What is an absolute contraindication to applying PEEP?

• A. Untreated pneumothorax
• B. Atelectasis
• C. Pulmonary edema
• D. Hypovolemia

Answer: (A)

Applying PEEP raises intrathoracic pressure to keep alveoli open and improve oxygenation, but it also increases the pressure in the chest and can worsen air leaks or venous return. The only absolute contraindication here is an untreated pneumothorax because adding PEEP would push more air into the pleural space, potentially enlarging the pneumothorax and risking a life-threatening tension physiology. In contrast, atelectasis can often be recruited with PEEP, pulmonary edema may improve with PEEP by stabilizing alveoli and reducing shunt, and hypovolemia is a relative concern since PEEP can decrease venous return, but it isn’t an outright contraindication—it’s managed by addressing volume status and hemodynamics first.