Continuous Transcutaneous Gas Monitoring in Adults on Regular Dialysis Treatment

Abstract

We tested a transcutaneous (tc) oxygen (O2) and carbon dioxide (COz) sensor in 15 normal adults and in 20 patients on regular dialysis treatment (RDT). We compared the tc gas values (ptcO2, PtcCO2) with the gas tension values in arterial blood samples (PaO2, PaCO2), in normal adults and in RDT-patients at the end of a 30-min test and six times during RDT. During the test, PtcO2 correlated with PaO2 both in normal adults (r 0.72p<0.01) and in RDT patients (r 0.41 p<0.05). PtcCO2 correlated with PaCO2 (r 0.59 in normal adults and r 0.76 in RDT). During 14 acetate dialyses the changes were expressed as %Δ from time 0. %Δ PaO2 was – 12.7 at 60 min, + 4.8 at 240 min; %Δ PtcO2 – 6.0 at 60 min, + 9.7 at 240 min; %Δ PaCO2 – 17.7 at 240 min, – 1.8 1 h later; %Δ PtcCO2 was – 15.8 at 240 min, – 3.2 1 h later. Both in normal adults and in RDT, patients there was a good relationship between PtcCO2 and PaCO2 values. In normal adults the absolute PtcO2 values were always lower than PaO2 (– 14.4± 10 mmHg); in RDT-patients this difference was more pronounced (– 27.6± 15.1) and is probably attributable to the lower Hb levels (6.7± 1.1 vs 12.4± 1.2). During RDT the pattern was the same between tc and gas tension values. The tc-sensor seems to be useful in continuous monitoring, especially in acetate dialysis and/or in patients suspected of developing hypoxemia, but it cannot replace direct blood gas measurements in arterial blood samples.