Regional cooling patch employing an endothermic reaction of soluble chemicals to reduce pain in inserting the needles

Abstract

In order to reduce pain in needle insertion for hemodialysis, the author tried to develop a regional cooling patch employing an endothermic reaction of soluble chemicals. In this study, a prototype with urea was designed and evaluated by a human simulator to mimic temperature response by heat transfer from the blood flow. Surface area of the regional cooling patch was determined 1260 mm2 after the conventional handy-type regional cooling device. A prototype patch was made of a heat insulation sheet. Thirteen grams of urea was added to ten milliliters of distilled water inside the prototype patch. As a result of experiment, skin temperature of the human simulator kept between 15 and 20 degree Celsius for ten minutes.