Am. J. Respir. Crit. Care Med., Vol 150, No. 3, Sep 1994, 747-751.
Role of cardiopulmonary exercise testing and the criteria used to determine disability in patients with severe chronic obstructive pulmonary disease
F Ortega, T Montemayor, A Sanchez, F Cabello and J Castillo
Pneumology Service, University Hospital, Virgen del Rocio, Seville, Spain.
The aim of this study was to evaluate the precision and variability with
which resting pulmonary function tests (resting PFTs) can be used to
predict the capacity in exercise, and the usefulness of the different
measurements of pulmonary function in the evaluation of
impairment/disability in patients with chronic obstructive pulmonary
disease (COPD). We studied 78 patients with stabilized COPD (FEV1 45.1 +/-
17.1%). Of these, 39 suffered severe impairment according to the resting
PFTs. Both the group with severe impairment (maximal oxygen consumption
[VO2,max]: 16.22 +/- 5 ml/kg/min; maximal minute ventilation [VEmax]: 31.87
+/- 7.1 L/min; maximal heart rate [HRmax]: 133.8 +/- 10.9 beats/min) and
the group with nonsevere impairment according to the resting PFTs (VO2max:
22.55 +/- 7.9 ml/kg/min; VEmax: 42.11 +/- 10.9 L/min; HRmax: 138 +/- 13.7
beats/min) showed ventilatory limitation during exercise. FEV1 was the most
prevalent criterion for the determination of severe impairment (FEV1 <
40%), and was the variable best correlated to VO2max (r = 0.52 with VO2max
as absolute value and r = 0.54 with VO2max expressed as a percentage of the
reference value), but the resting PFTs were not predictive of exercise
performance including patients with severe COPD. Evaluation of working
capacity (based on VO2max) revealed a significant number of inaccurate
predictions among the results of the resting PFTs. Sensitivity and
specificity analysis were used to compare the different criteria used to
evaluate the severity of disability. They reveal that the classification
will be different according to the criteria used.(ABSTRACT TRUNCATED AT 250
WORDS)
