Sullivan K J, Durand M, Chang H K
Department of Biomedical Engineering, University of Southern California, Los Angeles 90089-1451.
Pediatr Res. 1991 Jan;29(1):82-8. doi: 10.1203/00006450-199101000-00016.
Short pulses in airway pressure were used to assess the pulmonary mechanical function of nine infants suffering acute respiratory distress syndrome or bronchopulmonary dysplasia. All patients were intubated, spontaneously breathing, and mechanically ventilated at the time they were examined. The endotracheal tube was disconnected from the ventilator and connected to a mechanical oscillator that produced brief pulses in airway pressure at a rate of two pulses/s. These pulses were applied to the infants airway for 20-30 s, at which time the infant was replaced on the ventilator. The mean airway pressure during the procedure was maintained at the level of the positive and expiratory pressure that was set on the ventilator. Two classes of patients were identified from the pulse response primarily by the presence or absence of a local resonance in the impedance spectra. Similar results were obtained in five other patients who were examined with zero mean airway pressure, suggesting that the pulse response is little influenced by changes in mean lung volume or total lung compliance. Patient classification appeared related to the duration of ventilation therapy and the transition from one class to another was consistent with the development of high peripheral airway resistance and significant volume shunting in the central airways. These results suggest that brief pulses in airway pressure can be used to detect changes in the pulmonary mechanical function of preterm infants that result from long-term ventilation therapy.
采用气道压力短脉冲来评估9名患有急性呼吸窘迫综合征或支气管肺发育不良的婴儿的肺机械功能。所有患者在接受检查时均已插管、自主呼吸并接受机械通气。将气管内导管从呼吸机上断开，连接到一个机械振荡器上，该振荡器以每秒2次脉冲的速率产生气道压力的短暂脉冲。这些脉冲施加于婴儿气道20 - 30秒，然后将婴儿重新连接到呼吸机上。在该过程中，平均气道压力维持在呼吸机设定的呼气末正压水平。根据脉冲反应主要通过阻抗谱中是否存在局部共振来识别出两类患者。在另外5名以零平均气道压力进行检查的患者中也获得了类似结果，这表明脉冲反应受平均肺容积或总肺顺应性变化的影响很小。患者分类似乎与通气治疗的持续时间有关，从一类转变为另一类与外周气道阻力增加以及中央气道中显著的容积分流的发展相一致。这些结果表明，气道压力短脉冲可用于检测长期通气治疗导致的早产儿肺机械功能变化。
