Hyperbaric oxygen (HBO) therapy in treatment of diabetic foot ulcers

Abstract

Background: The cause of diabetic foot ulcers is multifactorial, e.g., neuropathy and angiopathy, leading to functional disturbances in the macrocirculation and skin microcirculation. Adequate tissue oxygen tension is an essential factor in infection control and wound healing. Hyperbaric oxygen (HBO) therapy, daily sessions of oxygen breathing at 2.5-bar increased pressure in a hyperbaric chamber, has beneficial actions on wound healing including antimicrobial action, prevention of edema and stimulation of fibroblasts. The aim of the present study was to investigate the long-term effect of HBO in treatment of diabetic foot ulcers. Methods: Thirty-eight diabetic patients (30 males) with chronic foot ulcers were investigated in a prospective study. The mean age was 60±13 years and the mean diabetes duration 27±14 years. All patients were evaluated with measurements of transcutaneous oxygen tension (tcPO₂), peripheral blood pressure, and HbA_1c. All patients had a basal tcPO₂ value lower than 40 mmHg, which increased to ≥100 mmHg, or at least three times the basic value, during inhalation of pure oxygen. Seventeen patients underwent 40–60 sessions of HBO therapy, while 21 patients were treated conventionally. The follow-up time was 3 years. Results: 76% of the patients treated with HBO (Group A) had healed with intact skin at a follow-up time of 3 years. The corresponding value for patients treated conventionally (Group B) was 48%. Seven patients (33%) in Group B compared to two patients (12%) in Group A went to amputation. Peripheral blood pressure, HbA_1c, diabetes duration, and basal values of tcPO₂ were similar in both groups. Conclusions: Adjunctive HBO therapy can be valuable for treating selected cases of hypoxic diabetic foot ulcers. It seems to accelerate the rate of healing, reduce the need for amputation, and increase the number of wounds that are completely healed on long-term follow-up. Additional studies are needed to further define the role of HBO, as part of a multidisciplinary program, to preserve a functional extremity, and reduce the short- and long-term costs of amputation and disability.

Introduction

Nonhealing foot ulcer is a common and expensive complication in diabetic patients and may lead to amputation. Almost 50% of all amputations not due to trauma are performed in diabetic patients (Boulton, Connor, & Cavanagh, 1994). The three most common causes of amputations are ischemia, infection, and retarded wound healing Boulton et al., 1994, Larsson & Apelqvist, 1995. Retarded wound healing is related to impaired oxygenation of the skin as well as impaired cellular function secondary to hyperglycemia Boulton et al., 1994, Hehenberger, 1997, Kalani et al., 1999, Tooke, 1989 The processes involved in ulcer healing are increased oxygen demanding thus a sufficient supply of blood is of great importance. Disturbances both in the macro- and microcirculation may cause local relative ischemia leading to impaired oxygen supply to the ulcer area.

Treatment of diabetic foot ulcer includes improvement of microcirculation of the skin; that is treatment of edema, anemia, and off-loading. In patients with ischemia due to advanced arterial insufficiency, the prognosis is poor without vascular reconstruction or angioplasty Kalani et al., 1999, McNeely et al., 1995.

Hyperbaric oxygen (HBO) therapy is a medical treatment in which a patient breathes 100% oxygen (O₂) inside a pressurized treatment chamber. It increases blood and tissue oxygen content in hypoxic tissues, which may help maintain cellular integrity and function. Intermittent HBO may help in salvaging marginally perfused tissues. It also improves (a) infection control due to enhanced mobility and bacteria-killing ability of leukocytes, (b) granulation tissue formation due to stimulation of fibroblast proliferation and collagen synthesis, and (c) microcirculation due to edema reduction and angiogenesis Hunt & Pai, 1972, Knighton et al., 1981. It is used to treat a variety of infected, hypoperfused, and hypoxic problem wounds including chronic diabetic foot ulcers (Cianci & Hunt, 1993) and selected cases of limb-threatening foot lesions with microvascular ischemia (Faglia et al., 1996).

The present study was undertaken to investigate the long-term effect of adjunctive HBO therapy in the treatment of chronic foot ulcers in diabetic patients with peripheral hypoxia.