The aim of this study was to assess the influence of the true operating room (OR) ventilation on the risk of revision due to infection after primary total hip arthroplasty (THA) reported to the Norwegian Arthroplasty Register (NAR). 40 orthopedic units were included during the period 2005 – 2015. The Unidirectional airflow (UDAF) systems were subdivided into small-area, low-volume, vertical UDAF (lvUDAF) (volume flow rate (VFR) (m3/hour) <=10,000 and diffuser array size (DAS) (m2) <=10); large-area, high-volume, vertical UDAF (hvUDAF) (VFR >=10,000 and DAS >=10) and Horizontal UDAF (H-UDAF). The systems were compared to conventional, turbulent ventilation (CV) systems. The association between revision due to infection and OR ventilation was assessed using Cox regression models, with adjustments for sex, age, indication for surgery, ASA-classification, method of fixation, modularity of the components, duration of surgery, in addition to year of primary THA. All included THAs received systemic, antibiotic prophylaxis.Aim
Method
The aim of this study was to validate the information on operating room ventilation reported to the Norwegian Arthroplasty Register (NAR) and to assess the influence of this ventilation on the risk of revision due to infection after primary total hip arthroplasty (THA). Current and previous ventilation systems were evaluated together with the hospitals head engineer in 40 orthopaedic hospitals. The ventilation system of each operating room was assessed and confirmed as either conventional ventilation, vertical laminar airflow (LAF) or horizontal LAF. We then identified cases of first revision due to deep infection after primary THA and the type of ventilation system reported to the NAR in the period 1987–2014. The association between revision due to infection and operating room ventilation was estimated by relative risks (RR) in a Cox regression model.Aim
Method
The aim of this study was to validate the information on operating room ventilation reported to the Norwegian Arthroplasty Register (NAR). We then wanted to assess the influence of operating room ventilation on the rate of revision due to infection after primary THA performed in operating rooms with conventional ventilation, “greenhouse”–ventilation and Laminar Airflow ventilation (LAF). We identified cases of THA revisions due to deep infection and the type of ventilation system reported to the NAR from the primary THA. We included 5 orthopaedic units reporting 17947 primary THAs and 136 (0.8%) revisions due to infection during the 28 year inclusion period from 1987 to 2014. The hospitals were visited and the current and previous ventilation systems were evaluated together with the hospitals head engineer, and the factual ventilation on the specific operating rooms was thereby assessed. The association between revision due to infection and operating room ventilation was estimated by calculating relative risks (RR) in a Cox regression model. 73% of the primary THAs were performed in a room with LAF, in contrast to the reported 80 % of LAF. There was similar risk of revision due to infection after THA performed in operating rooms with laminar air flow compared to conventional ventilation (RR=0.7, 95 % CI: 0.2–2.3) and after THA performed in operating rooms with “greenhouse”-ventilation compared to conventional ventilation (RR=1.2, 0.1–11). Surgeons are not fully aware of what kind of ventilation there is in the operating room. This study may indicate that, concerning reduction in incidence of THA infection, LAF does not justify the substantial installation cost. The numbers in the present study are too small to conclude strongly. Therefore, the study will be expanded to include all hospitals reporting to the NAR.
