The applicability of the thermodilution method for determination of pulmonary blood flow and pulmonary vascular resistance in infants and children with ventricular septal defects.

The thermodilution method is accepted for measuring cardiac output in adults without shunts. It has been shown to work in animals the same size as newborn infants and has recently been used in children with congenital heart defects. We have proved its clinical applicability in determining the pulmonary blood flow, in twenty-five infants and children with VSD. The pulmonary vascular resistance can be calculated more accurately than by the Fick principle with an assumed O2 consumption, which has often had to be done in earlier studies.