Soffler Morgan I, Hayes Margaret M, Schwartzstein Richard M
Massachusetts General Hospital and Beth Israel Deaconess Medical Center Combined Fellowship in Pulmonary and Critical Care Medicine, Harvard Medical School, Boston, Massachusetts.
Division of Pulmonary and Critical Care Medicine and the Carl J Shapiro Institute for Education and Research at Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
Respir Care. 2017 Sep;62(9):1212-1223. doi: 10.4187/respcare.05198. Epub 2017 Jun 27.
Dynamic hyperinflation is a common cause of dyspnea and functional limitation in patients with emphysema. Dynamic hyperinflation occurs in individuals with air-flow limitation when expiratory time is decreased during periods of relative tachypnea (such as during exercise or agitation, for example). In this setting, patients with emphysema develop lung hyperinflation, impairment of inspiratory respiratory muscles, and an increase in work of breathing. The associated decrease in inspiratory capacity results in the stimulation of several receptors, including chemoreceptors and pulmonary receptors, which signal the brain to increase tidal volume. The inability of the respiratory system to respond to signals of increased demand (eg, by enlarging tidal volume and increasing inspiratory flow) results in a dissociation between afferent and efferent signaling thereby intensifying breathing discomfort, or what clinicians term dyspnea. A thorough understanding of the physiology of dyspnea and pathophysiology of dynamic hyperinflation informs the interventions used to mitigate sensations of dyspnea and the physiologic effects of dynamic hyperinflation, respectively. Pharmacotherapy, pulmonary rehabilitation, breathing techniques, positive airway pressure, and lung volume reduction are well-studied interventions that target pathways to dyspnea in patients with dynamic hyperinflation.
动态肺过度充气是肺气肿患者呼吸困难和功能受限的常见原因。动态肺过度充气发生在气流受限的个体中，当在相对呼吸急促期间（例如在运动或激动时）呼气时间缩短时。在这种情况下，肺气肿患者会出现肺过度充气、吸气呼吸肌功能受损以及呼吸功增加。吸气能力的相关下降会刺激多种受体，包括化学感受器和肺受体，这些受体会向大脑发出信号以增加潮气量。呼吸系统无法对需求增加的信号做出反应（例如通过增大潮气量和增加吸气流量）会导致传入和传出信号之间的脱节，从而加剧呼吸不适，即临床医生所说的呼吸困难。对呼吸困难的生理学和动态肺过度充气的病理生理学有透彻的了解，分别为减轻呼吸困难感觉和动态肺过度充气的生理影响所采用的干预措施提供了依据。药物治疗、肺康复、呼吸技术、气道正压通气和肺减容术是针对动态肺过度充气患者呼吸困难途径的经过充分研究的干预措施。
