Transpulmonary thermodilution in a pediatric patient with an intracardiac left-to-right shunt

Monitoring of cardiac output (CO) in the perioperative period and in seriously ill pediatric patients is of major importance for medical management. Hemodynamic monitoring, using transpulmonary thermodilution (TPTD) via a single thermal indicator injection, allows for measurements of CO, volumetric variables and extravascular lung water (EVLW). We describe and explain the influence of a left-to-right shunt on TPTD curve characteristics and EVLW measurements in a young child undergoing a surgical atrial septal defect repair. We suggest that these specific changes in the TPTD curve and the overestimation of EVLW detected by current device, in absence of gas exchange abnormalities, could be indicators of existing circulatory shunts in pediatric patients.