A neonate scheduled for corrective cardiac surgery under cardiopulmonary bypass requires packed red cell transfusion. To minimise the risk of transfusion-associated hyperkalaemia, the anaesthetist should request:
- A Packed cells stored for 28 to 35 days
- B Packed cells less than 5 to 7 days old ✓
- C Irradiated packed cells of any age
- D Leucoreduced packed cells of any age
Correct answer: B. Packed cells less than 5 to 7 days old
Explanation
Extracellular potassium rises progressively during storage as red cells lose cation pump activity, reaching concentrations of several tens of mmol/L near expiry. Infusion of older units through central lines during bypass can produce arrhythmogenic hyperkalaemia, particularly in small children where the infused volume is large relative to blood volume. Fresh units under about one week old keep potassium low. Irradiation accelerates potassium leakage and leucoreduction does not address it, so neither substitutes for using fresh blood.
Reference: Miller's Anesthesia, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.