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Increased myocardial contractility during endotoxin shock in dogs
The American Journal of Physiology
|October 11, 1985
Summary
Endotoxin administration initially increased left ventricular (LV) end-systolic pressure-diameter relationship (Ees), indicating preserved myocardial contractility. Early cardiovascular decline in endotoxic shock resulted from decreased preload, not cardiac dysfunction.
Area of Science:
- Cardiovascular Physiology
- Septic Shock Pathophysiology
Background:
- Sepsis-induced cardiovascular dysfunction is complex.
- Understanding the role of myocardial contractility versus preload is crucial.
Purpose of the Study:
- To investigate the impact of endotoxin on left ventricular (LV) end-systolic pressure-diameter relationship (Ees) in dogs.
- To differentiate between cardiac dysfunction and preload changes in early endotoxic shock.
Main Methods:
- Open-chest, anesthetized dogs underwent measurements of ECG, systemic arterial pressure, LV pressure, LV dP/dt, and LV diameter.
- Salmonella enteritidis endotoxin or saline was administered.
- Ees was calculated before and after endotoxin/saline.
Main Results:
- Ees remained stable in control dogs but significantly increased in endotoxic dogs, except in the terminal phase.
- End-diastolic diameter decreased post-endotoxin, returning towards baseline later.
- Peak LV dP/dt was depressed, but myocardial contractility was preserved until the terminal stage.
Conclusions:
- Early cardiovascular impairment in endotoxic shock is primarily due to reduced preload.
- Myocardial contractility is not significantly depressed until the terminal phase of endotoxemia.