Department of Anaesthesia, Critical Care and Pain Medicine, University of Edinburgh, Royal Infirmary of Edinburgh, Edinburgh, UK.
Anaesthesia. 2010 Jul;65(7):670-3. doi: 10.1111/j.1365-2044.2010.06327.x. Epub 2010 Apr 1.
Invasive ventilation poses a risk of respiratory infection that can be drug-resistant. One means of reducing transmission of infection is the use of a breathing system filter. Filters are intended to be used with dry gas. Current international standards do not require that filters prevent bacterial transfer when wet. It is not known whether microorganisms pass through wet filters, but theory predicts that this might occur. We tested six filters from three different manufacturers. We passed a suspension of microorganisms through the filters using the least pressure necessary, and incubated a sample of the filtrate on blood agar. All the filters tested allowed free passage of both Candida albicans and coagulase-negative staphylococci. The median (IQR [range]) pressure required for fluid to flow across the filter varied greatly between different filter types (20 (0-48 [0-138]) cmH(2)O). We conclude that even large microorganisms pass across moist breathing system filters in conditions that are found in clinical practice.
有创通气存在发生耐药性呼吸道感染的风险。一种减少感染传播的方法是使用呼吸回路过滤器。过滤器旨在与干燥气体一起使用。目前的国际标准并不要求过滤器在潮湿时阻止细菌转移。尚不清楚微生物是否会通过湿的过滤器，但理论上预测可能会发生这种情况。我们测试了来自三个不同制造商的六个过滤器。我们使用所需的最小压力使微生物混悬液通过过滤器，并将滤过液的样本接种于血琼脂平板上培养。所有测试的过滤器均允许白色念珠菌和凝固酶阴性葡萄球菌自由通过。穿过过滤器的液体所需的压力中位数（IQR [范围]）在不同的过滤器类型之间差异很大（20（0-48 [0-138]）cmH2O）。我们的结论是，即使是大的微生物也会在临床实践中发现的潮湿条件下穿过湿润的呼吸回路过滤器。
