| Abstract | A pump control system using a microcomputer for cardiopulmonary bypass has
been developed. The parameters monitored by the computer are central venous
pressure, aortic pressure, blood volume in a reservoir, and collapsing of a
small vinyl bag in a venous withdrawal tube. Both pumps in the arterial
infusion and the venous withdrawal lines are automatically controlled through
an interface unit throughout cardiopulmonary bypass. The system regulates
central venous pressure with a proportional-integral control algorithm to
maintain intravascular volume constant. A screening algorithm is devised to
remove artifacts introduced to the pressure measurement. During the weaning
period, a perfusionist can select either the central venous pressure control or
a reservoir blood volume control. Computerized pump perfusion was applied on 15
children during cardiac operations. Perfusion flow and central venous pressure
were controlled satisfactorily with stable operation. Compared with
conventional manually controlled pump perfusion, no significant difference was
noted in mean aortic pressure, central venous pressure, net fluid balance,
total urination, blood chemistry, and urinalysis. This system is useful and is
expected to improve the safety of pump perfusion. |