Delirium is a Strong Predictor of Mortality in Patients Receiving Non-invasive Positive Pressure Ventilation

Non-invasive positive pressure ventilation (NIPPV) has gained popularity over the years in the treatment of acute respiratory failure (ARF). Preliminary evidence suggests that delirium is an important factor contributing to NIPPV failure and death. This study was conducted to evaluate delirium and other associated factors of deaths in patients with ARF requiring the use of NIPPV.

A prospective observational study was conducted in a specialised NIPPV unit. Consecutive patients admitted for ARF requiring NIPPV were assessed by a psychiatrist for presence of delirium using the Diagnostic and Statistical Manual Version IV (DSM-IV). APACHE II score, co-morbidities-, and lung function were also assessed. Patients were followed until their deaths for a minimum of 1 year. Univariate and multivariate Cox's regression analyses were performed to explore predictive factors for death.

A total of 153 subjects were recruited, 49 (32.0 %) of whom had delirium. On univariate analysis, higher APACHE II score, lower BMI, presence of delirium, higher Charlson's co-morbidity index but not FEV₁ were associated with earlier death. On multivariate analysis, delirium (HR 4.4; 95 % CI 2.6-7.4; p < 0.001) and lower BMI (HR 0.92; 95 % CI 0.86-0.98; p = 0.013) were independently associated with earlier death within 1 year.

There is a high prevalence of delirium in patients requiring NIPPV. The presence of delirium is a strong predictor of mortality. There is strong need to identify and manage these high-risk patients to improve their mortality. The collaboration between psychiatrists and physicians should be strengthened.