What is a major hemodynamic consequence of excessive PEEP?

What is a major hemodynamic consequence of excessive PEEP?

• A. Decreased preload and CO due to reduced venous return
• B. Increased preload and CO due to venous return
• C. Decreased PVR
• D. Improved oxygen transport

Answer: (A)

Excessive PEEP increases intrathoracic pressure, which directly reduces the pressure gradient that normally drives venous blood back to the right heart. As a result, right-sided preload falls, so the amount of blood the ventricles can stretch and pump out with each beat decreases. Because stroke volume drops with lower preload, cardiac output falls as well. This is the major hemodynamic impact of too much PEEP. Keep in mind that PEEP can sometimes improve oxygenation by keeping alveoli open, but the flip side is the potential reduction in venous return and cardiac output. In some patients, this reduced preload can be exacerbated if venous volume is low or if PVR increases, adding afterload to the right ventricle and further compromising output.

Excessive PEEP increases intrathoracic pressure, which directly reduces the pressure gradient that normally drives venous blood back to the right heart. As a result, right-sided preload falls, so the amount of blood the ventricles can stretch and pump out with each beat decreases. Because stroke volume drops with lower preload, cardiac output falls as well. This is the major hemodynamic impact of too much PEEP.

Keep in mind that PEEP can sometimes improve oxygenation by keeping alveoli open, but the flip side is the potential reduction in venous return and cardiac output. In some patients, this reduced preload can be exacerbated if venous volume is low or if PVR increases, adding afterload to the right ventricle and further compromising output.