Clinical Institute of Hospital Hygiene, Medical University of Vienna, Austria.
Am J Infect Control. 2011 Sep;39(7):e25-9. doi: 10.1016/j.ajic.2010.10.035. Epub 2011 Apr 15.
This study investigated the influence of the size of unidirectional ceiling distribution systems on counts of viable microorganisms recovered at defined sites in operating room (ORs) and on instrument tables during orthopedic surgery.
We compared bacterial sedimentation during 80 orthopedic surgeries. A total of 19 surgeries were performed in ORs with a large (518 cm × 380 cm) unidirectional ceiling distribution (colloquially known as laminar air flow [LAF]) ventilation system, 21 procedures in ORs with a small (380 cm × 120 cm) LAF system, and 40 procedures in ORs with no LAF system. Bacterial sedimentation was evaluated using both settle plates and nitrocellulose membranes.
Multivariate linear regression analysis revealed that the colony-forming unit count on nitrocellulose membranes positioned on the instrument table was significantly associated only with the size of the unidirectional LAF distribution system (P < .001), not with the duration of the surgical intervention (P = .753) or with the number of persons present during the surgical intervention (P = .291).
Our findings indicate that simply having an LAF ventilation system in place will not provide bacteria-free conditions at the surgical site and on the instrument table. In view of the limited number of procedures studied, our findings require confirmation and further investigations on the ideal, but affordable, size of LAF ventilation systems.
本研究调查了单向天花板分布系统的大小对手术室（OR）中特定位置和手术器械台上可培养微生物计数的影响，以及在骨科手术期间。
我们比较了 80 例骨科手术中的细菌沉降。共有 19 例在具有大（518 cm×380 cm）单向天花板分布（俗称层流空气 [LAF]）通风系统的 OR 中进行，21 例在具有小（380 cm×120 cm）LAF 系统的 OR 中进行，40 例在无 LAF 系统的 OR 中进行。使用沉降平板和硝酸纤维素膜评估细菌沉降。
多元线性回归分析显示，放置在器械台上的硝酸纤维素膜上的菌落形成单位计数仅与单向 LAF 分布系统的大小显著相关（P <.001），与手术干预持续时间（P =.753）或手术干预期间在场的人数（P =.291）无关。
我们的研究结果表明，仅仅安装 LAF 通风系统并不能在手术部位和器械台上提供无菌条件。鉴于研究的手术数量有限，我们的研究结果需要进一步确认和研究理想但负担得起的 LAF 通风系统的大小。
