Guidelines to transfusion therapy RED CELL PRODUCTS –

Whole blood- Changing concepts prefer need- specific individual component use; indications aremassive hemorrhage, Exchange transfusion etc.

Red cell concentrates – Indicated whenever there is impaired Oxygen carrying capacity, Chronic anaemias, Bone marrow failure, Transfusion of ‘O’ group RBC concentrate in emergency where ABOgrouping of blood is not feasible.

Leukocyte reduced RBCs- 85-90% depletion of leukocytes; Indicated in conditions where immunerelated post-transfusion febrile reactions are troublesome.

Washed RBCs- Plasma depleted, Leukocyte depleted, must use within 24 hours; Indicated in severeallergic reactions and in anaphylaxis in IgA deficiency.

Frozen RBCs- long term storage, plasma and Leukocyte depleted; to be used within 24 hours ofthawing- Indicated in autologous storage in postponed surgery. Rare donor unit.

Storage and problems associated with it

 ·       AIM- To maintain RBC ATP concentration, which is essentials for red cell survival

·       Temperature- 4-6⁰ C. At this temperature the Na/K pump stops working. Therefore the intracellular and extracellular potassium concentrations equilibrate.

·       Hemolysis- In prolonged storage due to ATP depletion in RBCs

·       Hyperkalemia- in the supernatant plasma- Due to the above two factors – namely hemolysis and potassium redistribution and equalization; but rarely of any consequences unless A single unit of RBC concentrate has only 70 ml of plasma and a potassium of 5.5 meq/L at product expiry.

·       Citrate toxicity – This is seen in large volume transfusions; more so in the setting of liver dysfunction. Hypocalcemia with its cardiovascular ill effects in the presence of a near normal total Serum Calcium is characteristically seen. IV Calcium gluconate in such settings can be considered where citrate toxicity is anticipated.

·       Microaggregates – Stored blood has microaggregates made of platelets, fibrin and red cells. These are thought to cause post- transfusion hypoxia due to pulmonary microembolism called as TRALI (transfusion related acute lung injury). Therefore if >5U of blood are transfused at the same time, 20-40 um pore sized filters are to be used.

Guidelines to replacement therapy

 ·       Should target a Hb of 8 g% for all medical conditions. A higher Hb is not additionallybeneficial to the patient.

·       Earlier concept of perioperative blood transfusion as soon as the Hb falls to the ‘magic’ figure of 10gm/dl- (to cause faster wound healing and avoid the risks of general anaesthesia)has been thrown away. Now a Hb of 7gm% is used as a cut off instead.

·       In case of hemorrhage/ surgery with blood loss,

<10% of blood volume loss needs no transfusion;

</= 20% requires crystalloids exclusively;

>25% requires red cells along with crystalloids and colloids because the volume afterreplacement has a still poor oxygen carrying capacity and therefore tissue hypoxia.

PLATELET TRANSFUSION

Guidelines to replacement therapy-

 ·       Platelet lifespan = 9.6 +/- 6 days.

·       Normal rate of platelet destruction/ day is 3.6 x 1010 platelets

·       Platelet concentration of <10 x 109 /dL increases chances of spontaneous intracerebralbleeds and can present as serious GI/GU bleeds

·       At <5 x 109 /dl can present as serious GI/GU bleeds

·       If there is major bleeding of platelet concentrations of more than 20 x 109 /dl, a vessel wallor platelet dysfunction should be looked for.

·       One unit of platelet rich concentrate contains >5.5 x 1010 platelets and at good centres, itmay even contain 7.0 x 1010 platelets.

·       Transfused platelets distribute as 1/3rd into a normal sized splenic pulp and 2/3rd in theintravascular compartment

·       A single PRC increases the platelet concentration in a 75kg man by 6 x 109 or 8 x 109 plateletsdepending on the platelet concentration in the unit, apart from the normal splenic pooling.

·       Therefore in a production defect, replacement dose would be 1U/ day, providing at least 3.7 x 1010 platelets in the intravascular compartment.

·       Hypersplenism – It is unusual for this to present with platelets <40-50 x 109 platelets / dl. Therefore never calls for transfusion. If needed, another possible cause for bleeding shouldbe sought for.

·       Consumptive coagulopathy – Needs supportive therapy and treatment of the cause. Mayneed platelet transfusion to stop troublesome bleeding.

Indications for platelet transfusion

 ·       <5 x 109 platelets in a production disorder is an indication for prophylactic platelettransfusion.

·       6-10 x 109 platelets with fresh minor haemorrhages.

·       11-20 x 109 platelets with co-existing coagulation factor deficiency/ Heparin therapy/planned lumbar puncture.

PLASMA DERIVATIVES

 FFPs – Fresh frozen plasma – frozen plasma within 6 hours of donation at a temperature of </= - 18C. Should be used within 1 year. Should be used after 20-30 mins of thawing and before 24 hours;because factors V and VIII degrade to inadequate levels after 24 hours of thawing.

Indications –

 ·       Multiple coagulation factor defects (e.g. CLD – just before a procedure only if PT > 16-18 secs, or in Massive transfusions – of 6-10 U of RBCs with post – transfusion bleeding)

·       DIC (If bleeding or before any procedure)

·       Rapid oral anticoagulant reversal (Stopping drug with normal GI absorption of Vitamin K takes 48h for normalization of coagulation parameters; With inj. Vitamin K it takes 12-18h;With FFP, immediate reversal occurs.)

·       TTP/ HUS

·       Congenital coagulation defects

·       C1 esterase deficiency (life threatening angio- edema)

Not indicated:-

 ·       Immunodeficiency

·       Burns

·       Volume expansion

·       Source of nutrition

·       Reconstitution of packed red cells

Composition-

 1 U of FFP contains 200-280 ml of plasma.

0.7 -1.0 U/ml of each of the coagulation factors per ml of FFP. 1-2 mg of Fibrinogen per ml of FFP

Dosage - depends on the desired increment needed in the level of the clotting factors. Alternatively, 10-15 ml/kg can be used as a general guideline along with monitoring the clinical response.

CRYOPRECIPITATE - Prepared by refreezing at < - 18C, the precipitate from a thawed FFP at 4C, afteraddition of 10-15 ml of plasma. It can be stored for 1 year at < - 18C.

Properties and composition – Richest source of factor VIII, vWF and fibrinogen, Contains 80-100 Uof factor VIII, 250mf of Fibrinogen, 50-60 ml of Fibronectin, 40-70% of the original vWF concentration (has no factor IX)

Indications –

 ·       Hemophilia A/ vWD

·       Fibrinogen deficiency ( < 100 mg/dL)

·       Dysfibrinogemia

Not inidicated –

·       Uremic bleeding

·       Sepsis

Goal is to maintain a fibrinogen level of > 100mg/dL. 2-4 U/10kg if the FFP is poorer in consumption.

U/10kg if it is rich in its factor and fibrinogen content.

·       Large volume paracentesis

ALBUMIN

Indications

·       Nephrotic syndrome with resistant ascites.

·       Volume / fluid replacement

·       Thermal injury

·       Cerebral ischemia

·       Plasmapheresis

·       Support blood pressure during haemodialysis.

Caution-Indiscriminateuseofalbuminisassociatedwithamodestincreasein the rates lofmortality in critically ill patients. (Ref : intensive Care Med 1999, Vol 25:321-324;BritMedJ1998;317: