Andersons pediatric cardiology 1854

mL/kg per day or 1 to 2 mL/h) early in the postoperative period, whereas others allow a strategy of oral feeding with the volume determined by the neonate.4,17,148–156 TPN is continued until continuous enteral feeds are advanced to goal Later in the recovery period, oral enteral feeds may be attempted, but only after the evaluation of oral-motor coordination and aspiration risk Advancement of feeds may be difficult in the setting of protracted cardiorespiratory failure, feeding intolerance, or vocal cord paresis following arch reconstruction The prophylactic use of antireflux medications, while common, may alter the microbiome of the gut, increase the risk of infection, and increase the risk of necrotizing enterocolitis The palliated neonate with a fUVH is at high risk for the development of necrotizing enterocolitis Risk factors include diastolic runoff from an aortopulmonary shunt, ischemic injury from cardiopulmonary bypass, high-dose infusions of vasoactive drugs, thromboemboli to the systemic circulation, decreased gastric mobility, and anatomic anomalies of the gastrointestinal tract; these predispose this cohort to an increased risk of gut malperfusion There is an increased risk of necrotizing enterocolitis in low-birth-weight and premature infants In neonates with a fUVH who develop necrotizing enterocolitis in the postoperative period, length of stay is longer and mortality rates are as high as 25% Given this risk, enteral feed advances are often deferred until there is sustained evidence of adequate systemic DO2 and a reduction in vasoactive infusion rates A protocolized approach to enteral feed advances may reduce the risk of necrotizing enterocolitis Careful monitoring for evidence of any evolving abdominal pathology is warranted Feed intolerance, changes in abdominal girth, guaiac-positive stools, unexplained metabolic acidosis, or thrombocytopenia may be early indicators of necrotizing enterocolitis and should prompt a careful abdominal examination and radiographic evaluation The bedside clinician should maintain a low threshold for medical management of suspected necrotizing enterocolitis, including discontinuation of feeds and antibiotic therapy Consultation with a general surgery team is often indicated.149,157–159 Deviations From the Expected Postoperative Course The postoperative course following surgical treatment of fUVH in the neonate is more variable and unpredictable than perhaps any other congenital lesion Much of what is known of the expected postoperative course has been learned from patients following stage I palliation for hypoplastic left heart syndrome and variants Nonetheless, the mortality and morbidity risks following an isolated aortopulmonary shunt for neonates with a fUVH are very similar, whereas the typical postoperative course for neonates following hybrid palliation has been limited to only a few centers For the purposes of the following section, most of what is described has been reported in neonates with hypoplastic left heart undergoing stage I reconstruction, but these observations are applicable to all neonates with a fUVH and multidistribution circulation These findings are likely to change as neonatal management evolves For neonates with a fUVH, hospital length of stay is frequently measured in months rather than days or weeks; indeed, in most large series, hospital length of stay is greater than 2 months in 15% to 25% of cases (Fig 71.8).14,102,105,160–162 Complications such as feeding difficulties, vocal cord paresis, diaphragm paresis, and sepsis are common; they prolong the initial hospital stay, increase resource utilization, and reduce quality of life in the survivors.105,159,163,164 Most importantly, the need for cardiopulmonary resuscitation, with or without extracorporeal membrane oxygenation (ECMO), is approximately 10% to 15% in most large series.105,163,165–167 FIG 71.8 Analysis of the single-ventricle reconstruction trial database showing the impact of the weekday versus weekend admission and outcome In transplant-free survivors, hospital length of stay was similar between the weekend and the weekday (From Johnson JT, Sleeper LA, Chen S, et al Associations between day of admission and day of surgery on outcome and resource utilization in infants with hypoplastic left heart syndrome who underwent stage I palliation (from the single ventricle reconstruction trial) Am J Cardiol 2015;116[8]:1263–1269.) Evaluation and Management of Acute Decompensation After Surgery Clinical deterioration of the postoperative patient with a fUVH is typically characterized by the development of inadequate Qs and DO2 and less often by a limitation of Qp with arterial hypoxemia The most frequent etiology is the development of ventricular dysfunction with or without AV valve regurgitation If ventricular and AV valve function are intact it is unlikely that systemic perfusion will be limited However, if ventricular function begins to wane, the inefficiency of the multidistribution circulation begins to manifest Even with a “balanced circulation” (Qp:Qs ratio of about 1 to 1.5), the total cardiac index requirement must exceed 5 to 6 L/min per square meter to maintain adequate Qp and Qs (see Chapter 70) The limitations of standard hemodynamic parameters and the perfusion examination in determining the adequacy of DO2 have been discussed, as have the utility of venous and NIRS oximetry and lactate levels The extent to which ventricular systolic and AV valve function are compromised may be appreciated with echocardiography; however, it is important to appreciate that even “mildly” impaired systolic function and “mild” AV valve regurgitation are of concern when one considers total CO requirements A limited Qs and DO2 stimulate neurohormonal activation, which, if due to impaired systolic function, causes stroke volume and CO to decrease In the multidistribution circulation, this is compounded by the increase in SVR/PVR ratio driving Qp at the expense of Qs, and a positive feedback cycle is created, with further decreases in Qs driving further increases in the SVR/PVR relationship If Qs/DO2 is severely limited and or hypotension is present, one may choose to initiate therapy with epinephrine, as it provides unparalleled inotropic support without increasing SVR With an increasing Qs/DO2 and adequate blood pressure, afterload reduction may be indicated, as it increases stroke volume in proportion to the degree of systolic dysfunction and AV regurgitation if present Nonselective vasodilators increase stroke volume and CO, Qp, CaO2, and Qs, the net effect being a marked increase in DO2 and a