First author [Ref.] | Favours bilevel n | Favours control n | MD±se | Weight % | MD (random) 95% CI |
Ambrosino 25 | 7 | 7 | 382.0000±58.2666 | 21.59 | 382.00 (267.80–496.20) |
Highcock 18 | 8 | 8 | 164.0000±165.1882 | 13.03 | 164.00 (−159.76–487.76) |
Lien 26 | 11 | 11 | 50.0000±54.3557 | 21.86 | 50.00 (−56.54–156.54) |
Lin 27 | 10 | 12 | 23.0000±13.9401 | 23.68 | 23.00 (−4.32–50.32) |
Nava 17 | 6 | 7 | 380.0000±81.1858 | 19.85 | 380.00 (220.88–539.12) |
Total | 42 | 43 | 100 | 195.64 (21.97–369.31) |
MD: mean difference; CI: confidence interval. Comparison: crossover trials of bilevel noninvasive positive pressure ventilation versus all modalities. Outcome: VT mL. Test for heterogeneity: Chi squared = 53.19, df = 4 (p<0.00001), I2 = 92.5%. Test for overall effect: Z = 2.21 (p = 0.03).