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An analysis of tolazoline therapy in the critically-ill neonate
Insights
Tolazoline improved oxygenation in neonates with persistent fetal circulation (PFC), especially those on mechanical ventilation. However, it did not improve survival rates for infants with congenital diaphragmatic hernia.
Area of Science:
- Neonatology
- Pediatric Critical Care
- Pharmacology
Background:
- Persistent fetal circulation (PFC) is a critical condition in neonates causing severe respiratory distress.
- Congenital diaphragmatic hernia (CDH) is a major cause of severe respiratory distress in infants.
- Tolazoline is a vasodilator drug used to manage PFC.
Purpose of the Study:
- To evaluate the efficacy and safety of tolazoline in neonates with persistent fetal circulation (PFC).
- To assess the impact of tolazoline on oxygenation and survival in neonates with medical causes of respiratory distress and CDH.
- To identify adverse effects associated with tolazoline treatment.
Main Methods:
- A protocol-driven study involving 47 neonates with medical causes of respiratory distress and 10 with CDH treated with tolazoline.
- Assessment of positive response defined as a significant increase in partial pressure of oxygen (pO2).
- Evaluation of survival rates and neurodevelopmental outcomes at 1 year using Bayley Scales.
Main Results:
- 60% of neonates with medical causes of respiratory distress showed a positive response to tolazoline (increase in pO2 ≥ 24 mm Hg).
- 4 out of 7 infants with CDH had a positive response, but tolazoline did not improve mortality in this group.
- Common adverse effects included erythema, hematest positive gastric aspirates, and thrombocytopenia. Survival was 57% for medical cases and 28% for CDH cases.
- 80% of medically-treated survivors evaluated at 1 year showed normal neurodevelopmental outcomes.
Conclusions:
- Tolazoline is a useful adjunct for managing neonates with PFC, particularly those on mechanical ventilation with paralytic agents.
- While effective in improving oxygenation, tolazoline did not demonstrate improved survival for neonates with CDH and severe PFC.
- Tolazoline treatment was associated with several adverse effects, but survivors generally had normal neurodevelopmental outcomes.
Abstract:
There were 47 seriously-ill neonates with medical causes of respiratory distress and 10 infants with severe respiratory distress secondary to a congenital diaphragmatic hernia treated with tolazoline according to a strict protocol designed to manage persistent fetal circulation (PFC). Of the 47 infants, 28 (60%) had a positive response defined as an increase in the pO2 greater than or equal to 24 mm Hg within 4 hr of beginning the drug. Of 7 infants, 4 with congenital diaphragmatic hernia had a positive response. The mean increase in the pO2 for the 47 infants was statistically significant (p less than .05). Of the 47 infants with medical disorders, 27 survived (survival 57%), whereas only 2 of the 10 infants with congenital diaphragmatic hernia and severe persistent fetal circulation survived (survival 28%). Erythema (60%), hematest positive gastric aspirates (55%), thrombocytopenia (45%), hyponatremia (40%) and increased gastric aspirates (36%) were the most common adverse effects occurring during tolazoline infusion. Hypotension occurred in nine cases, but was transient. Of the 27 survivors, 20 with medical causes of persistent fetal circulation were evaluated at age 1 yr. Eighty percent of these infants studied were considered normal as defined by an MDI and PI of the Bayley Scales of greater than or equal to 70. These data suggest that tolazoline is a useful adjunct in the management of neonates with PFC. In addition, tolazoline was more effective in mechanically ventilated neonates treated with respiratory paralytic agents. Although tolazoline resulted in a significant improvement in the paO2 in 4 infants with congenital diaphragmatic hernia, it did not appear to improve mortality in these infants.