Habib M P, Engel L A
Am Rev Respir Dis. 1978 Feb;117(2):265-71. doi: 10.1164/arrd.1978.117.2.265.
In 7 normal subjects we studied the effect of different panting techniques on the measurement of thoracic gas volume (VTG). When inspiratory efforts against the occluded airway were performed primarily with intercostal and accessory muscles, the value of VTG was significantly larger than during efforts performed primarily with the diaphragm. The difference could be as large as 900 ml during the same occlusion and was due to compression and decompression of abdominal gas. The divergence of the measured VTG from the true VTG depended on the volume of abdominal gas (Vab) and the ratio of gastrict to mouth pressure changes (deltaPg/deltaPm). In our normal subjects, Vab was 358 +/- 65 ml (mean +/- SE) and deltaPg/deltaPm ranged from 0.7 to -2.5. In 10 randomly selected patients with a variety of pulmonary disorders, the mean value of deltaPg/deltaPm was 0.32. In one subject with asthma who increased his total lung capacity by one liter after exercising, deltaPg/deltaPm did not change significantly from the control value. Our results indicated that the pattern of panting is an important determinant of the accuracy of plethysmographic measurement of VTG. However, preliminary results from studies of patients suggest that the error is small and does not account for the large changes in lung volume measured in patients with acute asthma.
在7名正常受试者中，我们研究了不同的呼吸急促技术对胸腔气体容积（VTG）测量的影响。当主要通过肋间肌和辅助肌对闭塞气道进行吸气努力时，VTG的值显著大于主要通过膈肌进行努力时的值。在相同的闭塞过程中，差异可能高达900毫升，这是由于腹部气体的压缩和减压所致。测量的VTG与真实VTG的差异取决于腹部气体容积（Vab）以及胃内压与口腔压力变化的比值（deltaPg/deltaPm）。在我们的正常受试者中，Vab为358±65毫升（平均值±标准误），deltaPg/deltaPm范围为0.7至-2.5。在10名随机选择的患有各种肺部疾病的患者中，deltaPg/deltaPm的平均值为0.32。在一名哮喘患者中，运动后其肺总量增加了1升，deltaPg/deltaPm与对照值相比无显著变化。我们的结果表明，呼吸急促模式是体积描记法测量VTG准确性的重要决定因素。然而，对患者研究的初步结果表明，误差较小，且不能解释急性哮喘患者所测量的肺容积的大幅变化。
