Microvolumetric Determination of CO2 and O2 Tensions in Arterial Blood

Abstract

The original Riley-Proemmel-Franke method for the analyses of O2 and CO2 tension in blood was modified by the elimination of physiological saline soln. from the capillary washing. The NaOH soln. is applied for both the capillary washing and the simultaneous CO2 combining as well, thereby eliminating 1 source of error. The accuracy of this modification was tested with a special open-circuit tonometer. The results found in 41 equilibrated arterial blood samples from tuberculous patients were statistically evaluated. The accuracy for the detns. of CO2 tension was -2.37 [plus or minus] 0.59 and for the O2 tension it was -1.77 [plus or minus] 0.77 mm. Hg. The mean difference for CO2 tensions was significant and may be due to some methodical or technical error in the method. The mean difference for O2 tensions was not significant and established the reliability of the method. A comparison was made between the results of Riley, Proemmel and Franke and our values. There was approx. the same difference in CO2 tension detns., whereas the O2 tension detns. according to the modification applied were more reliable.