Tissue oxygen tension in rabbits measured with a galvanic electrode

A galvanic electrode which generates current in response to oxygen was used to measure tissue PO2 in 10 rabbits. Sixteen electrodes were calibrated in vitro at PO2 = 0 mmHg and PO2 = 100 mmHg before implantation into muscle and peritoneal cavity. Electrode calibration was checked after removal 7-20 days later; mean +/- SE reading at PO2 = 0 was 1.5 +/- 1.83 mmHg and at PO2 = 100 was 98.1 +/- 6.49 mmHg. Continuous recordings of tissue PO2 showed little fluctuation in unanesthetized rabbits resting quietly. Tissue PO2 was lower than arterial or venous PO2 during air breathing but frequently exceeded venous PO2 during O2 breathing. Highly significant correlations (P less than 0.001) were found between blood and tissue PO2 over a wide range of values obtained during air breathing and during 10%, 50%, and 100% O2 breathing. Thus, the galvanic electrode provided a reliable measure of tissue PO2 and maintained its stability in vivo for periods as long as 20 days.