Continuous intravascular monitoring of plasma potassium using potassium-selective electrode catheters

A fast-responding, potassium-selective electrode catheter suitable for continuous intravascular monitoring is described. Traces illustrating its performance in human patients and anesthetized greyhounds are shown. There was no significant difference between off-line blood samples analysis (using an in vitro electrode) and results obtained with the in vivo electrode; mean absolute difference was 0.11 +/- 0.11 (SD) mM. The technique described is simple and reliable, and represents an advance on existing intermittent sampling methods for detailed monitoring of rapid changes in plasma potassium.