Gastric and colonic oxygen tension measured with a vacuum-fixed oxygen electrode

A new electrode system for determination of visceral oxygen tension is presented. The system consists of a transcutaneous oxygen electrode (E5242 Radiometer A/S, Copenhagen), which is screwed into a suction ring and fixed to the organ by applying a vacuum. The electrode membrane is then in contact with the organ surface via a fluid layer with a thickness of a few micrometres, without interference from atmospheric air and without mechanical disturbance of the membrane. The electrode system was tested on the gastric and colonic wall in six pigs. As reference, a silicone tonometer was placed subserously beneath the vacuum-fixed electrode. The silicone tonometer was connected to a second transcutaneous oxygen electrode. The tissue oxygen tension was changed by subjecting the animals to various inspiratory concentrations of oxygen and to hypovolaemia. The oxygen tension measured by the vacuum-fixed electrode (Po2vac) was compared with the oxygen tension measured by the tonometer (Po2tono). A good correlation w...