THOR-AABB Working Party Recommendations for a Prehospital Blood Product Transfusion Program

Abstract

The evidence for the lifesaving benefits of prehospital transfusions is increasing. As such, emergency medical services (EMS) might increasingly become interested in providing this important intervention. While a few EMS and air medical agencies have been providing exclusively red blood cell (RBC) transfusions to their patients for many years, transfusing plasma in addition to the RBCs, or simply using low titer group O whole blood (LTOWB) in place of two separate components, will be a novel experience for many services. The recommendations presented in this document were created by the Trauma, Hemostasis and Oxygenation Research (THOR)-AABB (formerly known as the American Association of Blood Banks) Working Party, and they are intended to provide a framework for implementing prehospital blood transfusion programs in line with the best available evidence. These recommendations cover all aspects of such a program including storing, transporting, and transfusing blood products in the prehospital phase of hemorrhagic resuscitation.

Key words:

• prehospital transfusion
• emergency
• whole blood
• recommendations
• plasma
• red blood cells

Introduction

Traumatic hemorrhage is a leading cause of death and disability, especially in younger adults (1). Traumatic hemorrhagic shock in adults has a mortality approaching 20% at 24 hours post-injury (2). In children, the mortality is 24% at 24 hours and 36% at 28 days (3). More than half of potentially preventable civilian prehospital deaths are due to hemorrhage (4), and approximately 85% of the 30,000 potentially preventable deaths per year in the US happen before the patient arrives at the hospital (5, 6). A recent study of trauma mortality in one large American county found that 36% of prehospital deaths from hemorrhage were either preventable or potentially preventable (4). Furthermore, 74% all of the analyzed trauma deaths in this county occurred either in the prehospital setting or within one hour of emergency department (ED) arrival, and 35% of these deaths were preventable or potentially preventable. Clearly, more effective prehospital treatments for massive bleeding are required (7).

A massively bleeding patient should be resuscitated with fluids that closely resemble what they are bleeding in order to maintain tissue oxygenation and promote hemostasis. For many years, resuscitation protocols focused on treating post-traumatic hypotension with early and aggressive use of crystalloids, such as normal saline, because they were inexpensive, easily transported at room temperature in resilient plastic bags, and they did not carry the infectious and noninfectious risks of transfusing human blood products (8).

Recently, evidence supporting the use of blood products early in the resuscitation has been published. For example, a study of 502 military combat casualties demonstrated that the provision of primarily red blood cells (RBC) within approximately 30 minutes of injury improved both 24-hour and 30-day survival compared to patients who did not receive any blood products or who received them later in the resuscitation (9). Subsequently, in the multicenter Prehospital Air Medical Plasma (PAMPer) trial, civilian trauma patients, whose median helicopter transport time to the hospital was approximately 40 minutes, were randomized to receive two units of plasma in addition to that base’s standard treatment while en route to the hospital. This study found that 30-day mortality was significantly improved compared to patients who received the prehospital standard of care, which, in many cases, was crystalloid fluid only (10). In a secondary analysis of this trial, the greatest survival benefit was demonstrated amongst those who received the combination of RBCs and plasma compared to those who received plasma alone (11). Receipt of any blood product during prehospital resuscitation yielded a significantly improved 30-day survival rate compared to patients who received crystalloids alone. Additionally, compared to those who received any type of blood product(s) during their helicopter transport, each liter of crystalloid that was administered was associated with a 65% increase in 30-day mortality. Other military and civilian studies have also underscored the importance of the prompt resuscitation of injured patients with blood products (12–15). The experience of transfusing blood products to injured pediatric patients is also beginning to be reported with lessons learned from battlefield resuscitation potentially being applicable to prehospital civilian pediatric trauma resuscitation (16, 17).

As evidence of the lifesaving benefits of prehospital blood product transfusion continue to accumulate emergency medical services (EMS) agencies might increasingly become interested in providing this important intervention (18). While a few EMS and air medical agencies have been providing exclusively RBC transfusions to their patients for many years, transfusing plasma in addition to the RBCs, or simply using low titer group O whole blood (LTOWB) in place of two separate components, will be a novel experience for many agencies. The evidence for administering LTOWB is currently the most developed for injured patients (19), although trauma is not necessarily the most common bleeding etiology for which prehospital transfusions are administered (20). The advantages of using LTOWB over an equivalent volume of conventional components have been reviewed in detail elsewhere (21–24), and are summarized in Table 1.

Table 1. Advantages of using low titer group O whole blood (LTOWB) over conventional components.

• Simplifies the logistics of the resuscitation by providing balanced resuscitation fluid in one bag instead of three

• More concentrated product compared to reconstituting whole blood with conventional components

• Provides cold stored platelets that have improved in vitro and perhaps in vivo hemostatic function compared to room temperature platelets in this patient population

• Provides for a longer shelf life for stored platelets compared to room temperature storage

• Provides for the availability of platelets where they might otherwise not have been available

• Reduces the bacterial contamination rate of a platelet-containing product

• Reduces the incidence of ABO mis-transfusion during the resuscitation

• Reduces donor exposures

• Transported under identical conditions as RBCs.

The intention of this document is to provide best practice recommendations for implementing a prehospital blood transfusion program for all patients who require a prehospital transfusion or a transfusion during an inter-facility transfer. These recommendations were created by the Trauma, Hemostasis and Oxygenation Research (THOR)-AABB (formerly known as the American Association of Blood Banks) Working Party, which featured representation from trauma surgery, critical care medicine, emergency medicine, transfusion medicine, and EMS physician medical directors. Included amongst the authors are leadership members of the National Association of EMS Physicians (NAEMSP®) and the Metropolitan EMS Medical Directors Global Alliance.

These recommendations are organized into 4 pillars; 1. Rationale for the use, and description, of blood products that can be transfused in the prehospital setting, 2. Storage of blood products outside of the hospital blood bank and how to move them to the patient in the prehospital setting, 3. Prehospital transfusion criteria and administration personnel, and 4. Documentation of prehospital transfusion and hand over to the hospital team. The recommendations in this document can be adapted for the local environment, and all applicable laws and regulations should be followed, as appropriate.

Insofar as possible, these recommendations are based on published evidence and the AABB Standards for Blood Banks and Transfusion Services, but where such data or practice standards are lacking, a consensus opinion from this Working Party is provided noting specifically that the recommendations in Pillars 2-4 are largely the opinion of this Working Party unless noted with a reference. These opinions can change over time, might not be applicable in all circumstances, and the AABB Standards themselves are produced using both data and consensus opinion and are therefore not strictly evidence-based. Accordingly, this document should not be viewed as standards to which a service could be accredited or held accountable, but rather as guidance from practitioners with extensive experience in storing, transporting, and transfusing blood products in the prehospital phase of hemorrhagic resuscitation.

Pillar 1: Rationale for the Use, and Description, of Blood Products That Can Be Transfused in the Prehospital Setting

Literature Demonstrating the Benefits of Prehospital Transfusions

• The use of saline as a volume expander can lead to increased mortality in certain trauma patients, therefore it should not be utilized as the first-choice resuscitation fluid(25)

• Supplementing the resuscitation fluid standard of care for injured civilian patients transported to hospital by helicopter with up to two units of plasma has been shown to reduce mortality in a multicenter randomized trial (10)

  • The greatest survival benefit was seen in patients who received both red blood cells (RBC) and plasma during their transport (11)

  • Patients who received saline without blood products had the lowest survival (11)

• Some other civilian studies have also demonstrated benefits of transfusing blood products during transport to definitive care (14, 15)

• Studies of military casualties have also demonstrated a survival benefit following the early transfusion of blood products (9, 26)

Description of Blood Products That Could Be Transfused in the Prehospital Phase of the Resuscitation

• The blood products that are most likely to be transfused in the prehospital setting include RBCs, plasma, and low titer group O whole blood (LTOWB)

• There is no evidence that leukoreduction of RBCs (27–30) or LTOWB (31) improves outcomes in injured patients; the role of leukoreduction in other patient groups that might require prehospital transfusions has not been well studied

• Table 2 describes the uses of these blood products and lists their shelf lives, as well as the storage conditions that need to be maintained while the product is outside of the blood bank, either in a remote refrigerator at an emergency medical service (EMS) base or while being transported to the scene by road ambulance or helicopter

  Table 2. Indications and storage characteristics of blood products that could be used in the prehospital resuscitation phase. Data taken from AABB Standard 5.1.8A (32). The listed times and temperatures might vary between jurisdictions, in particular outside of the US. Section 2.1 discusses the differences between storage and transport.

  Blood product	Reason for transfusion	Storage conditions	Transport conditions	Maximum length of storage
  Red blood cells (RBC)	Increase oxygen carrying capacity	1-6 °C	1-10 °C	ACD/CPD/CP2D: 21 days, CPDA-1: 35 days, additive solution: 42 days
  Plasma	Correct coagulopathy, restore endothelial integrity	Once thawed: 1-6 °C	1-10 °C	Once thawed: 5 days from date product was thawed or original expiration, whichever is sooner, if issued as thawed plasma
  Platelets (PLT)	Promote hemostasis	Conventional: 20-24 °C with continuous, gentle agitation Cold stored: 1-6 °C agitation optional	Conventional: as close as possible to 20-24 °C, maximum time without agitation: 30 hours Cold stored: 1-10 °C	Conventional: 24 hours to 5 days depending on collection system. Cold stored: according to manufacturer's written instructions
  Low titer group O whole blood (LTOWB)	Contains all constituents of blood	1-6 °C	1-10 °C	CPD: 21 days CPDA-1: 35 days

RBCs and LTOWB Units That Are Transfused before the Recipient’s ABO Group is Known Must Be Group O (AABB Standard 5.27.1)(32)

• During the prehospital phase of the resuscitation, the patient’s ABO group will not be known

• All recipients will have antibodies to the A and/or B antigens that they lack on their RBCs and other tissues (Table 3)

  Table 3. Antigens on red blood cells (a) and antibodies in the plasma (b) by ABO group

  (a).

  ABO Group	Antigens on RBCs
  A	A
  B	B
  AB	AB
  O	Neither
  (b)
  ABO Group	Antibodies in plasma
  A	B
  B	A
  AB	Neither
  O	A, B

  • For example, group O individuals have anti-A and anti-B in their plasma, whereas group AB individuals do not have either anti-A or anti-B in their plasma

  • These antibodies can activate complement if they bind to incompatible RBCs and cause shock and possibly death (8, 33)

• Group O RBCs lack both the A and B antigens and are therefore safe to administer to all recipients no matter their ABO group (Table 4a)

  Table 4. ABO compatibility between donor red blood cells (a) and plasma (b) and recipient ABO group

  (a).

  Recipient ABO group	Donor RCB Compatibility
  A	A, O
  B	B, O
  AB	A, B, O, AB
  O	O
  (b)
  Recipient ABO group	Donor plasma Compatibility
  A	A, AB
  B	B, AB
  AB	AB
  O	A, B, AB, O

Plasma from Several Different ABO Groups Can Be Transfused in the Prehospital Phase of the Resuscitation

• Group AB plasma does not contain antibodies to either the A or B antigens and is compatible with the ABO group of any recipient (Table 4b)

• Only ∼3% of North American blood donors are group AB, so AB plasma is a scarce commodity

• It might not be feasible to store group AB plasma outside of the blood bank due to its scarcity

• Group A plasma is increasingly being used in the US for the initial resuscitation of injured patients whose ABO group is unknown (34)

  • About 40% of North American blood donors are group A

  • Group A plasma contains anti-B and will be incompatible with groups B and AB recipients

  • In spite of the incompatibility, several multicenter studies have demonstrated that receipt of incompatible plasma in trauma resuscitation does not increase mortality compared to those who did not receive incompatible plasma (35, 36)

  • In a 2021 survey of Level 1 trauma centers that had a 55% response rate (34), 94/103 (91%) of the respondents indicated that they use group A plasma in the initial management of trauma patients, and the vast majority (78/94, 83%) do not titer the anti-B before using the plasma unit

• The use of plasma that is potentially incompatible is permitted in the AABB Standards so long as the transfusing facility has a policy in place (AABB Standard 5.15.4) (32)

• Group O whole blood contains both anti-A and anti-B

  • 43/103 (42%) of Level 1 centers surveyed use LTOWB for the initial management of trauma patients (34)

  • In order to use group O whole blood in patients whose ABO group is not known at the time of transfusion, the whole blood must contain low titers of both anti-A and -B (AABB Standard 5.27.1.1) (32)

  • The definition of low titer is determined at each blood center or hospital

  • Any titer <256 is likely to be serologically safe as reviewed in reference (37), but there is not a titer below which hemolysis is guaranteed not to occur

• Therefore, both group A plasma, if AB plasma is not available, and LTOWB can be safely administered to recipients whose ABO group is unknown at the time of the transfusion

Selecting the RhD Type of RBCs and LTOWB Units for Prehospital Transfusion

• Only ∼15% of North American blood donors are RhD negative, so RhD negative RBCs and LTOWB are a scarce resource

• Conventional teaching indicates that RhD negative products should be transfused, especially to females of childbearing potential

  • Since the RhD type of the patient is not known in the prehospital resuscitation phase, it was felt to be imperative not to transfuse an RhD positive unit to a woman who could be RhD negative

    • Such a transfusion could result in the woman making an antibody to the RhD antigen

    • Anti-D can complicate future pregnancies by causing a disease known as hemolytic disease of the fetus and newborn (HDFN)

  • However, recent studies have shown the D-alloimmunization rate to be much lower than had been previously thought

    • Historically, the rate was considered to be ∼80% (38), but this was the rate amongst 11 healthy male volunteers

    • In RhD-negative trauma patients who receive at least one RhD-positive unit, the D-alloimmunization rate likely lies between 7.8%-42.7% (39, 40)

    • These rates were derived from injured patients who were transfused in the hospital

  • Most importantly, advances in maternal-fetal medicine have greatly reduced the rate of fetal/neonatal demise due to HDFN (41)

• Several recent studies have calculated the rate of HDFN following the transfusion of RhD positive RBCs or LTOWB units to injured RhD negative females of childbearing potential (42–44)

  • The calculated rates of HDFN range from 0.3% (42) to ∼7% based on the age of the patient when she is transfused (43, 44)

  • The HDFN rate depends on the severity of HDFN observed, and factors such as the mortality rate from trauma, the D-alloimmunization rate, the number of live births and the mother’s age at each parturition, age at which a female patient is transfused during her trauma resuscitation, frequency of multiple fathers, and the frequency of the RHD gene in the population (43)

  • Therefore, the calculated HDFN rates are very much lower than the mortality reduction associated with receiving prehospital transfusions during trauma resuscitation (see section 1.1)

• It is uncommon for injured, RhD-negative females of childbearing potential to require transfusions with RhD-positive products

  • One study calculated that one injured RhD-negative female of childbearing potential was transfused with an RhD-positive LTOWB unit every 30 months at their institution (45)

    • These authors estimated that it would take approximately 250 years for between 3-30 females of childbearing potential to become D-alloimmunized

  • Another study estimated that five injured RhD-negative females of childbearing potential could be transfused at a Level 1 trauma center per year (43)

    • The estimated HDFN rate at this center as a result of those RhD-positive transfusions would be 1.2 cases every 5 years

• The frequency of encountering a female of childbearing potential who requires a transfusion would be expected to increase if other patient populations, such as peri-partum hemorrhage, are considered

• If RhD negative blood products are available, they should be preferentially used over RhD positive blood products if the patient’s RhD type is not known, especially to females of childbearing potential

  • However, a lifesaving RhD positive transfusion should never be denied to any patient of any age or sex if RhD negative blood products are not available

Pediatric Patients with Life Threatening Traumatic Bleeding

• The mortality for children with life threatening traumatic bleeding is similar or slightly higher than it is for adults (3, 46)

• While there are no direct data examining the effectiveness and safety of prehospital transfusion for children with life threatening bleeding the principles and concepts in this section should be practiced in children (16, 17)

Pillar 2: Storage of Blood Products Outside of the Hospital Blood Bank and How to Move Them to the Patient in the Prehospital Setting

Storage Conditions for Blood Products to Be Used in the Prehospital Setting

• Table 2 demonstrates the required temperature range for storing and transporting blood products and the maximum storage durations (i.e., shelf lives) for the various blood products in the US.

  • LTOWB in particular might not be maintained in inventory for the maximum allowable shelf life due to concerns about degradation of platelet (PLT) hemostatic function during storage

• While blood products are in storage, the acceptable temperature range is 1-6 °C (AABB Standard 5.1.8A) (32)

• While blood products are in transport, the acceptable temperature range is 1-10 °C (AABB Standard 5.1.8A) (32)

• According to the US Food and Drug Administration (FDA), the institution (e.g., hospital, blood collector, EMS agency) that is responsible for maintaining the blood products that are brought to the scene in a climate-controlled container (herein referred to as a cooler) must decide if the “intention” of the use of the cooler is for transport or for storage

  • The FDA provided this additional guidance during a question and answer session at the AABB annual meeting in 2008 as follows: “(The FDA) consider(s) storage to be when blood is in inventory or at rest waiting to be transfused or waiting to be packed and shipped to another location. Once the blood is in movement or being moved from the storage situation to another site, then it meets the definition of transport”

  • In the absence of a definitive answer about the nature of the coolers used for prehospital blood product transfusion, the following are conservative approaches to storage and transportation cooler validation:

    • Validate the coolers used to bring blood products to the prehospital phase of the resuscitation where they are intended to be transfused as storage coolers (i.e., 1-6 °C)

    • Validate the coolers used to resupply the EMS base by a blood collector or hospital as transport coolers as the blood products would immediately be placed into storage conditions when they arrive at the base and are not intended for immediate transfusion. This type of cooler would also be employed if the EMS base recycles blood products that are close to their expiration date back to a blood collector or hospital (see section 2.5)

• The AABB Standards for storage would clearly apply to blood products that are stored for future use in monitored refrigerators or long-term storage coolers such as those located at an EMS base or in the emergency department (ED) at a trauma hospital

• The same cooler can be used for both storage and transportation as long as the relevant temperature ranges can be maintained during these different conditions (47)

• Note that cooler validation for the maintenance of a specified internal ambient air temperature range is only required if continuous internal ambient air temperature monitoring is not performed

• Coolers should be utilized in accordance with the manufacturer’s instructions, if applicable

Locations for Storing Blood Products to Be Used in the Prehospital Setting

• These locations should be determined locally

• In some situations, installing a monitored refrigerator that is specific for storing blood products at an EMS base might be the preferred solution

  • The EMS base would need to develop a plan for monitoring and servicing the refrigerator, and responding to alarms (AABB Standards 3.5, 3.6, 3.7, 3.9 and others) (32)

  • The EMS base would need to enter into an agreement with a local blood collector or hospital to ensure that a consistent supply of blood products is maintained, and to arrange for the routine resupply of blood products to the EMS base, and perhaps the return of unused products to the hospital near the end of their shelf lives (see sections 2.4 and 2.5)

  • To ensure that a consistent and adequate supply of prehospital blood products is maintained, local blood collectors or hospitals should work collaboratively with the EMS agency (48)

• Some EMS systems may not find it practical to store blood at EMS bases and yet they may have the capacity to administer blood in the field. These systems should be encouraged to devise local solutions for the timely access of a predefined quantity of blood for the EMS team through agreements with local hospitals, blood collectors or depots

Transporting Blood Products to the Scene

• All of the blood products listed in Table 2 require some degree of refrigeration, i.e., cooling, while being moved to the scene

• Generally, the required refrigeration can be achieved using a cooler with a coolant material that has been validated to maintain the internal ambient air temperature within the selected range for a desired period of time depending on whether the cooler is locally considered to be a storage or transport device (AABB Standard 5.1.8.2.1) (32)

  • The duration of time for which the cooler maintains the appropriate internal ambient air temperature should be decided locally

    • Often coolers are validated for a period of 12 hours to permit maximum flexibility when using the cooler and to reduce wastage

    • Continuous internal ambient air temperature monitoring obviates the need to validate the cooler for a specified storage period (see below)

  • The validation of these coolers can be performed by individuals with appropriate training and experience in conducting validation studies. These individuals may be from the EMS service, and/or the hospital, and/or the blood collector

  • Appropriate documentation of the validation should be maintained by the organization that performs the validation

    • Coolers should be periodically revalidated for the desired internal ambient air temperature range if continuous internal ambient air temperature monitoring is not performed

  • It is essential that the blood products be packed in the cooler underneath the coolant material or else the internal ambient air temperature will rapidly exceed the maximum permitted temperature (49), unless specified otherwise by the cooler’s and/or coolant material’s manufacturer

    • The need to physically separate the coolant material from the RBCs directly below it to prevent hemolysis should be determined during the validation process

  • The external air temperature can affect the cooler’s internal ambient air temperature

    • A cooler that is validated, for example, for 12 hours for indoor use in a hospital use might not maintain the appropriate internal ambient air temperature for the same length of time if used outside of the hospital, particularly in extremely hot or extremely cold climates

    • Cooler validation at the extremes of the anticipated external temperature range is recommended or use continuous internal ambient air temperature monitoring

  • If cooler validation to ensure the maintenance of a certain range of internal ambient air temperature is not performed, the cooler’s internal ambient air temperature can be monitored directly by an air temperature thermometer

  • Thermometers that measure the internal temperature of the blood product itself can also be affixed to each unit, however these sticker-thermometers tend to be expensive and are usually not reusable

  • A surrogate marker of the blood units’ temperature can also be used for temperature monitoring

    • One surrogate method involves the inclusion in the cooler of a saline bag affixed with a sticker-thermometer; the saline bag should not be infused to the patient, and it can be reused in subsequent coolers provided that the temperature indicator has not turned positive

• The cooler’s internal ambient air temperature should be verified before the products are removed and transfused

  • Blood products should not be used from the cooler if its internal ambient air temperature has been found to be in excess of the maximum permitted temperature depending on the nature of the cooler (storage or transport)

    • The products in the cooler at the time that the temperature exceeded limits must be discarded

    • A root cause analysis should be performed if a cooler fails to maintain the required internal ambient air temperature within the time period for which it had been validated

Disposition of Unused Blood Products

• There must be a plan for the disposition of unused blood products

  • Unintentionally wasting unused blood products by not having a plan for their return is a waste of money and a precious resource

• It might be possible to return the unused products to the hospital or blood collector from which they were initially picked up, or for the EMS base to return them into their remote refrigerator’s inventory

• The ability to prove that the cold chain has been maintained while the products were outside of a monitored refrigerator or long-term storage cooler is essential for the integrity of the returns process

  • This is why measuring the cooler’s internal ambient air temperature, or validating the cooler, is essential (see section 2.3)

  • Blood products that have been maintained in the appropriate storage temperature range can be re-inventoried and used for a different patient

• Blood products that have not been stored within the appropriate storage temperature range must be discarded

• The EMS agency must clearly define whose responsibility it is to return the unused blood products and to which facility they are to be returned

  • If the products are returned to a hospital or blood collector, these facilities must have a process for validating the temperature of the units and, if acceptable, accepting these units back into inventory

Methods for Reducing the Wastage of Blood Products as They near Their Expiration Date

• If the blood products are stored at EMS facilities, short-dated units could be brought to high transfusion volume hospitals where the units would be more likely to be used (50–52)

  • Returning short-dated units to the blood collector might also be an option

• If such a recycling program is not possible, consider other options such as:

  • Use the units for their maximum shelf life (e.g., the maximum shelf life for LTOWB collected in CPD and CPDA-1 are 21 and 35 days, respectively; Table 2)

  • Do not over stock the EMS base with blood products

Pillar 3: Prehospital Transfusion Criteria and Administration Personnel

Ensuring the Safety of the Recipient and the Transfusion Provider

• Before initiating the transfusion it is important to ensure that the environment in which the transfusion is administered will be relatively safe for both the recipient and provider

  • For example, it is important that the administration of the transfusion does not otherwise prolong the patient’s time to definitive care

  • Providers should not attempt to initiate a transfusion when doing so could compromise their own safety or the integrity of the blood unit

Minimum Equipment Needed for Initiating and Monitoring a Transfusion

• Blood Products:

  • LTOWB

  • Plasma and RBC (preferably in 1:1 ratio)

  • Plasma or RBC alone

• Blood product transport cooler

  • See Pillar 2 for details on the appropriate use and validation/monitoring of the cooler

• Administration

  • Personal protective equipment

  • Blood IV set with approximately 170-200 micron inline filter

  • Alcohol or detergent to clean IV site

  • 16-18g access preferred with a minimum of 22g

  • Intraosseous (IO) back up for access

  • Disposable pressure infuser

  • Patient monitoring devices

    • Cardiac monitor

    • Thermometer

    • Pulse oximeter

• Point of care testing device, if available

• Blood Warming – optimal for care

  • Active devices with disposable units

    • The EMS agency must have an established bio-electronics QA program

    • Devices must undergo initial validation and routine testing on a regular basis

  • Passive methods

    • Commercial chemical warmers

    • It is essential that these methods be validated to not damage or degrade the blood products before placing in service

    • Consultation with your blood supplier is recommended to assist in the validation of passive warming methods

• Point of care testing – not required to initiate a transfusion and can be used if available, including FDA Clinical Laboratory Improvement Amendments (CLIA) waived tests:

  • Hemoglobin concentration/hematocrit meter

  • Lactate Meter

  • Portable blood gas and INR instrument

    • Results of point of care testing should not override clinical judgment about the appropriateness of initiating a transfusion nor should an indicated transfusion be delayed awaiting these results

Qualifications and Medical Oversight of Transfusion Personnel

• Medical oversight by an EMS physician medical director is a fundamental and mandatory component of a prehospital transfusion program

  • The EMS physician medical director approves the training program, credentials the providers and oversees the associated ongoing quality program

• The nature of the qualifications needed to initiate a prehospital transfusion vary by jurisdiction and all applicable laws must be followed

  • No current national standard exists for prehospital blood transfusion practice; EMS Medical Directors and agencies will need work within their State Scope of Practice and Formulary to develop appropriate EMS administration guidelines at the Paramedic level

• Some examples of personnel who might be eligible to initiate a prehospital transfusion based on state law include:

  • Paramedics via indirect medical oversight (e.g., protocol/guideline driven using standing orders for transfusion when criteria are met)

  • Paramedics via direct medical oversight (e.g., radio/telephonic authorization)

  • Physicians on-scene (either in-person or via telemedicine if permitted by local jurisdiction)

  • Paramedics or registered nurses (RN) involved in continuance of care during an inter-facility transport

  • Critical care trained personnel and/or flight trained RN

  • In rural jurisdictions, especially those with long transport times, consideration for how to safely administer blood products in the prehospital setting should be made

• EMS physician medical directors in all cases, establish a clear definition of the indication(s) for transfusion, a line of accountability for ordering and initiating transfusion as well as for mandatory documentation of the transfusion and the order/authority to initiate the transfusion.

  • The roles and responsibilities of every person involved in administering a prehospital transfusion should be defined and documented in order to ensure that appropriate medical supervision over the process occurs

Criteria for Administering a Prehospital Transfusion

• The EMS physician medical director for each service should decide which blood product(s) will be routinely carried by their agency, provided to patients and in what quantity in collaboration with local receiving facilities

• The EMS physician medical director for each service must have defined criteria for the administration of a transfusion, and the order in which to use blood products if multiple products are available

  • Some examples of transfusion criteria for adults (not intended to be an exhaustive list):

    • Hemodynamically unstable – heart rate >120 bpm; systolic blood pressure ≤90 mmHg; consider mean arterial pressure (MAP) guidance e.g., MAP <60 mmHg if electronic measuring cuffs are employed

    • Penetrating and/or blunt trauma with significant injury

    • Positive focused assessment with sonography for trauma (FAST; if available in prehospital setting)

    • Lactate > 4 mmol/L (if available in prehospital setting)(53)

    • EtC02 waveform capnography reading <25 as surrogate for elevated lactate

    • Shock index ≥ 1 (or based on locally defined threshold)

    • Blood products initiated prior to transfer (inter-facility transfer)

    • Request and/or authorization by relevant medical authority

  • Some examples of transfusion criteria for pediatrics (not intended to be an exhaustive list)

    • Hemodynamic instability for age

    • Age-specific shock index >1.22 (ages 4–6), >1.0 (7–12), and >0.9 (13–16) (or based on locally defined threshold)(54–57)

    • MAP below age- appropriate value

• Special consideration should be given to geriatric patients and those experiencing a post-partum hemorrhage as their vital signs might not reveal the extent of their bleed

Initiating and Monitoring the Transfusion

• A transfusion should only be initiated after receipt of an order to transfuse, or documentation that the criterion/criteria in a standing order has/have been met

• The transfusion should only be initiated by personnel who have been trained to administer transfusions

  • Some aspects of the training to initiate a prehospital transfusion should include:

    • Logistics of product management

    • Types of blood products

    • Administration guidelines

    • Acute adverse event management guidelines

    • Appropriate hand off procedures

    • Documentation

• Blood products should only be removed from the cooler immediately before they are to be administered

  • The cooler should be brought close to the patient to facilitate rapid administration

  • The cooler’s lid should remain closed until the blood products are needed

  • Care should be taken not to place the cooler near sources of heat or exposure to cold climates as the internal ambient air temperature might be affected

• The cooler’s temperature monitor should be checked before each unit is administered to verify that the unit(s) has/have been stored in the appropriate internal ambient air temperature range

• The transfusion should be administered as quickly as possible to minimize the potential adverse effects of the environmental air temperature/climate on the blood product itself

  • The higher off the ground that the unit is hung, the faster it will be infused if using gravity as the infusion speed instead of a pressure bag

• Blood warmers and/or rapid infusers can be used if they have been validated by the EMS agency, and/or the hospital, and/or the blood collector

  • Periodic revalidation of these devices is recommended

  • Specific maintenance and record retention requirements for these devices might also exist

  • Can be used for transfusing children

Special Considerations for Administering Prehospital Transfusions

• Prehospital transfusions are administered to patients in extremis and as such, a higher threshold for pausing a prehospital transfusion is acceptable because the risk-to-benefit ratio is different than for a routine in-hospital transfusion

• A prehospital transfusion should not be paused for the appearance of a simple rash, no matter how widespread or the presence of pruritis

  • These minor cutaneous reactions can be managed with anti-histamine medications

  • However, if unexplained dyspnea/desaturation, hypotension, angioedema or other signs and symptoms of a severe allergic reaction/anaphylaxis occur then the transfusion should be paused

• Similarly, a rise in temperature of ≥1 °C should also not result in pausing the transfusion

  • Minor temperature elevations can be managed with anti-pyretic medications

  • However, if the rise in temperature is excessive and/or there is other evidence of hemolysis (e.g., hypotension, unexplained lower back pain, dark red-coloured urine, unexplained shock etc.), the transfusion should be paused

  • Anti-histamines and anti-pyretics could be carried together on the emergency vehicle as a transfusion reaction treatment kit

• The development of unexplained dyspnea/desaturation could be evidence of a transfusion reaction

  • The transfusion provider must consider the patient’s entire clinical situation to determine the probability that the dyspnea/desaturation is related to the transfusion versus a more likely cardiovascular/pulmonary etiology

Pillar 4: Documentation of Prehospital Transfusion and Hand over to the Hospital Team

Documentation of Prehospital Transfusion

• At a minimum, the following parameters should be collected vis-à-vis the prehospital blood transfusion(s):

  • Type of blood product transfused (e.g., RBC, plasma, LTOWB)

  • ABO and Rh group of each transfused product as applicable

  • Blood product unit numbers

  • Volume of each product transfused (especially important for pediatric patients)

  • Any adverse events noted or suspected including vital sign changes and description of the event

    • Documentation of pre- and post-transfusion vital signs is recommended, especially if an adverse event is suspected

• This information can be recorded on the trip sheet, electronic medical record, or on a separate form that is specifically designed for blood products

  • The form with this information should be forwarded to the blood bank at the receiving hospital

    • If the transfusion-specific information is recorded on a paper trip sheet such that the original cannot be sent to the blood bank, a photocopy could be sent

    • Entering the transfusion-specific information into the patient’s electronic medical record at the receiving hospital obviates the need to send paper documents around the hospital

Handover Process When the Patient Arrives at the Hospital

• As part of the patient hand-over process, the receiving team at the hospital should be notified that the patient had been transfused en route to the hospital

  • Not all adverse events happen during or immediately after the transfusion so being made aware of the transfusion can help in the differential diagnosis should a suspected reaction occur later in the patient’s hospital course

• A segment from the RBC/LTOWB unit(s) that was/were transfused in the prehospital phase should be sent to the hospital blood bank for crossmatching

  • It is not generally necessary to send segments from plasma or PLT units to the blood bank

  • Empty blood bags can be discarded after the relevant information from each unit has been documented and the segment removed as necessary

  • If an adverse event related to the transfusion is suspected, the implicated blood product unit should not be discarded, even if it appears empty

    • The remnant of the implicated unit(s) should be sent to the hospital’s blood bank

    • The blood bank should be notified that a suspected adverse event has occurred, and the transfusion reaction policy followed

• If an RhD positive RBC or LTOWB unit has been administered to a female patient who appears to be of childbearing age (often cited as <45-50 years), this information in particular should be communicated to the receiving team and the hospital blood bank (see section 1.5)

  • AABB accredited hospital blood banks are required to have a policy for managing the situation when an RhD negative female of childbearing age receives an RhD positive unit (see section 1.5)

• The trauma center should share the outcomes of patients who receive prehospital transfusion with their EMS agencies as allowed by law

Process Review and Improvement

• At a suitable time after each prehospital transfusion event, regardless of whether a transfusion was actually administered, the event should be reviewed, and the EMS practitioners debriefed along with the responsible EMS physician medical director(s)

  • Errors or inefficiencies in the process should be discussed in a constructive, non-punitive manner with a view to improving and streamlining the process

  • Root cause analyses of errors should be performed when indicated