0914 Interventions for pulmonary hypertension (PHT) in the newborn

While the range of therapeutic options for management of PHT appears to be quite wide, management is often still challenging for paediatricians faced with a near-term neonate with nothing to find other than the PHT. In refractory cases pulmonary barotrauma remains a concern particularly if one seeks to hyperventilate; induced alkalosis is not regarded as completely safe; and ECMO and high frequency ventilation are not universally available (and where they are one might not have staff competent to manage the equipment). The traditional medical regimen of volume and bicarbonate administration together with pressor support and prostaglandins may not reverse the process, and one is therefore pushed to consider additional or alternative measures such as nitric oxide and/or sildenafil. The former, while shown to be effective, is usually impractical unless one is in a unit treating many such infants and where it makes sense to have a continual supply of fresh gas and a reliable administration setup. On the other hand, sildenafil, while not formally approved for use as a pulmonary vasodilator, is readily available and has a reasonable record of success in treating idiopathic PHT as well as PHT post cardiac surgery (oral doses ranging from 0.5 to 2mg/kg 4-6 hrly). Consideration could perhaps also be given to administration of the physiological precursors of nitric oxide i.e. arginine or citrulline. There is certainly good evidence that arginine and NO metabolite levels are lower in infants with PHT (idiopathic and post cardiac surgery) vs controls, and both arginine (single dose of 500mg IV over 30 mins) and citrulline (stat dose IV plus ~9mg/kg/hr) have been shown to reduce pulmonary arterial pressure in small studies involving PHT (idiopathic or post cardiac surgery). Note should be taken of the fact that while apparently successful, there is inadequate evidence from randomized controlled trials to fully support the use of these agents.

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J Thorac Cardiovasc Surg 2007; 134: 319-26
J Cardiothorac Vasc Anesth 2007; 21: 203-7
Biol Neonate 1995; 67: 240-3