Bedside transthoracic echocardiography (TTE) provides rapid and noninvasive hemodynamic assessment of critically ill patients but is limited by the immediate availability of experienced sonographers and cardiologists.
Forty-four patients in the medical ICU underwent near-simultaneous limited TTE performed by intensivists with minimal training in echocardiography, and a formal TTE that was performed by certified sonographers and was interpreted by experienced echocardiographers. Intensivists, blinded to the patient's diagnosis and the results of the formal TTE, were asked to determine whether left ventricular (LV) function was grossly normal or abnormal and to place LV function into one of the following three categories: 1, normal; 2, mildly to moderately decreased; and 3, severely decreased.
Using the formal TTE as the “gold standard,” intensivists correctly identified normal LV function in 22 of 24 cases (92%) and abnormal LV function in 16 of 20 cases (80%). The κ statistic for the agreement between intensivist and echocardiographer for any abnormality in LV function was 0.72 (95% confidence interval [CI], 0.52 to 0.93; p < 0.001). Intensivists correctly placed LV function into one of three categories in 36 of 44 cases (82%); in 6 of the 8 cases that were misclassified, the error involved an overestimation of LV function. The κ statistic for agreement between the intensivist and echocardiographer with regard to placement into one of three categories of LV function was 0.68 (95% CI, 0.48 to 0.88; p < 0.001).
Intensivists were able to estimate LV function with reasonable accuracy using a hand-held unit in the ICU, despite having undergone minimal training in image acquisition and interpretation.