Prognostic value of noninvasive measures of contractility in emergency department patients with severe sepsis and septic shock undergoing early goal-directed therapy

Abstract

Purpose Reversible ventricular dysfunction is common in sepsis. Impedance cardiography allows for noninvasive measurement of contractility through time interval or amplitude-based measures. This study evaluates the prognostic capacity of these measures in patients with severe sepsis or septic shock in the emergency department. Methods This is a prospective observational cohort study of 56 patients older than 18 years meeting criteria for early goal-directed therapy (lactate level >4 mmol/L or systolic blood pressure <90 mm Hg after 2-L isotonic sodium chloride solution). Continuous collections of contractility measures were performed, and patients were followed until discharge or in-hospital death. Results A significant 57% reduction in the accelerated contractility index (ACI) in nonsurvivors (71 1/s 2 [41-102]) compared with survivors (123 1/s 2 [98-147]) existed. Only ACI predicted in-hospital mortality (area under the receiver operating characteristic curve = 0.70, P < .01). Accelerated contractility index did not correlate with amount of prior fluid administration, central venous pressure, number of cardiac risk factors, or troponin I value. An ACI of less than 40 1/s 2 is 95% (84-99) specific with a positive likelihood ratio of 8.8 for predicting in-hospital mortality. Conclusions A reduced ACI is associated with mortality in critically ill emergency department patients presenting with severe sepsis and septic shock meeting criteria for early goal-directed therapy. This association appears to be independent of clinical or laboratory predictors of cardiac dysfunction or preload.