Use of electrochemical sensors for on-line monitoring of ionized calcium, potassium, and glucose in whole blood of living dogs.

Abstract

Abstract We report the development and evaluation of electrochemical sensors for continuous on-line measurement of whole-blood ionized calcium, potassium, and glucose in living animals. Ionized calcium and potassium are measured with ion-selective electrodes, by using a unique differential approach. A polarographic sensor coupled with a membrane with bound glucose oxidase is used in the glucose analyzer. The modular concept of instrument design permits one mainframe, computer, and pump system to house any analyzer module or a combination of modules. A small volume of venous blood (about 2 mL/h) is continuously withdrawn from the subject through a double-lumen catheter and pumped through the analyzer(s). Results of in vitro correlation studies and studies in normal dogs (including responses of ionized calcium, potassium, and glucose to various stresses) support the validity of the measurements.