Forearm heating band used in apheresis therapy that employs a positive-temperature coefficient polymer heater
For standard apheresis therapy, blood is withdrawn from the ante-cubital vein of one arm and processed blood is returned to a vein of the opposite arm. For low-density lipoprotein apheresis or for the treatment of patients with Guillain-Barré syndrome, a sufficient quantity of blood is readily obtained by this method. In some patients with collagen diseases, however, it may be difficult to secure a reliable vein due to vasospasm or it may not be possible to obtain sufficient blood flow. We constructed a forearm heating band by employing a positive-temperature coefficient heater and evaluated the device to determine whether the application of heat to the forearm is effective in securing a sufficient quantity of blood in those patients with collagen disease (eight with systemic lupus erythematosus and one with multicentric Castleman's disease). Both forearms were heated by using this heating band, in addition to systemic warming with an electric blanket, starting 30 minutes before apheresis. The body surface temperature was sequentially monitored by employing a needle-type thermometer. The surface temperature of the heated area became constant at 37.6+/-0.3 degrees C within approximately 20 minutes (34.7+/-1.3 degrees C at the control site, P<0.001). It was found that this heating band makes it possible to obtain the quantity of blood that is necessary for apheresis and reduce the time required for the treatment. No adverse effects attributable to heating of the forearm were recognized.