Freyschuss U, Hedlin G, Hedenstierna G
Am Rev Respir Dis. 1984 Nov;130(5):888-94. doi: 10.1164/arrd.1984.130.5.888.
In order to elucidate the mechanisms underlying the hypoxemia associated with exercise-induced asthma (EIA), ventilation-perfusion (VA/Q) relationships were investigated in 11 children with a history of EIA. A virtually continuous distribution of VA/Q ratios was measured by the multiple inert gas technique with the children at rest before and after an exercise test. All children displayed a unimodal distribution before the test. In 4 of the children, the exercise test did not provoke asthma, and the unimodal (VA/Q) distribution was maintained. Of the 7 children who developed asthma, 6 displayed a bimodal distribution. One mode fell within normal VA/Q regions but with increased perfusion to regions with VA/Q ratios of 0.1 to 1, which correlated well to the hypoxemia noted during asthma. The other mode fell within regions with high VA/Q ratios, and the magnitude of the mode correlated to the reduction in FEV1 and PaO2. No one had a shunt or a clearly low VA/Q mode (VA/Q less than 0.1). We hypothesize that the high VA/Q was caused by increased intrathoracic pressure impeding regional blood flow.
为了阐明运动诱发哮喘（EIA）相关低氧血症的潜在机制，我们对11名有EIA病史的儿童的通气-灌注（VA/Q）关系进行了研究。采用多惰性气体技术在运动试验前后测量孩子们静息时的VA/Q比值，发现其呈现几乎连续的分布。所有孩子在试验前均表现为单峰分布。其中4名儿童运动试验未诱发哮喘，单峰（VA/Q）分布得以维持。在出现哮喘的7名儿童中，6名表现为双峰分布。一个峰位于正常VA/Q区域内，但VA/Q比值为0.1至1的区域灌注增加，这与哮喘发作时出现的低氧血症密切相关。另一个峰位于高VA/Q比值区域，该峰的幅度与第一秒用力呼气量（FEV1）和动脉血氧分压（PaO2）的降低相关。没有人存在分流或明显低VA/Q模式（VA/Q小于0.1）。我们推测高VA/Q是由胸内压升高阻碍局部血流所致。
