Heldt G P, Clements J A, McIlroy M B, Tooley W H
J Appl Physiol Respir Environ Exerc Physiol. 1982 Jun;52(6):1667-71. doi: 10.1152/jappl.1982.52.6.1667.
An intercostal retractometer was developed for estimation of intrapleural pressure changes in infants. It consists of a flat reference plate which floats over the interspace and is attached to the skin by a flexible plastic film. The pressure inside the device is measured with a strain gauge. The volume inside the device is adjusted, so that the intercostal space is brought to a condition of flatness and pressure changes in the device correlate linearly with intrapleural pressure changes. The retractometer is calibrated against overall intrapleural pressure changes by matching its output to changes in airway pressure during occlusion of the airway. The calibration factor is qualitatively proportional to the thickness of the subcutaneous tissue. Retractometer and intrapleural pressures were simultaneously measured in two infant rhesus monkeys with small pneumothoraces. Esophageal and retractometer pressures were compared in seven preterm infants with an average weight of 1345 g. The device estimated the monkeys' intrapleural pressure changes to within 1.2 cmH2O and the human preterm infants' esophageal pressure changes to within 1.3 cmH2O (95% confidence limits of a linear regression).
开发了一种肋间回缩计，用于估计婴儿的胸腔内压力变化。它由一个扁平的参考板组成，该参考板漂浮在肋间间隙上方，并通过柔性塑料薄膜附着在皮肤上。用应变仪测量装置内部的压力。调节装置内部的体积，使肋间间隙达到平坦状态，并且装置内的压力变化与胸腔内压力变化呈线性相关。通过使其输出与气道阻塞期间气道压力的变化相匹配，对回缩计进行针对整体胸腔内压力变化的校准。校准因子与皮下组织的厚度定性成比例。在两只患有小气胸的恒河猴幼崽中同时测量了回缩计和胸腔内压力。在七名平均体重为1345克的早产儿中比较了食管压力和回缩计压力。该装置估计猴子的胸腔内压力变化在1.2 cmH2O以内，人类早产儿的食管压力变化在1.3 cmH2O以内（线性回归的95%置信限）。
