Mobile laminar air flow screen for additional operating room ventilation: reduction of intraoperative bacterial contamination during total knee arthroplasty

Abstract

BackgroundSurgical site infections are important complications in orthopedic surgery. A mobile laminar air flow (LAF) screen could represent a useful addition to an operating room (OR) with conventional turbulent air ventilation (12.5 air changes/h), as it could decrease the bacterial count near the operating field. The purpose of this study was to evaluate LAF efficacy at reducing bacterial contamination in the surgical area during 34 total knee arthroplasties (TKAs).Materials and methodsThe additional unit was used in 17 operations; the LAF was positioned beside the operating table between two of the surgeons, with the air flow directed towards the surgical area (wound). The whole team wore conventional OR clothing and the correct hygiene procedures and rituals were used. Bacterial air contamination (CFU/m3) was evaluated in the wound area in 17 operations with the LAF unit and 17 without the LAF unit.ResultsThe LAF unit reduced the mean bacterial count in the wound area from 23.5 CFU/m3 without the LAF to 3.5 CFU/m3 with the LAF (P < 0.0001), which is below the suggested limit for an OR with ultraclean laminar ventilation. There were no significant differences in the mean bacterial count in the instrument table area: 28.6 CFU/m3 were recorded with the LAF (N = 6) unit and 30.8 CFU/m3 (N = 6) without the LAF unit (P = 0.631). During six operations with LAF and six without LAF, particle counts were performed and the number of 0.5 μm particles was analyzed. The particle counts decreased significantly when the LAF unit was used (P = 0.003).ConclusionWhen a mobile LAF unit was added to the standard OR ventilation, bacterial contamination of the wound area significantly decreased to below the accepted level for an ultraclean OR, preventing SSI infections.

Laminar air flow reduces particle load in TKA—even outside the LAF panel: a prospective, randomized cohort study

“…Another factor which is often discussed but has not yet been thoroughly examined, is the turbulent air flow occurring at the margin of the LAF panel or even inside the LAF area due to obstacles. Only few studies compare concentration of suspended particles depending on position inside the LAF area or examines particles as potential bacteria carriers in the operative arthroplasty setting [ 11 , 12 , 19 ]. No study currently examines the quantitative and qualitative particle load or its distribution during total knee arthroplasty (TKA) in comparison with or without working of LAF system.…”

Single-use instrumentation in posterior lumbar fusion could decrease incidence of surgical site infection: a prospective bi-centric study

“…This greatly reduces their risk of contamination by air-borne bacteria in the operating theatre, as would happen with standard instrumentation that it exposed on a table throughout the duration of surgery, and re-sterilized between operations. Contamination of instruments on tables in the operating theatre by air-borne bacteria remains a considerable cause of surgical site infections at present, despite advances in laminar air flow technology and surgical staff clothing, and textile or plastic field protection of surfaces [31][32][33][34].…”

Local and general ventilation system for an operating room with surgeons and patient

“…The range of the velocities that were studied were between 0.3÷0.5 m/s for the UAF and 0.3÷0.7 m/s for the MLAF. The range of velocity used for the UAF represents the typical ranges of velocity recommended by the literature (norms, books, clean rooms good practice guidelines) [18][19][20][24][25][26]. We didn't include in our analysis velocities lower than 0.3 m/s because it has been showed that for a typical height of 2.5 m for an OR, velocities ≤ 0.2 m/s may not overcome the thermal plumes from the occupants and the medical equipment [27][28][29].…”

“…The high energy consumption is due to the high air changes per hour recommended in the existing norms worldwide. The general goal of this study is to determine how the air flow from a unidirectional air flow (UAF) [15] system, also known as laminar air flow (LAF) [16] system, and a local ventilation system, similar to a mobile laminar air flow (MLAF) [17][18][19][20] system, will interact with each other. The study analyzes the air circulation near the operating table at different air flow velocities from both systems.…”