Hyperbaric oxygen therapy for diabetic foot

Hyperbaric oxygen therapy (HBOT) is a treatment modality that has been used in chronic wounds for about 40 years (1,2)

• teatment involves placing the patient in a compression chamber, increasing the environmental pressure within the chamber, and administering 100% oxygen for respiration. In this way, it is possible to deliver a greatly increased partial pressure of oxygen to the tissues
  • typically, treatments involve pressurisation to between 2.0 and 2.5 atmospheres absolute (ATA) for periods between 60 and 120 minutes once or twice daily. A typical course might involve 15 to 30 such treatments
  • rationale for HBOT is that, despite the wide range of causative pathologies, the common denominator in many wounds is tissue hypoxia
    • wound healing is a complex and incompletely understood process. While it appears that in acute wounds healing is enabled by the initial hypoxia, low pH, and high lactate concentrations found in freshly injured tissue, some elements of tissue repair are extremely oxygen dependent, for example collagen elaboration and deposition by fibroblasts and bacterial killing by macrophages. In a complicated balance between wound hypoxia and peri-wound oxygenation, it would seem that successful healing relies on adequate tissue oxygenation in the area surrounding the fresh wound. Certainly, wounds that lie in hypoxic tissue beds are those that most often display poor or absent healing (2)
      • in wound healing, insufficient supply of oxygen may prevent normal healing processes
        • intermittent presentation of oxygen to those hypoxic tissues, therefore, may allow a resumption of normal healing. HBOT administration in man has been demonstrated to cause hyper-oxygenation of tissue, vasoconstriction, fibroblast activation, down regulation of inflammatory cytokines, up-regulation of growth factors, antibacterial effects, potentiation of antibiotics, and a reduction in leukocyte chemotaxis
      • adverse effects
        • oxygen in high doses is toxic to normally perfused tissue, in particular the brain and lungs. Therefore it is not possible to expose patients to typical wound treatment pressures for longer than 1 to 2 hours on a regular basis
        • HBOT is associated with some risk of adverse effects including damage to the ears, sinuses and lungs from the effects of pressure, temporary worsening of short-sightedness, claustrophobia and oxygen poisoning
          
          
• two independent systematic reviews on HBOT (1,2) concluded that systemic HBOT may reduce the incidence of major amputation in people with diabetic foot ulcers
  • however, most of the studies evaluated were relatively small. Therefore, further evidence is required from larger, more robust, and blinded studies. Nonetheless, systemic HBOT may be considered in patients with ischaemic ulcers and where revascularization is not possible (3)

Reference:

• 1) Hinchliffe RJ, Valk GD, Apelqvist J, et al. A systematic review of the effectiveness of interventions to enhance the healing of chronic ulcers of the foot in diabetes. Diabetes Metab Res Rev. 2008;24(Suppl 1):S119-S144.
• 2) Kranke P, Bennett M, Roeckl-Wiedmann I, Debus S. Hyperbaric oxygen therapy for chronic wounds. Cochrane Database Syst Rev. 2004;2:CD004123.
• 3) Ndip A et al. Neuropathic diabetic foot ulcers - evidence-to-practice. Int J Gen Med. 2012;5:129-34. Epub 2012 Feb 10.