Pulmonary changes and redox status after fractionalized dose of prophylactic surfactant treatment in preterm neonatal lambs

Abstract

The present study aimed to analyse the effects of exogenous surfactant administration in premature lambs on oxidative stress profile, oxygenation and lung histology. Preterm lambs (n = 22) were randomly assigned to: Control (n = 5), Single Surfactant (n = 5; single intratracheal administration of 100 mg/kg surfactant), Double Surfactant (n = 6; two equal doses of surfactant at 0 and 30 min) and Triple Surfactant (n = 6; three doses at 0, 20 and 40 min). Lambs were subjected to vitality score, oximetry, arterial blood pH, lactatemia, oxidative stress and antioxidant profile during 24 h. Lambs that died were subjected to pulmonary histology. Double group survived longer than Triple group. However, Control presented higher survival time, vitality, oxymetry and blood pH in comparison to surfactant groups. Fractionalized groups had higher vitality, oxymetry and blood pH in comparison to single group. Lactatemia of Control was lower in comparison to surfactant groups, while single group was higher than fractionalized groups. Catalase concentration was higher in fractionalized groups compared to single group. Treated groups had higher superoxide dismutase concentration compared to Control. In conclusion, single dose of intratracheal surfactant in preterm lambs compromises pulmonary adsorption and impairs neonatal antioxidant performance, leading to poor clinical and respiratory outcome, besides being preventive for excessive invasive manipulation.

Keywords

• oxidative stress
• antioxidant
• superoxide dismutase
• lactatemia
• monocyte