Discussion: Diathermy apparatus for the rapid rewarming of whole animals from 0° C and below

Abstract

The apparatus mentioned by Dr Smith consisted of an oscillator operating at 27 Mc/s with an output power of approximately 500 W. The cold or frozen animal was heated by placing it in the coil of an external resonant circuit tuned to the same frequency as the oscillator and coupled to it by a short length of 400 ohm feeder. The resonant circuit was at d. c. earth potential, as was the feeder cable. In this method the animal was heated principally by induced currents from its coupling to the coil of the resonant circuit. It was found that the dielectric heating method suitable for the rewarming of the smaller animals (Smith 1956) was not practical with the larger animals; this was because of the great difficulty in obtain­ing a uniform field distribution when an animal as large as a rabbit or a galago was placed between the condenser plates of the resonant circuit. The non-uniform distri­bution of the electric field caused superficial burns at all but the lowest power inputs.