Surgical Smoke and Airborne Microbial Contamination in Operating Theatres: Influence of Ventilation and Surgical Phases

Abstract

Air cleanliness is a crucial factor in operating theatres (OTs), where the health of patients and staff must be preserved by controlling air contamination. Particular attention must be paid to ultrafine particles (UFPs) size range, generated for instance by electrosurgical instruments (ESTs). OT contamination is also affected by ventilation systems, medical staff and their gowning system, staff routines, instruments, etc. This comparative study is based on experimental measurements of airborne microbial contamination and UFPs carried out during real ongoing surgeries in two OTs equipped with upward displacement ventilation (UWD) and hybrid ventilation, with unidirectional airflow on the operating table and peripheral mixing (UDAF+Mixing) ventilation systems. Airborne contamination concentration at the exit grilles has been analyzed as function of four different surgical phases normally performed during an operation. Results highlight that airborne contamination is influenced by the activities carried out during the surgical phases. EST usage affects the contamination level more than staff size during operation observed. Colony forming unit (CFU) values in the protected area close to the patient’s wound are influenced more by the type of ventilation system than by surgical phases. CFU values decrease by 18 to 50 times from the UWD system to the hybrid one. The large airflow volumes supply together with high air velocities in OTs equipped with UDAF+Mixing systems guarantee a better and a safer airborne contamination control for patients and medical team in comparison with UWD systems.

Influence of the Built Environment on Airflow, Contamination, and Infection in the Operating Room: A Systematic Literature Review

“…One study stood out due to its investigation of upward displacement ventilation (UWD), which was compared to downward unidirectional airflow (UDF) combined with mixing ventilation. 108 This study ultimately found that the microbial contamination in operating rooms equipped with UWD averaged around 27 CFU/m 3 , as opposed to the average 1 CFU/m 3 found in UDF ORs; whether this result was statistically significant was not specified. Two of the 11 articles only reported particle concentrations as the outcome of their study.…”

“…Of the 46 studies on OR ventilation that were based on empirical data, 22 did not investigate LAF. 7,22,[98][99][100][101][102][103][105][106][107][108]46,109,110,53,66,70,[94][95][96][97] It is important to note that the conflicting way in which authors use the term "unidirectional airflow" may have led to an underestimate of the number of papers that investigated LAF. Some authors equate unidirectional airflow with LAF and use these terms interchangeably, while others do not; some studies explicitly differentiate between the two.…”

Operating Theatre Ventilation Systems and Their Performance in Contamination Control: “At Rest” and “In Operation” Particle and Microbial Measurements Made in an Italian Large and Multi-Year Inspection Campaign

“…The fabric quality of the medical team gowning systems and the covering of equipment and surgical tools (e.g., cotton vs. polyester/TNT) can deeply influence the contamination emission rate [33], and affect the final contaminant concentrations. A further limitation may result from the different type of surgical operations monitored and the use of electrosurgical tools during operations [34,35,43].…”

“…The efficiency of a ventilation system is influenced by multiple factors, such as the position of the operating table, the operating team, the surgical lamps, the type of personnel clothing systems, the surgical equipment [18,[32][33][34][35], and the frequency of door opening. The surgical procedures [8] and the local risk assessment adopted for preventing SSI [18] also present particular relevance, as confirmed by recent studies on MAF [1,12,36,37] and P-UDAF systems [1,8,12,[38][39][40][41][42].…”

Exposure of operating room surgical staff to surgical smoke under different ventilation schemes

“…Romano et al measured 23 the concentration during 13 real surgical operations in two operating rooms with different ventilation schemes: one operating room with an upward displacement flow (DV) with an air change rate of 19 1/h and the other, a hybrid operating room equipped with UDAF above the surgical table (air change rate of 48 1/h) in combination with mixing ventilation diffusers in the peripheral area outside the UDAF zone (9 1/h), resulting in a total air change rate of 57 1/h. The concentration of ultrafine particles in the size range of 0.02–1 µm was measured in one of four extract openings during the operations.…”