Outcomes of morbidly obese patients requiring mechanical ventilation for acute respiratory failure

Objective: To examine the outcomes of morbidly obese patients with acute respiratory failure treated with mechanical ventilation. Design: Retrospective study. Setting: A 14-bed medical intensive care unit in an 800-bed university-based hospital. Patients., A total of 50 morbidly obese subjects with acute respiratory failure requiring ventilatory assistance. Interventions. None. Measurements: Arterial blood gas measurements, intubation rate, days of mechanical ventilation, intensive care unit length of stay, hospital length of stay, and mortality. Results. From January 1997 to December 2004, 50 morbidly obese patients with acute respiratory failure were treated with mechanical ventilation. Invasive mechanical ventilation was implemented in 17 patients with a mean body mass index of 53.2 +/- 12.2 kg/m(2). A total of 33 patients were treated with noninvasive ventilation (NIV), of which 21 avoided intubation (NIV success) and 12 required intubation (NIV failure). Mean body mass index for the NIV success group was significantly less than for the NIV failure group (46.9 +/- 8.9 and 62.5 +/- 16.1 kg /m(2), respectively, p =.001). Acute Physiology and Chronic Health Evaluation II scores were similar for patients treated with invasive and noninvasive ventilation. Significant improvements in pH and PaCO2 were noted for the invasive mechanical ventilation and NIV success groups. No improvements in gas exchange were noted in the NIV failure group. Of patients treated with NIV, 36% required intubation. Hospital mortality for the invasive ventilation and NIV failure groups was increased. Conclusion., The type of ventilatory assistance may influence clinical outcomes in morbidly obese patients with acute respiratory failure.