Effects of blood storage on ice in biochemical and arterial blood gas analysis of rats

Purpose: To investigate the effects of blood storage in biochemical and arterial blood gas analysis of Wistar rats. Methods: Ten adult male rats with weights between 300-350 g were used. The catheterization of the internal carotid artery were performed, followed by withdrawal of 3 ml of blood using 3 separate syringes each containing I ml. The syringes were fulfilled one after another and numerated according to the order of collection. Then, the following groups were devised: GT1 - samples that were firstly analyzed in 20 minutes and the second exam 65 minutes after the collection; GT2 - samples that were firstly analyzed in 35 minutes and the second exam 80 minutes after the collection; GT3 - samples that were firstly analyzed in 50 minutes and the second exam 95 minutes after the collection. The samples were stored in a container with a temperature between 0 C degrees and 4 C degrees. Upon analysis the values of pH, PaCO2, PaO2, HCO3, SatO(2), SBE, Na+ and K+ concentrations and glucose were compared. Results: No statistically relevant difference (p<0.05) between the GT1, GT2 or GT3, when measuring pH, PaCO2, PaO2, HCO3-, SatO(2), SBE or glucose, were found. However, Na+ concentration decreased and the K+ concentration increased (p<0.05) when comparing the first analysis (20 minutes) with the last one (95 minutes). Conclusion: The blood storage on ice does not interfere in the results of arterial blood gas analysis for the period of at least 95 minutes, except for the Na+ e K+ levels, which are practicable until 80 minutes after storage.