Electrode size and tissue pO2 measurement in rats exposed to air or high pressure oxygen

Abstract

A comparison has been made of values of pO2 recorded in several rat tissues with 60-μ or 330-μ flexible gold electrodes. Although qualitatively both sizes of electrodes give similar results, the quantitative values of pO2differ. Such large differences as are found in some cases between electrodes varying only in physical dimensions are thought to reflect the amount of trauma caused in the tissue under investigation due to electrode insertion. Errors in pO2 estimations due to tissue damage are considered to outweigh any other errors such as those due to electrode calibration. Soft, highly vascular tissues, such as liver, kidney, and spleen, which show macroscopic bruising over quite a large area when electrodes are inserted, show the greatest difference in estimations of the pO2 value. Recordings of tissue pO2 were made while animals breathed air and when compressed to 4 or 5 atm in pure oxygen, and the pattern of response of tissue pO2 to such exposure of the animal to high pressures of oxygen is described. values of pO2; flexible electrodes; tissue damage; compressed in pure oxygen Submitted on July 24, 1964