Background:Unidirectional displacement flow (UDF) ventilation systems in operating rooms are characterized by a uniformity of velocity ≥80% and protect patients and operating room personnel against exposure to hazardous substances. However, the air below the surgical lights and in the surrounding zone is turbulent, which impairs the ventilation system’s effect.Aim:We first used the recovery time (RT) as specified in International Organization for Standardization 14644 to determine the particle reduction capacity in the turbulent spaces of an operating room with a UDF system.Methods:The uniformity of velocity was analyzed by comfort-level probe grid measurements in the protected area below a hemispherical closed-shaped and a semi-open column-shaped surgical light (tilt angles: 0°/15°/30°) and in the surrounding zone of a research operating room. Thereafter, RTs were calculated.Results:At a supply air volume of 10,500 m3/h, the velocity, reported as average uniformity ± standard deviation, was uniform in the protected area without lights (95.8% ± 1.7%), but locally turbulent below the hemispherical closed-shaped (69.3% ± 14.6%), the semi-open column-shaped light (66.9% ± 10.9%), and in the surrounding zone (51.5% ± 17.6%). The RTs ranged between 1.1 and 1.7 min below the lights and 3.5 ± 0.28 min in the surrounding zone and depended exponentially on the volume flow rate.Conclusions:Compared to an RT of ≤20 min as required for operating rooms with mixed dilution flow, particles here were eliminated 12–18 times more quickly from below the surgical lights and 5.7 times from the surrounding zone. Thus, the effect of the lights was negligible and the UDF’s retained its strong protective effect.

中文翻译：

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手术室湍流空间中单向置换流通风的感染预防及防护效果


背景：手术室中的单向置换流 (UDF) 通风系统的特点是速度均匀度≥80%，可保护患者和手术室人员免受有害物质的影响。然而，手术灯下方及周围区域的空气处于湍流状态，这会损害通风系统的效果。目的：我们首先使用国际标准化组织14644中规定的恢复时间（RT）来确定手术灯中的颗粒减少能力。方法：通过在半球形封闭形和半开放柱形手术灯下方的保护区内的舒适度探头网格测量来分析速度的均匀性（倾斜角度： 0°/15°/30°）以及研究手术室的周围区域。此后，计算 RT。结果：送风量为 10,500 m 时3 /h，速度报告为平均均匀度±标准偏差，在无光保护区内是均匀的（95.8％±1.7％），但在半球形封闭形状下方局部湍流（69.3％±14.6％），半球形开放柱形光（66.9%±10.9%），以及周围区域（51.5%±17.6%）。 RT 范围在灯光下方 1.1 至 1.7 分钟之间，周围区域为 3.5 ± 0.28 分钟，并且与体积流量成指数关系。结论：与混合稀释流手术室所需的 ≤ 20 分钟 RT 相比，颗粒物从手术灯下方消除的速度快 12-18 倍，从周围区域消除的速度快 5.7 倍。因此，灯光的影响可以忽略不计，UDF 保留了其强大的保护作用。