Increased physiological dead space at exercise is a marker of mild pulmonary or cardiovascular disease in dyspneic subjects

• Main Authors: Laurent Plantier, Christophe Delclaux
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2018-01-01
• Series: European Clinical Respiratory Journal
• Subjects: Dead space; efficiency; exercise; cardiopulmonary exercise testing; lung disease; cardiovascular disease
• Online Access: http://dx.doi.org/10.1080/20018525.2018.1492842

Background: The characteristics of cardiopulmonary exercise testing (CPET)-derived parameters for the differential diagnosis of exertional dyspnea are not well known. Objectives: We hypothesized that increased physiological dead space ventilation (VD/Vt) is a marker for mild pulmonary or cardiovascular disease in patients with exertional dyspnea. Design: We used receiver operating characteristic analysis to determine the performance of individual CPET parameters for identifying subjects with either mild pulmonary or cardiovascular disease, among 77 subjects with mild-to-moderate exertional dyspnea (modified Medical Research Council scale 1–2). Results: In comparison with subjects without disease, subjects with pulmonary disease (n = 31) had higher VE/V′CO2 slope, higher VD/Vt, and lower ventilatory reserve. Subjects with cardiovascular disease (n = 14) had lower heart rate and cardiovascular double product and higher VD/Vt at peak exercise. At a threshold of 28%, the sensitivity and specificity of VD/Vt at peak exercise for identifying pulmonary or cardiovascular disease were 89% (95% CI: 64–98%) and 72% (95% CI: 46–89%), respectively. Conclusions: Increased physiological VD/Vt at exercise is a sensitive and specific marker of mild pulmonary or cardiovascular disease in dyspneic subjects.