Introduction: Ambulatory oxygen (O2) 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 O2 flow preventing oxygen saturation by pulse oximetry (SpO2) from falling below 88%. His study was designed to generate a 6MWT index predicting the O2 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 (O2-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 O2-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 SpO2 falling below 88% validated in the validation population (r(2) = 0.842; p < 0.001).
Conclusions: The O2-GAP index appears to be a useful tool to titrate ambulatory O2 with a single 6MWT on room air in ILD patients with breathlessness and dyspnea on exertion.
Keywords: 6-min walk test; Exercise testing; Interstitial lung disease; Oxygen therapy.
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