Optimal protocol selection for cardiopulmonary exercise testing in severe COPD.
BACKGROUND
The current recommendations of 8 to 12 min for the optimal targeted duration of symptom-limited maximal cardiopulmonary exercise testing (CPET) to attain maximal oxygen consumption are based on results from healthy individuals and may not be applicable to patients with severe COPD. We aimed to determine the optimal duration for a CPET to attain the peak oxygen consumption (VO2peak) in a group of patients with severe COPD using different carefully conducted workload protocols.


METHODS
We studied 11 subjects with severe COPD (mean FEV1, 32% predicted; 95% confidence interval [CI], 27 to 38% predicted). They completed four incremental, symptom-limited exercise tests on a cycle ergometer using four protocols (4, 8, and 16 W/min continuous ramp protocols, and 8 W/min step protocol) using a randomized double-blind design.


RESULTS
The mean duration of these 44 tests was 6.3 min (95% CI, 5.0 to 9.0 min). The duration of the exercise tests differed significantly for the protocols used, as follows: 16-W ramp protocol, 4.0 min (95% CI, 3.0 to 5.1 min); 8-W ramp protocol, 6.6 min (95% CI, 5.0 to 9.0 min); 8-W step protocol, 6.0 min (95% CI, 4.0 to 8.0 min); and 4-W ramp protocol, 8.7 min (95% CI, 4.4 to 13.0 min; p<0.001). The maximal workload significantly increased as the ramp slope increased from 4 to 8 to 16 W/min (maximal workload, 35.6 vs 50.7 vs 64.3 W, respectively; p<0.001). Maximal minute ventilation, heart rate, Borg ratings, and VO2 peak, were not different among the four protocols. No differences were found between the ramp and step protocols.


CONCLUSIONS
In patients with severe COPD (Global Initiative for Chronic Obstructive Lung Disease stages III-IV), a targeted duration of 5 to 9 min for a CPET appears to be more appropriate than the 8 to 12 min proposed in the current guidelines. Maximal workload, in contrast to VO2peak, is highly dependent on the ramp incrementation rate.
Benzo
Roberto P
RP
Division of Pulmonary and Critical Care Medicine, University of Pittsburgh, Suite 1211 Kaufmann Building, 3471 Fifth Ave, Pittsburgh, PA 15213, USA. benzorp@upmc.edu
Paramesh
Sriram
S
Patel
Sanjay A
SA
Slivka
William A
WA
Sciurba
Frank C
FC
D000368:Aged; D000704:Analysis of Variance; D002985:Clinical Protocols; D016001:Confidence Intervals; D005080:Exercise Test / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D013997:Time Factors