The Science Journal of the American Association for Respiratory Care

2010 OPEN FORUM Abstracts

DETERMINANT FACTOR OF OXYGEN DESATURATION RECOVERY TIME AFTER A SIX MINUTES WALK TEST IN PATIENTS WITH COPD

Chika Hirota1,2, Tetsuo Miyagawa2, Kaoru Konishi3, Kaori Tsuruta3,4; 1Department of Rehabilitation, Nippon Koukan Hospital, Kawasaki, Japan; 2Department of Respiratory Care,Graduate School of Nursing and Rehabilitation Sciences, Showa University, Yokohama, Japan; 3Department of Community Health & Home Care Management,Graduate School of Nursing and Rehabilitation Sciences, Showa University, Yokohama, Japan; 4Rehabilitation, Kanagawa Cardiovascular and Respiratory Center, Yokohama, Japan

Background: Because patients with COPD leads to exercise induced hypoxemia, it is necessary to monitor the oxygen saturation by using a pulse oximetry in pulmonary rehabilitation. There are many studies related to the exercise capacity or change of SpO2 in a six minute walk distance testing (6MWDT). It has been reported that the SpO2 decreases immediately after the patients start walking. However there is no study related to SpO2 recovery after 6MWDT and the mechanism of the SpO2 recovery has not been clarified. The aim of this study is to examine the factors related to SpO2 recovery time after 6MWDT in patients with COPD. Methods: 52 stable COPD outpatients enrolled in this study. We compiled the data of pulmonary function, dyspnea scale, GOLD classification, BODE index, and ADL. The SpO2 was recorded 3 minutes before walking at the rest sitting, also until completely recovery after walking. Bivariate analysis is performed by Mann-Whitney U test and correlation coefficient is estimated by Spearman rank method. Each of these possible explanatory variables was independently evaluated to determine their association with SpO2 recovery in a multiple regression analysis. We also analyzed cutoff value of SpO2 during the walk by using ROC curve. Result: There were 40 cases of patients with a fall in SpO2 after 6MWDT. The SpO2 recovery time correlated significantly with DSpO2, %DLco, 6MWD walk load, 6MWD, %DLco/VA, and MRC dyspnea scale. In a multiple regression analysis, a subgroup of two variables had the association DSpO2 and BODE index (p<0.04). Moreover, the cutoff value of SpO2 which a ROC curve shows was 88%. When the lowest values of SpO2 were classified by 88%, %88% group was significantly lower than >88% group in %DLco(p=0.03). Conclusion: In this comprehensive evaluation using the BODE index, it was effective in finding the severity for patients. Moreover it was necessary to evaluate not only the SpO2 measurement value but also DSpO2 during the pulmonary rehabilitation. SpO2 88% is the cutoff value for SpO2 during walk and is a reference value in the home oxygen therapy in Japan. SpO2 88% were also identified discontinuance criteria of exercise in pulmonary rehabilitation. FEV1.0% was not correlated with the SpO2 recovery time and SpO2 lowest value. However %DLco was a high correlation with the SpO2 recovery time, DSpO2 and SpO2 lowest value. Sponsored Research - None