Rapid cardiovascular effects of dexamethasone in rabbits with meconium-induced acute lung injury.

Abstract

Glucocorticoids may improve lung function in newborns with meconium aspiration syndrome (MAS), but information on the acute side effects of glucocorticoids in infants is limited. In this study using a rabbit model of MAS, we addressed the hypothesis that systemic administration of dexamethasone causes acute cardiovascular changes. Adult rabbits were treated with 2 intravenous doses of dexamethasone (0.5 mg/kg each) or saline at 0.5 h and 2.5 h after intratracheal instillation of human meconium or saline. Animals were oxygen-ventilated for 5 h after the first dose of treatment. Blood pressure, heart rate, and short-term heart rate variability (HRV) were analyzed during treatment, for 5 min immediately after each dose, and for the 5 h of the experiment. In the meconium-instilled animals, dexamethasone increased blood pressure, decreased heart rate, increased HRV parameters, and caused cardiac arrhythmia during and immediately after administration. In the saline-instilled animals, the effect of dexamethasone was inconsistent. In these animals, the acute effects of dexamethasone on blood pressure and cardiac rhythm were reversed after 30 min, whereas heart rate continued to decrease and HRV parameters continued to increase for 5 h after the first dose of dexamethasone. These effects were more pronounced in meconium-instilled animals. If systemic glucocorticoids are used in the treatment of MAS, cardiovascular side effects of glucocorticoids should be considered.

• Authors: Daniela Mokra, Ingrid Tonhajzerova, Juraj Mokry, Anna Drgova, Maria Petraskova, Andrea Calkovska, Kamil Javorka
• Journal: Canadian journal of physiology and pharmacology (Can J Physiol Pharmacol) Vol. 86 Issue 11 Pg. 804-14 (Nov 2008) ISSN: 0008-4212 [Print] Canada
• PMID: 19011676 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Anti-Inflammatory Agents
• Dexamethasone

Topics

• Animals
• Anti-Inflammatory Agents (therapeutic use, toxicity)
• Arrhythmias, Cardiac (chemically induced, prevention & control)
• Blood Pressure (drug effects)
• Chinchilla
• Dexamethasone (therapeutic use, toxicity)
• Dose-Response Relationship, Drug
• Heart Rate (drug effects)
• Humans
• Infant, Newborn
• Meconium Aspiration Syndrome (drug therapy, physiopathology)
• Rabbits
• Respiratory Function Tests
• Trachea (physiology)