Comments: A newborn with this anatomical background will have limited pulmonary blood flow and severe cyanosis. The establishment of an aortopulmonary shunt, in this case subclavian artery to pulmonary artery, will enhance pulmonary blood flow, improve systemic oxygenation, and foster proper growth of the pulmonary arteries.

Most patients with a normally functioning Fontan circulation will be able to participate in normal daily activities. The biggest difference with peers is decreased exercise capacity, usually 50% to 70% of normal for young individuals.

Comments: Edema of nondependent areas, such as eyelid edema, suggests hypoalbuminemia and low osmotic pressure rather than heart failure.

Fontan patients have an increased incidence of coagulation factor deficiencies including protein C, protein S, and antithrombin III, as in any patient with hepatic congestion. Thrombosis is more likely to occur in patients with low cardiac output and more than usual atrial and systemic venous dilatation and blood stasis, as can be expected in any patient with an atriopulmonary connection. Some clinicians advocate anticoagulation for every patient with a Fontan circuit; however, there are clearly subgroups of patients with a very low risk. Full anticoagulation should be prescribed in patients with previous thrombi, poor cardiac output (frequently associated with spontaneous contrast on echo), congestive heart failure, dilation of venous or atrial structures, and atrial flutter or fibrillation.

Comments: Immunization against influenza is recommended. Influenza is always associated with bronchitis, which increases pulmonary vascular resistance and is poorly tolerated by a Fontan patient (whose physiology requires low pulmonary vascular resistance).

Comments: Mild arterial desaturation is frequently seen in Fontan patients. However, in this patient the discrepancy between pulse oximetry and the peripheral cyanosis reflects poor cardiac output (with sluggish tissue perfusion and excessive oxygen extraction peripherally).

The RA in an atriopulmonary Fontan is usually dilated and overstretched; it does not generate a significant contraction.

Plastic bronchitis can be another expression of lymphatic leakage into the bronchi, chyle leaks into the bronchi forming casts that will impede adequate ventilation. This can be clinically very difficult to detect if the patient does not expectorate the casts. This diagnosis is then made, unfortunately, at autopsy. Any Fontan patient with progressive respiratory insufficiency needs a bronchoscopy to exclude this possibility.

These auscultatory findings are typical of a Fontan patient: single S1 and S2, no murmurs.

Comments: The hemoglobin is normal, as expected, as there is no resting central cyanosis.

Total protein and albumin are significantly decreased. These levels are invariably associated with edema.

In an adult, a normal liver can compensate loss of albumin up to 4 g per day. Losses beyond this will result in hypoalbuminemia.

The indium 111 or 51 Chr-albumin test indicates a large amount of undigested protein loss through the bowels. With this test protein (transferrin or albumin) labeled with indium 111 or 51 chromium is given intravenously; the patients are scanned at given intervals for several hours to localize the earliest site of protein loss; stools are collected for 5 days. Normally less than 2% of the total dosage may appear in the stools.

The findings here confirm the diagnosis of PLE, a condition associated with chronically elevated central venous pressures and characterized by excessive protein loss in the stool.