Energetics and Hemodynamic Changes of Normal and Various Right Heart Bypass (Fontan) Circulations in Lambs under Varying Respiration Parameters

The Fontan circulation or one of its many modifications is a common surgical procedure implemented in children with congenital heart defects to improve pulmonary circulation. Two modifications are the atriopulmonary connection (AP) and the modified total cavopulmonary connection (TCPC). Successful AP and TCPC operations performed in lambs show respiration has a major influence on systemic and pulmonary hemodynamics. Instantaneous pressure and flow waveforms are obtained before and after the procedure and energies are calculated. Hemodynamic changes in relevant vessels are also acquired. Time delays due to respiration will be calculated and transfer functions computed. The purpose of this study is to examine these waveforms and energy gains/losses under varying respiration parameters in order to aid in determining an optimal surgical protocol as well as assist in the development an accurate computer simulation model.