Influence of dexamethasone and surfactant in the vitality and lung function of preterm lambs born by cesarean section

Abstract

The aim of this study was to assess the vitality and lung function of preterm lambs. Twenty seven preterm lambs were divided in four groups. Group I (n=6) preterm lambs/ control; group II (n=9) lambs born to mothers that were treated with dexamethasone antepartum; group III (n=6) lambs treated with surfactant; and group IV (n=6) lambs treated with surfactant and born to mothers that were treated with dexamethasone antepartum. The APGAR score was performed after birth (T0) and 15 minutes later (T1/4) to assess vitality. The vital signs, blood gas analysis, spirometry and capnometry were assessed immediately after birth and continued until 48 hours. Chest radiographs were performed at T0, T24 and T48. Significant rectal temperature interactions occurred at T1 and T6 depending on the type of treatment used. All animals showed low pH values, which were associated with high pCO2 values and HCO3 -values that increased over time from immediately after birth to two days of age. Higher tidal volume values were observed at T1/4, T1 and T24 when the animals were not treated with surfactant. Capnometry showed significant interactions between treatments at T0. Premature animals showed low vitality and impaired pulmonary function.

Meconium Aspiration Syndrome in Animal Models: Inflammatory Process, Apoptosis, and Surfactant Inactivation

“…This confirms that components such as serum, cholesterol, and triglycerides can directly inactivate the surfactant and induce changes in its dynamics [ 108 ]. For this reason, and supported by animal models in lambs and guinea pigs, it has been suggested that surfactant replacement therapy should be accompanied by a drug that allows its mechanism of action to be carried out successfully [ 109 , 110 ].…”

“…The treatment of MAS is controversial; since its use does not clearly influence decreasing neonatal mortality incidence, monotherapies such as corticosteroids, antibiotics, and phosphodiesterase inhibitors have presented variable results over time in reducing clinical signs of MAS [ 7 , 17 , 114 ]. Thus, it might be necessary to explore the combined use or multimodal therapy of the different drugs, as has been observed with the combined use of surfactant with glucocorticoids or the use with antibiotics that can help reduce the inactivation of the surfactant by increasing resistance to it [ 109 , 115 ]. Likewise, explore the use of vasodilators not only to reduce the incidence of pulmonary hypertension but also to consider that they may avoid hypoxia and reduce acidosis in the newborn [ 116 , 117 ].…”