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Right atrial pressure: determinant or result of change in venous return?
1Surgical Intensive Care Division, Geneva University Hospitals, Switzerland. Karim.Bendjelid@hcuge.ch
Chest
|November 24, 2005
Insights
Guyton
Area of Science:
- Cardiovascular Physiology
- Hemodynamics
Background:
- The Guytonian concept posits that cardiac output is primarily regulated by venous return.
- Venous return is determined by the pressure gradient between mean systemic venous pressure and right atrial pressure.
Purpose of the Study:
- To analyze the historical debate surrounding the venous return curve.
- To clarify the relationship between right atrial pressure and venous return.
Main Methods:
- Literature review and conceptual analysis.
- Examination of the "venous return curve" and its interpretations.
Main Results:
- The debate centers on whether right atrial pressure or venous return is the dependent variable.
- One perspective views right atrial pressure as dependent on cardiac output, while another views venous return as the independent variable.
Conclusions:
- The 50-year-old debate highlights differing interpretations of cardiovascular control mechanisms.
- Clarifying the independent and dependent variables in venous return is crucial for understanding cardiac output regulation.
Abstract:
According to the concept of Guyton, cardiac output is largely controlled by venous return, which is determined by the difference between mean systemic venous pressure and right atrial pressure. In the analysis of the venous return curve, other authors have suggested that right atrial pressure is the dependent variable and venous return is the independent variable (right atrial pressure decreased because cardiac output increased). The present report analyzes this historical debate, which has already lasted > 50 years.
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