General ward and pneumonia size as predictors of noninvasive ventilation failure

Introduction. Shortage of intensive care beds has led to more frequent use of noninvasive ventilation (NIV) outside respiratory units, and data on NIV efficacy and safety on general wards is lacking. Objective. The aim was to identify potential predictors for NIV failure. Methods. This was a retrospective analysis of patients treated with NIV at the Institute for Pulmonary Diseases of Vojvodina from 2009 to 2013. Demographics, blood gases, chest radiographs, setting, and outcomes were analyzed to identify predictors of NIV failure. Results. A total of 138 patients (65% men, mean age 66 ± 11 years) were treated with NIV. Indications for NIV were acute exacerbation of chronic obstructive pulmonary disease (85%) and cardiogenic pulmonary edema (7%), as well as respiratory insufficiency related to obesity and central hypoventilation (5%) and neuromuscular disease (3%). Rate of NIV failure was 34.8%. In 86 patients NIV was applied in the High Dependency Unit (HDU), while 52 received NIV on the general ward. Baseline characteristics in terms of gender, arterial blood gases, and the extent of consolidation on chest radiographs were similar. Patients treated in HDU were younger (64.4 ± 1.2 vs. 69.4 ± 1.5 years, p < 0.001). NIV on the general ward compared to HDU had higher rates of NIV failure (28/52 vs. 20/86, p < 0.001). Presence of consolidation involving two or more quadrants on chest radiograph (55% vs. 29%, p < 0.001) was associated with NIV failure. When adjusted for age and the extent of consolidation on chest radiograph, NIV failure was still less likely in patients treated in HDU (OR 0.23, 95% CI 0.10-0.50). Conclusion. Patients with consolidation on chest X-ray and patients treated with NIV outside of dedicated respiratory units are at a higher risk for NIV failure.