Baseline extracellular potassium level as an indicator of the rate of increase of the same on further storage in CPDA-1 whole blood units: a potential approach to complement FIFO system for prioritisation of blood bags for release from blood-banks.

Abstract

Potassium levels in stored blood bags increases as they age. Hyperkalemia in transfused blood has undesirable cardiac effects. Within a 19-month period, baseline and weekly samples from 15 CPDA-1 whole blood bags were collected till 28 days of storage and analysed for potassium, sodium, uric acid, albumin and whole blood haemoglobin. One unit increase in baseline (0 day) potassium in extracellular fluid of blood units was associated with the following increases in potassium levels on later days of storage: around two unit increase at 1 week (r2 = 0·50, P < 0·01) of storage; four units increase at 2 weeks (r2 = 0·64, P < 0·001) and 3 weeks (r2 = 0·51, P < 0·01) of storage; six units at 4 weeks (r2 = 0·53, P < 0·01) of storage. Baseline whole blood haemoglobin showed a moderate association with baseline potassium (r2 = 0·36, P < 0·05) and 2-week potassium (r2 = 0·35, P < 0·05) values. For CPDA-1 blood bags (i) low baseline potassium blood bags might be preferred for transfusion in cases demanding a low potassium load and (ii) coordinating the ‘first-in-first-out’ (FIFO) policy with ‘early release of blood-bags with high initial potassium’ might be helpful in improving the release of suitable blood units from blood-banks.