EFFECTS OF OXYGEN AND CARBON-DIOXIDE ON MEAN CELL-VOLUME

Changes in mean cell volume (MCV) following addition of CO2, O-2 or bo th to venous blood treated with ethylenediaminetetraacetic acid were s tudied in an attempt to evaluate the effects of saturation with these gases. The MCV before the addition was taken to be 100%. When CO2 was mixed with each of 353 samples, the mean increase (+/-SD) was 6.10 +/- 1.72%. When O-2 was added to 335 specimens, the mean decrease was 1.4 2 +/- 0.96%. When first CO2 and then O-2 was added to 266 samples, the mean change (the sum for each sample of the absolute value of the inc rease plus that of the decrease) was 7.39 +/- 1.90%. Results of sample s of venous and arterial blood from 15 subjects were compared to check these observations in vivo. The MCV of venous blood was always larger than that of arterial blood.