This section gives general guidance about transfusion management of a bleeding patient who is likely to need rapid infusion of substantial volumes of fluid together with red cell replacement, sometimes referred to as massive haemorrhage. (See also obstetric haemorrhage and gastrointestinal haemorrhage.) See also the 2006 BCSH Guideline (www.bcshguidelines.com).
Systematic reviews reveal uncertainty about the best approach to restoration of circulating volume in hypovolaemic shock. Full restoration of volume may worsen bleeding by increasing blood pressure and diluting clotting factors in the blood. Some patients, e.g. those with ruptured aortic aneurysm or blunt chest trauma, do not benefit from full restoration of blood volume and blood pressure before surgical control of bleeding. However, with severe head injuries, restoration of blood volume and pressure may reduce the extent of ischaemic brain damage.(PMID11869596)(PMID12535407)(PMID15266460)(PMID15495001)
A recent randomised controlled trial of 5% human albumin vs saline infusion showed in a heterogeneous population of adult ICU patients that albumin can be considered safe, without demonstrating any clear efficacy advantage over saline. There is no firm evidence that the use of any colloid solution is superior to any other or that colloid solutions are associated with better outcomes than crystalloids in patients with trauma or burns or following surgery. Some colloid solutions affect haemostatic function and so could contribute to a bleeding tendency. It is advisable to adhere to the maximum doses recommended by the manufacturers.
Clinical and laboratory evidence of coagulopathy
This term describes a condition following major blood loss in which there is abnormal bleeding with oozing from tissues and puncture sites in a patient who has major bleeding, clotting problems resulting from dilution and/or consumption of platelets and coagulation factors.
Fibrinogen concentration halves after every 0.75 blood volume replaced. As a rough guide it is likely to fall to < 1 g/l after replacement of 12 units of red cells or 1.5 x blood volume. Other clotting factors fall by varying degrees because some, such as factor IX, have considerable extravascular distribution, whereas factor VIII is largely intravascular but is released from endothelial cells at times of stress. As a guide, when red cells in additive solution are transfused, a prothrombin time ratio (PTR) of > 1.5 (clotting factors approximately 50% of normal) will be reached after replacement of 1−1.5 x blood volume, or transfusion of 8−12 units of red cells. A PTR of > 1.8 (clotting factors approximately 30% of normal) will be reached after replacement of 2 x blood volume. Platelet count will halve for every 1 x blood volume replaced and, depending on the starting count, will usually fall to 50−100 x 109/l after 2 x blood volume replacement, or transfusion of > 15 units of red cells.
Disseminated intravascular coagulation
Acute disseminated intravascular coagulation (DIC) results from activation of the coagulation and fibrinolytic systems leading to consumption of platelets, coagulation proteins, fibrinogen and platelets. It is most often seen in patients with sepsis or an obstetric complication. There may be severe microvascular bleeding with or without thrombotic complications. DIC may be provoked by tissue damage due to trauma or by underperfusion, hypothermia, sepsis or obstetric complications. Diagnosis is by clinical signs of unexpected bleeding or thrombosis, low fibrinogen or platelets, prolonged PTR and raised fibrin degradation products (FDP) or d-dimers.
Hypothermia, acidosis, hypocalcaemia in massive haemorrhage
May occur during haemorrhage and resuscitation and must be corrected as they contribute to the bleeding tendency. see Table 8.(PMID9087467)(PMID8569362)(PMID15988284)(PMID:9087467)
Blood salvage (cell salvage)
May be an important contribution to management in some cases of major haemorrhage (see Intra- and post-operative blood conservation).
Table 8 Other complications of large-volume transfusions
Hypothermia, coagulopathy and O2 delivery
Hypothermia impairs haemostasis and shifts the Bohr curve to the left, reducing red cell oxygen delivery to the tissues. Rapid transfusion of blood at 4°C can lower the core temperature by several degrees.
Keep the patient warm.
FFP or platelets contain citrate anticoagulant (red cells in additive solution contain only traces of citrate). In theory, infused citrate could lower plasma ionised calcium levels, but in adults rapid liver metabolism of citrate usually prevents this.
In neonates and patients who are hypothermic, the combined effects of hypocalcaemia and hyperkalaemia may be cardiotoxic.
If there is ECG or clinical evidence of hypocalcaemia, give 5 ml of 10% calcium gluconate (for an adult) by slow IV injection and, if necessary, repeated until the ECG is normal.
It is very unusual for IV calcium to be needed during blood component transfusion.
The plasma or additive solution in a unit of red cells stored for 4−5 weeks may contain 5−10 mmol of potassium. In the presence of acidaema and hypothermia, this additional potassium can lead to cardiac arrest.
Keep the patient warm and monitor potassium levels during massive transfusion.
Despite the lactic acid content of transfused blood (1−2 mmol/unit of red cells, 3−10 mmol/unit of whole blood), fluid resuscitation usually improves acidosis in a shocked patient. Transfused citrate can contribute to metabolic alkalosis when large volumes of blood components are infused.
Adult respiratory distress syndrome
1. Due to large volume transfusion.
2. Transfusion-related acute-lung injury (TRALI) due to reaction with antibodies in a single plasma-containing component should be considered (see pg ref=60).
The risk is minimised if good perfusion and oxygenation are maintained and over-transfusion is avoided. Monitor appropriately. Treat with oxygen, positive end-expiratory pressure and mechanical ventilation. Beware of sudden systemic hypovolaemia with TRALI.
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