pediatrics
Tetralogy of Fallot
Treatment of Tetralogy of Fallot
For symptomatic neonates, prostaglandin E1 infusion For hypercyanotic spells, knee-chest positioning, calming, oxygen, IV fluids, and sometimes drugs Surgical repair Neonates with severe cyanosis may be palliated with an infusion of prostaglandin E1 (beginning at 0.05 to 0.1 mcg/kg/minute IV) to open the ductus arteriosus and thereby increase pulmonary blood flow. Hypercyanotic spells require immediate intervention. The first steps are to Place infants in a knee-chest position (older children usually squat spontaneously and do not develop hypercyanotic spells) Establish a calm environment Give supplemental oxygen Give IV fluids for volume expansion If the spell persists, standard medical therapy includesmorphine,phenylephrine, and beta-blockers (propranololoresmolol): see table. If standard measures do not control the spell, systemic blood pressure can be increased withketamine0.5 to 2 mg/kg IV or 2 to 3 mg /kg intramuscular injection (ketaminealso has a beneficial sedating effect). for management of hypercyanotic spells. These medications have the advantage of not requiring IV access ( Treatment references ). , 1 mEq/kg IV, may be given if Metabolic Acidosis is present. Ultimately, if positioning and medications do not relieve the spell or if the infant is rapidly deteriorating, tracheal intubation with muscle paralysis and general anesthesia, extracorporeal membrane oxygenation (ECMO), or urgent surgical intervention may be necessary. Propranolol0.25 to 1 mg/kg orally every 6 hours (given until surgical repair) may prevent recurrences. Most experts think that even one significant spell indicates the need for expeditious surgical repair. Complete repair of tetralogy of Fallot consists of patch closure of the ventricular septal defect, widening of the right ventricular outflow tract with muscle resection, pulmonic valvuloplasty and, when warranted, patch augmentation of the main pulmonary artery. If there is significant hypoplasia of the pulmonic valve annulus, a transannular patch is placed. Surgery is usually done electively at age 2 to 6 months but can be done at any time if symptoms are present or right ventricular outflow tract obstruction is severe. In some neonates with low birth weight or complex anatomy, initial palliation may be preferred to complete repair; the usual procedure is a modified Blalock-Taussig-Thomas shunt, in which the subclavian artery is connected to the ipsilateral pulmonary artery with a synthetic graft. More recently, transcatheter intervention to stent the right ventricular outflow tract or PDA has been used as an alternative palliative procedure with good outcomes ( Treatment references ). Perioperative mortality rate for complete repair is<5% for uncomplicated tetralogy of Fallot. For untreated patients, survival rates are 55% at 5 years and 30% at 10 years. Prevention is recommended preoperatively but is required only for the first 6 months after repair unless there is a residual defect adjacent to a surgical patch or prosthetic material. 1.Montero JV, Nieto EM, Vallejo IR, et al: Intranasalmidazolamfor the emergency management of hypercyanotic spells in tetralogy of Fallot.Pediatr Emerg Care31(4): 269–271, 2015. 2.Tsze DS, Vitberg YM, Berezow J, et al: Treatment of tetralogy of Fallot hypoxic spell with intranasalfentanyl.Pediatrics134(1): e266–e269, 2014. 3.Sandoval JP, Chaturvedi RR, Benson L, et al: Right ventricular outflow tract stenting in tetralogy of Fallot infants with risk factors for early primary repair.Circ Cardiovasc Interv9(12): pii: e003979, 2016. 