Effect of Defocused CO2Laser on Equine Tissue Perfusion

Treatment with defocused CO.sub.2 laser can have a therapeutic effect on equine injuries, but the mechanisms involved are unclear. A recent study has shown that laser causes an increase in equine superficial tissue temperature, which may result in an increase in blood perfusion and a stimulating effect on tissue regeneration. However, no studies have described the effects on equine tissue perfusion. The aim of the present study was to investigate the effect of defocused CO.sub.2 laser on blood perfusion and to correlate it with temperature in skin and underlying muscle in anaesthetized horses. Differences between clipped and unclipped haircoat were also assessed. Eight horses and two controls received CO.sub.2 laser treatment (91 J/cm.sup.2) in a randomised order, on a clipped and unclipped area of the hamstring muscles, respectively. The significant increase in clipped skin perfusion and temperature was on average 146.3 [+ or -] 33.4 perfusion units (334%) and 5.5 [+ or -] 1.5[degrees]C, respectively. The significant increase in perfusion and temperature in unclipped skin were 80.6 [+ or -] 20.4 perfusion units (264%) and 4.8 [+ or -] 1.4[degrees]C. No significant changes were seen in muscle perfusion or temperature. In conclusion, treatment with defocused CO.sub.2 laser causes a significant increase in skin perfusion, which is correlated to an increase in skin temperature. Keywords: equine, CO.sub.2 laser therapy, therapeutic heat, blood perfusion, laser Doppler flowmetry, temperature, rehabilitation.