What is the ABC (Airway, Breathing, Circulation) rule for massive transfusion?

From the Guidelines

The ABC rule for massive transfusion prioritizes a balanced approach to blood product administration, focusing on a 1:1:1 ratio of packed red blood cells (PRBCs), fresh frozen plasma (FFP), and platelets to mimic whole blood composition and address all components of clotting simultaneously. For massive transfusion protocols, administer blood products in this ratio, typically starting with 6 units of PRBCs, 6 units of FFP, and 1 unit of platelets (equivalent to 6 units) as the initial resuscitation package 1. Additionally, consider administering 1 gram of tranexamic acid (TXA) within the first 3 hours of bleeding onset, followed by 1 gram over 8 hours, and monitor calcium levels closely to supplement with calcium gluconate or calcium chloride as needed 1. This approach helps prevent the lethal triad of hypothermia, acidosis, and coagulopathy that often develops during massive hemorrhage. Key points to consider include:

• Administering plasma (fresh frozen plasma or pathogen-inactivated plasma) or fibrinogen in patients with massive bleeding, with an optimal plasma:red blood cell ratio of at least 1:2 1
• Avoiding plasma transfusion in patients without substantial bleeding 1
• Monitoring coagulation parameters and adjusting the transfusion ratio as needed, with some studies suggesting a maximal haemostatic effect with a plasma:RBC ratio ranging between 1:2 and 3:4 1
• Being aware of the potential risks and complications associated with plasma transfusion, including circulatory overload, ABO incompatibility, transmission of infectious diseases, and transfusion-related acute lung injury (TRALI) 1

From the Research

ABC Rule for Massive Transfusion

The ABC rule, also known as the Assessment of Blood Consumption score, is used to guide the activation of massive transfusion protocols (MTPs) in trauma patients. The score assesses the patient's risk of massive transfusion based on their vital signs, laboratory results, and clinical presentation.

• The ABC score takes into account factors such as the patient's heart rate, systolic blood pressure, and hemoglobin level 2
• A high ABC score indicates a higher risk of massive transfusion and prompts the activation of MTPs 2
• The use of the ABC score has been shown to lead to earlier activation of MTPs and improved outcomes in trauma patients 2

Components of the ABC Rule

The ABC rule typically includes the following components:

• Airway: assessment of the patient's airway patency and protection 3
• Breathing: assessment of the patient's respiratory function and oxygenation 3
• Circulation: assessment of the patient's circulatory function and blood pressure 3

Activation of Massive Transfusion Protocols

MTPs are typically activated when a patient's ABC score meets certain criteria, such as:

• An ABC score of 2 or higher 2
• A patient who is predicted to require more than 5 units of packed red blood cells within 24 hours of admission 2
• A patient with a high risk of massive transfusion based on their clinical presentation and laboratory results 2

Benefits and Limitations of the ABC Rule

The ABC rule has been shown to be effective in identifying patients who require massive transfusion and improving outcomes in trauma patients 2, 4. However, the rule also has some limitations, such as:

• The potential for over-activation of MTPs, leading to unnecessary blood product waste 2
• The need for clinical judgment and experience in interpreting the ABC score and activating MTPs 2, 4