A 6MWT index to predict O2 flow correcting exercise induced SpO2 desaturation in ILD

Introduction: Ambulatory oxygen (O-2) is prescribed to interstitial lung disease (ILD) patients with mild hypoxemia, breathlessness and dyspnea on exertion. Oxygen titration is generally done with the 6 minute walk test (6MWT) to determine the O-2 flow preventing oxygen saturation by pulse oximetry (SpO(2)) from falling below 88%. His study was designed to generate a 6MWT index predicting the O-2 flow allowing completion of the 6MWT without oxygen desaturation. Methods: Oxygen titration data from a group of 66 ILD patients and 30 controls, were used to generate the algorithm determining an index (O-2-GAP) predicting oxygen flow required to complete a 6MWT without desaturation below 88%. This index was validated in a group of 93 ILD patients. Results: The O-2-GAP index, as obtained from the derivation population, (r(2) = 0.97, p < 0.001) was shown to correctly predict the oxygen flow required to complete the 6MWT without SpO(2) falling below 88% validated in the validation population (r(2) = 0.842; p < 0.001). Conclusions: The O-2-GAP index appears to be a useful tool to titrate ambulatory O-2 with a single 6MWT on room air in ILD patients with breathlessness and dyspnea on exertion. (C) 2013 Elsevier Ltd. All rights reserved.