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Effect of hyperosmotic mannitol on myocardial oxygen consumption
The American Journal of Physiology
|October 11, 1977
Summary
Hyperosmotic mannitol reduces myocardial oxygen consumption (MVO2) during reduced coronary perfusion, enhancing cardiac efficiency. This finding is crucial for understanding mannitol
Area of Science:
- Cardiology
- Pharmacology
- Physiology
Background:
- Hyperosmotic mannitol shows beneficial effects in experimental myocardial ischemia.
- Mannitol's positive inotropic effect may increase myocardial oxygen consumption (MVO2), potentially worsening ischemic injury.
- The direct impact of mannitol on MVO2 requires clarification.
Purpose of the Study:
- To investigate the effect of hyperosmotic mannitol on myocardial oxygen consumption (MVO2) under controlled hemodynamic conditions.
- To determine if mannitol alters MVO2 independently of its inotropic effects.
- To assess mannitol's influence on myocardial efficiency during ischemia.
Main Methods:
- Anesthetized dogs on right-heart bypass with controlled hemodynamics were studied.
- Mannitol was infused to increase osmolality by 35 mosmol.
- Myocardial oxygen consumption (MVO2) was measured, while heart rate and cardiac output were controlled to maintain or increase left ventricular end-diastolic pressure and tension-time index.
Main Results:
- Myocardial oxygen consumption (MVO2) significantly decreased (P < 0.025) despite reduced coronary perfusion.
- A significant increase in the peak rate of rise of left ventricular pressure (LV dP/dt) was observed (P < 0.001).
- This indicates increased myocardial efficiency under the experimental conditions.
Conclusions:
- Hyperosmotic mannitol decreases MVO2 under conditions of reduced coronary perfusion.
- Mannitol enhances myocardial efficiency, even with increased contractility (indicated by LV dP/dt).
- These findings suggest a potential therapeutic benefit of mannitol in ischemic heart conditions by improving oxygen utilization.