What risk increases when PEEP is greater than 10?

• A. Improved cardiac output
• B. Decreased tidal volume
• C. Impact on cardiac output and risk for barotrauma
• D. Decreased FiO2 requirement

Answer: (C)

Raising PEEP above 10 cm H2O increases mean intrathoracic pressure. That pressure makes it harder for blood to return to the heart, lowering venous return (preload) and often reducing cardiac output, especially in patients with limited cardiovascular reserve. At the same time, the higher airway pressures raise the risk of alveolar overdistension and barotrauma, such as pneumothorax or pneumomediastinum, particularly in already stiff lungs or injured tissue. While PEEP can improve oxygenation and sometimes reduce the need for higher FiO2, the biggest increases in risk at higher levels are diminished cardiac output and barotrauma, which is why that option best fits the question. The other options describe effects that aren’t the primary risks associated with higher PEEP.