Studies of Thermal Injury. VIII. Automatic Recording Caloric Applicator and Skin-Tissue and Skin-Surface Thermocouples

Abstract

An automatic recording caloric applicator is described and evaluated. This apparatus enables the skin surface to be brought immediately to and maintained at a constant, predetermined temperature. Further, it continuously records the rate of the perpendicular flow of heat through this skin site during the entire heat exposure. A 120×0.04‐cm stainless‐steel hypodermic needle thermocouple is described and evaluated. This instrument was designed to enable a 10‐ to 25‐cm lateral penetration of cutaneous and subcutaneous tissue and, therefore, is especially suited to the measurement of temperature changes within a skin site subjected to the caloric applicator. In view of its small diameter, maneuverability, accuracy, and non‐fragility, this trocar is well suited for the measurement of tissue temperatures in general. A 0.05‐mm wire thermocouple of simple design, which was constructed to measure ``true'' skin‐surface temperature, is described and evaluated.