Efficacy of the exogenous surfactant therapy in premature calves with respiratory distress syndrome (RDS)

The aim of the present study is to search efficacy of exogenous surfactant therapy in premature calves with respiratory distress syndrome (RDS). Twenty premature calves with RDS diagnosed by systematical clinical examination were used. To obtain surfactant, lung lavage fluid of freshly sacrified healthy young cattle was collected. After the cellular debris of the fluid was removed, pellet, which was consisted of surfactant, was obtained. The concentration of surfactant extract which was obtained by extraction of the pellet with choloroform-methanol was defined by colorimetric phosphate assay. The bovine lung surfactant extract was administered by tracheal instillation to the calves in a dose of 100 mg per kilogram of body weight. Arterial blood samples were withdrawn anaerobically from the a. brachialis of all the calves before and 2 and 24 hours after the therapy. Arterial blood pH, pO2, pCO2, lactate and HCO3 values were determined by using blood gase analyzer. Mean arterial pH value was significantly elevated (p<0.01) 24 hours after the therapy compared to the values determined before and 2 hours after the therapy. Average arterial pO2 value was found to be elevated 2 and 24 hours (p<0.01, p<0.05, respectively) after the therapy compared to values determined before the therapy. Mean arterial pC02 value was decreased 24 hours after the therapy in comprasion to values determined before and 2 hours after the therapy (p<0.01, p<0.05, respectively). Average arterial lactate value was decreased (p<0.05) and average arterial HCO3 value was elevated (p<0.05) 24 hours after the therapy compared to values determined before and 2 hours after the therapy.Although 12 out of 20 calves survived, 7 calves died within the 24 hours and one calf died five days after the therapy. These results indicate that exogenous surfactant therapy in premature calves with RDS is a successful treatment procedure. It is believed that when it is used as a common treatment procedure in veterinary medicine, the rate of calf deaths in relation to the premature delivery and consequently economical losses will be decreased. Key Words: Premature, calf, surfactant, respiratory distress syndrome (RDS), treatment