Dyspnea and decreased variability of breathing in patents with restrictive lung disease
Dyspnea and decreased variability of breathing in patents with restrictive lung disease
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DOI：
10.1164/rccm.2201018
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发表时间：
2002-05-01
影响因子：
24.7
通讯作者：
Tobin, MJ
中科院分区：
文献类型：
--
作者：
Brack, T;Jubran, A;Tobin, MJ
限制性肺病患者通常呼吸困难，由于肺弹性增加，整体呼吸中枢驱动力增加。当我们让健康的志愿者承受外部弹性负荷时，他们的呼吸变异性减少了。因此，我们假设限制性肺病患者显示呼吸变异性降低，并且呼吸变异性降低与呼吸困难有关。在10例限制性肺病患者和7例健康受试者中，非侵入性地测量了1小时以上的呼吸模式。在一个单独的场合，呼吸困难进行了测量，而所有受试者复制不同的潮气量和频率。与健康受试者相比，限制性肺病患者的呼吸变异性随机分数减少：呼气时间减少27倍，潮气量减少12倍，吸气时间减少6倍（每种情况下p < 0.01）。相反，患者潮气量的非随机相关分数几乎增加了3倍（p < 0.01）。与平均静息潮气量的微小变化导致患者呼吸困难显著增加，相关性呈抛物线（r（2）= 0.97; p < 0.001）。总之，限制性肺病患者采用严格限制的呼吸模式，可能是避免呼吸困难的一种策略。
Patients with restrictive lung disease are typically dyspneic and have an increase in overall respiratory center drive, as a result of increased lung elasticity. When we subjected healthy volunteers to external elastic loads, their variability of breathing was lessened. Accordingly, we hypothesized that patients with restrictive lung disease display decreased variability of breathing and, also, that decreased variability of breathing is related to dyspnea. Breathing pattern was measured nonobtrusively over 1 hour in 10 patients with restrictive lung disease and in 7 healthy subjects. On a separate occasion, dyspnea was measured while all subjects copied different tidal volumes and frequencies. Compared with healthy subjects, the random fraction of breath variability was reduced in patients with restrictive lung disease: 27 times for expiratory time, 12 times for tidal volume, and 6 times for inspiratory time (p < 0.01 in each instance). Conversely, the nonrandom, correlated fraction for tidal volume was increased almost 3-fold in the patients (p < 0.01). Small variations from average resting tidal volume caused marked increases in dyspnea in patients, and the relationship was parabolic (r(2) = 0.97; p < 0.001). In conclusion, patients with restrictive lung disease adopt a tightly constrained breathing pattern, probably as a strategy for avoiding dyspnea.