Effect Of Hyperbaric Oxygen Therapy On Uptake Of Split Thickness Skin Grafts – A Randomised Control Trial

It is a well-known fact that sufficient oxygen supply and avoidance of wound infection is critical to healing process. The ischemic tissues heals poorly and get easily infected. Animal experimentations have shown that arterial hypoxia retards healing and also reduces tensile strength of the wound.Popular theory a decade ago has been that haemoglobin level should be maintained above 10g/dL to promote wound healing.2,3 As a result, some physicians and surgeons have been promoting blood transfusion to raise the haemoglobin level for better wound healing.

To achieve similar effect and improve oxygen perfusion, promote antimicrobial effect and promote neo-vascularization of the target site it was hypothesized that exposure to hyperbaric oxygen chamber could achieve better results. Rates of re-epithelisation (of the donor site) were also suggested to be affected positively by Hyperbaric Oxygen Therapy (HBOT) and thus included in study.

The success of a skin graft or its take depends on nutrient uptake and vascular in growth from the recipient bed. This occurs in three phases namely inflammatory response/plasmatic imbibitions, inosculation, angiogenesis and reinnervation. Proper skin graft dressing prevents graft mobility and seroma formation. Factors that affect take of graft include seroma or hematoma formation, poorly vascularized wound bed, contaminated bed, shearing of graft and lack of adequate tissue oxygen perfusion.4 Apart from these, cormobid conditions, some medicines like steroids, smoking and malnutrition affect take of graft.

In the first 48 h of grafting, the graft survives by “plasmatic imbibition.â€7 As discussed earlier, oxygen is the most critical needs of tissues. Improved oxygen availability contributes to better graft survival and engraftment. In the usual circumstances, this should not be necessary. However, in the compromised graft/bed, it may be invaluable. The benefit has been established in several animal and clinical studies.

Oxygen is vital for hydroxylation of lysine and proline residues during collagen synthesis and for cross linking and maturation of collagen which is required for strong wound healing.6 Lack of oxygen is corrected during HBOT, leading to adequate amounts of mature collagen formation.

HBOT works through both primary and secondary effects. Primary effects involve both increased pressure and hyperoxia by upto 20 times.Hyperoxygenation is an application of Henry’s law and results from an increase in dissolved oxygen in plasma as a result of increased partial pressure of arterial oxygen. A pressure of 3 ATA results in 6 ml of Oxygen being dissolved per 100 ml of plasma, thus rendering as much Oxygen delivery as by haemoglobin bound Oxygen.5Secondary effects as a result of a controlled oxidative stress include antimicrobial effects, blunting of ischemia–reperfusion injury, and wound healing. Wound healing is the result of both local and systemic effects.