Comparison of transpulmonary thermodilution, transthoracic echocardiography and conventional hemodynamic monitoring in neonates and infants after open heart surgery: a preliminary study.

BACKGROUND: Transpulmonary thermodilution (TPTD) is an increasingly popular method used to monitor the complex hemodynamic changes in critically ill children. The purpose of our study was to examine the relationship between transthoracic echocardiographic (TTE) parameters and global hemodynamic variables derived from TPTD and those derived from conventional measurements in infants and neonates undergoing corrective cardiac surgery.

METHODS: After approval from the Ethics Committee of Gottsegen György Hungarian Institute of Cardiology and individual parental consent were obtained, patients were prospectively enrolled. In parallel with continuous postoperative conventional monitoring, TPTD was measured four times daily, and TTE was performed once per day. Conventional hemodynamic, TPTD and TTE parameters were compared with weighted linear regression statistics and a Pearson correlation.

RESULTS: One hundred forty-five TPTD measurements and 35 TTE examinations of thirteen enrolled patients were analyzed. Global end-diastolic volume index (GEDVI) was correlated with the fractional shortening (SF, r=0.67, P=0.001) measured by TTE. Among the preload parameters, the percentage change of GEDVI between two consecutive time points showed a pertinent correlation with changes of cardiac index (r=0.67, P=0.001) and changes of stroke volume index (r=0.57, P=0.008). Percentage changes in SF demonstrated a strong negative correlation with changes of left ventricular end-systolic diameter (r=-0.86, P<0.001). There was no significant relationship between alterations in arterial or central venous pressure values with TTE or TPTD parameters.

CONCLUSION: Both TPTD and TTE may be used in the estimating volumetric preload parameters. The time course of TPTD-derived parameters may have clinical relevance in pediatric critical care practice.