Effect of Cryotherapy Modalities on Skin Temperature, Radial Artery Size and Flow Where Arterial Puncture Are Performed

Pain caused by arterial puncture for blood gas analysis is one of the most common problems with this procedure. The low utilization rates of effective methods by healthcare providers for pain reduction, such as subcutaneous infiltration of anesthetics, make it necessary to search for effective and simple methods. The use of cryotherapy devices has proven effective for this purpose because the decrease in temperature increases pain threshold and tolerance due to a reduction in nerve conduction velocity and inhibition of nociceptors. In order to standardize these devices, it is necessary to understand the specific thermodynamic and hemodynamic effects of these devices. At the hemodynamic level, the reduction in temperature can produce arterial vasoconstriction. This effect may decrease the palpation of the radial artery, a necessary step for the identification of the optimal point of arterial puncture. Our hypothesis is that there are differences in temperature reduction, radial artery internal lumen dimensions and blood flow inside the radial artery depending on the different cryotherapy modalities applied in the anatomical area of the wrist, the point of arterial puncture for blood gas analysis. In order to obtain an answer to this hypothesis, we will propose a randomized controlled clinical trial with a sham comparator and two active interventions: crushed ice and frozen peas. In addition, this trial has a crossover design with the aim of minimizing the differences that may arise due to individual particularities (within-group variability), and thus increase the possible effect of the interventions (between-group variability). This choice has its justification in that the application of cryotherapy, according to some studies, has a thermal reducing effect with high individual variability. In this study, adults with a good general state of health, who specifically do not have factors that could affect their thermoregulation or vascular pathologies, will be recruited.