Four patients aged 8 to 54 years, under mechanical ventilation, presented with sudden tension mediastinal emphysema and exhibited typical clinical symptoms of compromised venous return. Diagnosis of tension mediastinal emphysema was confirmed by CT. A percutaneous catheter with a diameter varying from F12 to F20 was inserted in the anterior mediastinal compartment with CT control and connected to a waterseal aspiration. Emergency treatment was efficient in all patients. Percutaneous aspiration was continued for 3 to 20 days.