The effect of body mass index on outcomes of patients receiving noninvasive positive-pressure ventilation in acute respiratory failure.

BACKGROUND A study was undertaken to determine factors present in adult patients, newly admitted to the hospital, that predict the inability of noninvasive positive-pressure ventilation (NPPV) to sustain the work of breathing and avoid endotracheal intubation. METHODS Data were collected prospectively from patients with acute respiratory failure who were admitted to Hackensack University Medical Center from August 2001 to August 2002 and received NPPV. Physiologic characteristics of those patients on admission were compiled into a database, with the hypothesis that those with the worst initial physiologic characteristics would subsequently fail NPPV and require endotracheal intubation with mechanical ventilation. RESULTS Seventy-five patients were included. Sixty-four patients (85%) successfully avoided endotracheal intubation and were discharged. Of the 11 patients who failed NPPV, 8 were intubated and 5 expired. The groups were comparable in age, sex, arterial blood gases, and Acute Physiology and Chronic Health Evaluation score (p > 0.05). The success group, however, had a significantly higher body mass index (29 kg/m(2) vs 23 kg/m(2), p = 0.0167). CONCLUSIONS The following can be concluded from our study: there is a low failure rate for NPPV (15%); patients with a low body mass index are more likely to fail NPPV and require endotracheal intubation; and patients who fail NPPV have a higher risk of mortality (p = 0.00016).