Therapeutic Management. The symptomatic newborn (severe desaturation related to decreased pulmonary blood flow or frequent tet spells) frequently need continuous PGE infusion to maintain ductal patency. Palliative or definitive surgical intervention is necessary in the first days of life.
Medical Management. Older infants need very close monitoring for signs and symptoms of worsening hypoxemia.Illnesses that put them at risk for dehydration must be treated promptly. Hemoglobin levels and hematocrite values may be evaluated to assess for anemia. Close monitoring for hypercyanotic episode may detect some very subtle and often self limiting episodes lasting 10 to 15 minutes.
Surgical Management. Choices in surgical management include palliative procedures to increase pulmonary blood flow or a definitive intracardiac repair. Decisions and considerations regarding palliative or definitive repairs include institutional approach, associated anatomic issues such as abnormal coronary arteries, branch pulmonary artery size or stenosis, infant size, and whether pulmonary atresia is also present. Earlier surgical intervention is indicated for increasing or severe cyanosis, significant polycythemia, or hypercyanotic episodes. In recent years, primary repair during infancy has become the treatment of choice at many centers, with surgery scheduled at 2 to 4 months of age for asymptomatic infants and sooner, if indicated, for certain symptomatic infants. The rationale for early definitive repair is to normalize the physiology sooner and promote normal growth of the pulmonary arteries. Definitive repair requires cardiopulmonary bypass. Postoperative complications include rhythm disturbances ( e.g., a narrow complex tachycardia, varying degrees of heart block), residual ventricular septal defect, low cardiac output related to right ventricular dysfunction, residual right ventricular outflow obstruction, and branch pulmonary artery stenosis. Mortality rate for uncomplicated tetralogy of Fallot repair is reported at 2% to 5%.
Some symptomatic newborns are poor candidates for primary repair. These infants may benefit from the lower risk surgical creation of a systemic pulmonary artery shunt to increase pulmonary blood flow. The most commonly performed is the modified Blalock Taussing procedure. This usually is not done with the child on cardiopulmonary bypass. The complications are the same as for other thoracotomy incisions, including pneumothorax, stridor from recurrent laryngeal nerve injury, diaphragm paresis from phenic nerve injury, and chylothorex from injury to the thoracic duct. In addition, shunt failure because of thrombosis or clot remains a potential major problem.