Aims: Benefits of nasal continuous positive airway pressure (CPAP) in patients presenting with chronic heart failure (CHF) are controversial. The purpose of this study was to compare the hemodynamic effects of CPAP and bilevel positive airway pressure (BiPAP) in patients with or without CHF.
Methods and results: Twenty patients with CHF and 7 with normal left ventricular function underwent cardiac catheterization. Measurements were made before and after three 20-min periods of BiPAP: expiratory positive airway pressure (EPAP) = 8 cm H2O and inspiratory positive airway pressure (IPAP) = 12 cm H2O, EPAP = 10 cm H2O and IPAP = 15 cm H2O, and CPAP = EPAP = IPAP = 10 cm H2O administered in random order. Positive pressure ventilation decreased cardiac output (CO) and stroke volume. No change was observed in either pulmonary or systemic arterial pressure. There was no difference in the hemodynamic effects of the three ventilation settings. Only mean pulmonary wedge pressure (MPWP) and heart rate were lower with CPAP than with BiPAP. CO decreased only in patients with low MPWP (</=12 mm Hg). BiPAP ventilation increased PaO2 and decreased PaCO2 more than CPAP.
Conclusions: In patients with cardiac failure, a decrease in CO occurs both during CPAP and BiPAP, when pulmonary wedge pressure is low (</=12 mm Hg).