Master thesis presentation – Assessing blood perfusion and fluid balance in residual limbs
For people with vascular dysfunction because of diabetes and/or peripheral vascular disease, amputation may be a lifesaving operation. Amputation can reduce the risk of foot ulcers and limb necrosis, while it at the same time allows the patients to maintain mobility. However, individuals that undergo amputation due to vascular dysfunction may continue to have problems with blood perfusion that can affect the general health of their residual limb. While the use of vacuum-assisted suspension systems have shown to maintain better volume of the residual limb, it is less clear what its effect is on skin and subcutaneous tissue blood perfusion, and thereby if it may promote better skin health and prevent ulcer formation.
The use of radioactive isotopes injected into a tissue of interest has proven to be a good tool to evaluate local blood perfusion. The blood perfusion can be estimated as washout of the injected tracer. In this pilot project, the short term effects of using vacuum-assisted suspension, as compared to a conventional non-vacuum-assisted suspension system, were analyzed by doing perfusion measurements using radioactive isotopes.
Five male trans-tibial amputees, 37-69 years of age, participated in the study. All had been amputated for at least 12 months and had a healthy residual limb. The isotopes were injected subcutaneously in the distal part of the residual limb and washout measured in combination to rest, sitting and walking on the two respective suspension systems. Perfusion graphs were established by doing regular radiation counts in relation to the different activities. In four of the five participants, the overall washout of the radioactive tracer was lower when using vacuum-assisted suspension system compared to the non-vacuum-assisted suspension system, meaning that the blood perfusion was lower. Similar results were also observed for the individual activities.
Consistent with the residual limb volume stabilizing effect, it seems as the net pressure altering effect of the vacuum-assisted suspension system is to diminish the subcutaneous tissue perfusion with withdrawal and retainment of fluids from the vascular system. The one individual that showed noticeable increase in washout of the radioactive tracer in combination to using the vacuum-assisted suspension had been amputated due to vascular dysfunction as a result of diabetes. Improved blood flow and tissue perfusion in individuals with vascular dysfunction would be of great value and could support better general health of the residual limb. Further and more extended testing of vacuum-assisted suspension system is needed before any final conclusion about its net effect on tissue perfusion and skin health of residual limbs can be drawn.
Presented by Valgeir Tómasson, MPBME
Supervisors: Kristleifur Kristjánsson, Egill Egilsson and Freygarður Þorsteinsson, Össur, Reykjavik, Iceland.
Examiner: Sabine Reinfeldt
Date: Tuesday, June 3rd
Time: 10.00 pm
Location: EB-salen, Hörsalsvägen 11, Chalmers