An Experimental Investigation of Burn Injury in Living Tissue

The effects of thermal insult on living tissue have been studied by direct microscopic observation of the circulatory system’s response to a controlled trauma regimen. An experimental apparatus has been developed which utilizes a unique high and low temperature stage in conjunction with a precision thermal control system to examine the injury process in the microcirculation of the golden hamster cheek pouch. Unique features of this experimental apparatus are: (1) continuous monitoring of the injury processes at the cellular level, (2) capability for quantitative assay of thermal injury, (3) precise control over the thermal parameters that govern injury, (4) versatility in isolating the effects of these individual parameters. The important thermal parameters monitored using this experimental procedure are the time rates of change of temperature during burning and cooling, the maximum temperature reached, and the length of time the tissue was held at this temperature. With this type of experimental apparatus any portion of the burn protocol, such as the maximum temperature reached during burning, may be varied while holding all other parameters constant. It is well documented that the microvascular bed is a primary site for manifestation of burn wound injury. Burn injury occurs as a consequence of rate dependent physiochemical processes, and, therefore, develops over a finite period of time subsequent to trauma. The experimental technique is designed to determine the gross response of the microvascular system to burn trauma. Initial investigations on burn injury have demonstrated a direct dependency of the extent of damage upon both the maximum temperature attained and the duration of exposure. The minimum temperature required to produce stasis within 20 s after completion of the burn in 95 ±5 percent of the microcirculation decreased exponentially with burn duration between the extremes of 85°C for 1 s exposure and 60°C for 100 s exposure.