Better Operating Room Ventilation as Determined by a Novel Ventilation Index is Associated With Lower Rates of Surgical Site Infections

Abstract

Objective: The aim was to assess the impact of operating room (OR) ventilation quality on surgical site infections (SSIs) using a novel ventilation index. Background: Previous studies compared laminar air flow with conventional ventilation, thereby ignoring many parameters that influence air flow properties. Methods: In this cohort study, we surveyed hospitals participating in the Swiss SSI surveillance and calculated a ventilation index for their ORs, with higher values reflecting less turbulent air displacement. For procedures captured between January 2017 and December 2019, we studied the association between ventilation index and SSI rates using linear regression (hospital-level analysis) and with the individual SSI risk using generalized linear mixed-effects models (patient-level analysis). Results: We included 47 hospitals (182 ORs). Among the 163,740 included procedures, 6791 SSIs were identified. In hospital-level analyses, a 5-unit increase in the ventilation index was associated with lower SSI rates for knee and hip arthroplasty (−0.41 infections per 100 procedures, 95% confidence interval: −0.69 to −0.13), cardiac (−0.89, −1.91 to 0.12), and spine surgeries (−1.15, −2.56 to 0.26). Similarly, patient-level analyses showed a lower SSI risk with each 5-unit increase in ventilation index (adjusted odds ratio 0.71, confidence interval: 0.58-0.87 for knee and hip; 0.72, 0.49-1.06 for spine; 0.82, 0.69-0.98 for cardiac surgery). Higher index values were mainly associated with a lower risk for superficial and deep incisional SSIs. Conclusions: Better ventilation properties, assessed with our ventilation index, are associated with lower rates of superficial and deep incisional SSIs in orthopedic and cardiac procedures. OR ventilation quality appeared to be less relevant for other surgery types.

Quantifying and Interpreting Inequality in Surgical Site Infections per Quarter Among Anesthetizing Locations and Specialties

“…Although Figure 2 appears impressive in that it shows 10% of combinations of anesthetizing location and specialty accounted for 76% of infections, generally a hospital cannot target a specialty for infection prevention by location unless the location is used exclusively for the specialty. For example, while greater operating room ventilation (e.g., through the use of single large diffusers) may be beneficial for orthopedic trauma surgery [12,38], operating room ventilation systems are installed in operating rooms, not in locations for the exclusive use of one specialty. Results for a combination of location and specialty are useful for reducing the fixed costs of clinical trials aiming to reduce S. aureus (or other pathogens) transmission and surgical site infections [2,[4][5][6].…”

Perspectives on research needs in healthcare epidemiology, infection prevention, and antimicrobial stewardship: what’s on the horizon—Part II

“…An example from our own experience is a study into the effect of operation room ventilation on SSIs, for which we worked with a team of ventilation engineers. 10 Owing to this collaboration, we were able to identify the need for a straightforward descriptor of ventilation quality in operating rooms. Very likely, this need would not have been recognized by either collaboration partner alone.…”

Bone Cement Fumes Generated in Laminar Airflow Versus Conventionally Ventilated Operating Rooms

“…LAF systems continuously filter, circulate, and remove clean air in a uniform current. The efficacy of LAF in reducing the rate of surgical site infections in orthopaedic procedures has been investigated in depth, yielding a wide array of results [5][6][7][8][9] . CV is a mixed airflow system that introduces highefficiency particulate filtered air into the OR through a perforated plate system above the sterile field with removal through wall vents, although such removal can still be turbulent 10 .…”