Frantz I D, Close R H
Am Rev Respir Dis. 1985 Jan;131(1):134-8. doi: 10.1164/arrd.1985.131.1.134.
We measured lung volume, tidal volume, and pressures at the airway opening, trachea, and alveoli during jet ventilation of rabbits at frequencies from 2 to 15 Hz when inspiratory time was varied from 10 to 50% of the ventilator cycle. Lung volume was determined dynamically and was dependent on tidal volume, expiratory duration, and the expiratory time constant of the respiratory system. Tidal volume decreased with increasing frequency and lung volume, and was greater than estimated dead-space volume over most of the frequency range studied. Pressure at the airway opening was not a good estimate of either mean pressure or pressure swings in the alveoli. Tracheal pressure corresponded fairly well to alveolar pressure. Alveolar pressure swings diminished with increasing frequency and decreasing inspiratory duration. In the clinical setting these results mean that measurement of pressures at the airway opening is not an adequate way to monitor patients during jet ventilation. In addition, the clinician must be aware that substantial increases in functional residual capacity may occur during jet ventilation, thereby placing the patient at risk of pneumothorax.
我们在兔的喷射通气过程中，当吸气时间在呼吸机周期的10%至50%之间变化时，测量了频率为2至15赫兹时气道开口、气管和肺泡处的肺容积、潮气量和压力。肺容积是动态测定的，并且取决于潮气量、呼气持续时间和呼吸系统的呼气时间常数。潮气量随频率和肺容积的增加而减小，并且在研究的大部分频率范围内大于估计的死腔容积。气道开口处的压力不是肺泡平均压力或压力波动的良好估计值。气管压力与肺泡压力相当吻合。肺泡压力波动随频率增加和吸气持续时间缩短而减小。在临床环境中，这些结果意味着在喷射通气期间测量气道开口处的压力不是监测患者的充分方法。此外，临床医生必须意识到在喷射通气期间功能残气量可能会大幅增加，从而使患者有气胸的风险。
