What are the interventions to be used before and after an echocardiogram on an infant?

None: It's just a routine test. Before it is done, someone must have examined the patient and found some reason to do the test, like a heart murmur. After it is completed it would be interpreted and the results could lead to some form of treatment such as medication or surgery.

For transthoracic : There are generally none...The calming presence of a concerned parent is sufficient.

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