Noninvasive pressure support ventilation vs. continuous positive airway pressure in acute hypercapnic pulmonary edema

Objective This study compared noninvasive pressure support ventilation (NIPSV) and continuous positive airway pressure (CPAP) in patients with acute hypercapnic pulmonary edema with regard to resolution time.Design and setting Randomized prospective study in an emergency department.Patients and participants We randomly assigned 36 patients with respiratory failure due to acute pulmonary edema and arterial hypercapnia (PaCO₂ >45 mmHg) to NIPSV (n=18) or CPAP through a face mask (n=18).Measurements and results Electrocardiographic and physiological measurements were made over 36 h. There was no difference in resolution time defined as clinical improvement with a respiratory rate of fewer than 30 breaths/min and SpO₂ of 96% or more between CPAP and NIPSV groups. Arterial carbon dioxide tension was significantly decreased after 1 h of ventilation (CPAP, 60.5±13.6 to 42.8±4.9 mmHg; NIPSV, 65.7±13.6 to 44.0±5.5 mmHg); respective improvements were seen in pH (CPAP, 7.22±0.11 to 7.37±0.04; NIPSV, 7.19±0.11 to 7.38±0.04), SpO₂ (CPAP, 86.9±3.7% to 95.1±2.6%; NIPSV, 83.7±6.6% to 96.0±2.9%), and respiratory rate (CPAP, 37.9±4.5 to 21.3±5.1 breaths/min; NIPSV, 39.8±4.4 to 21.2±4.6 breaths/min). No significant differences were seen with regards to endotracheal intubation and in-hospital mortality.Conclusions NIPSV proved as effective as CPAP in the treatment of patients with acute pulmonary edema and hypercapnia but did not improve resolution time.