UCSF

The Use of Transesophageal Echocardiography for the Assessment of Left Ventricular Volume and Function in Patients Undergoing Acute Normovolemic Hemodilution as a Human Hemorrhagic Model BACKGROUND: Since the development of the sphygmomanometer in 1896, the several methods to monitor volume resuscitation in hypovolemic trauma patients have been examined. Recently, transesophageal echocardiography (TEE) has been considered for this use. PURPOSE: This study examined the use of TEE for the assessment of left ventricular volume and function during graded blood removal in a human hemorrhagic model. DESIGN: Following IRB approval, 38 patients undergoing acute normovolemic hemodilution (ANH) intraoperatively were consented to have 15% of their total blood volume removed (according to ANH protocol) in 5% aliquots and stored in the operating room for re-infusion. After blood withdrawal, 5% aliquots of Hextend® was infused, equal the amount of blood removed. Left ventricular (LV) chamber dimensions and trans-mitral Doppler flow measurements were obtained with TEE at baseline and at each blood withdrawal and replacement of Hextend®. LV measurements analysis included: one-dimensional (1D) end-diastolic diameter (EDD), end-systolic diameter (ESD), and fractional shortening (FS); two-dimensional (2D) end-diastolic area (EDA), end-systolic area (ESA), and fractional area change (FAC); three-dimensional (3D) end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (EF); trans-mitral Doppler flow measurements of E and A-wave morphology. RESULTS: Statistically significant differences were demonstrated for measurements of: 1D EDD (p < .0001) and ESD (p < .0001); 2D EDA (p < .0001) and ESA (p < .0001) during blood removal. No statistically significant differences were observed for FS (p = .371) or FAC (p = .369). Statistically significant differences were demonstrated for 3D measurements of EDV (p < .0001) and EF (p = .002) during both blood removal and replacement with Hextend®. No statistical significance was observed with ESV measurements (p = .427). Only the trans-mitral Doppler measurement of peak E-wave velocity demonstrated a statistically significant difference (p < .0001). CONCLUSION: Although all measurements of LV dimensions can detect 5% changes during blood removal, 3D measurements of EDV and EF can detect changes during both blood removal and replacement of Hextend®, possibly making it better at guiding volume replacement during blood loss. Trans-mitral Doppler flow may not be as effective as a guide for fluid management.