Whole Blood

Whole blood is a single donation containing red cells, plasma, anticoagulant and preservative, with or without removal of leucocytes. It supplies oxygen carrying capacity, volume, coagulation factors and some platelet function in one product, which makes it logical for massive haemorrhage and useful where component separation or supply is limited. Low titre group O whole blood is group O whole blood screened for low levels of anti-A and anti-B in the plasma, so that it can be given to recipients of any ABO group in emergencies.

Composition. A unit is usually about 450 to 500 mL including 63 mL of anticoagulant, with a haematocrit of about 35 to 45%. Plasma coagulation factors are present, but labile factors V and VIII fall during storage. Platelets in cold stored whole blood retain some haemostatic function, but their number and function are unreliable and they must not be counted on to correct thrombocytopenia.

Storage and shelf life. 2 to 6 degrees Celsius, with shelf life about 21 days in citrate phosphate dextrose and about 35 days in citrate phosphate dextrose adenine. Leucodepletion is by a whole blood filter before storage in many systems.

Low titre definition. The cut-off for anti-A and anti-B titre varies by system (usually between 1 in 50 and 1 in 256) and by assay, and must be stated by the supplying blood bank.

Special groups. Group O whole blood carries passive anti-A and anti-B and is not suited to repeated large volumes in non-group O recipients, to neonates and to small children without the blood bank's agreement. In East Africa, whole blood may be the main or only product for children with severe anaemia and for haemorrhage where components are not available.

Indications.

• Life-threatening haemorrhage, particularly in trauma and obstetric haemorrhage, where it replaces red cells, plasma and some haemostatic function together.

• Severe anaemia where only whole blood is available, especially in children with severe malarial anaemia.

• Exchange transfusion in selected settings, using fresh reconstituted or whole blood as the blood bank directs.

Non-indications and cautions.

• Chronic compensated anaemia in a normovolaemic patient, because the plasma volume adds overload risk. Red cells are preferred.

• Heart failure and renal failure.

• Patients who need a specific component only (platelets, cryoprecipitate).

Recipient selection for low titre group O whole blood.

• Males of any age and females beyond childbearing potential: RhD positive units are acceptable when RhD negative units are limited.

• Girls and women of childbearing potential: RhD negative, and where possible K negative, units, with anti-D immunoglobulin and specialist advice if an RhD positive unit is given.

• After the first units, switch to group specific whole blood or to group specific components once the recipient's group is known. Prolonged use of non-identical group O whole blood in non-group O recipients increases the risk of haemolysis from passive antibodies, and the maximum number of units is set by the blood bank, usually a small number of units.

Warm fresh whole blood. Collected from a donor at the time of need and not fully tested, it carries a real infection risk and is a last resort where no tested product exists.

Dose.

• Adult: one unit is about 450 to 500 mL. In haemorrhage, give as the blood loss and response demand, and reassess after each unit.

• Children: 20 mL/kg is a usual dose for severe anaemia with decompensation, and about 6 mL/kg raises haemoglobin by about 1 g/dL.

• Neonates: whole blood is not usual for non-bleeding indications.

Testing and compatibility. Group specific whole blood must be ABO identical with the recipient. Low titre group O whole blood is released uncrossmatched in emergencies, and a sample must be taken before the first unit so testing continues.

Rate and time limit. Start slowly for the first 15 minutes in non-bleeding patients, then run each unit over 2 to 4 hours, completed within 4 hours of leaving controlled storage. In haemorrhage, give rapidly through a blood warmer and large bore access. Children with severe anaemia usually receive 20 mL/kg over about 3 to 4 hours, slower when there is cardiac failure.

Equipment and fluids. Blood giving set with a 170 to 200 micrometre filter. Only 0.9% sodium chloride in the same line, and no drugs, dextrose or calcium containing solutions.

Monitoring. Temperature, pulse, blood pressure, respiratory rate and oxygen saturation before, at 15 minutes, hourly and at completion. In massive transfusion, monitor ionised calcium, potassium, temperature, acid base state and coagulation.

Special groups.

• Neonates and small children: blood bank approval, and group matched or compatible plasma content.

• Pregnancy: RhD negative and K negative units for women of childbearing potential.

• Heart or kidney failure: slow rate, small aliquots and cautious volume.

Expected effects. Rise in haemoglobin, improved perfusion, and some correction of coagulopathy through plasma factors.

Serious reactions. Acute haemolytic reaction (including from passive anti-A or anti-B), anaphylaxis, bacterial contamination, circulatory overload, lung injury, hyperkalaemia, citrate toxicity with hypocalcaemia in massive transfusion, hypothermia and delayed haemolysis.

Immediate interruption criteria. Fever with rigors, chest or back pain, dyspnoea, hypotension, haemoglobinuria, urticaria with systemic signs or unexplained deterioration. Stop the transfusion, assess the patient, keep intravenous access, recheck identity of patient and unit, and inform the blood bank. Do not restart without authorised clinical evaluation.

Follow up. Haemoglobin and coagulation after resuscitation. After non-identical group O whole blood, monitor for delayed haemolysis (jaundice, falling haemoglobin, dark urine) over 1 to 2 weeks and send a direct antiglobulin test when suspected.

Referral and escalation. Blood bank medical staff for non-identical unit limits, recipients who are female and of childbearing potential, and any suspected haemolysis. Report all reactions.