Peripheral arteriopathy disease (PAD) affects 1 million people in France. In its most advanced stage: chronic permanent ischemia also called critical ischemia, the prognosis of patients is burdened with a one-year mortality rate of 30%. Chronic permanent ischemia results from a lack of oxygen supply to the microcirculatory network, responsible for tissue death and the development of trophic disorders. In this context, many studies have focused on the contribution of hyperbaric oxygen therapy, however none demonstrates with certainty its beneficial effect with a heavy set-up for teams and patients. Furthermore, it appears that normobaric oxygen therapy could have its place in this context by temporarily restoring a sufficient level of transcutaneous oxygen. However, even if normobaric oxygen therapy is common practice although empirical for some practitioners, no data demonstrates its real interest. The purpose of this study is therefore to report the proportion, in usual practice, of patients with permanent chronic ischemia of the lower limb(s), benefiting from normobaric oxygen therapy, but also to show the interest of the contribution of this therapy in usual comprehensive management of these patients. This is a pilot study, after which, if the hypothesis is confirmed, it may be proposed to carry out a randomized study, on a large scale, in order to validate the use of normobaric oxygen therapy in the context of chronic permanent ischemia.

In arterial pathology of the lower limbs at the stage of chronic permanent ischemia, very few data exist on the benefit of normobaric oxygen therapy in these patients. The purpose of the present study is to report the proportion in usual practice of patients benefiting from normobaric oxygen therapy and to show the interest of the contribution of this therapy in the usual global management of patients presenting with chronic permanent ischemia of the lower limbs.

Regarding the Wound, Ischemia, Foot Infection Score (WIfI score), it includes three sub-parts, each of which has a specific evaluation grid scoring between 0 and 3. From this evaluation grid, an overall score can be calculated with different interpretations to determine the risk of amputation at one year as well as the probability of improvement in the event of revascularization, ranging from very low risk to high risk. Nevertheless, the overall evaluation of the score could mask a significant improvement in one of the items evaluated, impacting the clinical management and the future of the patient. This is why, during this study, the improvement of each item of the WIfI score separately will be studied.

The hypothesis is that putting patients in chronic permanent ischemia on oxygen therapy, which is performed frequently, brings a medical benefit compared to patients who do not benefit from it.

Inclusion Criteria:

• Patient hospitalized in the recruiting centre.
• Patient fulfilling the clinical and paraclinical criteria (resting TcpO2 values < 30mmHg) of the definition of chronic permanent ischemia with or without trophic disorders.

Exclusion Criteria:

• Patient suffering from acute or decompensated heart or respiratory failure.
• Patient suffering from chronic obstructive pulmonary disease (COPD) stage III or IV.
• Patient with allergies to medical adhesives

hospitalized patient with symptoms of chronic permanent ischemia