Weber K, Courtney S E, Pyon K H, Chang G Y, Pandit P B, Habib R H
Department of Pediatrics, Robert Wood Johnson Medical School at Camden, The Children's Regional Hospital at Cooper Hospital/University Medical Center, Camden, New Jersey 08103, USA.
J Appl Physiol (1985). 2000 Jul;89(1):364-72. doi: 10.1152/jappl.2000.89.1.364.
Positive airway pressure (Paw) during high-frequency oscillatory ventilation (HFOV) increases lung volume and can lead to lung overdistention with potentially serious adverse effects. To date, no method is available to monitor changes in lung volume (DeltaVL) in HFOV-treated infants to avoid overdistention. In five newborn piglets (6-15 days old, 2.2-4.2 kg), we investigated the use of direct current-coupled respiratory inductive plethysmography (RIP) for this purpose by evaluating it against whole body plethysmography. Animals were instrumented, fitted with RIP bands, paralyzed, sedated, and placed in the plethysmograph. RIP and plethysmography were simultaneously calibrated, and HFOV was instituted at varying Paw settings before (6-14 cmH(2)O) and after (10-24 cmH(2)O) repeated warm saline lung lavage to induce experimental surfactant deficiency. Estimates of Delta VL from both methods were in good agreement, both transiently and in the steady state. Maximal changes in lung volume (Delta VL(max)) from all piglets were highly correlated with Delta VL measured by RIP (in ml) = 1.01 x changes measured by whole body plethysmography - 0.35; r(2) = 0.95. Accuracy of RIP was unchanged after lavage. Effective respiratory system compliance (Ceff) decreased after lavage, yet it exhibited similar sigmoidal dependence on Delta VL(max) pre- and postlavage. A decrease in Ceff (relative to the previous Paw setting) as Delta VL(max) was methodically increased from low to high Paw provided a quantitative method for detecting lung overdistention. We conclude that RIP offers a noninvasive and clinically applicable method for accurately estimating lung recruitment during HFOV. Consequently, RIP allows the detection of lung overdistention and selection of optimal HFOV from derived Ceff data.
高频振荡通气（HFOV）期间的气道正压（Paw）会增加肺容积，并可能导致肺过度扩张，产生潜在的严重不良反应。迄今为止，尚无方法可监测接受HFOV治疗的婴儿的肺容积变化（ΔVL）以避免过度扩张。在5只新生仔猪（6 - 15日龄，体重2.2 - 4.2千克）中，我们通过与全身体积描记法进行对比评估，研究了直流电耦合呼吸感应体积描记法（RIP）在此方面的应用。对动物进行仪器植入，佩戴RIP带，使其麻痹、镇静，然后置于体积描记仪中。同时对RIP和体积描记法进行校准，在重复温热盐水肺灌洗以诱导实验性表面活性剂缺乏之前（6 - 14 cmH₂O）和之后（10 - 24 cmH₂O），在不同的Paw设置下进行HFOV。两种方法对ΔVL的估计在瞬态和稳态下均高度一致。所有仔猪的肺容积最大变化（ΔVL(max)）与通过RIP测量的ΔVL高度相关（以毫升为单位）= 1.01×通过全身体积描记法测量的变化 - 0.35；r² = 0.95。灌洗后RIP的准确性未变。灌洗后有效呼吸系统顺应性（Ceff）降低，但在灌洗前后，它对ΔVL(max)均表现出类似的S形依赖关系。随着ΔVL(max)从低Paw有条不紊地增加到高Paw，Ceff（相对于先前的Paw设置）降低，这提供了一种检测肺过度扩张的定量方法。我们得出结论，RIP提供了一种非侵入性且临床适用的方法，可准确估计HFOV期间的肺复张情况。因此，RIP能够检测肺过度扩张，并根据导出的Ceff数据选择最佳的HFOV。
