The authors report two cases of artificial ventilation with the assistance of a membrane oxygenator that was used, on the one hand, in the case of a 'malignant pneumopathy' and, on the other hand, in the case of a cardio-respiratory failure after a complete mending of a tetralogy of Fallot. Recovery was obtained in the second case. They specify the method and the watching of anti-coagulation. They insist upon the merit of a re-injection of oxygenated blood into the ascending aorta. They recall the necessity to lay down instructions according to very strict criteria, by taking into account the degree and the visceral repercussions of hypoxia and the reversibility of lung lesions in so far as it is a matter of a very heavy palliative therapy upon whose efficiency it is difficult to pass a judgment.