Computer simulation of fluid resuscitation in thermal injury. A. B. Wallace memorial lecture 1987

Following thermal injury many subsystems of the human body interact closely. The effects both of the pathological event in one subsystem and the subsequent therapy are masked or compensated by changes in other homeostatic subsystems. Not until the capacity of the homeostatic subsystems and/or the therapy is inadequate will the effects become obvious. The very complex postburn situation explains why there are so many different shock-preventing fluid therapy programmes and such crude and insecure monitoring of the therapy. In these situations when there are too many factors to be grasped by the unaided human mind, a computer-based 'patient-simulator' could be of value in diagnosis, monitoring and therapy of the severely ill patient with trauma. An extensive pathophysiological model has been designed to describe fluid shifts and haemodynamics in connection with fluid therapy of traumatic patients. The model makes it possible to calculate and predict clinically important state variables on the basis of fluid input and fluid losses. Sample runs are presented for illustrations in haemorrhage and fluid and salt loading. The model is also used to simulate treatment of a burn patient and the results are compared with measured physiological and biochemical variables. Furthermore, four different formulae for resuscitation of patients with thermal injuries according to Evans, Brooke, Parkland and a hypertonic fluid programme are simulated. The results illustrate the potential use of the 'patient-simulator' for designing fluid resuscitation programmes and attempt to optimize them with respect to infusion rate of the fluid administered.