The nurse is caring for a patient whose ventilator settings include 15 cm H2O of positive end- expiratory pressure (PEEP). The nurse understands that although beneficial. PEEP may result in:

Rationale: A. High levels of PEEP increase intrathoracic pressure, which can decrease venous return to the heart, reduce preload, and consequently lower cardiac output. This is a known hemodynamic complication of PEEP, especially at levels ≥10–15 cm H₂O, and requires careful monitoring of blood pressure, heart rate, and perfusion. B. PEEP generally improves oxygenation by preventing alveolar collapse at end-expiration and increasing functional residual capacity. Hypoxemia is usually corrected by appropriate PEEP titration, not caused by it. C. PEEP does not cause fluid overload. In fact, the reduction in venous return can sometimes lead to relative hypovolemia, not fluid overload. Fluid management may need adjustment, but PEEP itself is not a direct cause of overload. D. PEEP does not improve cardiac output or cardiac index. Excessive PEEP can actually impair ventricular function by increasing afterload on the right ventricle and reducing preload, making this option inaccurate.