Faculty of Allied Medical Science

Faculty of Allied Medical Science Blood Banking (MLBB 201)

Changes that occur in Stored Blood Bags Prof.DrNadia AlySadek Prof. in Haematology and Director of Blood Bank Centre, Medical Research Inst, University of Alexandria Presented by: Tamer mohamedallam Aymanmohamedelsaeed

Changes that occur in Stored Blood Bags

Outcomes • By the end of this lecture, the students will be able to: • Know the changes that occur in blood bags with storage • Know what is blood filtration and its types.

Anticoagulants

Additive Solution (AS) • Primary bag with satellite bags attached. • One bag has additive solution (AS) • Unit drawn into CPD anticoagulant

Whole Blood • Clinical indications for use of WB are extremely limited. • Used for massive transfusion to correct acute hypovolemia such as in trauma and shock, exchange transfusion. • RARELY used today, platelets non-functional, labile coagulation factors gone. • Must be ABO identical.

Storage Lesion Long storage times of blood bags may influence the quality of blood that is transfused. During storage, the red cells undergo a number of physical and chemical changes including:

Storage Lesion Increased membrane rigidity Loss of organic phosphates Release of pro-inflammatory cytokines Some changes take place slowly and some take place rapidly.

Consequences of transfusing older blood 1- Increased in-hospital mortality 2- Increased rates of sepsis 2- Delayed healing of wounds 3- Tumor recurrence.

Consequences of transfusing older blood • Immediately after blood donation, the red cells are subjected to an acidic, hypotonic, anticoagulant solution which damages a small proportion of them irreversibly. • Cells that survive the first 24 hours will remain viable for the end of their life spans.

Consequences of transfusing older blood • At least 70% of them remain viable in the recipient’s circulation 24 hours after transfusion. • Granulocytes become non-functional after 24 hours, but still they can cause febrile transfusion reactions.

Consequences of transfusing older blood Some lymphocytes may remain viable for several weeks. Platelet function declines to zero after 24 hours of storage.

Biochemical changes 1- Oxygen affinity • increasing the oxygen affinity of hemoglobin = less release of oxygen to the tissues. 2- ATP • There is a time-dependent reduction in intracellular RBC ATP

Biochemical changes • The biochemical changes that occur in the stored bags leads to alteration in corpuscle shape, decreased deformability, increased aggregability and intracellular viscosity as well as changes in osmotic fragility.

Electrolytes 1- Potassium: • During storage, there is constant leak of potassium out of the cells and levels may sometimes exceed 30mmol/L. After transfusion, potassium rapidly enters the red cells as they begin active metabolism.

Plasma hemoglobin Plasma K+ Na+ K+ Viable cells pH ATP 2,3-DPG Plasma Na+ Helps release oxygen from hemoglobin (once transfused, ATP & 2,3-DPG return to normal)

2- Calcium • Each unit of blood contains 3g. Citrate which binds ionized calcium. The liver is able to metabolize 3g of citrate every 5 minutes. • In patients with impaired liver function, there is a risk of citrate toxicity and hypocalcemia. It does not affect coagulation but patients may have transient tetany and hypotension.

Acid-Base balance • During storage, there is gradual accumulation of lactic acid with a resultant fall in pH, but it is rapidly metabolized and the citrate by the recipient to bicarbonate which may then produce metabolic alkalosis.

Coagulation • Labile coagulation factors i.e. FV and FVIII have a 50% decrease in activity within the first 72 hours of storage, but the other coagulation factors remain normal.

Study questions 1- Complete:- a- Storage produces………..in DPG and ATP b- Oxygen affinity is……..by storage c- The pH of stored blood………due to gradual accumulation of …………

Assignments • Stem cell transplantation سامى حصافى صالح

Thank you

Faculty of Allied Medical Science