Whole blood storage
[Ref: PK1:p253-254; KB2:p184-185]
Collection
400-480mL of blood is taken, with 63mL of anticoagulant
* Citrate combines with calcium and anticoagulates the blood
Criteria
- Minimum acceptable survival rate is 70% survival of transfused RBC at 24 hours after transfusion
- CPDA1 blood has 70% survival when stored for 35 days at 4C
- Adsol blood has a shelf-life of 42 days
Methods of preservation
- Addition of preservative solution at the time of collection
- Storage condition (low temperature)
* Blood is stored at 4-6C
--> Minimise bacterial growth and decrease metabolic rate
- Aseptic technique to minimise risk of contamination
Types of anticoagulant/preservative solutions
Citrate-phosphate-dextrose (CPD)
* Sodium citrate 1.66g
* Anhydrous dextrose 1.46g
* Citric acid monohydrate 206mg
* Sodium acid phosphate 158g
* Water to 63mL
CPD-adenine
* Sodium citrate 1.66g
* Anhydrous dextrose 1.82g
* Citric acid monohydrate 206mg
* Sodium acid phosphate 158mg
* Adenine 17.3mg
* Water to 63mL
SAG-M
* Saline, adenine, glucose, and mannitol
Adsol
* Adenine, glucose, mannitol, and sodium chloride
* ??Same as SAG-M
* Shelf-life = 42days
Purpose of each ingredient
- Citrate
--> Anticoagulates by binding to Ca2+ (reducing [Ca2+] to zero)
- Phosphate
--> Buffers which also provides phosphate source for metabolism
- Dextrose
--> Provides energy source for continued glycolysis and ATP production
- Adenine
--> Provides substrate for ATP synthesis
* Addition of adenine to CPD prolongs shelf-life to 35 days
NB:
- Anticoagulant solution dilutes the plasma by about 20%
- CPD and CPDA1 have higher pH
--> 2,3 DPG levels are maintained longer
Changes in whole blood during storage
RBC
- As storage time increase, some RBC becomes spherical due to metabolic changes
* Associated increase in cell rigidity
- RBC transfused at maximum storage time
--> 10-20% may be destoryed within 24 hours
WBC
- Granulocytes lose phagocytic and bactericidal properties within 4-6 hours
- Maintains their antigenic properties
Platelets
- Platelets becomes non-functional within 36-48 hours in blood stored at 4C
Factor 5 and 8
- Factors 5 and 8 are also called labile factors
* Also inactivated by activated protein C
- Decreases with storage of whole blood
[KB2:p185]
- Factor 5 decreases to 50% at 14 days
- Factor 8 decreases to 50% by 24 hours and 6% after 21 days
[PK1:p254]
- Factor 5 decrease to 50% by 21 days
- Factor 8 decreases exponentially to 75% by 24 hours and to 30% after 21 days
NB:
- Normal haemostasis requires
* Factor 5 at 5-20% of normal level
* Factor 8 at 35% of normal level
- Following massive transfusion, coagulopathy due to dilutional thrombocytopaenia usually occurs before coagulopathy due to coagulation factor deficiency
ATP
- ATP falls slowly to 75% at 28 days
2,3-DPG
Also see 2,3-Diphosphoglycerate (2,3 DPG)
- In CPD-A blood, 2,3-DPG decreases to 50% at 14 days and 5% at 28 days
- Low pH increases rate of 2,3-DPG loss
- Decrease in 2,3-DPG is mainly due to reduction in glycolysis
* [JN5:p270]
- Clinically, changes in p50 due to changes in 2,3-DPG do not usually exceed 3.8mmHg
Potassium level
- After the first 48 hours
--> Progressive loss of K+ from RBC into plasma
--> Plasma [K+] increase to about 12mmol/L at 7 days and 30mmol/L at 28 days
Other changes
- Rise in RBC [Na+]
- Fall in pH
- Loss of Ca2+
- Formation of microaggregates
- Small amount of haemolysis
Other notes
High [K+] does not normally cause problem because
- Restoration of RBC metabolic activity
--> Reuptake of K+
- Elevated catecholamine in patient
--> Increased cellular uptake of K+
- Dilutional effect
- Slow transfusion process
Changes in stored blood
[PK1:p254, Table 9.1]
Change |
0 |
7 |
14 |
21 |
28 |
RBC survival (%) |
100 |
98 |
85 |
80 |
75 |
2,3DPG (%) |
100 |
99 |
50 |
15 |
5 |
pH |
7.2 |
7 |
6.9 |
6.8 |
6.7 |
Na+ (mmol/L) |
168 |
166 |
163 |
156 |
154 |
K+ (mmol/L) |
3.9 |
11.9 |
17.2 |
21 |
28 |
Glucose (mmol/L) |
19.2 |
17.3 |
15.6 |
12.8 |
12.2 |
Free Hb (microgram/L) |
1.7 |
7.8 |
12.5 |
19 |
29 |