a Center for Health-Related Aerosol Studies, Department of Environmental Health, College of Medicine , University of Cincinnati , Cincinnati , Ohio.
b University of Eastern Finland , Department of Environmental and Biological Sciences , Kuopio , Finland.
J Occup Environ Hyg. 2018 Aug;15(8):607-615. doi: 10.1080/15459624.2018.1479065.
Millions of workers, including firefighters, use respiratory protective device. The key aspect in assuring the intended protection level of a respirator is its fit. However, even if the respirator originally fits well, the faceseal may be breached during its use. Until now, there have been no practically viable, inexpensive means to monitor the performance of a respirator during actual use. A novel Respirator Seal Integrity Monitor (ReSIM) was developed and recently evaluated on manikins by our team. The objective of this study was to evaluate the ReSIM effectiveness on respirator-wearing firefighters exposed to aerosols while performing simulated routine operational activities. Initially, 15 subjects were recruited for the study. Following a preliminary investigation that resulted in modifications in the ReSIM prototype and testing protocol, a subset of nine firefighters was chosen for a full-scale evaluation. The testing was conducted in a 24.3-m exposure chamber using NaCl as the challenge aerosol. Controlled faceseal leaks were established by opening a solenoid valve for 10, 15, or 20 sec. Leaks were also established as the tested firefighter slightly repositioned the respirator on his/her face. During the testing, the ReSIM measured particles inside a full-face elastomeric respirator with a 72.7% leak detection sensitivity (probability of correct leak identification) and an 84.2% specificity (probability of correct identification of the intervals which are absent of any leak). After adjusting for false negatives and persistent false positives, sensitivity and specificity increased to 83.6% and 92.2%, respectively. The factors causing minor limitations in leak detection sensitivity and specificity can be attributed to variability among subjects, moisture's effect on the particle sensor, and some in-mask sampling bias. In conclusion, the ReSIM can promptly detect the breach in a respirator faceseal with high sensitivity and specificity. Due to its capability to alert the wearer of possible overexposure to hazardous aerosols, the ReSIM concept has a remarkable potential to be applied in various working environments, where respirators are used.
数以百万计的工人，包括消防员，使用呼吸防护设备。确保呼吸器预期防护水平的关键方面是其适配性。然而，即使呼吸器最初适配良好，在使用过程中面部密封也可能会被破坏。到目前为止，还没有实际可行且价格低廉的方法来监测呼吸器在实际使用过程中的性能。我们团队开发了一种新型的呼吸器密封完整性监测器（ReSIM），并最近在模型上进行了评估。本研究的目的是评估 ReSIM 在佩戴呼吸器的消防员在执行模拟常规操作活动时暴露于气溶胶时对呼吸器的有效性。最初，有 15 名受试者被招募参加这项研究。在对 ReSIM 原型和测试方案进行初步调查导致修改后，选择了 9 名消防员进行全面评估。测试在一个 24.3 米的暴露室内进行，使用 NaCl 作为挑战气溶胶。通过打开电磁阀 10、15 或 20 秒来建立受控的面部密封泄漏。当测试消防员稍微重新定位呼吸器在他/她的脸上时，也会建立泄漏。在测试过程中，ReSIM 测量了全脸弹性呼吸器内部的颗粒，泄漏检测灵敏度为 72.7%（正确识别泄漏的概率），特异性为 84.2%（正确识别无任何泄漏的间隔的概率）。在调整假阴性和持续假阳性后，灵敏度和特异性分别提高到 83.6%和 92.2%。导致泄漏检测灵敏度和特异性略有限制的因素可归因于受试者之间的变异性、水分对颗粒传感器的影响以及一些面罩内采样偏差。总之，ReSIM 可以快速检测到呼吸器面部密封的破裂，具有高灵敏度和特异性。由于其能够提醒佩戴者可能过度暴露于危险气溶胶，因此 ReSIM 概念具有在各种使用呼吸器的工作环境中应用的巨大潜力。
