Dorneles Rui Gustavo, Plachi Franciele, Gass Ricardo, Toniazzo Vinicius Timm, Thome Paulo, Sanches Paulo R, Gazzana Marcelo B, Neder J Alberto, Berton Danilo C
Universidade Federal do Rio Grande do Sul (UFRGS) & Hospital de Clinicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil.
Laboratory of Clinical Exercise Physiology, Kingston Health Science Center & Queen's University, Kingston, ON, Canada.
Respir Physiol Neurobiol. 2019 Mar;261:40-47. doi: 10.1016/j.resp.2019.01.002. Epub 2019 Jan 7.
We aimed to assess detailed ventilatory and sensory responses to exercise contrasting subjects with and without PAH. 20 non-smoking patients with PAH (37.5 ± 12.1 ys; FEV/FVC = 0.77 ± 0.04; mPAP by heart catheterization = 50.6 ± 18.1 mmHg) and 10 matched controls performed cycling cardiopulmonary exercise test with serial assessments of dyspnea, airway occlusion pressure during the first 0.1 s (P0.1) of tidal volume and inspiratory capacity (IC). Patients showed lower spirometric variables compared to controls. Dyspnea and ventilation (V) were significantly higher in patients for a given work rate. Dyspnea persisted more intense in patients even when expressed as a function of V. Lower IC at rest (in non-hyperinflators; n = 10) or exercise-induced reduction in IC (in hyperinflators) predisposed patients to achieve earlier and at lower workloads a critical inspiratory reserve volume (IRV). At this point, there was a sudden rise in P0.1 and dyspnea perception. Attainment of a critical IRV at premature workloads leads to neuromechanical dissociation with an abrupt increment in exertional dyspnea.
我们旨在评估有无肺动脉高压（PAH）的受试者在运动时详细的通气和感觉反应。20名不吸烟的PAH患者（37.5±12.1岁；FEV/FVC = 0.77±0.04；经心导管检查测得的平均肺动脉压[mPAP] = 50.6±18.1 mmHg）和10名匹配的对照者进行了踏车心肺运动试验，并对呼吸困难、潮气量和吸气容量（IC）的前0.1秒期间的气道闭塞压（P0.1）进行了连续评估。与对照组相比，患者的肺量计变量较低。在给定的工作负荷下，患者的呼吸困难和通气（V）明显更高。即使以V的函数表示，患者的呼吸困难仍持续更强烈。静息时较低的IC（在非肺过度充气者中；n = 10）或运动诱发的IC降低（在肺过度充气者中）使患者在较早且较低的工作负荷下就达到临界吸气储备量（IRV）。此时，P0.1和呼吸困难感知突然升高。在过早的工作负荷下达到临界IRV会导致神经机械分离，并使运动性呼吸困难突然增加。
