Lansing R W, Im B S, Thwing J I, Legedza A T, Banzett R B
Physiology Program and Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts 02115, USA.
Am J Respir Crit Care Med. 2000 Nov;162(5):1690-6. doi: 10.1164/ajrccm.162.5.9907096.
Dyspnea in patients could arise from both an urge to breathe and increased effort of breathing. Two qualitatively different sensations, "air hunger" and "respiratory work and effort," arising from different afferent sources are hypothesized. In the laboratory, breathing below the spontaneous level may produce an uncomfortable sensation of air hunger, and breathing above it a sensation of work or effort. Measurement of a single sensory dimension cannot distinguish these as separate sensations; we therefore measured two sensory dimensions and attempted to vary them independently. In five normal subjects we obtained simultaneous ratings of air hunger and of work and effort while independently varying PCO(2) or the level of targeted voluntary breathing. We found a difference in response to the two stimulus dimensions: air hunger ratings changed more steeply when PCO(2) was altered and ventilation was constant; work or effort ratings changed more steeply when ventilation was altered and PCO(2) was constant. We conclude that "air hunger" is qualitatively different from "work and effort" and arises from different afferent sources.
患者的呼吸困难可能源于呼吸冲动和呼吸用力增加。据推测，存在两种性质不同的感觉，即源于不同传入源的“空气饥饿感”和“呼吸功与用力感”。在实验室中，低于自主呼吸水平的呼吸可能会产生不舒服的空气饥饿感，而高于自主呼吸水平的呼吸则会产生功或用力的感觉。单一感觉维度的测量无法将这些区分为不同的感觉；因此，我们测量了两个感觉维度，并试图独立改变它们。在五名正常受试者中，我们在独立改变二氧化碳分压（PCO₂）或目标自主呼吸水平的同时，获得了空气饥饿感以及功与用力的同步评分。我们发现对这两个刺激维度的反应存在差异：当二氧化碳分压改变而通气量恒定时，空气饥饿感评分变化更剧烈；当通气量改变而二氧化碳分压恒定时，功或用力感评分变化更剧烈。我们得出结论，“空气饥饿感”与“功与用力感”在性质上不同，且源于不同的传入源。
