Journal List > Tuberc Respir Dis > v.64(6) > 1001240

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Kim, Park, Mo, Choi, Nam, Lee, Yoo, Yang, Moon, Kim, Lee, Jin, Lee, and Chun: Predicting Oxygen Uptake for Men with Moderate to Severe Chronic Obstructive Pulmonary Disease
Original Article
Tuberculosis and Respiratory Diseases

Tuberculosis and Respiratory Diseases 2008; 64(6): 433-438.

Published online: 30 June 2008

DOI: https://doi.org/10.4046/trd.2008.64.6.433

Predicting Oxygen Uptake for Men with Moderate to Severe Chronic Obstructive Pulmonary Disease

Changhwan Kim, M.D.1, Yong Bum Park, M.D.1, 2, Eun Kyung Mo, M.D.1, Eun Hee Choi, M.D.3, Hee Seung Nam, M.D.3, Sung-Soon Lee, M.D.4, Young Won Yoo4, Yun Jun Yang, M.D.5, Joung Wha Moon6, Dong Soon Kim, M.D.7, Hyang Yi Lee7, Young Soo Jin, M.D.8, Hye Young Lee8, Eun Mi Chun, M.D.9

1Department of Internal Medicine, Hallym University College of Medicine, Korea.

2Lung Research Institute, Hallym University College of Medicine, Korea.

3Department of Rehabilitation Medicine, Hallym University College of Medicine, Korea.

4Department of Internal Medicine, Inje University College of Medicine, Korea.

5Department of Family Medicine, Inje University College of Medicine, Korea.

6Sports Medicine Center, Inje University College of Medicine, Korea.

7Department of Internal Medicine, Asan Medical Center, Ulsan University College of Medicine, Korea.

8Sports Medical Center, Asan Medical Center, Ulsan University College of Medicine, Korea.

9Department of Internal Medicine, Ewha University College of Medicine, Seoul, Korea.

Address for correspondence: Yong Bum Park, M.D. Department of Internal Medicine, Kangdong Sacred Heart Hospital, 445, Gil-dong, Gangdong-gu, Seoul 134-701, Korea. Phone: 82-2-2225-2754, Fax: 82-2-478-6925, bfspark@medimail.co.kr

Received 28 May 2008       Accepted 12 June 2008

Copyright © 2008 The Korean Academy of Tuberculosis and Respiratory Diseases

Abstract

Background

Measurement of the maximum oxygen uptake in patients with chronic obstructive pulmonary disease (COPD) has been used to determine the intensity of exercise and to estimate the patient's response to treatment during pulmonary rehabilitation. However, cardiopulmonary exercise testing is not widely available in Korea. The 6-minute walk test (6MWT) is a simple method of measuring the exercise capacity of a patient. It also provides high reliability data and it reflects the fluctuation in one's exercise capacity relatively well with using the standardized protocol. The prime objective of the present study is to develop a regression equation for estimating the peak oxygen uptake (VO2) for men with moderate to very severe COPD from the results of a 6MWT.

Methods

A total of 33 male patients with moderate to very severe COPD agreed to participate in this study. Pulmonary function testing, cardiopulmonary exercise testing and a 6MWT were performed on their first visits. The index of work (6Mwork, 6-minute walk distance [6MWD]×body weight) was calculated for each patient. Those variables that were closely related to the peak VO2 were identified through correlation analysis. With including such variables, the equation to predict the peak VO2 was generated by the multiple linear regression method.

Results

The peak VO2 averaged 1,015±392 ml/min, and the mean 6MWD was 516±195 meters. The 6Mwork (r=.597) was better correlated to the peak VO2 than the 6MWD (r=.415). The other variables highly correlated with the peak VO2 were the FEV1 (r=.742), DLco (r=.734) and FVC (r=.679). The derived prediction equation was VO2 (ml/min)=(274.306×FEV1)+(36.242×DLco)+(0.007×6Mwork)-84.867.

Conclusion

Under the circumstances when measurement of the peak VO2 is not possible, we consider the 6MWT to be a simple alternative to measuring the peak VO2. Of course, it is necessary to perform a trial on much larger scale to validate our prediction equation.

Keywords: COPD, Peak oxygen uptake, 6-minute walk test

Figures and Tables

Figure 1
Index of work (6Mwork) was better correlated to peak oxygen uptake (VO2) than 6-minute work distance (6MWD). Scatterplot of peak VO2 to 6MWD (r=0.415, p=0.016) (A). Scatterplot of peak VO2 to 6Mwork (r=0.597, p<0.001) (B).
trd-64-433-g001
Figure 2
FEV1 and DLco were highly correlated, but age was not correlated with peak oxygen uptake (VO2). Scatterplot of peak VO2 to FEV1 (r=0.742, p<0.001) (A). Scatterplot of peak VO2 to DLco (r=0.734, p<0.001) (B). Scatterplot of peak VO2 to age (r=-0.334, p>0.05) (C).
trd-64-433-g002
Table 1
Demographic characteristics of the patients
trd-64-433-i001

SD: standard deviation; BMI: body mass index.

Table 2
Indices of pulmonary function, peak work performance, and 6MWT
trd-64-433-i002

6MWT: 6-minute work test; SD: standard deviation; FEV1: forced expiratory volume in 1 second; FVC: forced vital capacity; DLco: diffusing capacity; VO2: oxygen consumption; VCO2: CO2 excretion; VE: ventilation; HR: heart rate; RR: respiration rate; 6MWD: 6-minute work distance; 6Mwork: index of work in 6 minutes.

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