1. Antenatal dexamethasone vs. betamethasone dosing for lung maturation in fetal sheep.
- Author
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Schmidt AF, Kemp MW, Kannan PS, Kramer BW, Newnham JP, Kallapur SG, and Jobe AH
- Subjects
- Adrenal Cortex Hormones administration & dosage, Adrenal Cortex Hormones therapeutic use, Animals, Betamethasone analogs & derivatives, Betamethasone therapeutic use, Blood Pressure, Dexamethasone therapeutic use, Female, Fetal Organ Maturity, Gestational Age, Glucocorticoids administration & dosage, Glucocorticoids therapeutic use, Injections, Intramuscular, Lung physiology, Male, Pregnancy, Sheep, Sheep, Domestic, Time Factors, Betamethasone administration & dosage, Dexamethasone administration & dosage, Lung drug effects, Lung embryology
- Abstract
Background: Dexamethasone-phosphate (Dex-PO
4 ) and the combination betamethasone-phosphate (Beta-PO4 ) + betamethasone-acetate (Beta-Ac) are the most used antenatal corticosteroids to promote fetal lung maturation. We compared fetal lung maturation induced by Beta-Ac+Beta-PO4 , Dex-PO4 , or Beta-PO4 alone., Methods: Pregnant ewes received two intramuscular doses 24 h apart of 0.25 mg/kg/dose of Beta-Ac+Beta-PO4 , Dex-PO4 or Beta-PO4 ; or 2 doses of 0.125 mg/kg/dose of Beta-PO4 at 6, 12, or 24 h intervals. Fetuses were delivered 48 h after the first dose and ventilated for 30 min. We assessed ventilatory variables, vital signs, and blood gas. After ventilation pressure-volume curves were measured and lungs were sampled for analysis., Results: All treatments improved lung compliance and ventilation efficiency. Only Beta-Ac + Beta-PO4 required lower positive inspiratory pressure compared with control. Beta-Ac + Beta-PO4 and Beta-PO4 alone, but not Dex-PO4 , increased the mRNA of surfactant proteins compared with control. Low-dose Beta-PO4 did not increase mRNA of surfactant proteins. There were no differences among Beta-PO4 treatment intervals., Conclusion: Beta-Ac + Beta-PO4 given as two doses 24 h apart was more effective in promoting fetal lung maturation than Dex-PO4 or Beta-PO4 alone, consistent with a prolonged exposure provided by the Beta-Ac + Beta-PO4 . These results support the clinical use of combined Beta-Ac + Beta-PO4 preparations over phosphate corticosteroids alone for fetal lung maturation.- Published
- 2017
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