Cardiopulmonary exercise test interpretation using age-matched controls to evaluate exertional dyspnea.
BACKGROUND
Cardiopulmonary exercise testing (CPET) is one method to diagnose unexplained dyspnea in young adults, yet few normal reference values exist in this population. This study evaluated interpretation of maximal CPET in a young adult cohort with known pulmonary disorders using published reference values compared to age-matched normal controls.


METHODS
A control population of 69 healthy military volunteers with normal chest radiographs, pulmonary function testing, and bronchoprovocation testing were compared to 105 patients with exertional dyspnea. Both groups underwent a standardized evaluation including CPET on a graded exercise treadmill to maximal exercise with expired gas analysis.


RESULTS
Measurements from CPET in the dyspnea group were interpreted using published reference values compared to control population results (mean +/- 1.65 x SD). Statistical comparison of predicted normals (reference vs. control) of maximal oxygen consumption (> 83% vs. 82%), ventilatory anaerobic threshold (> 40% vs. 53%), respiratory rate (< 60 vs. 56 breaths/min), tidal volume to inspiratory capacity (< 80% vs. 111%), ventilatory equivalent for carbon dioxide production (< 40 vs. 38), and maximal voluntary ventilation minus minute ventilation (> 11 vs. -1 L/min) was performed. The overall specificity for tidal volume to inspiratory capacity improved using age-matched controls but sensitivity was decreased. Other parameters were not significantly different.


CONCLUSIONS
The use of age-matched controls for CPET results in an increase in specificity and decrease in sensitivity for respiratory limitations to exercise, when compared to reference values. The study findings suggest that CPET may be insensitive in detecting mild disease in young healthy adults.
Sill
Joshua M
JM
Pulmonary Disease/Critical Care Medicine Service, Department of Medicine, Brooke Army Medical Center, 3851 Roger Brooke Road, Fort Sam Houston, TX 78234-6200, USA.
Morris
Michael J
MJ
Johnson
James E
JE
Allan
Patrick F
PF
Grbach
Vincent X
VX
D000328:Adult; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D004417:Dyspnea / Q000175:diagnosis* / Q000503:physiopathology; D005080:Exercise Test; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D008297:Male; D008889:Military Personnel; D012016:Reference Values; D012044:Regression Analysis; D012129:Respiratory Function Tests