Fig. 2From: High-flow nasal cannula oxygen versus conventional oxygen therapy for acute respiratory failure due to COVID-19: a systematic review and meta-analysisForest plot of intubation rate comparison between HFNC and COT from randomized controlled trials (fixed-effects meta-analysis by the Mantel–Haenszel method). COT conventional oxygen therapy; HFNC high-flow nasal cannula; M-H Mantel–HaenszelBack to article page