Storage Effect on Serum Electrolytes and pH in Whole Blood Stored in Traditional Refrigerator

Whole blood storage is needed for the maintenance of readily and sufficient blood supply for transfusion. Survey has shown that most laboratories in Nigeria use traditional refrigerator instead of the standard blood bank for blood storage. Bizarre changes in the biochemistry of stored blood have been reported particularly when standard conditions are not adhered to strictly. This prompted the need for the investigation of probable changes in electrolytes (Na+, K+, Cl-, HCO3-) and pH during whole blood storage using citrate phosphate dextrose adenine (CPDA-1) in traditional refrigerator (TR) and using values from samples stored in a standard blood bank (SBB) (approved blood bank refrigerator) as standard values. . Thirty seven (37) apparently healthy voluntary adult male donors (aged 19 to 30 years) were recruited. Twenty (20) donors donated 450mls of whole blood each into CPDA-1 anticoagulant blood bag. These units were stored in SBB. While 17 subjects also donated 450mls of whole blood each into bags with the same anticoagulant. These latter units were instead stored in a TR and both refrigerators were allowed the same relatively stable power supply for 35 days. Samples were collected at Days 1, 7, 14, 21, 28 and 35. Serum Electrolytes (Na+, K+, Cl -, HCO3-) and pH were analyzed using an Automated Biochemistry Analyzer (Olympus AU400 Automated Chemistry Analyzer). Mean sodium levels for TR refrigeration dropped from 136.6 1.14 mmol/L (Day 1) to 132.0 1.32 mmol/L (Day 35) as against 138 0.22mmol/ L - 132.0 1.32 mmol/L for SBB. This indicates that Na+ levels declined as the number of days of storage increased. When mean values for SBB and TR for sodium were compared using an independent sample t-test, significant decreases were observed at days 7 (F= 1.684, t= 2.305, p= 0.027) and 14 (F= 1.623, t= 2.761, p= 0.009). Tremendous increase in K+ levels from Day 1 to Day 35 was also observed. Mean K+ values of 9.48 0.94mmol/L and 2.52 1.72mmo/L were respectively observed for the last and first days for TR refrigeration. Significant increase was observed when mean values of K+ for SBB were compared with those of TR for all the days with the inferential statistics values Day 7 (F=17.256, t= 9.283 p= 0.000), Day 14 (F= 10.358, t= -15.197, p= 0.000), Day 21 (F= 14.381, t= -20.285, p= 0.000), Day 28 (F= 4.810, t= -19.016, p= 0.000) and Day 35 (F=0.499, t=-11.979, p=0.000). Bicarbonate, pH and chloride levels for both groups were observed to decrease with storage time. Significant decreases were observed for Cl- and HCO3- for Day 7 (F= 17.019, t=-6.496, p= 0.000 and F= 0.404, t=-2.177, p= 0.035 respectively), Cl- only for Day 14 and 21 (F= 3.253, t= -5.553, p= 0.000 and F= 2.112, t= -4.964, p= 0.000) respectively. The results show that there were significant changes in the levels of all electrolytes and pH at different weeks of storage and the changes were more in the units stored in the traditional refrigerator and this could be clinically detrimental to the recipient on transfusion if adequate measures are not taken, particularly in massive transfusion and/or if the recipient already has an established clinical sequela that could exacerbate the condition.