Effect of electrode temperatures on monitoring of transcutaneous carbon dioxide (TcPCO2) in prematures.

To establish the optimal electrode temperature for monitoring of transcutaneous PCO2 (TcPCO2) in neonates, a study was performed using electrode temperatures of 37, 42, and 44 degrees C, respectively. The tests were performed by means of TcPCO2 electrodes designed by Radiometer A/S, Copenhagen. In 22 neonates 22 paired values of TcPCO2 and arterial PCO2 (PaCO2) were obtained at each of the above-mentioned electrode temperatures. The correlation coefficient obtained at an electrode temperature of 37 degrees C was 0.83. At electrode temperatures of 42 and 44 degrees C the correlation coefficients were improved to 0.96 and 0.94, respectively, TcPCO2 always being higher than the simultaneously measured PaCO2. An enlarged study comprising 32 neonates at an electrode temperature of 42 degrees C showed the regression line between PaCO2 (mm Hg) and TcPCO2 (mm Hg) to be PaCO2 = 0.81 . TcPCO2 - 2.8.