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Rapid cardiovascular effects of dexamethasone in rabbits with meconium-induced acute lung injury
Daniela Mokra1, Ingrid Tonhajzerova, Juraj Mokry
1Department of Physiology, Jessenius Faculty of Medicine, Comenius University, Martin, Slovakia. mokra@jfmed.uniba.sk
Insights
Dexamethasone, used for meconium aspiration syndrome (MAS), can cause acute cardiovascular side effects like altered heart rate and blood pressure in newborns. These effects are more pronounced in MAS infants, requiring careful consideration during treatment.
Area of Science:
- Neonatal Physiology
- Pharmacology
- Cardiovascular Research
Background:
- Glucocorticoids may benefit lung function in newborns with meconium aspiration syndrome (MAS).
- Limited data exists on the acute cardiovascular side effects of glucocorticoids in infants.
- Understanding these effects is crucial for safe clinical application.
Purpose of the Study:
- To investigate the acute cardiovascular effects of systemic dexamethasone administration in a rabbit model of MAS.
- To test the hypothesis that dexamethasone causes significant cardiovascular changes in MAS neonates.
Main Methods:
- Adult rabbits received intravenous dexamethasone or saline after meconium or saline instillation.
- Cardiovascular parameters including blood pressure, heart rate, and heart rate variability (HRV) were monitored.
- Measurements were taken during and after drug administration, and throughout a 5-hour ventilation period.
Main Results:
- In meconium-instilled rabbits, dexamethasone increased blood pressure, decreased heart rate, elevated HRV, and induced cardiac arrhythmia.
- In saline-instilled rabbits, dexamethasone's effects on blood pressure and rhythm were transient, but heart rate and HRV changes persisted.
- Cardiovascular effects were more severe in the meconium-instilled group.
Conclusions:
- Systemic dexamethasone administration can lead to significant acute cardiovascular side effects in a MAS model.
- These side effects, including arrhythmias and altered hemodynamics, warrant careful monitoring in clinical settings.
- Cardiovascular risks associated with glucocorticoid use in MAS neonates should be considered.
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.
