Lonky S A, Tisi G M
Chest. 1980 Jun;77(6):741-8. doi: 10.1378/chest.77.6.741.
Sixteen patients with suspected reversible airway obstruction who had previously demonstrated an increase in specific airway conductance after isoproterenol, but who had not demonstrated an increase in forced expiratory flow were studied using a measurement of submaximal flow. Flow during tidal breathing (VTV) was measured spirometrically, and VTV increased in all 16 patients from a value of 0.61 L/sec before isoproterenol to 0.80 L/sec after isoproterenol. In addition, each of these 16 patients experienced a significant increase in vital capacity and a significant decompression of functional residual capacity after isoproterenol. If plethysmography is not available, the measurement of VTV may provide evidence of bronchodilatation. The mechanism responsible for the dichotomy between maximal and submaximal flow is the compression of airways by high positive pleural pressure which is present during maximal, but not submaximal maneuvers.
对16例疑似可逆性气道阻塞的患者进行了研究，这些患者之前使用异丙肾上腺素后特定气道传导率有所增加，但用力呼气流量未增加，采用次最大流量测量法。通过肺活量测定法测量潮气呼吸时的流量（VTV），所有16例患者的VTV均从异丙肾上腺素使用前的0.61升/秒增加至使用后的0.80升/秒。此外，这16例患者在使用异丙肾上腺素后肺活量均显著增加，功能残气量显著减少。如果没有体积描记法，VTV的测量可能提供支气管扩张的证据。最大流量和次最大流量之间二分法的机制是在最大动作而非次最大动作时存在的高正胸膜压力对气道的压缩。
