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24-10-2012Blood components therapy
Whole Blood:Acute Haemorrhage
Oligaemic Shock
Neonatal Transfusion
Exchange Transfusion
Whole blood should not be used in chronic anaemias, which are better treated with red cell concentrate, as whole blood may cause cardiac overload
Granulocytes & platelets present in stored whole blood are not functional, whole blood is also deficient in labile clotting factors
1 unit is expected to increase Hb by 10 g /L in adults. After transfusion, the increase may be not apparent for 48 72 hr while the patients blood volume readjusts to normal.
Red Cell Concentrate:
It is the preparation of choice when the main purpose of blood transfusion is to provide a means for the transport of oxygen
Red cell concentrate carries the same risk of haemolytic transfusion reaction & transmission of viral diseases as does whole blood. The use of red cell concentrate reduces the amount of anticoagulant & electrolyte transfused
It is more viscose than whole blood & usually takes longer to transfuse.
Leukocyte - poor RBC:
These are red cell preparations from which most of the white cells & platelets have been removed
Several methods are available to produce leucocyte poor red cell preparations including: sedimentation, centrifugation, washing & filtration.
The volume & composition of the final product depend on the method of preparation. Washed cells are also free from plasma proteins.
Can be used in the following conditions:
To prevent transfusion reaction in patients with known WBC AbsTo prevent sensitization to WBC Ags in patients requiring multiple transfusions (thalassaemia, haemolytic anaemias, etc.) or in potential BM transplant candidates
To transfuse patients who are allergic to plasma proteins ( washed cells only)
They carry the same risk of haemolytic transfusion reaction & transmission of viral diseases.
Platelets Conc. ( Random Donor (:
Each unit of random donor platelets concentrate contain an average of 5 X 1010 / L ( 0.5 X 1011 / L ) suspended in about 50 ml of plasma. It also contains some leucocytes & RBC.Cross matching is not necessary but ABO compatible platelets should be used, as platelets express ABO antigens. Although platelets do not express Rh Ag, Rh compatible platelets should be used where possible, because all platelet preparations also contain RBC. This particularly important in Rh negative females of productive age, if it happen , the use of Anti D for prevention of Rh immunization should be considered.
Each unit of platelet concentrate will rise the platelet count of an average adult by 5 10 X 109 / L under optimal conditions.
A standard dose of platelets is about 6 units (one unit per 10 kg of body weight)
Massive splenomegaly, high fever, sepsis, DIC & platelets/ HLA Abs can cause less than expected platelet count increment & survival. The 1 hr post transfusion platelet count increment is less affected by splenomegaly, high fever, & DIC than by the presence of platelet or HLA Ab. If the 1 hr increment is less than 50 % of expected, the patient is considered to be refractory & should be screened for HLA Ab & should be HLA typed.
The platelet count increment can be corrected for difference in body size so that more reliable estimates of expected platelet increment can be determined. The minimal expected corrected increment is 10,000 / l / m2.
Absolute platelet increment / l X body surface area (m2)
Number of platelets transfused ( 1011)
The number of platelet transfused can be estimated by multiplying the number of units by the 0.55 ( the number of platelets in each unit expressed in 1011)
Platelets Conc. (Single Donor):
A standard or a larger dose of platelets can be obtained from a single donor by the use of cell separator. It contain 2 6 X 1011 platelets with an average of 3 X 1011.
In addition to the indications where random platelet concentrate is used, single donor platelet concentrates can be HLA matched with the patient.
Each unit is expected to rise platelet count by 30 60 X 109 / L
Absolute platelet increment / l X body surface area (m2)
Number of platelets transfused ( 1011)
Fresh Frozen Plasma:
Treatment of multiple coagulation factor deficiencies ( massive transfusion, trauma, liver disease, DIC, unidentified deficiency)
Content: 150 250 ml plasma containing all coagulation factors except platelets ( 400 mg fibrinogen + 1 unit / ml all other factors )
It should be thawed at a temperature of 35 & 37 C. The thawing process takes about 20 min. FFP should be used soon after thawing, preferably within 2 hr.
FFP must be transfused though a standard blood filter at a rate not exceeding 10 ml / min.
The dosage of FFP depends on the clinical situation & must be assessed for individual case. An average dose varies between 5 15 ml / kg. Repeated transfusions, however, would be required for surgical patients until healing has occurred, e.g., factor IX has a half life of 18 24 hr, requiring daily transfusions.
FFP should not be used for blood volume expansion or protein replacement because safer products are available; serum albumin, synthetic colloids, and balanced salt solutions, none of which transmits disease or cause severe allergic reactions.
Cryo Precipitated Antihaemophilic Factor:
Indications:Factor VIII deficiency
VonWillebrand`s disease
Factor XIII deficiency
Fibrinogen deficiency, dysfibrinogaemia
Content : VIII = 80 150 U
vWF = 40 70 % of whole blood level
XIII = 20 30 % of whole blood level
I = 150 250 mg
Factor VIII
Increment desired X body weight
2
The number of bags required = no of units / 80
The dose is given 8 12 hourly
Fibrinogen
Increment desired (in mg/ml) X plasma volume
The number of bags required = total dose / 250
Fibrinogen 2.5 g / L = 250 mg / dl = 2.5 mg / ml
e.g. 0.3 g / L, plasma volume 2500 ml, needing surgery?
(1 0.3) X 2500 = 1750 mg is needed
1750 / 250 = 7 bags of cryo-ppt are needed