Determination of Blood pCO2

[摘要] It is demonstrated that the most accurate and precise method of determining whole blood pCO2 is with the Severinghaus modification of the pCO2 electrode. The coefficient of variation is only ± 0.33 per cent. Experiments show that the pCO2 may not be stable for more than 30 min. when whole blood is stored at O° when whole blood is diluted with saline, the pCO2 falls in exact proportion to the dilution.The p H/log pCO2 curves of separated plasma and of whole blood have the same slope when temperature is changed. The pCO2 of cold-separated plasma is lower than the pCO2 plasma separated at body temperature. The variation of pCO2 with temperature appears to follow pari passu the variation of p H with temperature.The mean p K' of 18 patient samples equilibrated at 37.5° was 6.103. The standard deviation was ± 0.012. Calculated pCO2, utilizing the Henderson-Hasselbalch equation, can have a coefficient of variation of ± 2.5 per cent if proper temperature corrections are made. If temperature corrections are not made, calculated pCO2 may have a coefficient of variation greater than ± 5 per cent.

[学科分类] 过敏症与临床免疫学