Near fatal pulmonary hypertension after surgical repair of congenital diaphragmatic hernia

Abstract

SummaryThe addition of 10-20 parts per million nitric oxide to the inspired gas was successful in controlling near fatal pulmonary hypertension after surgical repair of a congenital diaphragmatic hernia in a neonate. A preceding prostacyclin infusion was unable to prevent the failure of pulmonary perfusion. No side effect of nitric oxide therapy was observed, and ventilatory support could be substantially reduced as a result of the treatment. On the basis of the striking and lifesaving effects of nitric oxide therapy demonstrated in this child, we believe that nitric oxide treatment will prove to be a major contribution to the management of postoperative pulmonary hypertensive crises. Key wordsSurgery; congenital diaphragmatic hernia. Lung; blood flow. Complications; pulmonary hypertension. Gases, nonanaesthetic; nitric oxide.Pulmonary vasospasm with severe pulmonary hypertension is a much feared complication following surgery for congenital diaphragmatic hernia. The condition is difficult to manage and carries a substantial mortality [I]. State of the art therapy includes prophylactic hyperventilation, with careful control of acid-base balance and profound sedation. Life-threatening pulmonary hypertension with cardiac failure and refractory hypoxaemia may be treated with extracorporeal membrane oxygenation (ECMO), if available, although the use of this treatment is still controversial [2]. Pharmacological efforts to dilate the pulmonary vasculature often result in systemic dilatation and hypotension, since no vasodilator used so far has proved to be selective for the pulmonary vasculature.Nitric oxide has been identified as endothelium-derived relaxing factor (EDRF) [3]. Recently, the addition of low doses (5-80 parts per million, ppm) of nitric oxide to inspired gas has been shown to provide selective pulmonary vasodilatation in awake sheep [4, 51. Selective pulmonary vasodilatation with inhaled nitric oxide was also confirmed in healthy volunteers in whom acute pulmonary hypertension was provoked, by the inhalation of a hypoxic (12% 0,) gas mixture [6]. A similar effect was also found in patients with established pulmonary hypertension of varied aetiology [7-91. The rationale for inhalation of nitric oxide is to supply the vasodilator directly to the lung via the inspired gas, whilst its rapid inactivation by binding to haemoglobin in blood will protect the systemic vascular bed from its vasodilatator effects and the resultant unwanted systemic hypotension [4]. We report a case of near fatal pulmonary hypertension following surgical repair of congenital diaphragmatic hernia in a full term baby. Inhalation of nitric oxide, 5-10 ppm for 60 h, reversed hypoxaemia, reduced pulmonary hypertension and permitted a substantial reduction in ventilatory support. Case historyThe human ethics committee of the Karolinska Institute has approved the use of nitric oxide inhalation in patients

Pediatric Pulmonary Hypertension

“…244 Early reports demonstrated that iNO can improve oxygenation and PH in some infants with severe CDH shortly after birth. 244,245 However, 2 RCTS of iNO treatment in the first hours after birth for CDH have been reported, 206,246 showing that early iNO treatment in patients with CDH had no effect on the combined end point of death and ECMO use. 206,246 In 1 trial, ECMO use was significantly higher in the iNO-treated group.…”

Inhaled nitric oxide in infants with developing or established chronic lung disease

“…The dose of NO used for these patients has been in the same dose range as in our patients with no observed adverse reactions (24, 25, 26). Successful NO administration has also been reported in one preterm infant with pulmonary vasospasm associated with respiratory distress syndrome (27) and other case reports have also described a beneficial effect of inhaled NO in neonates and children (28,29,30,31). We chose a short exposure time at each dose level based on ethical considerations and previously published experiences indicating a rapid response time to inhaled NO (30,32).…”

UK guidelines for the use of inhaled nitric oxide therapy in adult ICUs

“…Only two case reports of clinically significant methaemoglobinaemia during inhaled NO therapy have been published. Both were in neonates, one of which was given an inadvertent overdose [30,31]. Inhaled NO has now been used in many thousands of patients in doses recommended in this document without reports of clinically significant methaemoglobinaemia.…”