical intraoperative phases: turnover-Anaesthesia-Disinfection (T1), Skin Incision (T2), 1 Hour into Surgery (T3), and Wound Closure (T4). Concurrently, personnel numbers and cumulative door openings were recorded.
Findings:
Significant temporal variations occurred in all air quality parameters (P < 0.001). Airborne and settling bacteria concentrations peaked significantly at T4, exceeding levels at T2 (P < 0.001) and T3 (P < 0.001). Airborne bacteria at T1 were significantly higher than at T3 (P < 0.001). Particle counts for all sizes were highest at T3, significantly surpassing T1 and T2 (P < 0.001 for 0.3 μm, 0.5 μm, 1.0 μm; P < 0.0083 for others). Door opening frequency was highest at T4 and T1. Overall dynamic air quality compliance was 93.33% (28/30). Compliance was 100% at T2 and T3, 96.67% at T1, and 93.33% at T4.
Conclusion:
Cleanroom OR air quality is highly dynamic, with distinct contamination peaks: microbial loads surge during wound closure (T4), while particulate matter peaks mid-surgery (T3). These peaks correlate strongly with increased door openings and activity levels. Current static standards inadequately reflect intraoperative contamination risks. Mandatory real-time dynamic monitoring during high-risk phases (T1, T3, and T4) and stringent protocols to minimise door openings are essential for effective SSI prevention.
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