1997 OPEN FORUM Abstracts
INHALED NITRIC OXIDE (I-NO) THERAPY Use in Neonatal Hypoxemic Respiratory Failure
John E. Thompson, R.R.T., Sunday, December 7, 1997.
This presentation will focus on nitric oxide for three main disorders: persistent pulmonary hypertension of the newborn (PPHN), diaphragmatic hernia, and prematurity.
Nitric oxide may have an important role in transition from fetal circulation to normal circulation by promoting vasorelaxation. Pulmonary hypertension of the newborn is characterized by an increase in pulmonary vascular resistance and extra pulmonary shunting. The clinical studies to date suggest that nitric oxide effectively improves systemic oxygenation in near and full term newborns diagnosed with PPHN. It appears that nitric oxide doses of 20 PPM or lower are effective and provide a sustained response without any side effects such as methemoglobinemia or nitrogen dioxide toxicity. Optimal response to nitric oxide therapy seems to be related to early administration and a concomitant use with other therapies such as high frequency ventilation and surfactant replacement. A reduction in ECMO use was noted in these studies.
Management of infants with congenital diaphragmatic hernia continues to be challenging because of the associated physiology and often labile clinical course. The case series describing the potential benefits for nitric oxide may be as a stabilizing therapy particularly in the pre-operative period. A variety of reported responses may indicate that a particular subset of this population may have the optimal response. A randomized clinical trial may not be possible with the low numbers of patients with congenital diaphragmatic hernia. Series and trial and error may be the best clinical data to date. The use of nitric oxide in the preterm infant remains controversial. PPHN is believed to occur primarily in near or full term infants and often not associated in the clinical management of preterm infants. There is some evidence, however, that pulmonary hypertension is associated with severe hyaline membrane disease, (HMD). A small series of preterm infants have been reported with successful use of nitric oxide. This series suggests that nitric oxide may have a role in the treatment of pulmonary hypertension associated with HMD. One concern that was highlighted was potential increase in bleeding time. To date, the main focus of nitric oxide therapy has been with the patient with pulmonary hypertension of the newborn and continues to be the focus in neonatal nurseries.
AARC 50th Anniversary, December 6 - 9, 1997, New Orleans, Louisiana.