CONTINUOUS EXTRACORPOREAL MONITORING OF ANIMAL BLOOD USING GLUCOSE ELECTRODE

A continuous extracorporeal monitoring system for blood glucose, employing an electrochemical sensor, is described. The sensor, about the size of a nickel, is rapid, is specific for glucose, generates its own power and consists of 2 galvanic oxygen electrodes. Over one O2 electrode is affixed a plastic matrix to which glucose oxidase is covalently bound; a blank matrix is over the other, which serves as a reference. O2 is consumed in the glucose-oxidase-containing matrix, decreasing the current from the underlying O2 electrode. The current decrease is nonlinearly proportional to the glucose concentration. The sensor is clamped between small blocks of plastic fitted with inlet and outlet nipples so that blood pumped from the animal passes over the 2 electrodes and thence to an automated chemical analysis for comparison. Blood is collected and anticoagulant added in a double-lumen catheter. Blood is withdrawn at the rate of 1 cm3/h. Results obtained by use of the system in rabbits are reported. The capacity of the system to continuously monitor changes in blood glucose produced by repeated glucose tolerances is shown in hypo-, normo- and hyperglycemic animals. Some properties of the system and its calibration are discussed.