Right ventricular ejection fraction measurement in moderate acute respiratory failure (ARF). Effects of PEEP.

Eight patients mechanically ventilated for acute respiratory failure were submitted to increasing levels of PEEP, from 0 to 15 cm H2O. Right ventricular ejection fraction (RVEF) and end-diastolic volume index (RVEDVI) were measured using the fast response thermistor Swan-Ganz catheter. PEEP induced a linear decrease of cardiac index, while the pulmonary artery pressure increased. In three patients (group A) with a RVEDVI larger than 120 ml at ZEEP, RVEF decreased and RVEDVI increased with PEEP. In the other five patients (RVEDVI less than 120 ml, group B), RVEF was unchanged and RVEDVI decreased at PEEP 15 cm H2O. This study suggest that RV changes induced by PEEP are probably a function of the initial RVEF and RVEDVI.