lesion involving RVOTO, experiences an event in which the muscular infundibular portion of the RVOT becomes diminishingly small, preventing blood flow to the lungs All blood is then shunted right-to-left across the nonrestrictive VSD The pulmonary stenosis murmur disappears Extreme cyanosis ensues which can ultimately lead to death if severe Treatment of a hypercyanotic event follows a stepwise progression Initially, bring the knees to the chest, allowing the parent to comfort the patient in this position Monitor closely Knee to chest position in infants, or squatting in older children, increases SVR and decreases right-to-left shunting Administer 100% oxygen If the spell persists, morphine (0.1 mg/kg IM or IV) can be used to calm agitation Normal saline bolus (10 mL/kg) ensures adequate preload and may be repeated if the patient is dehydrated If these steps are not successful, a continuous IV infusion of phenylephrine, an alpha agonist (0.5 to µg/kg/min), may be titrated to increase SVR Propranolol, a beta-blocker, may be used to decrease heart rate and promote ventricular filling, but care should be exercised when administering this drug as hypotension may occur If the spell persists, general anesthesia and emergent surgery for placement of a systemic–pulmonary shunt or full repair is the next step Ketamine to mg/kg IM or IV is an excellent option for sedation for endotracheal intubation or other procedures Emergency surgical repair or palliation with an aortopulmonary shunt are options if the hypercyanotic spell still cannot be corrected After stabilization the patient should be admitted to an intensive care unit skilled in cardiac care Chronic oral beta blocker therapy may be initiated in an attempt to decrease RVOT infundibular reactivity and thus prevent further spells Elective surgical management provides definitive care Management/Diagnostic Testing of Infant Presenting With Left-to-Right Shunt and Pulmonary Overcirculation Diuretic therapy is the mainstay of acute treatment for pulmonary overcirculation due to left-to-right shunt lesions When used with afterload reduction, the symptoms of overcirculation may be mitigated until the time of surgical repair Hospital admission may be necessary for initiation of medical therapy, treatment of concurrent infections, or surgery if medical management is not effective IV fluids and oxygen should be avoided in these patients, as either intervention will worsen pulmonary overcirculation Clinical Indications for Discharge or Admission Any child newly diagnosed with hemodynamically significant CHD should be admitted to the hospital Consultation with a pediatric cardiologist can guide this decision Very ill