Fig. 2From: Multi-center, randomized, placebo-controlled trial of nocturnal oxygen therapy in chronic obstructive pulmonary disease: a study protocol for the INOX trialDiagnostic procedures. In case of oximetry tracing suggestive of sleep apnea, patients are excluded, unless sleep apnea is ruled out on the basis of a formal sleep study (either of Type-1 or Type-2 – shaded area) performed off-protocolBack to article page