Key result
Continuous positive airway pressure and positive end-expiratory pressure decrease venous return by elevating upstream pressure, increasing venous resistance, and compressing the inferior vena cava.
Why the study?
How does continuous positive airway pressure (CPAP) affect venous return?
How does continuous positive airway pressure (CPAP) affect venous return?
This review highlights that CPAP/PEEP decreases venous return through complex mechanisms including increased venous resistance and direct inferior vena cava compression, rather than simply increasing right atrial pressure.
Continuous positive airway pressure, like positive end-expiratory pressure (PEEP), increases lung volume and pleural pressure and usually decreases venous return. The decrease in venous return has been ascribed to a simple increase in right atrial pressure. However, recent studies have demonstrated PEEP also changes the resistive and elastic properties of peripheral veins. PEEP elevates the upstream pressure driving venous return, increases venous resistance, and directly compresses the inferior vena cava. The dogma that PEEP decreases venous return by decreasing the pressure gradient driving blood from the systemic vessels to the heart appears to be untrue.
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H Fessler (1995) reported a review. Continuous positive airway pressure (CPAP) and positive end-expiratory pressure (PEEP) was evaluated on Venous return. Continuous positive airway pressure and positive end-expiratory pressure decrease venous return by elevating upstream pressure, increasing venous resistance, and compressing the inferior vena cava.
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