Study Status: Completed
Recruit Status: Completed
Study Type: Observational
Official Title: Single-Breath Measurement Underestimates Ventilatory Volume According to Emphysema Severity
Brief Summary: Although single breath helium (He) dilution measurement (VASB) is currently used in pulmonary function laboratories to assess functional alveolar volume and diffusing capacity for carbon monoxide, the extent to which VASB reflects ventilatory and thoracic volume has not been prospectively determined in emphysema. We hypothesized that VASB underestimates rebreathe helium dilution volume (VARB), and plethysmographic volume (VApleth) as clinical and physiologic severity of emphysema increases.