[Mineworker's dyspnea. 2. Evaluation of blood gas analysis using arterialized blood from the earlobe]

The authors compared the results of measurements of blood gases on arterialized blood taken at the earlobe and on arterial blood collected at the brachial artery. The measurements were made at rest and during exercise with the main pre-occupation of the respective feasibility and relevance of both techniques in epidemiology. Ninety-four in-patients suffering from respiratory diseases at various stages of their evolution were concerned by this investigation. The techniques of blood collection were standardized. In particular the authors took care that the blood samples were collected simultaneously at the brachial artery and at the earlobe. All blood samples were taken by the same trained experimenter. All the measurements were performed by the same experienced medical analyst. Both types of samples were compared by means of an apparatus Corning 165. As the authors also had a Corning 175 at their disposal, it was possible to investigate the importance of the factor "apparatus" in the differences which were stated. An approach of the role played by the measurement cells in these differences was possible by studying simultaneously by means of the Corning 165 a same sample of arterial blood before and after transfer in a heparinized capillary. The results suggest that the measurements on arterial and arterialized blood are concordant in in-patients at rest with the applied normalisation. During exercise, the differences are greater; nevertheless they are not large enough to reject the technics on arterialized blood in epidemiology. On the other hand the authors confirmed the observation of numerous other investigators showing that the method on arterialized blood gives on the average rise to underestimation. This might result from the technical characteristics of the measurement cells.