Variations in esophageal oxygen tension measured with intraluminal antimony electrodes

Monocrystalline antimony electrodes (crystallographically oriented monocrystalline antimony; COMA) are known to be sensitive to oxygen and to pH. Accordingly, it has been shown that COMA electrodes can be used for the measurement of tissue oxygen tension provided the pH remains constant or is accounted for by the simultaneous use of a glass electrode. In this study the combination of a COMA together with a glass electrode was evaluated for measurement of esophageal oxygen tension in 5 patients. The COMA electrodes showed a mean value of 2.1 pH units higher than the glass electrodes, corresponding to a pO2 level in the esophagus of 10 kPa. As the more protracted oxygen effect on the COMA electrodes was easily recognized, especially in levels of the pH above 7.8 units, they were used for indirect evaluation of intraluminal oxygen tension in the esophagus in a further 57 patients, monitored over 24 h for gastroesophageal reflux disease. The intraluminal pO2 decreased in the supine position and with increase in age. An increase in pO2 was seen after eating and during reflux periods. The changes in pO2 are interpreted as being secondary to blood flow alterations in the esophagus.