Vasodilators in persistent pulmonary hypertension of the newborn: a need for optimal appraisal of efficacy.

Tolazoline hydrochloride is usually the first choice pulmonary vasodilator in persistent pulmonary hypertension of the neonate (PPHN). The analysis of 26 articles including 467 tolazoline-treated infants has been hindered by many methodological drawbacks. Tolazoline has always been administered to infants suffering refractory hypoxemia, but, unfortunately, pulmonary hypertension has not usually been investigated. Moreover, 80% of the tolazoline-treated neonates had an underlying pulmonary parenchymal disease as a potential cause of severe hypoxemia. Noteworthy is that similar comments apply to all studies dealing with the use of other pulmonary vasodilators in PPHN. Pulsed Doppler echocardiography (PDE) should allow a qualitative and quantitative approach for PPHN and an analysis of both success and failure of vasodilator therapeutics. In the meantime, the use of PDE requires more intense investigation prior to wide application in PPHN.