Continuous tissue ph and transcutaneous PO 2 measurement as an index of tissue perfusion in critically ill patients

Abstract

Measurements of transcutaneous PO 2 (tc PO 2) and tissue pH (pHt) were compared with arterial values in 28 critically ill patients. Eleven of the patients were undergoing continuous flow cardiopulmonary bypass and the other 17 were admitted to the Intensive Therapy Unit (ITU) suffering from a variety of medical and surgical disorders. A total of 135 observations were made on the 28 patients. The overall correlation between the two sets of measurements was poor. The correlation coefficient ( r) between arterial PO 2 ( Pa,O 2) and tc PO 2 was 0.41 ( P < 0.01) and between arterial pH (pHa) and pHt 0.67 ( P < 0.01). However, the value varied greatly in different groups of patients. In those patients with cardiopulmonary failure, the tC PO 2 and pHt measurements rapidly and accurately reflected changes in peripheral tissue perfusion, by contrast the core-peripheral temperature deficit did not change significantly. It is concluded that the technique can be used as a sensitive index of peripheral blood flow and may have prognostic significance.