Effect of time delay and storage temperature on blood gas and acid-base values of bovine venous blood.

The aim of this study was to investigate possible changes in the gas composition and acid-base values of bovine venous blood samples stored at different temperatures (+4, 22 and 37 degrees C) for up to 48 h. Five healthy cattle were used in the study. A total of 15 blood samples collected from the animals were allocated into three groups, which were, respectively, then stored in a refrigerator adjusted to +4 degrees C (Group I, n=5), at a room temperature of about 22 degrees C (Group II, n=5) and in an incubator adjusted to 37 degrees C (Group III; n=5) for up to 48 h. Blood gas and acid-base values were analysed at 0 (baseline), 1, 2, 3, 4, 5, 6, 12, 24, 36 and 48 h of storage. A significant decrease (p<0.001) was found, in the pH of the refrigerated blood after 5 h and its maximum decrease was recorded at 48 h as 0.04 unit. There were also significant alterations (p<0.001) in the blood pH of the samples stored at room temperature and in the incubator after 2 and 3 h, respectively. The maximum mean alteration in pCO(2) value for Group I was -0.72 kPa during the assessment, while for groups II and III, maximum alterations in pCO(2) were detected as +2.68 and +4.16 kPa, respectively. Mean pO(2) values increased significantly (p<0.001) for Group I after 24 h and for Group II after 6 h, while a significant decrease was recorded for Group III after 24 h (p<0.001). Base excess (BE) and bicarbonate (HCO(3)) fractions decreased significantly for all the groups during the study, compared to their baseline values. In conclusion, acid-base values of the samples stored at 22 and +4 degrees C were found to be within normal range and could be used for clinical purposes for up to 12 and 48 h, respectively, although there were small statistically significant alterations.