Paton J Y, Swaminathan S, Sargent C W, Hawksworth A, Keens T G
Division of Neonatology and Pediatric Pulmonology, Children's Hospital of Los Angeles, University of Southern California School of Medicine 90027.
Am Rev Respir Dis. 1993 May;147(5):1185-91. doi: 10.1164/ajrccm/147.5.1185.
The role of the central and peripheral chemoreceptors in the hyperpnea of exercise has been controversial. We studied five children, age 6 to 11 yr, with absent hypercapneic and hypoxic ventilatory responses during wakefulness (congenital central hypoventilation syndrome, CCHS). Each child performed an incremental treadmill exercise test. Maximal oxygen consumption (VO2) and minute ventilation (VE) at maximal exercise were lower than but not significantly different from these values in a group of nine normal control children of similar age, height, and weight (VO2/kg, 33.7 +/- 5.0 versus 45.4 +/- 2.9 ml/kg/min, mean +/- SEM, NS; VE 28.3 +/- 7.3 versus 43.8 +/- 3.9 L/min, NS). Oxygen tension and saturation fell and CO2 tension rose significantly at maximal exercise in CCHS but not in control subjects. In contrast to control subjects, CCHS subjects increased VE largely by increasing respiratory frequency (f) rather than tidal volume (VT). In the oldest child, submaximal exercise tests at 50% VO2, with varying pacing rate, showed a significant positive relation between pacing rate and f, but not VT. Thus, VE was higher at the faster pacing rate. Further incremental testing in the two oldest subjects with recording of the pacing rate showed positive linear relations between pacing frequency and breathing frequency and between pacing frequency and VE up to a maximum pacing rate of 48 to 50 paces per 15 s. VE beyond this level varied randomly around the maximum level. We conclude that exercise-induced hyperpnea can occur in the absence of chemoreceptor function. In the CCHS children, limb movement is an important determinant of the ventilatory response to exercise.(ABSTRACT TRUNCATED AT 250 WORDS)
中枢和外周化学感受器在运动性通气增强中所起的作用一直存在争议。我们研究了5名6至11岁的儿童，他们在清醒状态下无高碳酸血症和低氧通气反应（先天性中枢性低通气综合征，CCHS）。每个儿童都进行了递增式跑步机运动试验。最大运动时的最大耗氧量（VO2）和分钟通气量（VE）低于一组年龄、身高和体重相似的9名正常对照儿童，但差异无统计学意义（VO2/kg，33.7±5.0对45.4±2.9 ml/kg/min，均值±标准误，无显著性差异；VE 28.3±7.3对43.8±3.9 L/min，无显著性差异）。CCHS患者在最大运动时氧分压和饱和度下降，二氧化碳分压显著升高，而对照组则无此现象。与对照组不同，CCHS患者主要通过增加呼吸频率（f）而非潮气量（VT）来增加VE。在年龄最大的儿童中，以50%VO2进行次最大运动试验，改变步速，结果显示步速与f之间存在显著正相关，但与VT无关。因此，步速越快，VE越高。对两名年龄最大的受试者进行进一步的递增试验并记录步速，结果显示在步频与呼吸频率之间以及步频与VE之间存在正线性关系，直至最大步速为每15秒48至50步。超过此水平的VE在最大水平附近随机变化。我们得出结论，在没有化学感受器功能的情况下也可发生运动诱发的通气增强。在CCHS儿童中，肢体运动是运动通气反应的重要决定因素。（摘要截短至250字）
