Impact of Early Enteral Feeding on Splanchnic Blood Flow After Surgery for Critical Heart Disease in the Newborn

Neonates with critical congenital heart disease (CHD) undergoing surgery often have postoperative decreases in cardiac output. These hemodynamic changes can result in varying levels of organ dysfunction, ranging from the subclinical to the more overt. Although this low cardiac output syndrome (LCOS) and accompanying multiorgan dysfunction syndrome (MODS) is in large part transient, the rapidity and completeness of resolution can vary greatly.

During postoperative care in the intensive care unit, knowledge of this phenomenon must be balanced against the desire to initiate enteral nutrition. Many studies have demonstrated that timely initiation of enteral feeds in the intensive care can reduce mortality, morbidity and costs. Practically speaking, the decision to initiate feeds is made based on the patient's postoperative hemodynamic status, a normal lactate, absence of vasopressor agents and presence of bowel sounds. Trophic enteral feeding can usually commence 24h postoperatively, even after complicated neonatal heart surgery,

The vast majority of postoperative neonates suffer no apparent ill effects from this management strategy. However, recent data have demonstrated an exceedingly high incidence (3.3-6.8%) of necrotizing enterocolitis (NEC) in CHD patients; a disease for which diminution in splanchnic blood flow and disruption of the mucosal barrier are felt to play an important role. These data suggest the combination of diminished cardiovascular reserve, cyanosis and increased myocardial oxygen demands may promote the development of NEC.

Preliminary data from Sickkids (Chanthong and Sivarajan, 2008) demonstrates an NEC incidence of 8% in CHD patients. Patients with NEC also accounted for 25% of all cardiac arrests in Cardiac CCU.