VOL: 97, ISSUE: 09, PAGE NO: 8
Mark Neal, PGDip, RN, is nurse manager, Diving Diseases Research Centre, Hyperbaric Medical Centre, PlymouthMark Neal, PGDip, RN, is nurse manager, Diving Diseases Research Centre, Hyperbaric Medical Centre, Plymouth
Diabetes is known to be a significant risk factor for peripheral vascular disease, neuropathy, infection and foot ulceration. Chronic hyperglycaemia causes alteration in cytokine expression, resulting in changes to the microvascular system (Skrha, 1998). Thickening of the basement membrane in muscle capillaries in these patients has an effect on microcirculatory blood flow (Logerfo and Coffman, 1984). Sensory, motor and autonomic neuropathy affects 30% of patients with diabetes. Of those patients presenting with foot lesions, some 80% have neuropathy (Jeffcoate and McFarlane, 1995).
HBO and diabetic problem wounds
Research in favour of HBO for diabetic foot lesions is available, but with small populations in most studies. The argument for not utilising HBO appears to be based on lack of chamber facilities, quality of studies backing HBO and a suggestion of resignation to amputation for this group of people. A recent NHS review of complications of diabetes failed to highlight the significant reduction in major amputation with HBO by regarding all amputations as a failure and therefore HBO as unproved and inappropriate (NHS Centre for Reviews and Dissemination, 1999).
Betty Smith had her fifth toe amputated in February 2000 which resulted in a non-healing ulcer (Fig 1). She was referred for HBO assessment in the middle of the following August and an in-chamber transcutaneous oxygen assessment was performed, which indicated an increased probability of healing.
Initially funding for HBO therapy was not granted. Conservative treatment using cadexomer iodine was therefore continued. The fourth toe became infected and required amputation in October 2000.
Because of Ms Smith's vascular problems a multidisciplinary meeting was convened. Although the possibility of further amputation was discussed, Ms Smith requested that HBO be considered. This suggestion was accepted and funding was granted five days postoperatively.
HBO therapy started the next day and within a week the wound showed signs of normal healing and closure (Fig 2).
The HBO therapy protocol involves treatment in a hyperbaric chamber at a pressure equivalent to 12 metres of sea water pressure for a period of two hours 10 minutes once or twice a day for 30-40 treatments. There is an attendant in the chamber to help the patient with the oxygen hood or mask and provide drinks at a halfway air break.
Patients breathe normally in the chamber and can relax by reading, listening to music or watching a video. Although some people are nervous at first, they soon relax as they become familiar with the routine.
Ms Smith's HBO therapy was augmented with meticulous wound care. Initially a simple dressing of knitted viscose primary dressing with a gauze secondary dressing was sufficient until Ms Smith was discharged from hospital and treated from home (Fig 3). Once home the primary dressing was changed to a povidone-iodine fabric dressing, as dog hairs from the family pet were penetrating the secondary dressing, increasing the potential for wound infection. An absorbent perforated dressing with an adhesive border and a gauze pad were placed over this. Footwear was inspected to ensure reduced risk of trauma and was found to be adequate. Healing of the ulcer continues (Fig 4).