Hyperbaric oxygen therapy (HBOT) increases tissue oxygenation and serves as an adjunct therapy for diabetic wounds. However, some patients have insufficient increase or even paradoxical decrease in tissue O2 due to vasoconstriction. The aim of the present study was to investigate the pathophysiology responsible for the different consequences of HBOT and to evaluate the effect of N-acetylcysteine (NAC) on these changes.

Methods: Prospective, randomized, cross-over trial including fifty diabetic patients with non-healing ulcers. All patients had two HBOT (100%oxygen, 2ATA) with NAC at the first or the second evaluation. At the beginning and at the end of each evaluation, ulcer oxygenation and plasma levels of malondialdehyde (MDA), total anti-oxidant status (TAOS) and nitric oxide (NO) were measured. Patients with ulcer oxygenation above 200mmHg, were subjected to complete HBOT protocol.

Inclusion Criteria:

• diabetic patients, aged 18 years or older, with non-healing foot ulcers

Exclusion Criteria:

• Patients with macrovascular disease amenable for revascularization with more than 70% obstruction in femoral artery (evaluated by US doppler) were excluded from the study. Similarly, patients with a documented allergy to NAC, liver cirrhosis or those receiving NAC for other indications were excluded. Finally, patients with chest pathology incompatible with pressure changes, patients with inner ear disease, or those suffering from claustrophobia were excluded.