Fig. 2From: Portable NIV for patients with moderate to severe COPD: two randomized crossover trialsa CONSORT flow diagram of the study enrolment process (Study I) [27]. b CONSORT flow diagram of the study enrolment process (Study II) [27]. The discrepancy between the sample size calculation and the final recruitment size is due to the recruitment process. There was no post-recruitmentBack to article page