Current understanding and perioperative management of pediatric pulmonary hypertension

Abstract

Summary Pediatric pulmonary hypertension is a complex disease with multiple, diverse etiologies affecting the premature neonate to the young adult. Pediatric pulmonary arterial hypertension, whether idiopathic or associated with congenital heart disease, is the most commonly discussed form of pediatric pulmonary hypertension, as it is progressive and lethal. However, neonatal forms of pulmonary hypertension are vastly more frequent, and while most cases are transient, the risk of morbidity and mortality in this group deserves recognition. Pulmonary hypertension due to left heart disease is another subset increasingly recognized as an important cause of pediatric pulmonary hypertension. One aspect of pediatric pulmonary hypertension is very clear: anesthetizing the child with pulmonary hypertension is associated with a significantly heightened risk of morbidity and mortality. It is therefore imperative that anesthesiologists who care for children with pulmonary hypertension have a firm understanding of the pathophysiology of the various forms of pediatric pulmonary hypertension, the impact of anesthesia and sedation in the setting of pulmonary hypertension, and anesthesiologists’ role as perioperative experts from preoperative planning to postoperative disposition. This review summarizes the current understanding of pediatric pulmonary hypertension physiology, preoperative risk stratification, anesthetic risk, and intraoperative considerations relevant to the underlying pathophysiology of various forms of pediatric pulmonary hypertension.

The Transitional Heart: From Early Embryonic and Fetal Development to Neonatal Life

“…Ventricular septal defects are characterized by membranous ventricular septum via the fusion of the endocardial outflow tract and atrioventricular canal, which allows blood to pass form the left-toright side of the heart [32]. If significant in size and unrepaired postnatally, they can result in elevation in pulmonary vascular resistance (PVR), pulmonary arterial pressure, hypoxia, and cyanosis [33].…”

“…Any perturbations to the transitional process may result in neonatal cardiopulmonary dysfunction. For instance, [33,75]. PPHN is the most common form of pediatric pulmonary hypertension and can lead to organ failure in severe cases [75].…”

“…PPHN is the most common form of pediatric pulmonary hypertension and can lead to organ failure in severe cases [75]. The pathogenesis of PPHN includes: (i) cardiovascular maladaptation presented in neonates with normal pulmonary vascular morphology but increased vascular reactivity and impaired vasodilation (sepsis, asphyxia, pneumonia, or respiratory distress syndrome); (ii) cardiovascular maldevelopment, including morphologically abnormal pulmonary vasculature observed in lung hypoplasia and idiopathic PPHN; and (iii) structurally abnormal heart diseases causing LV outflow tract obstruction, such as critical aortic stenosis and interrupted aortic arch [33,75]. Cutting the umbilical cord eliminates the low-resistance placental flow and stimulates peripheral and central chemoreceptors, which combined with other factors (thermal, neuroendocrine, and mechanical stimuli), contributes to the onset and maintenance of neonatal respiratory efforts.…”

Who are at high risk of mortality and morbidity among children with congenital heart disease undergoing noncardiac surgery?

“…In these children who are chronically exposed to suprasystemic PAP, acute RV failure and pulmonary hypertensive crisis may occur given the limited functional reserve of the RV. If coronary hypoperfusion occurs simultaneously, catastrophic results such as myocardial ischemia, fatal arrhythmia, and cardiac arrest may oc-cur even if the increase in PAP is small [25].…”

“…Whenever patients undergo surgery and general anesthesia, pulmonary hypertensive crisis can develop due to various causes including hypoxia, hypercarbia, acidosis, hypothermia, and sympathetic stimulation. Particularly in children whose PVR increases but remains responsive and modifiable, any causes that induce an increase in PVR can trigger a vicious cycle of pulmonary hypertensive crisis [25] (Fig. 2).…”