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Hemodynamic effects of epinephrine: concentration-effect study in humans
Journal of Applied Physiology (Bethesda, Md. : 1985)
|April 1, 1985
Summary
Epinephrine infusions increased heart rate, blood pressure, stroke volume, ejection fraction, and cardiac output in humans. These findings suggest epinephrine plays a key role in cardiovascular responses to stress.
Area of Science:
- Cardiovascular Physiology
- Pharmacology
Background:
- Epinephrine (adrenaline) is a key hormone involved in the body's stress response.
- Understanding its precise hemodynamic effects is crucial for clinical applications.
Purpose of the Study:
- To investigate the dose-dependent hemodynamic effects of epinephrine infusion in healthy humans.
- To compare epinephrine's effects with those observed during physiological stress.
Main Methods:
- Ten healthy subjects received graded epinephrine infusions (25, 50, 100 ng/kg/min).
- Hemodynamic parameters including heart rate, blood pressure, stroke volume, ejection fraction, and cardiac output were measured using radionuclide ventriculography.
- Plasma epinephrine levels were quantified.
Main Results:
- Epinephrine infusion led to dose-dependent increases in heart rate, systolic pressure, stroke volume, ejection fraction, and cardiac output.
- Systemic vascular resistance significantly decreased with increasing epinephrine levels.
- Hemodynamic changes during exercise mirrored those of epinephrine infusion at similar plasma concentrations.
Conclusions:
- Epinephrine significantly enhances cardiac performance and reduces systemic vascular resistance in a dose-dependent manner.
- Physiological levels of epinephrine, as seen during stress, can significantly alter cardiovascular function.
- Epinephrine release is a critical regulator of cardiovascular adjustments during physical and emotional stress.