Sly P D, Brown K A, Bates J H, Spier S, Milic-Emili J
Meakins-Christie Laboratories, McGill University, Montreal, Canada.
Pediatr Pulmonol. 1988 Jan-Feb;4(1):39-47. doi: 10.1002/ppul.1950040109.
Study of the mechanical properties of the respiratory system is needed to help provide a better understanding of the pathogenesis of diseases causing respiratory failure. The nature of neonatal intensive care requires that any technique for monitoring respiratory mechanics be simple, noninvasive, and allow continued free access to the neonate. The peak airway pressure developed during volume cycled ventilation reflects the mechanical properties of the respiratory system but cannot distinguish between changes in the flow-resistive or elastic properties. Similarly, dynamic compliance combines both the flow-resistive and elastic components of the respiratory system in a single number and flow-volume loops also reflect both elements. Extracting a single time-constant from the expiratory limb of the latter assumes a single-compartment model for the respiratory system and, as such, does not provide sufficient information to describe frequency dependence of resistance and compliance. Furthermore, flow-volume loops are markedly distorted by the presence of an endotracheal tube, which must be corrected for, before calculating values of resistance and compliance. To provide the information to understand better the physiologic processes and adaptive mechanisms in diseased states causing acute respiratory failure, it is necessary to use a method that is based on a more detailed and realistic model of the respiratory system. Two such techniques that appear to warrant further investigation in ventilated infants are the interrupter technique and the forced-oscillation technique.
需要对呼吸系统的力学特性进行研究，以帮助更好地理解导致呼吸衰竭的疾病的发病机制。新生儿重症监护的性质要求任何监测呼吸力学的技术都要简单、无创，并能持续自由接触新生儿。容量控制通气期间产生的气道峰压反映了呼吸系统的力学特性，但无法区分流阻或弹性特性的变化。同样，动态顺应性将呼吸系统的流阻和弹性成分合并为一个单一数值，流速-容量环也反映了这两个要素。从后者的呼气支提取单个时间常数假定呼吸系统为单室模型，因此，它没有提供足够的信息来描述阻力和顺应性的频率依赖性。此外，气管内插管的存在会使流速-容量环明显变形，在计算阻力和顺应性值之前必须对此进行校正。为了提供信息以更好地理解导致急性呼吸衰竭的疾病状态下的生理过程和适应机制，有必要使用一种基于更详细、更现实的呼吸系统模型的方法。在通气婴儿中似乎值得进一步研究的两种此类技术是间断技术和强迫振荡技术。
