Pulmonary and circulatory function in preterm lambs treated with hydrocortisone in utero

Area of Science:

• Neonatal Physiology
• Pulmonary Medicine
• Pharmacology

Background:

• Preterm birth poses significant challenges to lung development and cardiovascular adaptation.
• Hydrocortisone is a corticosteroid with known effects on fetal lung maturation.
• The impact of in utero hydrocortisone on postnatal hemodynamics, particularly ductal patency, requires further elucidation.

Purpose of the Study:

• To investigate the effects of in utero intravenous hydrocortisone administration on postnatal lung function.
• To assess the impact of prenatal steroid exposure on pulmonary and systemic hemodynamics in preterm lambs.
• To compare outcomes in steroid-treated and untreated preterm lambs.

Main Methods:

• Preterm fetal lambs received intravenous hydrocortisone in utero.
• Lung function was assessed via pressure-volume curves postnatally.
• Pulmonary and systemic hemodynamics were evaluated, focusing on the ductus arteriosus.
• Control group consisted of untreated lambs of similar gestational ages.

Main Results:

• Hydrocortisone administration led to statistically significant changes in lung pressure-volume curves.
• Despite lung function improvements, steroid-treated lambs still required ventilatory support.
• The ductus arteriosus was functionally closed or constricted in steroid-treated lambs at 2 hours of age.
• Untreated lambs exhibited a widely patent ductus arteriosus with significant left-to-right shunting, especially at <120 days gestation.

Conclusions:

• In utero hydrocortisone administration improves certain aspects of lung function in preterm lambs.
• Prenatal steroid treatment does not eliminate the need for postnatal ventilatory assistance.
• Hydrocortisone exposure in utero promotes premature closure of the ductus arteriosus, altering postnatal cardiovascular adaptation.