What is a potential cardiovascular effect of high PEEP?

• A. Increased venous return and higher cardiac output.
• B. No cardiovascular effects.
• C. Decreased venous return and potential hypotension.
• D. Increased heart rate.

Answer: (C)

High PEEP raises intrathoracic pressure, which reduces the gradient that drives blood back to the heart. That lowers venous return (preload) to the right heart, leading to decreased cardiac output and potentially hypotension, especially in patients who are volume-depleted or have limited preload reserve. While PEEP improves oxygenation by keeping alveoli open, its hemodynamic cost is the reduction in venous return. Increased venous return or no cardiovascular effects aren’t typical with high PEEP, and while a compensatory rise in heart rate can occur with hypotension, the direct effect described here is the fall in venous return.