Micro, Surface, and Needle Oxygen Electrodes: Comparison of Physiological Relevance and Clinical Acceptance

Abstract

The aim of a clinical determination of tissue Po₂ is to discriminate between levels of tissue oxygenation found in normal subjects and those levels found in patients with tissue hypoxia or anoxia where other diagnostic tests and clinical symptoms provide insufficient information. Micro, surface, and needle electrodes are available to determine Po₂ in tissue polarographically. A Polarographic electrode may be called a micro electrode (Kunze, 1966) when the outside diameter of the glass-insulated cathode is several urn’s. This type of Po₂ electrode may be ideal for tissue Po₂ measurements (Silver, 1966), but unfortunately it is too fragile for routine clinical application. Therefore, for clinical application two different types of Polarographic electrodes have been developed. The construction of a Po₂ micro electrode in a silver needle (Schuchhardt, 1971), or a stainless-steel needle (Whalen and Spande, 1980; de Koning and van der Kleij, 1980) provides a Po₂ electrode with an outside diameter which corresponds to the outside diameter of the needle. This type of needle electrode is rugged enough to be used in clinical situations. The outer type is the multi-wire-surface Po2 electrode (Kessler and Lübbers, 1966), which requires direct contact with the organ. In other words, a fasciotomy is necessary to measure the Po₂ of muscle tissue.