Wada O, Asanoi H, Miyagi K, Ishizaka S, Kameyama T, Seto H, Sasayama S
Second Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Japan.
Am Heart J. 1993 Mar;125(3):790-8. doi: 10.1016/0002-8703(93)90173-7.
Whether excessive ventilatory response to exercise is related to the maldistribution of pulmonary blood flow was examined in 23 patients with chronic heart failure and nine age-matched normal subjects. With the use of technetium 99m macroaggregated albumin, the resting distribution of pulmonary blood flow was assessed by the scintigraphic counts ratio of upper to lower lung fields. The ventilatory response to exercise was assessed by the slope of the relationship between minute ventilation and carbon dioxide production during exercise. Eight patients (group A) had slope less than 33, the upper limit of the normal range, and 15 patients had slope of 33 or greater (group B). In group B pulmonary blood flow was distributed more to the upper lung, which made the counts ratio (60%) higher than in normal subjects (34%) or in patients in group A (38%). There was no significant difference in pulmonary flow distribution between normal subjects and patients in group A. In group B tidal volume did not increase during exercise as much as it did in normal subjects and in patients in group A; therefore, the respiratory pattern was rapid and shallow. Although the ratio of physiologic dead space to tidal volume fell by 20% during exercise in normal subjects and by 23% in patients in group A, it failed to decrease in patients in group B (-1%), which indicates a relative increase in dead space respiration during exercise. These data indicate that decreased lung compliance and regional ventilation-perfusion mismatch caused by pulmonary vascular and parenchymal abnormalities would play an important role in the excessive exercise ventilation in chronic heart failure.
在23例慢性心力衰竭患者和9例年龄匹配的正常受试者中，研究了运动时过度通气反应是否与肺血流分布不均有关。使用锝99m标记的大颗粒白蛋白，通过肺上下野放射性计数比值评估静息状态下的肺血流分布。通过运动期间分钟通气量与二氧化碳产生量之间关系的斜率评估运动时的通气反应。8例患者（A组）的斜率小于正常范围上限33，15例患者的斜率为33或更高（B组）。B组肺血流更多地分布到上肺，使得计数比值（60%）高于正常受试者（34%）或A组患者（38%）。正常受试者与A组患者的肺血流分布无显著差异。B组运动期间潮气量增加幅度不如正常受试者和A组患者；因此，呼吸模式为快速浅呼吸。尽管正常受试者运动期间生理死腔与潮气量的比值下降20%，A组患者下降23%，但B组患者该比值未下降（-1%），这表明运动期间死腔呼吸相对增加。这些数据表明，由肺血管和实质异常引起的肺顺应性降低和局部通气-灌注不匹配在慢性心力衰竭运动时过度通气中起重要作用。
