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Effects of PEEP on systemic venous capacitance
B Lambermont1, O Detry, V D'Orio
1Experimental Hemodynamics Laboratory (HemoLiège), University of Liège, Belgium.
Archives of Physiology and Biochemistry
|August 26, 1998
Summary
Positive end-expiratory pressure (PEEP) reduces venous compliance and increases peripheral blood pooling. This impedes venous return, decreasing cardiac output due to reduced preload.
Area of Science:
- Physiology
- Cardiovascular System
- Respiratory System
Background:
- Positive end-expiratory pressure (PEEP) is used in mechanical ventilation.
- Its effects on peripheral venous capacitance and central hemodynamics require further elucidation.
Purpose of the Study:
- To determine the effects of PEEP on peripheral venous capacitance.
- To relate these changes to central hemodynamic disturbances.
Main Methods:
- Studied venous volume-pressure (V/P) relationships in 6 anesthetized pigs.
- Assessed systemic venous compliance and unstressed volume.
- Measured cardiac volumes and blood volume partitioning using thermo-dye dilution techniques.
Main Results:
- PEEP application (15 cm H2O) reduced venous compliance by 48%.
- Unstressed volume increased by 25%, with peripheral blood pooling rising from 63% to 74%.
- Left heart and right ventricular end-diastolic volumes decreased by 8% and 44%, respectively.
Conclusions:
- Increased venous unstressed volume and reduced compliance due to PEEP impede venous return.
- This leads to decreased cardiac output secondary to reduced preload.
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