Andersons pediatric cardiology 1843

ventricle physiology the opportunity to feed orally on demand without forced gastric tube supplementation This is the case even when indwelling umbilical arterial catheters are in situ or prostaglandin infusions are being given In cases where enteral nutrition is established, serial and careful monitoring of the abdominal exam and stool is paramount The clinician must have a low threshold for discontinuation of enteral feeds if there is any evidence of shock or poor intestinal perfusion Although human milk is the preferred option for enteral feeding, other options include donor milk or a standard-calorie neonatal formula If there is a contraindication to enteral feeding or any delay in the initial palliation, one should consider initiation of total parenteral nutrition (TPN) early and advance to full fluid (100 to 120 mL/kg per day), calorie (90 to 100 kcal/kg per day), and protein (1.5 to 3 g/kg per day) goals Elemental supplements of sodium, potassium, calcium, phosphorus, magnesium, zinc, and carnitine are also common Surgical Options in the Neonate Survival to birth of the individual with a fUVH is possible due to the presence of the arterial duct, which can allow the dominant ventricle to perform systemic work The diagnoses included in the general category of fUVH can be divided into several categories that correspond to surgical interventions The patient may have obstruction to pulmonary blood flow (such as tricuspid atresia with normally related great vessels), obstruction to systemic blood flow (such as, hypoplastic left heart syndrome), or absence of obstruction to either circulation Neonatal palliation is different for each of these conditions Restricted or Duct-Dependent Pulmonary Blood Flow Patients with pulmonary atresia or severe obstruction to pulmonary blood flow will require a stable source of pulmonary blood flow that will not result in excessive hypoxemia or excessive pulmonary blood flow at the expense of systemic blood flow Excessive pulmonary blood flow will lead to heart failure or elevation of PVR, which will complicate subsequent surgical palliation Options include a systemic-to-pulmonary artery shunt or ductal stenting The most common surgically created systemic-to-pulmonary artery shunt is the modified Blalock-Taussig shunt described by DeLeval and colleagues (Fig 71.1).65,66 Here an interposition graft of expanded polytetrafluoroethylene (ePTFE) is used to connect a systemic artery, most commonly the innominate artery, to the ipsilateral branch pulmonary Other options may include a central shunt in which the ePTFE graft is taken from the ascending aorta to the main or a proximal-branch pulmonary artery (Fig 71.2).67 Other shunts include direct connection of the ascending aorta to the right pulmonary artery (Waterston shunt) and direct connection of the left pulmonary artery to the descending thoracic aorta (Potts shunt).68,69 These are uncommonly used for surgical palliation, although the Potts shunt has found new life in the treatment of endstage pulmonary hypertension The decision regarding shunt construction depends on the patient's specific anatomy Patients with normally related great vessels and typical arch branching anatomy could undergo a modified BlalockTaussig shunt Individuals with pulmonary atresia with an intact septum and small branch pulmonary arteries or those with abnormal arch branching such as anomalous origin of the right subclavian artery with an isolated right carotid artery as the first vessel may benefit from construction of a central shunt from the aorta to the main pulmonary artery FIG 71.1 A modified Blalock-Taussig shunt using an expanded polytetrafluorethylene graft to connect the right subclavian artery to the right pulmonary artery (From Tweddell JS Principles and practice of pediatric surgery In: Oldham KT, Colombani PM, Foglia RP, et al, eds Annals of Surgery Philadelphia: Lippincott Williams & Wilkins; 2006:1804.) FIG 71.2 A central shunt using an expanded polytetrafluoroethylene graft from the ascending aorta (Ao) to the main pulmonary artery (PA) (From Gates RN, Laks H, Johnson K Side-to-side aorto-Gore-Tex central shunt Ann Thorac Surg 1998;65[2]:515–516.) Stenting of the arterial duct to provide a stable source of pulmonary blood flow was first reported in 1992.70 A recent retrospective multicenter analysis suggests that duct stenting may provide equivalent results to a surgical shunt in patients with suitable anatomy.71 Unlike the patent arterial duct as an isolated lesion, the duct in cyanotic heart disease has wide morphologic variability It may be long and curled, rendering stent implantation more challenging The newer coronary stents have better flexibility and trackability, making ductal stenting safer.72 Decisions regarding shunt type or the use of duct stenting frequently vary by institution, being based on anatomy and perceived local expertise; as yet no universally accepted criteria have been developed However, as techniques improve, duct stenting will play a bigger role in initial palliation  ... polytetrafluorethylene graft to connect the right subclavian artery to the right pulmonary artery (From Tweddell JS Principles and practice of pediatric surgery In: Oldham KT, Colombani PM, Foglia RP, et al, eds Annals of Surgery Philadelphia: Lippincott Williams & Wilkins; 2006:1804.)