VIRTUAL EXTRACORPOREAL-CIRCULATION PROCESS

Virtual instruments for an extracorporeal circulation (ECC) process we re developed to simulate the reactions of a patient to different artif icial perfusion conditions. The computer simulation of the patient tak es into account the hydraulic, volume, thermal and biochemical phenome na and their interaction with the devices involved in ECC (cannulae di mensions, oxygenator and filter types; pulsatile or continuous pump an d thermal exchangers). On the basis of the patient's initialisation da ta (height, weight, Hf) and perfusion variables (pump flow rate, water temperature, gas flow rate and composition) imposed by the operator, the virtual ECC monitors simulated arterial and venous pressure tracin gs in real time, along with arterial and venous flow rate tracings, ur ine production tracing and temperature levels. Oxyhemoglobin arterial and venous blood saturation together with other related variables (pO( 2), pCO(2), pH, HCO3) are also monitored. A drug model which allows th e simulation of the effect of vasodilator and diuretic drugs is also i mplemented. Alarms are provided in order to check which variables (pre ssure, saturation, pH, urine flow) are out of the expected ranges duri ng the ECC simulation. Consequently the possibility of modifying the c ontrol parameters of the virtual devices of the ECC in run-time mode o ffers an interaction mode between the operator and the virtual environ ment.