Closed loop control of PaCO2 during ECC
Chauveau, N.; Lautier, A.; Frikha, M.R.; Barthelemy, R.
International Journal of Artificial Organs 18(2): 81-85
1995
ISSN/ISBN: 0391-3988 PMID: 7558401 Document Number: 447507
A prototype for the control of blood gases during extracorporeal circulation (ECC) has been built. It is composed of a CD1300 continuous gas blood analyzer, a programmable gas blender and an IBM PC. The air blender is composed of three mass flow controllers (air, oxygen and total flow rate). The microcomputer commands these controllers in order to obtain the desired mixture of air and oxygen. The system acquires the data sent by the blood gas analyzer every 6 seconds and commands the gas blender in order to maintain the desired arterial dioxide partial pressure (PaCO-2) in the arterial line. The first experimental results on sheep show that if blood gas parameters are stable when beginning the closed loop control, then the desired PaCO-2 value may be obtained. Otherwise, the value of PaCO-2 under control is slightly different but a stable value is obtained after 10 minutes. More experiments must be done in order to establish the real limits of such a system and optimize the gain of the control system.