Correct!
1. Inhaled nitric oxide to lower the pulmonary artery pressure
In a previously asymptomatic 61year old with a right-to-left shunt the most likely explanation is that the operation caused an increase in pulmonary artery pressure opening a congenital heart defect. This could be from increased intrathoracic pressure from elevation of diaphragms or local hypoxia from splinting and atelectasis. Regardless of the cause lowering the pulmonary artery pressure would be an appropriate therapeutic strategy. Nitric oxide is a potent pulmonary vasodilator which can be given by inhalation (2). The patient was placed on inhaled nitric oxide at 40 ppb. Within minutes his oxygen saturations increased to the 90s. He was rapidly weaned from mechanical ventilation and extubated the following day.
A transesophageal echocardiogram (TEE) revealed an 11 mm patent foramen ovale with a right-to-left shunt. A cardiac surgery consult felt it best to wait until the patient recovered from his abdominal surgery to correct his aortic root aneurysm and patent foramen ovale (PFO)
PFO is a flap-like opening in the atrial septum of the heart and is the most common cause of a right to left shunt in an adult (3). PFO is seen in as many as one in four adults and is associated with an increased risk of migraine and stroke. Most experts recommend observation in a patient with asymptomatic PFO but closure either surgically or percutaneously if the PFO produces hypoxia or results in an embolic event.
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