The Role of Transesophageal Echocardiography in Optimizing Resuscitation in Acutely Injured Patients

Abstract

The goal of resuscitation is to correct the mismatch between oxygen delivery and that of cellular demands. The pulmonary artery catheter (PAC) is frequently used to gauge the adequacy of resuscitation and guide therapy based on ventricular filling pressures. Transesophageal echocardiography (TEE) has emerged as a potential tool in assessing adequacy of acute hemodynamic resuscitation. The purpose of this study was to evaluate the role of TEE in assessing preload during ongoing volume resuscitation in trauma patients. A retrospective review was conducted of acutely injured patients undergoing TEE during resuscitation from hemorrhagic shock from January 2002 to 2004 at a Level I trauma center. The indication for TEE was persistent hemodynamic instability in the absence of ongoing surgical hemorrhage. Variables included hemodynamic and PAC parameters, pre-TEE resuscitation volume, and vasopressor requirements. The impact of TEE findings on therapeutic decisions was evaluated. Twenty-five patients underwent TEE, 18 (72%) had an indwelling PAC with a mean pulmonary artery occlusion pressure of 19.3 mm Hg (range, 12-29 mm Hg) and mean cardiac index of 2.9 L/min/m2 (range, 1.6-4.6 L/min/m2). Twelve patients (48%) were receiving inotropes and/or vasopressors for hypotension at the time of TEE. Resuscitation volume within 6 hours before TEE included a mean of 6.5 L of crystalloid and 12.2 units of blood products (packed red blood cells, fresh frozen plasma, and platelets). TEE revealed left ventricular hypovolemia in 13 patients (52%) and altered therapy in 16 patients (64%), including additional volume (n = 13), addition of an inotrope (n = 4), and addition of a vasodilator (n = 1) in one patient with ventricular overdistention. Comparison of the abnormal and normal TEE groups revealed that only cardiac index was significantly different (2.6 L/min/m2 in the abnormal group vs. 3.9 L/min/m2 in the normal group; p = 0.005). Significant mitral valve regurgitation leading to valve replacement was identified in one patient. No clinically relevant pericardial effusion was identified. TEE altered resuscitation management in almost two thirds of patients. Many patients with "acceptable" pulmonary artery occlusion pressure parameters may in fact have inadequate left ventricular filling. In addition, TEE offers the advantage of direct assessment of cardiac valve competency, myocardial wall contractility, and pericardial fluid.