A disposable in vivo oxygen electrode for the continuous measurement of arterial oxygen tension.

An evaluation of the accuracy, perdision, and clinical safety of the IBC indwellling catheter electrode for the continuous monitoring of arterial oxygen tension during and after general anesthesia was made in a total of 62 patients. A comparison of the standard bench-type electrode (Radiometer) with the International Biophysics Corporation (IBC) electrode for the measurement of oxygen tension in tonometered blood also was performed. Three hundred and fifty comparisons in 51 patients were made of the indwelling electrode with a standard Radiometer unit and, while there was good correlation, there also was ome scatter. An additional small series of 44 comparisons in 11 patients was performed, the primary difference being that the electrode was maintained intr-arterially for approximately 1 day. In both in vivo studies there was excellent correlation but questionable precidion. Four IBC electrodes and eight Radiometer Pao2 electrodes in an additional study were compared at 11 different tonometered oxygen tensions in blood. The IBC electrodes measured oxyygen tension more accurately than did the Radiometer, and standard deviations were consistently smaller at all of 11 different oxygen tensions for the IBC unit. The authors believe that the poor precision within both in vivo studies might be due to the fact that the IBC probe, which was of unknown accuracy and precision, was compared to a standard device (the Radiometer) which in the in vitro investigation proved to be less accurate and less precise. No complications due to the insertion and maintance of this in vivo electrode were encountered. The authors suggest that the IBC method for measuring Pao2 continuously in vivo be considered as an alternative to intermittent gas analysis of oxygen tension.