- Massive transfusion is required when there is either an expected blood loss of:
- > one blood volume (70 mL/kg) in 24 hours, or
- > half a blood volume in 4 hours.
- Major blood loss should be managed by an experienced team using a protocol.
- Massive transfusion protocols can be directed by laboratory results or formula based.
- For every 2-4 units of erythrocytes, one unit of FFP should be given. Cryoprecipitate and platelets should be considered after 4-8 units of erythrocytes.
- Tranexamic acid, 1g over 10 minutes followed by 1g over 8 hours IV, should be given within 3 hours of trauma leading to major blood loss.
9.1 CRITICAL BLEEDING AND MASSIVE TRANSFUSION
Critical bleeding is bleeding requiring massive transfusion. This is defined as:
- Loss of one blood volume (adult: 70 mL/kg) in 24 hours,
- Need for 10 units of red cells in 24 hours,
- Need to replace half blood volume in 4 hours, or
- Blood loss of > 150 mL per minute.
All definitions are relevant. The most useful definitions in practice are a loss of one blood volume in 24 hours or half a blood volume in 4 hours.
9.2 PHYSIOLOGICAL EFFECTS OF MAJOR BLOOD LOSS
Risk factors for mortality with major blood loss and massive transfusion are:
- increased INR and aPTT,
- low fibrinogen, and
- low pH and low bicarbonate levels.
The aetiology of these changes are:
- anaemia and hypoxia (organ failure),
- consumption of coagulation and other plasma proteins,
- consumption of platelets, and
- metabolic derangements, hypothermia and acidosis.
9.3 MASSIVE TRANSFUSION PROTOCOL
Massive transfusion cannot occur in isolation. Surgery and interventional radiology play large roles in stopping bleeding. Tranexamic acid has a significant role in the reduction of erythrocyte and platelet needs in massive transfusion (CRASH2 study).
A standard adult dose of tranexamic acid for trauma is 1g IV within 3 hours of trauma followed by 1g IV over 8 hours.
Massive transfusion should follow a protocol endorsed by the local transfusion committee or clinical practice and quality committee. An overview of Massive Transfusion Protocol (MTP) is presented:
Step 1 Recognition and Activation
The senior clinician recognizes the patient meets criteria for massive transfusion:
- either expected blood loss of > one blood volume (70 mL/kg) in 24 hours, or
- expected blood loss of > half a blood volume in 4 hours.
This may occur in:
- severe trauma e.g. thoracic, pelvic, abdominal, and
- major obstetric, gastrointestinal or surgical bleeding.
The senior clinician activates the massive transfusion protocol.
Step 2 Patient Management
- Control bleeding with compression, tourniquet and specific surgical or radiological intervention.
- Consider cell salvage.
- Use crystalloid (e.g. 0.9% sodium chloride) first at approximately 1.5-2 times estimated blood loss, and consider the addition of colloid later.
- Avoid hypothermia – use active warming techniques.
- Permit mild hypotension (systolic 80–100 mm Hg).
- Keep the patient warm (aim for > 35°C).
- If trauma is < 3 hours ago, give 1g Tranexamic Acid over 10 minutes followed by 1 g over 8 hours.
- Recombinant FVIIa should not be routinely used.
- DDAVP has no role.
- Obtain baseline full blood count (Hb and platelet count); coagulation (aPTT, INR, Fibrinogen), biochemistry (especially calcium) and arterial blood gases (pH, base excess, lactate).
- While there is active large volume blood loss, repeat blood tests every 30–60 minutes may be required.
Based on the availability of testing, the patient should either receive blood components:
- based on results, or
- according to a formula.
Results based blood products:
|Test result||Blood component|
Hb < 70g/dL
1–2 units erythrocytes
4–5 units of WB derived platelets
INR > 1.5
Fibrinogen < 1.0g/L
3–4g fibrinogen which equates to 8–10 units cryoprecipitate
- Based on a formula:
Start with a pre-defined Massive Transfusion Pack (MTP) which consists of:
- 4 units erythryocytes, and
- 2 units FFP.
If bleeding is not controlled, give a second MTP (4 units erythrocytes and 2 units FFP) and add:
- 5 units platelets (1 standard adult dose)
- 8–10 units cryoprecipitate (1 standard adult dose)
- Continue with additional MTP, with cryoprecipitate and platelets with each second MTP, until bleeding is controlled.
Step 3 Stand-down
It is important to inform the laboratory and transfusion service that the massive transfusion protocol is finished.
The Hospital Transfusion Committee or Clinical Governance Committee should review all cases of massive transfusion.
9.4 NOTES ON AVAILABILITY OF BLOOD COMPONENTS
In most regions of Cambodia, FFP, Platelets and cryoprecipitate is not available.
In some regions erythrocytes are not available and only whole blood is available.
Whole Blood can be used as a substitute for erythrocytes however the volume is about double that of an erythrocyte.
Whole Blood, once > 24 hours old and refrigerated, does NOT contain any viable platelets and the labile coagulation factors are severely reduced. Stored whole blood is not a substitute for FFP or platelets or cryoprecipitate.
Unrefrigerated whole blood < 24 hours old does contain adequate platelets and coagulation factors. Unrefrigerated whole blood should only be used if full transmissible disease screening can occur. Some regions internationally use “emergency donor panels (EDP)”, however blood derived from emergency donors carries an increased risk. The hospital, government regulators and clinicians need to approve the use of an EDP in advance and the patient (or legal delegate) is required to consent.