SPONTANEOUS AIRWAY PRESSURE RELEASE VENTILATION (S-APRV). NOSOCOMIAL PNEUMONIA.

我们已经阐明了自发性气道压力释放通气（S-APRV）的机制，通过该机制，在高空气/氧气流通过小的微型气管切开管进入气管时，诱导自发性气道压力释放通气（S-APRV），而不诉诸机械通气。 通过直接经气管光纤可视化，我们观察到声门开口的自发闭合，随后通过空气/氧气流入气管对肺进行被动充气。声门一打开，立即发出声音。这些观察结果已被非侵入性超声成像证实。 重要的是，呼吸努力和呼吸功都减少了90%以上，S-APRV不需要气管插管，保留了发声，不干扰经口进食，患者活动能力受损最小。 持续的研究探讨了机械通气患者院内获得性肺炎的相关因素。 所有研究均在麻醉、麻痹、插管和机械通气3天的绵羊上进行。 没有使用抗生素。 对照组绵羊插管，头部向上倾斜（如人），根据需要抽吸。 对于研究绵羊，头部和气管导管保持水平，并且没有抽吸。 对照组中的所有绵羊均显示气管支气管树和肺部存在广泛的细菌定植，胸部X线检查异常，尸检发现肺炎。 集水器的大部分仍然没有粘液。 研究组中的所有绵羊均保持健康，胸部X光片和尸检结果正常。粘液和气管支气管分泌物自发积聚在水阱中。 我们的结论是，在机械通气的气管导管（和头部）的方向可以避免肺吸入（入侵）的口气管或胃内容物，并导致自发清除气管支气管分泌物，而不需要定期的气管吸在这个绵羊模型。

We have elucidated the mechanism through which Spontaneous Airway Pressure Release Ventilation (S-APRV) is induced during high air/orygen flow through a small minitracheostomy tube into the trachea, without resorting to mechanical ventilation. By direct transtracheal fiberoptic visualization, we observed spontaneous closure of the glottic opening, followed by passive inflation of the lungs through flow of air/oxygen into the trachea. Expiration followed immediately upon opening of the glottis. Those observations have been confirmed by non-invasive ultrasonic imaging. It is important that both effort of breathing, and work of breathing are reduced by well over 90%, S-APRV does not require tracheal intubation, vocalization is preserved, oral feeding is not interfered with, and patient mobility is minimally impaired. Continuing studies explore factors that contribute to nosocomial pneumonia in patients on mechanical ventilation. All studies are conducted on anesthetized, paralyzed sheep, intubated, and on mechanical ventilation for 3 days. No antibiotics are used. Control sheep were intubated and the head held angled upward (as in the human), suctioned as needed. For study sheep, head and tracheal tube were maintained horizontal, and there was no suctioning. All sheep in the control group showed extensive bacterial colonization of the tracheo-bronchial tree and lungs, with abnormal chest X-rays, and autopsy findings of pneumonia. The water traps remained for the most part clear of mucus. All sheep in the study group remained healthy, with normal chest X-ray films, and autopsy findings. Mucus and tracheobronchial secretions accumulated spontaneously in the water trap. We conclude that orientation of tracheal tube (and head) during mechanical ventilation can avert pulmonary aspiration (invasion) of orotracheal or gastric contents, and lead to spontaneous clearance of tracheobronchial secretions, without need for periodic tracheal suctioning in this sheep model.