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A1751 - The Effect of the Environment on Outdoor Six-Minute Walk Test Performance in Individuals with Alpha-1 Antitrypsin Deficiency and Chronic Obstructive Pulmonary Disease
Author Block: J. Chung1, A. Ataya2, J. Nolte2, V. A. Segui2, M. L. Brantly3, L. Benninger4; 1Pulmonary, Critical Care and Sleep Medicine, University of Florida, Gainesville, FL, United States, 2University of Florida, Gainesville, FL, United States, 3Univ of Florida Hlth Sci Ctr, Gainesville, FL, United States, 4Pulmonary and Critical Care, University of Florida, Gainesville, FL, United States.
Introduction To date, the impact of the environment on oxygen saturation and breathing in patients with obstructive lung disease has not been clearly studied. Research has linked worsening in other pulmonary conditions to high humidity, low barometric pressure, and temperature changes. A1ATD and COPD patients usually complain of shortness of breath during unfavorable weather conditions, including humidity and temperature extremes. We set out to study the impact of weather conditions on 6MWT performance and oxygen requirements. Preliminary results of ongoing study are presented. Method This was a single-center randomized, cross-over, clinical trial. We included adult patients with A1ATD and COPD with severe obstructive lung disease who were not on oxygen. Patients underwent both an indoor and outdoor 6MWT and we measured different parameters including particulate matter in the air, temperature, humidity and barometric pressure. Results 25 subjects (12 male, 13 female, age 62.9±6.1, FEV1 1.23±0.35, FVC 3.1±0.86, 21 A1ATD, 4 COPD) have been enrolled. A total of five subjects (20%) experienced oxygen desaturation only during the outdoor 6MWT that met criteria for oxygen therapy. There was no significant association between outdoor particulate matter, temperature, humidity and barometric pressure with isolated outdoor desaturation during the 6MWT. Patients who experienced an isolated outdoor desaturation had a significantly lower BMI (21.6±4.2 vs 28.6±5.5 p=.013; OR 0.66 [95% CI, 0.49 to 0.90]), FVC% (62.4±21.9 vs 82.3±15.3, p=.026 OR 0.93 [95% CI, 0.83 to 1.04]) and change in indoor Borg fatigue score (6.0±3.7 vs 2.7±2.3, p=.017, OR 1.52 [95% CI, 1.03 to 2.24]) compared to the group that did not have isolated outdoor desaturation. Discussion A total of 5 patients (20%) experienced oxygen desaturation that met criteria for home oxygen only during the outdoor 6MWT. No association between studied outdoor variables (particulate matter, temperature, humidity and barometric pressure) was present. Patients with a lower BMI , FVC% and who experienced a greater change in their indoor Borg Fatigue Score that did not meet oxygen requirements indoors were more likely to experience oxygen desaturation outdoors. Conclusion Physicians should consider performing outdoor 6MWT in certain patients with A1ATD and COPD who do not meet criteria for oxygen during an indoor 6MWT.