Cardiac fenestration

Fenestration means "opening" and comes from the Latin for window. Your fenestrated ASD patient likely had multiple small openings in the atrial septum rather than one large one, and a lot of right-to-left shunting. That sort of ASD can usually be closed with an Amplatzer device placed in the cath lab. Fenestration in the Fontan circulation is deliberate and is intended to improve the outcome in patients with pulmonary hypertension. At times when pulmonary vascular resistance is higher than usual it allows decompression of the pulmonary vascular bed into the left atrium. Over time pulmonary vascular resistance may return to near normal and the fenestration can then be closed. Sometimes the fenestration closes on its own as PVR normalizes and the heart grows. Lately we've seen an increase in the number of Fontans coming back unfenestrated, only to have them return to the OR to have a fenestration a day or two later due to ongoing pulmonary hypertension and poor cardiac output. Fenestration may also decrease the risk of pleural effusion and chylothorax by maintaining lower intrathoracic pressures; this has a positive effect on length of stay - they're generally shorter at each stage. Because the fenestration causes mixing of oxygenated blood from the IVC and the right pulmonary artery in the right atrium with blood returning to the heart from the pulmonary veins into the left atrium the sats will be low, with 75-85% being quite reasonable.

These kids always have a characteristic appearance with that "I've-just-eaten-a-purple-popsicle" feature, and the tips of their noses have a vaguely gray tinge.

Hope that helps.