Hemodynamic Response and Support After Deep Hypothermic Circulatory Arrest in Neonatal Patients Undergoing Surgical Repair of Congenital Heart Defects

Abstract

Corrective surgery is a common and often necessary treatment for children born with congenital heart defects. These are defects in the gross anatomy of the heart and often affect the circulation of oxygenated blood through the body. As a result, surgery is required at an extremely young and unstable age. Nearly all reparative surgeries for congenital heart defects require opening the chest and using cardiopulmonary bypass. The more severe defects require stopping the heart and dramatically cooling the body's temperature, causing a state of complete circulatory arrest. The human response to surgical stress has been well documented, but the effect of deep hypothermic circulatory arrest (DHCA) on hemodynamic responses has yet to be described. Blood pressure, heart rate, and the amount of infused inotropic support, serum lactate, bicarbonate, and pH levels were recorded in infants less than three months of age over a 48-hour period immediately after surgical repair of congenital heart defects. The patients who underwent DHCA demonstrated significantly increased levels of serum lactate, and required more inotropic support to maintain similar blood pressures and heart rates to those patients not undergoing DHCA. Increased serum lactate is an indicator of insufficient end-organ perfusion resulting from lower cardiac output as reflected by the need for greater inotropic support in this group. Infants under 90 days of age undergoing cardiac surgery and DHCA require greater inotropic support and have significantly higher serum lactate levels than those who undergo cardiac surgery with cardiopulmonary bypass only.