Arad M, Heruti R, Shaham E, Atsmon J, Epstein Y
Israel Defense Forces, Medical Corps, Tel Hashomer.
Chest. 1992 Dec;102(6):1800-04. doi: 10.1378/chest.102.6.1800.
The common chemical warfare protective masks impose an excessive respiratory load on the wearer due to elevated breathing resistance and increased dead space. For patients with severe respiratory disease, the excessive respiratory effort may be intolerable. Besides, the substantial negative pressure created within the mask during inspiration may result in an inward leakage in individuals having difficulties with proper facial fitting of the mask. The purpose of the current investigation was to evaluate the effects of a blower, actively driving air, through the mask's filter, at a flow (mean +/- SD) of 42 +/- 2 L/min, on respiratory parameters during rest and moderate exercise. Ten healthy subjects of either sex participated in two experimental sessions, wearing the mask with and without the blower. Each session included 6 min of sitting at rest and 6 min of walking on a treadmill (3.2 mph, and 10 percent grade). In nine of the subjects, the active air supply produced a positive inspiratory pressure at rest (5 +/- 4 vs -24 +/- 9 mm H2O peak inspiratory pressure with and without the blower, respectively, p < 0.0001). Inspiratory carbon dioxide concentration (FICO2) at rest was diminished (0.4 +/- 0.4 vs 1.3 +/- 0.7 percent with and without the blower, respectively; p < 0.01) while FIO2 increased from 19.5 +/- 0.7 percent to 20.6 +/- 0.4 percent with the device (p < 0.01). These changes were associated with a significant decrease in respiratory rate (15 +/- 2 vs 18 +/- 3 per minute, p < 0.01). During exercise the blower barely decreased the negative inspiratory pressures, had no effect on other respiratory parameters measured, but significantly shortened the inspiratory/cycle-length time ratio (0.46 +/- 0.03 vs 0.53 +/- 0.03, p < 0.005). The effects of active air supply were not different between male and female subjects. We conclude that the blower is expected to be a useful accessory to respiratory protective devices for patients with pulmonary disease.
普通化学战防护面具由于呼吸阻力增加和死腔增大，会给佩戴者带来过大的呼吸负担。对于患有严重呼吸系统疾病的患者来说，这种过度的呼吸用力可能无法耐受。此外，吸气时面罩内产生的较大负压可能会导致面罩面部贴合不当的人出现向内泄漏的情况。本研究的目的是评估在静息和中度运动期间，以42±2升/分钟的流量（平均值±标准差）通过面罩过滤器主动送风的鼓风机对呼吸参数的影响。十名健康受试者（男女不限）参加了两个实验环节，分别佩戴有鼓风机和无鼓风机的面罩。每个环节包括6分钟的静息坐姿和6分钟在跑步机上行走（速度为3.2英里/小时，坡度为10%）。在九名受试者中，主动送风在静息时产生了正吸气压力（分别为5±4与-24±9毫米水柱的峰值吸气压力，有和无鼓风机时，p<0.0001）。静息时吸气二氧化碳浓度（FICO2）降低（分别为0.4±0.4与1.3±0.7%，有和无鼓风机时；p<0.01），而使用该装置时FIO2从19.5±0.7%增加到20.6±0.4%（p<0.01）。这些变化与呼吸频率显著降低相关（分别为15±2与18±3次/分钟，p<0.01）。运动期间，鼓风机几乎没有降低负吸气压力，对所测量的其他呼吸参数没有影响，但显著缩短了吸气/周期时长比（0.46±0.03与0.53±0.03，p<0.005）。主动送风的效果在男性和女性受试者之间没有差异。我们得出结论，对于肺部疾病患者，鼓风机有望成为呼吸防护装置的有用附件。
