Such definitions are difficult to apply in acute situations. Practical, arbitrary definition is major haemorrhage leading to:
Heart rate > 110bpm.
SBP < 90mmHg.
All hospitals should have locally-agreed triggers for activation of massive transfusion protocols.
Organisational Aspects
Blood provision in emergencies must not be delayed, and requires the use of specifically-designed protocols.
Protocols should include:
Clearly-understood communication chains between clinical staff and laboratory staff.
Provisions for emergency release of blood without prior approval from a haematologist.
Protocols should be developed in concert with the relevant teams managing such bleeds, as they must be adapted for specific clinical areas.
All staff must know where to find the major haemorrhage protocol, and be familiar with its contents and their roles.
Team Leaders are usually the most senior doctors running the resuscitation; they will need to direct and coordinate management of the multidisciplinary team. Members may include:
Interventional radiology / specialists to help with haemostasis.
Porter / clinical support staff.
Transfusion laboratory.
Intensive care physicians.
Other laboratories.
There must be a clear mechanism for contacting team members, and a member of the team should be nominated to communicate with the transfusion laboratory.
Transfusion laboratory staff must be informed of major haemorrhage at the earliest opportunity to allow timely blood provision. The following must be communicated:
Patient’s full name, date of birth and unique patient identifier.
The degree of urgency (emergency O cells, group-specific blood requires ~30 minutes).
Whether the massive transfusion protocol should be activated.
If MTP not activated, the volume of blood components required (typically RBC 4-6 units, FFP 15-20ml/kg).
Unknown Patients
Positive patient identification is paramount.
All patients receiving a blood transfusion must wear a patient identification band, which should include:
Last name.
First name.
Date-of-birth.
Unique identification number.
In emergency situations, patient identifiers may not be known. At least two of the following must be supplied and written on the patient’s identification band:
One unique identification number (usually a temporary ID number such as the Emergency Department number).
Patient’s gender.
Transfusion must continue using the emergency ID until a new, fully-labelled sample with the patient identifiers is taken and processed (see table below).
In all cases, the details on the blood component identity tag must match the details on the patient ID band.
All samples must be taken and labelled by hand at the bedside (unless an electronic label generated by barcoded wristband is used).
A written / electronic request must be sent to the transfusion laboratory. If the sample is already in the transfusion laboratory, telephone requests may be accepted in emergencies, as long as clear documentation of methods is done to reduce transcription error.
Transfusion Support
Principles of major bleeding:
Assessment and resuscitation.
Local control of bleeding.
Haemostatic support.-
In the setting of massive bleeding, blood warmers and pressure infusers should be available and utilized.
All components given must be documented (legal requirement) for full traceability.
Red cells
Required for oxygen-carrying capacity and rheological effect resulting in margination of platelets and plasma.
European Guideline on Bleeding in Major Trauma recommends a Hb threshold of 7-9g/dL for transfusion.
However, note that Hb and Hct in bleeding patients are not reliable indicators of blood loss.
Transfusion is usually required when 30-40% of the blood volume has been lost (1.5L in a 70kg male).
The rate of transfusion should be guided by the rate of blood loss and the degree of haemodynamic compromise.
Hospitals must ensure that red cells are readily available in emergencies. This may necessitate the use of blood storage refrigerators in large hospitals with remote clinical areas. The massive transfusion protocol must state the location of the nearest group O units.
Prior to administration of emergency blood, all patients should have correctly-labelled samples taken.
24hr access to cell salvage should be available in cardiac, trauma, obstetric and vascular centres.
Haemostatic assessment and monitoring
Establish whether a patient is on antiplatelets or anticoagulation, and reverse the latter if possible.
Coagulopathy of bleeding is related to:
Consumption of coagulation factors.
Dilution.
Activation of fibrinolysis.
Blood loss.
These are all worsened by hypothermia, acidosis and hypocalcaemia.
Coagulation profiles (PT, APTT and fibrinogen) and platelet counts should be performed every 30-60min, depending on severity.
These should be used to guide appropriate use of haemostatic blood components.
FFP should initially be given in a 1:2 ratio (use a 1:1 ratio if bleeding is a result of major trauma) for major haemorrhage.
Subsequent replacement should be guided by results of coagulation tests, transfusing when either the PT or APTT and 1.5x the upper limit of normal.
Cryoprecipitate should be given if the fibrinogen falls below 1.5g/l.
The adult dose of cryoprecipitate is 2 five-donor pools (10 units), which should raise the fibrinogen level by 1g/l.
Platelet count should be kept > 50×109/L.
Platelets should be transfused when the platelet count falls below 100×109/L and if there is ongoing bleeding.
One adult therapeutic dose (ATD) of platelets is equivalent to one apheresed unit or four pooled units.
Blood Provision
If blood group O has been given, blood of the patient’s own ABO group should be given as soon as it has been determined.
Once the blood volume transfused in 24hr period is equivalent to one blood volume (8-10 units for adults, children 80-100ml/kg), ABO/RhD compatible blood can be supplied without the need for a serological cross-match.
Antigen-negative blood should be selected for patients with clinically-significant alloantibodies, but if demand outstrips supply, provision of untyped blood may be necessary.
Pharmacological Agents
Tranexamic acid reduces early and late trauma deaths if given in the first three hours (CRASH-2).
Tranexamic acid does not increase the rate of thromboembolic complications.
TXA should be given as a 1g bolus over 10 minutes, followed by a maintenance infusion of 1g over 8 hours.
Aprotinin, rVIIa and PCC are not recommended in major haemorrhage.
Thromboprophylaxis should be given ASAP after bleeding ceases.
Specific Situations
Post-partum haemorrhage
Defined as blood loss of >500ml after NVD or >1000ml after Caesarean section.
Most cases relate to uterine atony or placental retention.
TXA reduces death in PPH (WOMAN trial).
Fibrinogen levels are normally 4-6g/l at delivery. Hence, fibrinogen levels of 2-3g/l indicate significant blood loss in PPH.
Cryoprecipitate should be transfused when fibrinogen levels are <2g/l and there is ongoing bleeding.
Gastrointestinal bleeding
A restrictive transfusion threshold of 7g/dl should be used for RBCs.
This results in higher 6-week survival and lower re-bleeding rates.
Trauma
FFP, platelets and RBC should initially be given in a 1:1:1 ratio.
When bleeding is under control, FFP and platelet replacement should be guided by laboratory investigations.
Tranexamic acid should be given within 3h.
High risk surgery
TXA at a dose of 10mg/kg followed by 1mg/kg/hr infusion is recommended to prevent bleeding in high-risk surgery.
Higher doses have no increased haemostatic affect, but are associated with seizures.
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