Efficacy of Temperature-Controlled Airflow in Maintaining Ultraclean Conditions throughout the Operating Room

ABSTRACT

Thirty years of evidence supports the efficacy of ultra-clean air in preventing surgical site infection (SSI). Ultraclean is defined as fewer than 10 Colony Forming Units (CFUs) per cubic meter or <10CFU/m3 (35ft3) However, achieving and maintaining ultraclean conditions in the contemporary operating room has proven challenging. For decades, Laminar Air Flow (LAF) systems were recommended for use in rooms where infection sensitive joint arthroplasty procedures are performed. But, a growing body of evidence has called the efficacy of LAF in prevention of these infections into question. As a result, CD C no longer recommends use of LAF for joint arthroplasty. The WHO has gone a step further issuing a conditional recommendation against its use in these procedures. At the same time, demand for total hip and knee arthroplasties are expected to grow exponentially over the next decade and for reasons that are unclear rates of prosthetic joint infection (PJI) are on the rise. Taken together, these factors suggest that the time has come to rethink management of airborne contamination and ventilation technology in the operating room. Temperature-controlled Air Flow (TcAF) is a novel ventilation technology that has been proven to maintain ultra-clean conditions throughout the entire operating room. TcAF uses continuous HEPA filtration and combines a robust central unidirectional down-flow driven by gravity from a temperature gradient together with mixing ventilation in the periphery of the room. While TcAF has been scientifically validated to maintain ultra-clean conditions of <10CFU/m3(35ft3) throughout the entire operating room, the impact of TcAF on prevention of surgical site infection was unknown. The aim of this study was to evaluate the efficacy of TcAF on prosthetic joint infection (PJI). A retrospective case control study was performed with 1,000 consecutive cases of primary total joint arthroplasty before and 1,000 consecutive cases after the installation of an ultra-clean TcAF system. TcAF was associated with a statistically significant reduction in surgical site infection. With reduction in surgical site infection proving to be ever more challenging and demand for infection sensitive procedures rising, more rigorous attention to airborne contamination may represent a new pathway to improvement. While not the focus of this paper, the advent of Covid-19 should bring into greater focus the risk of airborne transmission andfurther incentiviņe mitigation.