Reproducibility of the 6-Minute Walk Test for Ambulatory Oxygen Prescription

Background: Ambulatory oxygen is frequently prescribed for patients with chronic obstructive pulmonary disease (COPD) who have oxygen desaturation ≤88% during exercise. The 6-min walk test (6MWT) with continuous pulse oximetry monitoring is a common method to document this oxygen desaturation, but the reproducibility of this test in determining the need for ambulatory oxygen in patients with COPD is not well documented. Objective:The aim of this study was to establish the reproducibility of the 6MWT in determining the need for ambulatory oxygen prescription in stable COPD patients using the Centers for Medicare and Medicaid (CMS) criteria for ambulatory oxygen prescription. Methods:The study was designed as a prospective observational study in an academic health center and associated pulmonary rehabilitation program. Eighty-eight COPD patients referred to pulmonary rehabilitation underwent continuous pulse oximetry while performing standard 6MWT on 3 separate days. Results: Fifty-one (58%) of these patients desaturated by continuous pulse oximetry to an SpO2 ≤88% on a least one of the 6MWTs. Only 26 patients (30%) demonstrated consistency in meeting the criteria for ambulatory oxygen set forth by the CMS on all three 6MWT with a κ statistic of 0.62. The percent agreement between 6MWTs for ambulatory oxygen prescription was 72% and the paired observation was 51%. Conclusions: The 6MWT distance is simple and widely used as a consistent measure of functional capacity in patients with COPD; however, the 6MWT oxygen saturation has only modest reproducibility in determining the need for ambulatory oxygen in stable COPD patients undergoing pulmonary rehabilitation.

[1]  D. Anantham,et al.  Ambulatory Oxygen in Chronic Obstructive Pulmonary Disease , 2011 .

[2]  Ciro Casanova,et al.  Distance and oxygen desaturation during the 6-min walk test as predictors of long-term mortality in patients with COPD. , 2008, Chest.

[3]  B. Make,et al.  Continuous oxygen use in nonhypoxemic emphysema patients identifies a high-risk subset of patients: retrospective analysis of the National Emphysema Treatment Trial. , 2008, Chest.

[4]  K. Schmidbauer,et al.  Predictive Significance of the Six-Minute Walk Distance for Long-Term Survival in Chronic Hypercapnic Respiratory Failure , 2007, Respiration.

[5]  T. Lasserson,et al.  A systematic review of randomized controlled trials examining the short-term benefit of ambulatory oxygen in COPD. , 2007, Chest.

[6]  S. Costi,et al.  Repeated Pulmonary Rehabilitation in Severe and Disabled COPD Patients , 2006, Respiration.

[7]  W. Bailey,et al.  Long-term oxygen treatment in chronic obstructive pulmonary disease: recommendations for future research: an NHLBI workshop report. , 2006, American journal of respiratory and critical care medicine.

[8]  J. Bradley,et al.  Short-term ambulatory oxygen for chronic obstructive pulmonary disease. , 2005, The Cochrane database of systematic reviews.

[9]  G. Guyatt,et al.  A randomized trial of strategies for assessing eligibility for long-term domiciliary oxygen therapy. , 2005, American journal of respiratory and critical care medicine.

[10]  A. Wells,et al.  Six-minute walk, maximal exercise tests: reproducibility in fibrotic interstitial pneumonia. , 2005, American journal of respiratory and critical care medicine.

[11]  Ronnie Driver,et al.  Biostatistics: a Methodology for the Health Sciences , 2005 .

[12]  Ciro Casanova,et al.  The body-mass index, airflow obstruction, dyspnea, and exercise capacity index in chronic obstructive pulmonary disease. , 2004, The New England journal of medicine.

[13]  Margareta Emtner,et al.  Benefits of supplemental oxygen in exercise training in nonhypoxemic chronic obstructive pulmonary disease patients. , 2003, American journal of respiratory and critical care medicine.

[14]  Robert A Wise,et al.  Six-minute walk distance in chronic obstructive pulmonary disease: reproducibility and effect of walking course layout and length. , 2003, American journal of respiratory and critical care medicine.

[15]  M. Poulain,et al.  6-minute walk testing is more sensitive than maximal incremental cycle testing for detecting oxygen desaturation in patients with COPD. , 2003, Chest.

[16]  C. Doré,et al.  Reliability, repeatability and sensitivity to change of externally and self-paced walking tests in COPD patients. , 2003, Respiratory medicine.

[17]  J. Garrett,et al.  Home overnight pulse oximetry in patients with COPD: more than one recording may be needed. , 2003, Chest.

[18]  ATS statement: guidelines for the six-minute walk test. , 2002, American journal of respiratory and critical care medicine.

[19]  D L Sherrill,et al.  Predictors of oxygen desaturation during submaximal exercise in 8,000 patients. , 2001, Chest.

[20]  N. Adair,et al.  Baseline oxygen saturation predicts exercise desaturation below prescription threshold in patients with chronic obstructive pulmonary disease. , 2001, Archives of internal medicine.

[21]  G. Guyatt,et al.  Appropriateness of domiciliary oxygen delivery. , 2000, Chest.

[22]  S J Jay,et al.  Reference equations for the six-minute walk in healthy adults. , 2000 .

[23]  Dunn Pj.  The demographics and economics of long-term oxygen therapy. , 2000 .

[24]  P. J. Dunne.  The demographics and economics of long-term oxygen therapy. , 2000, Respiratory care.

[25]  J Zieliński,et al.  Effects of long-term oxygen therapy on pulmonary hemodynamics in COPD patients: a 6-year prospective study. , 1998, Chest.

[26]  H. Folgering,et al.  Training with supplemental oxygen in patients with COPD and hypoxaemia at peak exercise. , 1997, The European respiratory journal.

[27]  S. Sasse,et al.  Comparison of oxygen saturation by pulse oximetry and co-oximetry during exercise testing in patients with COPD. , 1996, Chest.

[28]  W. O'Donohue,et al.  Magnitude of usage and cost of home oxygen therapy in the United States. , 1995, Chest.

[29]  J. Bugler,et al.  Effect of arterial oxygen desaturation on six minute walk distance, perceived effort, and perceived breathlessness in patients with airflow limitation. , 1993, Thorax.

[30]  P. Escourrou,et al.  Reliability of pulse oximetry during exercise in pulmonary patients. , 1990, Chest.

[31]  Leo Smith,et al.  American Association of Cardiovascular and Pulmonary Rehabilitation , 1986 .

[32]  N. Anthonisen,et al.  Selection of patients with chronic obstructive pulmonary disease for long-term oxygen therapy. , 1981, JAMA.

[33]  Cotes Je,et al.  LONG TERM DOMICILIARY OXYGEN THERAPY IN CHRONIC HYPOXIC COR PULMONALE COMPLICATING CHRONIC BRONCHITIS AND EMPHYSEMA Report of the Medical Research Council Working Party , 1981, The Lancet.

[34]  J. Oler.  The analysis of cross classification: by Henry T. Reynolds. New York: The Free Press, 1977, 236 pp., $12.95 , 1980 .

[35]  Continuous or nocturnal oxygen therapy in hypoxemic chronic obstructive lung disease: a clinical trial. Nocturnal Oxygen Therapy Trial Group. , 1980, Annals of internal medicine.

[36]  H. T. Reynolds,et al.  The analysis of cross-classifications , 1977 .

[37]  J. Fleiss,et al.  Statistical methods for rates and proportions , 1973 .