DOES POSITIVE END-EXPIRATORY PRESSURE VENTILATION IMPROVE LEFT-VENTRICULAR FUNCTION - A COMPARATIVE-STUDY BY TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN CARDIAC AND NONCARDIAC PATIENTS

Study objectives: Positive end-expiratory pressure (PEEP) has been pro posed to inprove cardiac output in patients with left ventricular (LV) dysfunction. This study was designed to compare quantitative global a nd regional LV performance in response to PEEP in patients with normal and poor LV function. Design: a prospective clinical trial. Setting: Adult medical ICU in a university hospital. Patients: Twelve criticall y ill patients requiring respiratory support and divided into two grou ps according to baseline transesophageal echocardiographic (TEE) measu rements: normal LV dimensions and fractional area of contraction (FAC= 61+/-5%) (n=7) and dilated cardiomyopathy with reduced FAC (21+/-1%) ( n=5). Measurements and results: All patients were studied when two suc cessive levels of PEEP (best PEEP as the highest value of respiratory compliance and high PEEP as best PEEP+10 cm H2O) were applied. Global systolic LV performance and quantitative regional wall motion analysis performed by the centerline method were assessed on the TEE transgast ric short-axis view. End-systolic wall stress (ESWS) was used as a rel iable indication of LT afterload, PEEP reduced LV dimensions asymmetri cally in both groups of patients and septolateral diameter significant ly decreased without affecting global LV systolic performance. Additio nally, high PEEP produced a significant impairment in septal kinetics as evidenced by the centerline method, High PEEP also decreased ESWS f or all patients (-27% in normal group and -23% in cardiac group, p<0.0 5) without significant improvement in global systolic LV performance ( FAC: +2% in normal group and +0% in cardiac group; not significant). C onclusions: PEEP cannot be recommended routinely to improve LV perform ance in patients with severe dilated cardiomyopathy.