1498332 Automatic control HOSPITAL FOR SICK CHILDREN 13 Jan 1976 [22 Jan 1975] 01264/76 Heading G3N A computer for use in an artificial beta cell is responsive to a programme to relate an input signal indicating the concentration of blood glucose in blood taken from a diabetic subject to an output signal which determines a rate of glucose infusion required to control the blood glucose at a desired level. As shown, in an artificial beta cell blood is withdrawn from a subject 20 through a catheter 22 and, together with an anti-coagulant from a reservoir 24, fed by a peristaltic pump 28 to a glucose analyzer 32. A visual read-out of blood glucose concentration (BG) is provided by a chestrecorder 34 having a retransmitting slide-wire. The analog signal BG is converted to a digital signal in a converter 36 and fed to a digital computer 38. The computer is programmed to average the differences in the values of BG over fixed time intervals and by weighting a succession of averages determine a rate of change of blood-glucose concentration BSP#/SPG. By an algorithm, set out in the Specification, the computer provides an output signal determining the required infusion rate of insulin (R1). This signal is fed to an interface 42 which controls a pulsatile pump 44 receiving insulin from a reservoir 46. Saline solution is added from a reservoir 56 by a peristaltic pump 54. A back-up dextrose supply, shown in dashed lines, may be provided.
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