Cardiac and respiratory effects of continuous positive airway pressure and noninvasive ventilation in acute cardiac pulmonary edema

Objective. Continuous positive airway pressure (CPAP) is considered an effective nonpharmacologic method of treating patients with severe acute cardiogenic pulmonary edema. However, we hypothesized that bilevel noninvasive positive-pressure ventilation (NPPV), which combines both inspiratory pressure support and positive expiratory pressure, would unload the respiratory muscles and improve cardiac and hemodynamic function more effectively than CPAP. Design. Randomized crossover study. Setting. Critical care unit, Raymond Poincard Hospital. Patients. Six consecutive patients with acute cardiogenic pulmonary edema. Interventions. Patients were sequentially treated with 5 cm H2O CPAP, 10 cm H2O CPAP, and NPPV in a random order. Measurements and Main Results. Cardiac and hemodynamic function and indexes of respiratory mechanics were measured at each treatment sequence. NPPV reduced the esophageal pressure swing and esophageal pressure-time product compared with baseline (p <.05). There was no reduction in esophageal pressure swing or esophageal pressure-time product with CPAP. NPPV and 10 cm H2O CPAP reduced the mean transmural right and left atrial filling pressures without a change in cardiac index. Conclusions. This study demonstrates that NPPV was more effective at unloading the respiratory muscles than CPAP in acute cardiogenic pulmonary edema. In addition, NPPV and 10 cm H2O CPAP produced a reduction in right and left ventricular preload, which suggests an improvement in cardiac performance.