Optimising the environment for treatment of patients with severe burns : the development and use of a computer-based monitoring system for heat transfer studies
Many of the contributing factors to heat transfer from severely burned patients have been studied. This work involved experiments with a torso shaped phantom to determine local coefficients for mass and heat transfer in several environments including that used for actual patient treatment at Aberdeen Royal Infirmary. Studies on 24 burns patients treated in three Aberdeen hospitals between 1986 and 1990 were undertaken to gain a quantitative understanding of changes in burn wound permeability with elapsed time and environmental variables. Skin temperatures were also investigated. A parallel study was made to investigate ways of clinical monitoring patient heat transfer. A computer-based system was designed consisting of: a data-logger for obtaining surface, core and environmental temperatures and relative humidity, a method of logging patient weight change and integration of a remote thermographic camera for monitoring burn wound temperatures. A method for fast detailed display of thermographic data and patient information was accomplished on an inexpensive computer by a hardware modification of the display electronics and the extensive use of assembly code and look-up table techniques. Implementation of a simple graphical interface allowed burned areas on the image to be selected using a mouse and also simplified measurements made with a probe evaporimeter. Experiments with a database programe were made to determine the feasibility of storing all relevant patient data and performing whole body heat-transfer calculations from that data using the program's limited facilities for scientific calculation. The goal of this project was both to investigate methods for effectively monitoring patients in a clinical environment and to determine guide-lines for the environmental conditions consistent with patient thermo-neutrality when treated by exposure to downward flowing clean air. Significantly, heat transfer is dependent on burn wound size, requiring an air temperature of nearly 37oC when treating patients with partial and full thickness skin losses totalling more than 75% of the total body surface area, while small burns of 5% require a temperature of only 31-32oC.