A Cochrane review included 16 studies with a total of 994 subjects with predominantly chronic obstructive pulmonary disease (COPD). Compared to the invasive positive pressure ventilation (IPPV) strategy, noninvasive positive pressure ventilation (NPPV) significantly decreased mortality in trials enrolling exclusively participants with COPD (RR 0.36, 95% CI 0.24 to 0.56) whereas in trials enrolling mixed populations the benefits for mortality were less significant (RR 0.81, 95% CI 0.47 to 1.40). NPPV significantly reduced weaning failure (RR 0.63, 95% CI 0.42 to 0.96) and ventilator-associated pneumonia (RR 0.25, 95% CI 0.15 to 0.43); shortened length of stay in an intensive care unit (mean difference [MD] –5.59 days, 95% CI –7.90 to –3.28) and in hospital (MD –6.04 days, 95% CI –9.22 to –2.87); and decreased the total duration of ventilation (MD –5.64 days, 95% CI –9.50 to –1.77) and the duration of endotracheal mechanical ventilation (MD –7.44 days, 95% CI –10.34 to –4.55) amidst significant heterogeneity. Noninvasive weaning also significantly reduced tracheostomy (RR 0.19, 95% CI 0.08 to 0.47) and reintubation (RR 0.65, 95% CI 0.44 to 0.97) rates. Noninvasive weaning had no effect on the duration of ventilation related to weaning.
ventilator associated pneumonia (RR 0.29, 95% CI 0.19 to 0.45), length of stay in an intensive care unit (WMD -6.27 days, 95% CI -8.77 to -3.78 days; statistical heterogeneity I2 = 77.4%) and hospital (WMD -7.19 days, 95% CI -10.80 to -3.58 days; statistical heterogeneity I2 = 76.8%), total duration of ventilation (WMD -5.64 days, 95% CI -9.50 to -1.77 days; statistical heterogeneity I2 = 85.6%) and duration of endotracheal mechanical ventilation (WMD - 7.81 days, 95% CI -11.31 to -4.31 days; statistical heterogeneity I2 = 89.9%). Noninvasive weaning had no effect on weaning failures or the duration of ventilation related to weaning. Subgroup analyses suggested that the benefits on mortality and weaning failures were nonsignificantly greater in trials enrolling exclusively COPD patients versus mixed populations.Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment) and by heterogeneity.