Level 2: Mid-level evidence
The Three Interventions in Cardiogenic Pulmonary Oedema (3CPO) trial evaluated ventilation strategies for patients with respiratory distress due to acute heart failure (N Engl J Med. 2008;359:142-151). Patients with acute cardiogenic pulmonary edema (N=1,156, mean age 78 years) were randomized to one of three interventions: supplemental oxygen via variable-delivery oxygen mask with reservoir to maintain oxygen saturations >92% vs. continuous positive airway pressure (CPAP) vs. noninvasive positive pressure ventilation (NIPPV). CPAP (Figure 1) was started at 5 cm H2O and increased to a maximum of 15; NIPPV was started at inspiratory positive airway pressure of 8 cm H2O (maximum 20) and expiratory positive airway pressure of 4 cm H2O (maximum 10). Mean duration of therapy was 2.2 hours for CPAP and 2 hours for NIPPV. Eighty-seven patients were excluded after randomization due to ineligibility or previous recruitment.
Comparing noninvasive ventilation (CPAP or NIPPV) vs. oxygen, there were no significant differences in mortality at seven days or 30 days, intubation within seven days, ICU admission, or incidence of MI. NIPPV was associated with a greater mean change in dyspnea score at one hour (4.6 vs. 3.9 [on a scale of 0-10, with 10 signifying maximal breathlessness], P=.008). There were no significant differences comparing CPAP vs. NIPPV for any clinical outcome.