A new approach to inline gas monitoring: development of an oxygen sensor

Abstract: A technique for monitoring the oxygen tension of blood in a bypass loop is described. The technique employed is to separate the blood from a thin electrolyte layer by means of an oxygenpermeable membrane. The membrane is sufficiently permeable to oxygen that the electrolyte layer rapidly equilibrates with the oxygen tension in the blood. A ‘Clark type’ polarographic oxygen electrode is then employed to measure the oxygen tension in the thin electrolyte layer. The oxygen consumption of the polarographic sensor is sufficiently low that the equilibrated oxygen tension is not disturbed by the measuring electrode. The technique has the advantage that the sensor can be removed from the measurement cell (for calibration checks etc.) without leakage of blood from the loop.