What Is the Impact of Mildly Altered Consciousness on Acute Hypoxemic Respiratory Failure with Non-invasive Ventilation?

Objective A severely altered level of consciousness (ALC) is considered to be a possible contraindication to non-invasive ventilation (NIV). We investigated the association between mild ALC and NIV failure in patients with hypoxemic respiratory failure. Methods A retrospective study was conducted by reviewing the medical charts of patients with de novo hypoxemic respiratory failure who received NIV treatment. The clinical background and the outcomes of patients with and without ALC were compared. Patients Patients who were admitted to our hospital for acute hypoxemic respiratory failure between July 2011 and May 2015 were included in the present study. Results Sixty-six of the 148 patients had ALC. In comparison to the patients without ALC, the patients with ALC were older (median: 72 vs. 78 years, p=0.02), had a higher Acute Physiology and Chronic Health Evaluation II score (18 vs. 19, p=0.02), and received a higher level of inspiratory pressure (8 cmH2 O vs. 8, p<0.01). The median Glasgow Coma Scale score of the patients with ALC was 14 (interquartile range, 11-14). There were no significant differences between the groups in the rates of NIV failure (24% vs. 30%, p=0.4) and in-hospital mortality (13% vs. 16%, p=0.3). Conclusion NIV may be successfully applied to treat acute hypoxemic respiratory failure with mild ALC. NIV may be performed, with careful attention to the appropriate timing for intubation.