|
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. |
|
Hypocalcaemia
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. |
|
Hyperkalaemia
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. |
|
Acid-base disturbance
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 page 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. |