Plasma - Fresh Frozen Plasma (FFP)

Fresh frozen plasma is the fluid portion of a unit of whole blood that is frozen in a designated time frame, usually within 8 hours. 

FFP contains all coagulation factors except platelets. 

FFP contains fibrinogen (400 to 900 mg/unit), albumin, protein C, protein S, antithrombin, tissue                                                                                                   factor pathway inhibitor. 

It is free of erythrocytes and leukocytes. 

FFP corrects coagulopathy by replacing or supplying plasma proteins in patients who are deficient in or have defective plasma proteins. 

A standard dose of 10 to 20 mL/kg (4 to 6 units in adults) will raise factor levels by approximately 20%. 

An increase of approximately 10% of several factors is enough to effect hemostasis. 

In addition, FFP provides some volume resuscitation as each unit contains approximately 250 ml.

FFP can only be administered intravenously. FFP must be ABO compatible with the recipient’s red cells. 

The FFP bag and fluid upon visual inspection should have no leakage, clots, or abnormal color.  

FFP is stored at -30 C.  

Prior to administration, FFP is thawed in a water bath at 30 to 37 C over 20 to 30 minutes or in an FDA-cleared device as quickly as 2 to 3 minutes. 

FFP should be administered immediately after thawing. 

If FFP is not given immediately after thawing, it should be stored at 1 to 6 C.  If the thawed FFP is not used in 24 hours, it should be discarded. 

Once thawed, the activity of clotting factors, particularly factor V and factor VIII, decline gradually. 

After initial dosage, re-administration may be needed every 6 to 8 hours if there is continued bleeding due to the short half-life of factor VII. Factor VII has a half-life of 2 to 6 hours.

Packed Red Blood Cells

Packed Red Blood Cells (PRBCs) are the most commonly used blood component. 

PRBCs are prepared from whole blood by centrifuge or by apheresis collection. 

Typically, one unit of PRBC is approximately 350 mL in volume, of which RBC volume is 200–250 ml. The remaining volume is due to plasma (typically <50 ml), White Blood Cells (WBCs), platelets and anticoagulants. 

The most commonly used anticoagulant is CPDA-1 (citrate, phosphate, dextrose and adenine), which allows for 35 days storage at 2–6°C. 

The hematocrit of such units is less than 80% (range, 70–80%).

Each unit of PRBC is expected to increase the hematocrit by 3% and the hemoglobin level by 1 g/dL. This effect can be measured 15 min after transfusion. 

In a bleeding patient, it must be remembered that transfusion of multiple units of PRBC will aggravate the coagulopathic state of the patient. 

The unit of PRBC that is being transfused must be compatible with the recipient’s plasma ABO antibodies. 

Thus, if the recipient is blood group A, he or she has anti-B antibodies and cannot be transfused with B or AB units. 

If the recipient is B, he or she has anti-A antibodies and cannot be transfused with A or AB units. 

Both A and B patients can receive O units. 

If the recipient is AB, he or she has no anti-A or anti-B antibodies and can therefore receive A, B, AB or O units. 

If the recipient is O, he or she has anti-A and anti-B antibodies and can receive only O units.

Whole Human Blood (WHB)

Whole blood can be stored under refrigeration for up to 35 days at 2 to 6'C 

The upper limit of 6 degree C is essential to minimize the growth of any bacterial contamination in the  unit of blood.

Below 2 degree C  red cells  become haemolysed.  So they must never be allowed to freeze. Haemolysed cells if transfused can cause renal failure & fatal bleeding problems.

Whole blood & red cells should be issued from the blood bank in the blood transport box or insulator carrier that will keep the temperature under 10 degree C, if the room temperature is greater than 25 degree C or if there is a possibility that blood will not be transfused within 30 minutes.

Once issued red blood cells should be transfused within ½ hour of release from BTS.  If not required should be sent back to Blood center immediately.

Whole Blood contains all the elements of blood that are necessary for oxygen delivery and hemostasis, in nearly physiologic ratios and concentrations. 

Whole blood is the preferred product for resuscitation of severe traumatic hemorrhage. 

Group O whole blood that contains low titers of anti-A and anti-B antibodies (low titer group O whole blood) can be safely transfused as a universal blood product to patients of unknown blood group, facilitating rapid treatment of exsanguinating patients. 

Fresh whole blood can be collected from pre-screened donors in a walking blood bank to provide effective resuscitation when fully tested stored whole blood or blood components are unavailable and the need for transfusion is urgent. 

Blood and Blood Components

Normally, 7-8% of human body weight is from blood.  

In adults, this amounts to 4.5-6 quarts of blood.  

This essential fluid carries out the critical functions of transporting oxygen and nutrients to our cells and getting rid of carbon dioxide, ammonia, and other waste products.  

In addition, it plays a vital role in our immune system and in maintaining a relatively constant body temperature.  

Blood is a highly specialized tissue composed of more than 4,000 different kinds of components.  

The components of human blood are:

•  Red blood cells (erythrocytes). These carry oxygen from the lungs to the rest of the     body
• 
  
•  White blood cells (leukocytes). These help fight infections and aid in the   immune process. Types of white blood cells include:

1.  Lymphocytes
2.  Monocytes
3.  Eosinophils
4.  Basophils
5.  Neutrophils

         Plasma. The liquid component of the blood in which the following blood cells are suspended:

        Platelets (Thrombocytes). These help in blood clotting.

Components Separating in Blood Bank:

The whole blood which is a mixture of cells, colloids and crystalloids can be separated into different blood components namely 

• Packed Red Blood Cell (PRBC) concentrate, 
• Platelet Concentrate, 
• Fresh Frozen Plasma,
• Cryoprecipitate. 

Each blood component is used for a different indication; thus the component separation has maximized the utility of one whole blood unit. 

Different components need different storage conditions and temperature requirements for therapeutic efficacy. 

A variety of equipment to maintain suitable ambient conditions during storage and transportation are in vogue. 

The blood components being foreign to a patient may produce adverse effects that may range from mild allergic manifestations to fatal reactions. Such reactions are usually caused by plasma proteins, leukocytes, red cell antigens, plasma and other pathogens. 

To avoid and reduce such complications, blood products are modified as leukoreduced products, irradiated products, volume reduced products, saline washed products and pathogen inactivated products. 

The maintenance of blood inventory forms a major concern of blood banking particularly of rare blood groups routinely and common blood groups during disasters. PRBCs can be stored for years using cryopreservation techniques. New researches in red cell cultures and blood substitutes herald new era in blood banking.

Antibodies

An antibody is a product of an antibody immune response and will react with that antigen in some observable way. Antibodies are immunoglobulins (Ig) immunoglobulins and are found in the gamma globulin part of plasma proteins.

There are five categories of immunoglobulins: IgG, IgM, IgA, IgD and IgE.

Blood group antibodies

These are usually produced when an individual is exposed to blood of a different group by transfusion or pregnancy (‘alloantibodies’). 

This is a particular problem in patients who require repeated transfusions, for conditions such as thalassaemia or sickle cell disease, and can cause difficulties in providing fully compatible blood if the patient is immunised to several different groups. 

Some antibodies react with red cells around the normal body temperature of 37°C (warm antibodies). Others are only active at lower temperatures (cold antibodies) and do not usually cause clinical problems although they may be picked up on laboratory testing. 

Antigens

An antigen is any antigen substance that, when introduced into a body and recognized as foreign, will bring about an immune response. This might result in the production of an antibody that will react specifically with that antigen in some observable way.

Blood group antigens

Blood is classified into different groups according to the presence or absence of molecules called antigens on the surface of every red blood cell in a person's body. 

Antigens determine blood type and can either be proteins or complexes of sugar molecules. The genes in the blood group antigen group provide instructions for making antigen proteins. 

Blood group antigen proteins serve a variety of functions within the cell membrane of red blood cells. These protein functions include transporting other proteins and molecules into and out of the cell, maintaining cell structure, attaching to other cells and molecules, and participating in chemical reactions.

Blood group antigens play a role in recognizing foreign cells in the bloodstream. For example, if a person with blood type A receives a blood transfusion with blood type B, the recipient's immune system will recognize the type B cells as foreign and mount an immune response. 

Antibodies against type B blood cells (anti-B antibodies) are made, which attack and destroy the type B blood cells. This sort of blood type mismatch can lead to illness. Some blood types are associated with more severe immune reactions than others. 

The blood type of donated cells, or tissues in the case of organ donation, is checked before being given to a recipient to prevent this immune response.

The Basic Elements of Blood

Most people have about 4-6 liters of blood. Your blood is made up of different kinds of cells that float in a fluid called plasma:

● Your red blood cells deliver oxygen to the various tissues in your body and remove carbon dioxide.

● Your white blood cells destroy invaders and fight infection.

● Your platelets help your blood to clot.

● Your plasma is a fluid made up of proteins and salts.

What makes your blood different from someone else’s is your unique combination of proteins molecules, called antigens and antibodies.

Antigens live on the surface of your red blood cells. Antibodies are in your plasma.

The combination of antigens and antibodies in your blood is the basis of your blood type.