Dependency on mask ventilation after acute respiratory failure in the intermediate care unit

The predictive factors for long-term dependency (LTD) on noninvasive ventilation (NIV) immediately after acute hypercapnic respiratory failure (AHRF) have not been identified. The present authors studied 42 patients with chronic obstructive pulmonary disease (COPD) and 58 non-COPD patients successfully treated by NIV for an AHRF episode. Parameters at stable state, at admission for AHRF and during a 1-yr follow-up were compared in patients with or without LTD-NIV at discharge. The incidence of LTD-NIV was 39% in non-COPD patients and 19% in COPD patients. Based on multivariate analysis with stepwise logistic regression, lower baseline pH values and noninfectious causes of AHRF were independently associated with LTD-NIV. Mutually adjusted odds ratios were found to be 1.316 (95% confidence interval (CI) = 1.127-1.536) for a 0.01 decrease of baseline pH value and 5.1 (95% CI = 1.8-14.0) for a noninfectious cause of AHRF. Outcome after 1 yr was poor in COPD patients. Long-term dependency on noninvasive ventilation is not an uncommon situation after resolution of an acute hypercapnic respiratory failure episode, especially in patients with non-chronic obstructive pulmonary disease causes of respiratory failure. The present study raises the need for prospective validation of a weaning protocol in patients managed by noninvasive ventilation for an acute hypercapnic respiratory failure episode.