A Comparative Study of the Electrode Systems of Three pH and Blood Gas Apparatus

Abstract

Winckers, Teunissen, Van den Camp, Maas and Veefkind: Comparative study of three blood gas electrode systems 175 J. Clin. Chem. Clin. Biochem. Vol. 16, 1978, pp. 175-185 A Comparative Study of the Electrode Systems of Three pH and Blood Gas ApparatusBy E. K. A. Winckers, A. J. Teunissen,R. A. M. Van den Camp, A. H (Received February 10/August 26, 1977) Summary: We present a comparative evaluation of the electrode systems of three modern blood gas analysers: IL-413, ABL-1 and AVL-937C.The response curves, accuracy and precision of the pH-, pCO 2 -and pO 2 -electrodes were established with tonometered blood and buffer solutions.pH values (range 6.8-7.8) measured on the AVL deviate (-0.03 pH for blood and + 0.03 pH for buffer) from those of BMS2 Mk2; whereas on the IL and ABL analysers the pH values deviate by not more than 0.01 pH. The standard deviation was better than 0.005 pH.pCO 2 values of blood and buffer (range 14-106 mm Hg) deviate from the calculated tonometer values by quantities ranging from 3 to 10 mm Hg. The average precision (CV) 1 ) of the pCO 2 measurement on each analyser was better than 1.8%.pO 2 values of blood (range 0-130 mm Hg) did not differ by more than 3 mm Hg from the calculated values. Above 130 mm Hg a linear negative increasing difference was seen.For buffer solutions a linear relationship between pO 2 difference and pO 2 value was found over the whole range from zero up to 642 mm Hg: a positive difference below and a negative difference above the pO 2 of the previous calibration; if the calibration pO 2 is higher, the sample pO 2 is shifted to a higher value.The average precision of the pO 2 measurements was better than 3 %. In the (patho)-physiological range the three instruments may provide suitable results for the clinician. Suggestions are made for standardization and improvement of the electrode systems. Vergleichende Untersuchung der Elektrodensy st erne von drei pH-und Blutgas-MeßgerätenZusammenfassung: Eine vergleichende Bewertung der Elektrodensysteme von drei modernen Blutgasanalysatoren (11-413, ABL-1 > AVL-937C) wird vorgestellt.Ansprechbarkeit, Richtigkeit und Zuverlässigkeit der pH-, pCO 2 -und pO 2 -Elektroden wurden mit tonometriertem Blut und Pufferlösungen festgestellt.Die am AVL gemessenen pH-Werte (Bereich 6,8) weichen für Blut um -0,03 und für Puffer um + 0,03 von den mit dem BMS2 Mk2 gemessenen ab, während sie am IL und ABL nicht mehr als 0,01 pH abweichen. Die Standardabweichung war besser ajs 0,005 pH. pCO 2 -Werte von Blut und Puffer (Bereich 14-106 mm Hg) weichen von den berechneten Tonometer-Werten um 3 bis zu 10 mm Hg ab. Der Mittelwert der Genauigkeit (VK) der pCO 2 -Messung an jedem Gerät war besser als 1,8%. Für Pufferlösungen wurde eine lineare Beziehung zwischen p0 2 -Differenz und pO 2 -Wert über den gesamten Bereich von 0 bis 642 mm Hg gefunden: eine positive Differenz unterhalb und eine negative oberhalb des pO 2 des letzten Kalibriergases; wenn das p0 2 des Kalibriergases höher ist, weicht der pO 2 -Wert der Probe zu einem höheren Wert hin...

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