Intraoperative transesophageal echocardiography for the detection of cardiac preload changes induced by transfusion and phlebotomy in pediatric patients

Abstract

Background: Intraoperative blood volume changes are difficult to monitor in pediatric patients. The authors tested the hypothesis that transesophageal echocardiography would identify changes in cardiac filling resulting from manipulations of blood volume.

Methods: Eleven patients (3-15 kg) were studied following sternal closure after repair of congenital heart lesions. Transesophageal echocardiography of the midpapillary left ventricular short axis view and hemodynamics were recorded at baseline (T1), during withdrawal of blood until the systolic blood pressure decreased by 5 mmHg (T2) and 10 mmHg (T3), and after reinfusion of the blood (T4). The identical cycle of blood withdrawal and reinfusion was repeated after administration of calcium chloride (10 mg/kg; T5-T8).

Results: Manually traced transesophageal echocardiography images of the left ventricular end-diastolic area decreased from 4.64 +/- 1.50 cm2 at T1 to 4.03 +/- 1.25 cm2 at T2 to 3.78 +/- 1.35 cm2 at T3, and increased to 4.42 +/- 1.75 cm2 at T4. Nearly identical results were obtained at T5-T8. End-systolic areas significantly decreased from 1.96 +/- 0.86 cm2 at T1 to 1.52 +/- 0.73 cm2 at T2 to 1.41 +/- 0.62 cm2 at T3, and increased to 1.87 +/- 0.88 cm2 at T4. An experienced anesthesiologist-echocardiographer blinded to study events was able to identify mild reductions in blood volume (T2, T3, T6, T7) from recorded cine-loop video recordings with high sensitivity (80-95%) and specificity (80%).

Conclusions: Transesophageal echocardiography is a potentially useful monitor of cardiac filling changes in pediatric patients.