In the fall of 2016, Medic One from Harris County (Texas) Emergency Services District #48 (HCESD 48) was dispatched to a shooting. The crew staged in a safe location until the scene could be secured by law enforcement.
After being cleared to enter, 15 minutes later, the Medic One ALS crew made patient contact and found an adult female in critical condition with a gunshot wound to the chest. As hemorrhage control procedures were underway by responding police officers, the critically injured patient was placed on a monitor that displayed an initial heart rate (HR) of 127, blood pressure (BP) of 75/43 and a respiratory rate (RR) of 22.
The patient was also placed on a non-rebreather mask (NRBM). A large-bore IV was established and one unit of packed red blood cells (PRBCs) and one unit of plasma were administered in the ambulance on the way to a trauma center. On arrival at the hospital, the patient’s vital signs were BP 130/90, HR 99 and SpO2 96% on NRBM.
Although the mainstay of resuscitation from hemorrhagic shock in the hospital setting has been the administration of blood products, management in the prehospital setting has been primarily limited to crystalloid solutions.
Harris County Emergency Services District #48 carries
O-negative blood and low-titer A-positive plasma.
A challenge to the HCESD EMS system is that transport to a Level 1 trauma center may be 20–30 minutes or longer depending on the traffic pattern and time of day. In the event of severe hemorrhage, this delay in resuscitation without the availability of blood products may contribute to increased mortality.
There continues to be significant debate regarding the efficacy of prehospital blood products (PHBP) given the current body of literature, risk of blood product transfusion, as well as significant logistical challenges associated with storage and administration. This article will address those issues.
In 2016, researchers performed a systematic review of seven qualitative and 22 quantitative studies related to PHBP administration. They concluded that there’s currently a lack of data to support or contradict the use of PHBP. The rate of mortality from prehospital traumatic hemorrhage remains exceedingly high at 23%, and unfortunately, relevant clinical outcome studies demonstrated a lack of statistical difference in long-term favorable outcomes in PHBP group vs. not PHBP recipients.1
Researchers weren’t able to draw conclusions about the relative mortality of patients who received a higher amount of PHBP to those who received lower amounts, but postulated that it would be similar to those patients who have worse outcomes with increased crystalloid administration in the prehospital environment.1
However, the administration of the same blood products to the same types of patients remains the standard of care in the hospital. And, although there have been logistical challenges in the past, the evidence emerging from the military demonstrates feasibility and has driven civilian EMS providers to also deploy blood products in helicopter EMS (HEMS).2
The reserve blood products are kept in a
station Helmer IB105 refrigerator.
The largest civilian study on PHBP use in hemorrhagic shock during trauma reported the results of a 20-month study involving the deployment of packed RBCs and plasma in the Memorial Hermann LifeFlight (LF) system, which serves the Houston region.2 It was postulated that, since early access to blood products in a trauma was related to improved outcomes, early access to PHBP for patients might improve mortality and survival outcomes.
The basis for this effort was in the improved outcomes of patients who had early access to RBCs and platelets in hemorrhagic shock, as observed in a previous study. Because the average time of death related to hemorrhage after injury is 2.6 hours, and patients become more coagulopathic with every minute that passes, the researchers postulated that providing PHBP would help alleviate some physiologic stress and prolong the time to treat these patients.3
The study compared adult trauma patients arriving by LF helicopter to similar patients who arrived by ground or other air service from September 2011 to April 2013. Two units of thawed plasma and two units of type O-negative
blood were stocked on LF helicopters, and the study included all patients who received blood products, prehospital or in hospital.3
After training the critical care flight paramedics on assessment of blood consumption (ABC), transfusion protocol criteria were used to determine eligibility for PHBP use. Any two of the following four criteria rendered a person eligible to receive PHBP:4
1. Penetrating trauma;
2. Systolic blood pressure < 90 mmHg;
3. HR > 120 bpm; and
4. Positive focused assessment with sonography (ultrasound) for trauma exam.
Of 8,536 potential patients, 1,677 were eligible for the study. These patients were highly traumatized with an injury severity score of > 24 and mortality rates of 26%. Of the eligible patients, 792 were transported on ground units, 716 were transported by LF and 169 were transported by other air ambulances (OA). Only 19%, or 137/716, of patients on LF helicopters were given PHBP. No patient from OA and ground transport was given PHBP.
The outcomes were then compared. There was no difference found in patients’ vital signs, physiologic stability, arrival point-of-care hemoglobin, or thromboelastogram values between LF and OA or ground transports.
Patients in the LF group were also found to have less time to cessation of significant bleeding as well as decreased amounts of in-hospital crystalloid fluid administration, which, as stated above, was an independent factor in mortality.Wastage of blood products was insignificant on LF helicopters secondary to PHBP resuscitative efforts.2
In addition, PHBP delivery in the LF patient population demonstrated a decreased number of acid-base disorders, a decreased mortality at six hours, and a decreased use of in-hospital blood products. It’s important to note, however, that the study observed no difference in overall mortality, nor any significant difference in 30-day mortality. Although this single-center study didn’t find any significant improvement in mortality at 24 hours or 30 days, it did provide evidence of feasibility of the model for field distribution with its report of only 1.9% wastage of blood products.2
Using the Right Products
In the case of patients who require massive transfusion of blood after hemorrhagic shock, the use of specific blood products in specific ratios has yielded the best results. In fact, earlier transfusions with higher blood product ratios (plasma, platelets and RBCs) during damage control resuscitative efforts is correlated with improved outcomes, as recognized in the PROPRR trial.2
In patients requiring blood after massive shock, the use of O-negative blood is still the standard due to its universal donor properties, minimized complications and adverse side effects. Although the standard in-hospital plasma product is AB titer, providing this plasma is increasingly difficult, especially in large trauma centers.5 Therefore, the use of low-titer A plasma is a safe alternative to the AB plasma group for emergent need and can be utilized in the same 1:1:1 damage control resuscitation protocol.6
The PHBP are deployed in the HCESD 48 EMS supervisor vehicles, which
stores them in coolers that are maintained between 2–5 degrees C
(35–40 degrees F). The temperature is maintained via ice pack
panels that are changed every 12–24 hours depending on the environmental conditions.
There have been many logistical challenges associated with transitioning this standard of care of blood product resuscitation into the prehospital environment. However, there have also been a number of advances that have overcome some of these barriers.
The use of PHBP has been primarily developed by the U.S. military, and their lessons learned and systems developed in Afghanistan and Iraq have created solutions that can be adapted to the civilian setting.
The primary challenges facing field deployment of PHBP are logistics and wastage of blood products. Pure RBCs, platelets and plasma have a limited shelf life and, if logistics aren’t considered and controlled appropriately, there’s risk of loss and wasted expense. To eliminate as much wastage as possible, the EMS system must either be a high utilizer of PHBP or have partnerships with hospitals to rotate stock. Although these negotiations may be significantly easier with hospital-affiliated EMS programs, other EMS systems will likely face significant obstacles associated with hospital hierarchy.
The other option, as was done at HCESD 48, is to have a direct affiliation with the regional blood center from which to purchase blood products and to serve as the mechanism for rotation of stock.
HCESD 48 had several incidents where blood from the helicopter EMS crew was essential in patient survival. Leadership started with the questions of both medicine and logistics (i.e., What are the usage levels and guidelines? How is blood stored and handed off for HEMS?) and were early able to convince their Emergency Services Development board and partners this was a beneficial idea. (See Table 1, p. 48.)
Support came from the trauma community, largely the Red Duke Memorial Hermann Trauma Institute and John Holcomb, MD, from the Department of Surgery, who had worked with HCESD 48 on other projects like implementing trauma triage guidelines for the region. Both the medical director and assistant medical director, as well as the blood bank, were fully behind the idea as well. However, buy-in with local hospitals was more complicated and took a little over a year from concept to inception to be fully supported by all shareholders. HCESD 48 brought these community hospitals and the blood bank together to work through logistics and medical concerns.
Once the blood products are ordered and received, there’s confirmation of appropriate product and blood type as well as expiration dates. A copy of the HCESD 48 blood tag is then applied and stored with the unit. The expiration dates of all units are kept on a white board above the blood refrigerator to monitor units that may need to be rotated back to the blood bank as the expiration date nears. With help from LifeFlight crews, all HCESD 48 staff were trained in blood product storage, retrieval and use.
However, one of the most critical challenges in PHBP administration has been the ability to maintain appropriate temperatures of blood products in austere and variable environments. The reserve blood products are kept in a station refrigerator with a unit cost of approximately $7,400. These are the same stainless steel refrigerators used in hospitals to store blood products.
The temperature is maintained between 2–5 degrees C (35–40 degrees F) and temperature is logged twice daily. The refrigerator is alarmed to send an alert via cell phone when any temperature changes outside the recommended range occur so that the issue can be immediately addressed.
The PHBP are deployed in the HCESD 48 EMS supervisor vehicles, which stores them in Pelican Pro Med 472 coolers that are also maintained between 2–5 degrees C (35–40 degrees F). The temperature is maintained via ice pack panels that are changed every 12–24 hours depending on the environmental conditions.
The blood products are stored in a plastic container to avoid direct contact with the ice pack panel surface. Maintenance of temperature also requires the vehicles to be kept under cover, garaged, or the vehicle has to be kept running.
Appropriate temperature control is a logistical challenge that requires significant investment in products, alarm systems and training to ensure that products aren’t lost to spoilage. Compliance with temperature control parameters will allow the pRBCs to be stored for up to 42 days and plasma for 25 days.
Warming Things Up
The HCESD 48 clinical guidelines for administration recommend the placement of at least a 20-gauge IV catheter, with a preference for an 18-gauge catheter or larger. The larger bore cannulas not only decrease the administration time but also help to prevent damage to the red blood cells, allowing them to function properly.
The IV is then connected to a saline lock and a Y-type blood set with PlasmaLyte or normal saline. Once the PHBP are confirmed to be O-negative pRBCs and low-titer A-positive plasma, the products are administered via the blood Y.
Due to the low temperature of the products, as well as the contribution of hypothermia to coagulopathy and mortality in trauma, the product needs to be warmed. There are a number of commercially available blood warmers on the market, including devices that are appropriately sized and priced for prehospital use.
HCESD 48 is a combination department and located in a direct west suburb of Houston, with a coverage area of 46 square miles and a population of 130,000. The department runs three mobile ICU (MICU) ambulances 24 hours a day, supported by a 12-hour peak time MICU ambulance. An EMS supervisor on the road supports these units 24 hours a day. Since March 2016, the department has transfused PHBP on 23 patients.
Although the use of PHBP has been robust in the military setting, the current data to support its use has been equivocal. Many of the larger studies performed have demonstrated logistical feasibility but not clear evidence of efficacy.
One of the consistent concerns when dealing with prehospital innovation is the concern regarding the impact it may have on scene times, with the understanding there must be careful attention paid to not delaying the transport for definitive management. Therefore, EMS services must strongly consider the impact of PHBP administration and ensure that there isn’t an unnecessary delay in transport.
Another important factor to consider is that not all need for PHBP administration is due to trauma. In fact, in the HCESD 48 system, the case series to date reveals a ratio of 4:1 for medical vs. trauma indications for emergent prehospital transfusion. Their project is now more than a year old and, because of its success, has expanded to the neighboring Cypress Creek EMS.
The emergent medical administration remains an understudied area of significant applicability in the civilian setting. As we continue to develop and refine successful deployment models for PHBP, we must advocate for multicenter trials involving medical and trauma patients to determine the financial and clinical efficacy of this innovation.
- Smith IM, James RH, Dretzke J, et al. Prehospital blood product resuscitation for trauma: A systematic review. Shock. 2016;46(1):3–16.
- Holcomb JB, Tilley BC, Baraniuk S, et al. Transfusion of plasma, platelets, and red blood cells in a 1:1:1 vs a 1:1:2 ratio and mortality in patients with severe trauma: The PROPPR randomized clinical trial. JAMA. 2015;313(5):471–482.
- Radwan ZA, Bai Y, Matijevic N, et al. An emergency department thawed plasma protocol for severely injured patients. JAMA Surg. 2013;148(2):170–175.
- Nunez TC, Voskresensky IV, Dossett LA, et al. Early prediction of massive transfusion in trauma: Simple as ABC (assessment of blood consumption)? J Trauma. 2009;66(2):346–352.
- Murthi SB, Dutton RP, Edelman BB, et al. Transfusion medicine in trauma patients. Expert Rev Hematol. 2008;1(1):99–109.
- Agaronov M, DiBattista A, Christenson E, et al. Perception of low-titer group A plasma and potential barriers to using this product: A blood center’s experience serving community and academic hospitals. Transfus Apher Sci. 2016;55(1):141–145.