2014B13 Briefly explain the changes that occur in stored whole blood.

· Whole blood

· Cell changes

· Plasma protein changes

· Metabolic changes and dissolved gases

Contents

· 45% Cells: red, white, platelet

· 55% Plasma: water >> other

Preservative

· Citrate: complexes Ca²⁺

· Phosphate: buffers H⁺, substrate for ATP

· Dextrose: for glycolysis

· Adenine: for ATP formation

Storage

· 4°C: avoid freeze-thaw damage

· Max 35 days: RBC survival 75%

	Change (at 4/52)	Reason
RBC	Spheroidal, rigid, fragile, ready lysis Survival 75% (or 35 days?) Free Hb 1-> 30mcg/L	↓ATP -> failure of Na+K+ATPase Cell lysis
WBC	Inactive (no phagocytosis, no bactericide) Remains antigenic	?↓pO_2, ↓ATP ?↓temp
Platelet	Non-functional at 48 hours	?↓temp (stored at room temp)

	Change	Reason
Factor V	50% at 3/52	Labile
Factor VIII	75% at 24h 30% at 3/52	Labile
Other	↔Albumin ↔Globulins ↔Fibrinogen	Stable

	Change	Reason
pH	7.4 -> 6.5	Anaerobic metabolism, lactic acidosis
Na⁺	170 -> 155mM (after 48h)	↓ATP -> failure of Na⁺K⁺ATPase Leak into cells
K⁺	4 -> 30mm (After 48h)	↓ATP -> failure of Na⁺K⁺ATPase Leak out of cells
Ca²⁺	2 -> ↓↓ (immediate, static)	Citrate
2,3-DPG	50% at 2/52 5% at 4/52	↓temp ↓glycolysis
ATP	75% at 4/52	Consumption by RBC
Glucose	20->12mM	Consumption by RBC
↓PaO₂	↓5mmHg per ↓1°C	↑Solubility (also consumed by WBC)
↓PaCO₂	↓2mmHg per ↓1°C	↑Solubility