An improved technique for continuous in vivo analysis of glucose

A number of problems were encountered during continuous monitoring of venous glucose which have been overcome. Clotting in the system is overcome by heparinizing the subject. The danger of severing the plastic cannula intravascularly by a metal needle is lessened by the use of a plastic needle. Irregularity of the recording is reduced by a modification of the flow system. Temperature artefacts are eliminated by use of an automatic timer to turn on temperature-sensitive instruments prior to use. A coating which was deposited in the colorimeter flow cell is eliminated by thorough washing with concentrated hydrochloric acid prior to use. Accuracy is enhanced by calibration of the autoanalyzer periodically during a run with a single standard. As heparin was found to raise recorded glucose values, standards are run only after the saline diluent is heparinized. In addition an enclosed mobile cart is described which may be used at the bedside. Using the above modifications the continuous in vivo analysis of glucose is a reliable technique.