Fig. 2
From: Randomized crossover trial of a demand oxygen delivery system in nocturnal hypoxemia

Twenty participants were assessed for eligibility. None of them met the exclusion criteria, and all of them were randomly assigned to either the auto-DODS followed by continuous flow group or the continuous flow followed by auto-DODS group (allocation ratio 1:1). One patient in the auto-DODS followed by continuous flow group was excluded from the largest analysis population because baseline data for VISIT1 were not available.