Saravolatz L D, Pohlod D J, Conway W, Haberaecker W, Markowitz N P, Popovich J
Am Rev Respir Dis. 1986 Aug;134(2):214-6. doi: 10.1164/arrd.1986.134.2.214.
Contaminated condensate might serve as a source for cross infection. Heat and moisture exchangers (HME) are devices that humidify inspired gases, which pass through a hygroscopic felt pad surrounded by a cellulose sponge housed in a plastic case. In our study, we used a Servo 150 HME in place of a cascade humidifier in mechanical ventilator circuits. We performed 2 studies to evaluate the microbiologic safety of the HME. First, 42 HMEs used by patients for 24 h were tested in the laboratory for contamination. To simulate patient/air exchange, the HMEs were connected to the Andersen Sampler (flow at 35 L/min x 20 min). Although the inner felt pad of the HMEs was contaminated in 74% of the units (31 of 42), only 4.8% (2 of 42) generated 1 to 2 bacteria/702 L of air. In a second study, HMEs contaminated with either Staphylococcus aureus or Pseudomonas aeruginosa (at 10(3), 10(5), or 10(8) organisms/ml) were connected to an Andersen Air Sampler to simulate a ventilator circuit. Bacterial aerosols were not generated, with the exception of 2 to 4 bacteria recovered after contamination with 10(8) bacteria. The HME can provide humidification for mechanically ventilated patients with little risk of generating respirable bacterial aerosols.
受污染的冷凝水可能成为交叉感染的源头。热湿交换器（HME）是一种用于对吸入气体进行加湿的装置，气体通过一个置于塑料外壳内、被纤维素海绵包围的吸湿毡垫。在我们的研究中，我们在机械通气回路中使用Servo 150热湿交换器替代级联加湿器。我们进行了两项研究以评估热湿交换器的微生物安全性。首先，对42个患者使用24小时后的热湿交换器在实验室进行污染检测。为模拟患者与空气的交换，将热湿交换器连接到安德森采样器（流量为35升/分钟×20分钟）。尽管74%（42个中的31个）的热湿交换器内部毡垫被污染，但只有4.8%（42个中的2个）每702升空气产生1至2个细菌。在第二项研究中，将被金黄色葡萄球菌或铜绿假单胞菌污染（污染浓度为每毫升10³、10⁵或10⁸个菌）的热湿交换器连接到安德森空气采样器以模拟通气回路。除了被10⁸个细菌污染后回收2至4个细菌外，未产生细菌气溶胶。热湿交换器可为机械通气患者提供加湿，产生可吸入细菌气溶胶的风险很小。
