RESEARCH NOTES 679 A GAS HEATING AND HUMIDIFYING ACCESSORY FOR THE UNIDIRECTIONAL RESPIRATOR1

When a bird in open thoracic surgery is maintained by unidirectional, artificial respiration as described by Burger and Lorenz (I960), the loss of heat both to the flowing stream of air and by the exposed tissue is excessive. Body temperature rapidly drops under these conditions, re-sulting in temperature recordings below 35°C. These low body temperatures un-doubtably alter physiological reactivity of various brain centers and accentuate the respiratory depression induced by the anesthesia. Although the previously described sim-ple bubble chambers for the humidifica-tion of the gas are apparently satisfactory in less drastic surgical procedures, treat-ing the incoming gas is desirable to pre-vent loss of heat by the respiratory system of the bird or even to add a moderate amount of heat to the animal in acute surgical procedures. No difficulty has been experienced in the maintenance of body temperatures at 40°C. or, in fact, above this temperature, with the appara-tus to be described. The basic apparatus is a hot-water spray confined in a 2 " by 16 " glass cylin-der. This spray produces a large gas-water interface which allows rapid heating and humidifying of the gas without introduc