DIAGNOSTIC-ACCURACY AND THERAPEUTIC IMPACT OF TRANSTHORACIC AND TRANSESOPHAGEAL ECHOCARDIOGRAPHY IN MECHANICALLY VENTILATED PATIENTS IN THEICU

Study objectives: To assess the respective diagnostic accuracy of tran sthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) and their therapeutic implications in mechanically ventilated pa tients, in the intensive care unit (ICU). Design: A prospective study. Settings: Intensive care units of two tertiary referral teaching hosp itals. Patients: One hundred eleven ICU patients (81 men and 30 women; mean age 57+/-16 years). Fifty-seven percent were hospitalized for me dical illnesses, 16.5 percent after thoracic surgery, 10.5 percent aft er other surgery, and 16.0 percent for multiple trauma. Their Simplifi ed Acute Physiologic Score was 16+/-5. Interventions: The echocardiogr ams were performed in order to solve well-defined clinical problems. T TE was the first step of the procedure and TEE was performed only when (1) TTE did not solve the clinical problems, and (2) TTE yielded unsu spected findings requiring TEE. During each echocardiographic study, t he following were noted: ventilatory mode, clinical problems, imaging quality, results, consequence on acute care, duration of the procedure , and potential complications of TEE, Diagnostic accuracy was defined as the proportion of solved problems, and therapeutic impact was defin ed as changes on acute care that resulted directly from the procedure. Measurements and Results: One hundred twenty-eight consecutive TTE an d 96 TEE were performed. TTE solved 60 of 158 clinical problems (38 pe rcent), whether positive end-expiratory pressure (>4 cm H2O) was prese nt or not(28 of 74 vs 32 of 84: p>0.50). TTE allowed evaluation of lef t ventricular function in 77 percent of cases and pericardial effusion in every case, but it did not solve most of the other clinical proble ms. Indeed, the diagnostic accuracy of TEE was markedly superior (95/9 8 vs 60/158: p<0.001), but TEE required a physician's presence longer (43+/-17 min vs 27+/-12 min: p<0.001). When TTE and TEE were scheduled (n=96), TEE yielded an additional diagnosis or excluded with more cer titude a suspected diagnosis, except in two cases. TEE had a therapeut ic impact more frequently than TTE (35/96 vs 20/128: p<0.001). Cardiov ascular surgery was prompted by echocardiographic findings in ten pati ents. TEE was well tolerated in all patients; there were no complicati ons. Conclusions: TEE is a valuable well-tolerated imaging technique i n mechanically ventilated patients. For the assessment of left ventric ular systolic function and pericardial effusion; however, TTE continue s to be an excellent diagnostic tool, even when positive end-expirator y pressure is present. Both TTE and TEE have a therapeutic impact in a pproximately 25 percent of cases.