The effect of ice application on blood vessels, measured using ultrasonography

The effect of ice application on blood vessels, measured using ultrasonography. S. Cook, R. Moss, B. Skinner and L. Hammond Moulton College, Northamptonshire, UK The application of cryotherapy agents is a commonly used treatment method for acute musculoskeletal injury and to aid recovery. Despite this, limited and conflicting research exist on the recommended length of application, when vasoconstrictioni s the desired outcome. It remains unclear at what phase the body’s natural response to shiver actually results in reverse effects and vasodilation. This study aimed to establish whether, through the use of ultrasound imaging, the dynamic process of the vas oconstriction-vasodilation effect can be measured whilst undergoing ice intervention. Following ethical approval from the University of Nor thampton, 13 participants (8 male, 5 fema le; age: 22±2. 6 year s) were selected by convenience sample for experimental design with repeated measures. After 20 minutes of equilibrating to room temperature, a baseline reading of the fem oral artery luminal diameter (mm) was taken using B-mode ultrasound in a longitudinal view. Ice chips were applied to the limb, in an ice bag, and subsequent ultrasound readings were taken every 5 minutes up to 20 minutes ice exposure. Mean luminal diameter decreased from 0 to 15 minutes (7.02±1.2, 6.26±1.0, 6.13±1.5, 5.98±1.2 mm respective ly), then increased to 6.71±1.1 mm between 15 and 20 minutes. A repeated measures ANOVA with Bonferroni correction revealed a significant difference between th e 5 time points (F(2,22) = 4.3 14, p=.029), with pairwise comparisons highlighting a significant decrease in vessel diameter at 0-5 minutes (p=.043) and significant increase in vessel diameter at 15-20 minutes (p=.005). These findings suggest that when vasoconstriction is the desired outcome, continuous application of ice for less than 20 minutes should be recommended as 20 minutes of continuous ice application results in reactive vasodilation of blood vessels, which results in increased blood flow. The study also demonstrates that ultrasonography is a useful method for visualising the reactive na ure of blood vessels during experimental intervention.