Dexamethasone treatment improved lung functions in meconium-instilled rabbits, but influenced cardiovascular variables.

BACKGROUND

In this study, the effects of single and repetitive dexamethasone administration on lung functions in meconium-instilled rabbits were compared. In addition, short-term adverse effects of dexamethasone on blood pressure, heart rate, and heart rate variability were evaluated.

METHODS

Artificially ventilated adult rabbits intratracheally received 4 ml/kg of meconium suspension (25 mg/ ml). When respiratory failure developed, animals received single-dose of dexamethasone (0.5 mg/kg i.v.) 0.5 h after meconium instillation (Dex1), two doses of dexamethasone (each 0.5 mg/kg i.v.) 0.5 and 2.5 h after meconium instillation (Dex2) or were left without treatment (Mec). Animals were oxygen-ventilated for 5 h after the first dose of treatment.

RESULTS

Dexamethasone treatment significantly improved gas exchange and reduced right-to-left pulmonary shunts, central venous pressure, and lung edema, whereas trend to more pronounced improvement in some parameters was observed after two doses of dexamethasone. There were no significant between-group differences in blood pressure, however, decreased heart rate and increased heart rate variability were observed particularly after repetitive dexamethasone administration.

CONCLUSION

Intravenous dexamethasone, especially when given in two doses, improved lung functions, but influenced cardiovascular variables in meconium-instilled rabbits (Tab. 2, Fig. 3, Ref. 34). Full Text (Free, PDF) www.bmj.sk.