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 SpO(2) 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), SpO(2) ( 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.