Chest
Volume 132, Issue 5, November 2007, Pages 1500-1505
Journal home page for Chest

Original Research
COPD
Optimal Protocol Selection for Cardiopulmonary Exercise Testing in Severe COPD

https://doi.org/10.1378/chest.07-0732Get rights and content

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 ( V˙o2peak) 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 V˙o2 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 V˙o2peak, is highly dependent on the ramp incrementation rate.

Section snippets

Materials and Methods

Eleven stable subjects (5 women, 6 men) with severe COPD (Global Initiative for Chronic Obstructive Lung Disease stage III–IV) were recruited for the study based on history, and findings of physical examination, chest radiographs, and pulmonary function testing. No subjects were receiving long-term oxygen therapy. Spirometry and single-breath diffusing capacity of the lung for carbon monoxide (corrected for hemoglobin) were performed in all subjects ( V˙max 6200; SensorMedics; Yorba Linda,

Subject Characteristics

Baseline characteristics of the study group are shown in Table 1.

Duration of the Exercise Tests

The mean duration for all 44 tests was 6 min (95% CI, 5 to 9 min). The test durations also differed significantly according to the protocol used (p < 0.001): 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). Thirty-three of the 44 tests (75%) lasted < 8 min.

Discussion

In this study, V˙o2peak, in a group of patients with severe COPD, was achieved in a shorter time frame than that proposed in the current exercise guidelines.10 The mean duration of CPET in our study based on 44 carefully executed tests was 6.3 min (95% CI, 5.0 to 9.0 min) [Fig 1]. This is shorter than the recommended duration of 8 to 12 min for CPET10 that was based on the only available data from a group of five healthy subjects.11 We found no significant differences in the V˙o2peak

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    Dr. Benzo is supported by grant No. 5k23CA106544 from the National Institutes of Health. Dr. Sciurba is supported by grant No. 1P50HL084948-0 from the National Institutes of Health.

    The authors have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

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