Rapid Infusion Techniques for Prehospital Whole Blood Transfusions

Introduction

In the early 1980s, penetrating trauma rates soared as battles over crack cocaine sales ravaged the inner city. Following the guidance of the new Advanced Trauma Life Support (ATLS) course in 1980, large volume infusion of intravenous (IV) crystalloid solutions like 0.9% sodium chloride and lactated ringers solution became the standard of care. Commonly, aggressive volume resuscitation was continued until blood pressure “normalized.”

Paramedics and nurses prided themselves (and still do!) on their prowess at inserting 14-gauge peripheral IV catheters. Researchers and industry worked to find the fastest means to infuse fluid into patients. Large bore, Y-type “trauma tubing” for high-flow infusion was one major development by the mid-1980s, adopted by some paramedic services.¹ Large volume infusion of crystalloids was standard of care for over a decade. However, calls for “permissive hypotension” in the setting of uncontrolled internal bleeding took hold in emergency rooms and ambulance services during the 2000s. One prominent study demonstrated that prehospital crystalloid infusion worsened outcomes.² Advocates suggested that infusing crystalloids would dilute clotting factors, prevent thrombin and fibrin formation, increase acidosis and hypothermia, while increasing blood pressure and circulating volume would “pop clots,” worsening any uncontrolled hemorrhage. 

Formalized in the Department of Defense’s Tactical Combat Casualty Care Guidelines, recommendations were made to use only an 18-gauge peripheral IV catheter as a means to restrict runaway fluid infusion.³ The civilian world followed. Those agencies following this guidance would use a minimum of IV fluids, with protocols generally calling for 250 or 500 mL boluses titrated to a blood pressure target of 90 mm Hg, radial pulses, and/or mental status improvement. The “pendulum” of expected care had swung wildly from some patients receiving four-to-five liters of prehospital crystalloid to some strong advocates suggesting that no “pasta water” should be given to bleeding patients. The need for rapid prehospital volume resuscitation had nearly vanished. Multiple products sold for the purpose of facilitating the rapid infusion of fluid in the prehospital setting were discontinued by their manufacturers and forgotten.

Prehospital transfusion of thawed plasma or packed red blood cells has been available for 30 years on a very limited basis, primarily on aeromedical services connected to hospital systems. In 2012, the military began to deploy blood products on select medical evacuation platforms and managed to expand it to other far-forward elements.⁴ The military experiences in the recent Afghanistan and Iraq conflicts also saw the return of fresh and stored whole blood (WB) in trauma care, as WB replaces “what the patient has lost.” Additional advantages include ease of administration with a single bag and decreased citrate preservative burden compared to separated components. 

In October 2018, San Antonio (TX) Fire Department Emergency Medical Service (SAFD EMS) was the third civilian ground ambulance service in the United States to overcome the many administrative and logistical obstacles and deployed WB for prehospital transfusion. The deployment of WB in San Antonio and its rapid expansion to surrounding areas reflects a complete reversal of typical fluid-sparing conventional prehospital practices. Rapid infusion of WB is long known to be potentially lifesaving for seriously injured trauma patients and those with gastrointestinal or obstetrical hemorrhage.⁵ Lessons learned and solutions during the 1980s and 1990s are relevant once again. Indeed, facilitating rapid infusion is more critical as WB is far more viscous than crystalloid IV fluids and thus slower to infuse under the same conditions.

Lessons Learned

The following are some best practices that can be deployed to increase the amount of fluid infused/transfused into a patient. Many of these practices are deployed or in the process of being deployed by UT Health San Antonio Emergency Health Sciences Office of the Medical Director (UTHSCSA OMD) which provides medical direction and training for SAFD EMS to increase the amount of blood transfused at point of injury to accomplish the most efficacious damage control resuscitation. 

1. Large-bore, Y-type trauma tubing sets have 5 mm or larger internal diameter tubing that greatly increases flow.⁶ At the time of this writing, only the Codan TraumaFlow product is available to the authors’ knowledge. These sets have been demonstrated to have three times the flow of standard hospital-type blood infusion tubing and six times the flow rate of usual 10 drop/mL macrodrip tubing when paired to a large-bore line.⁷ If trauma tubing is not available, Y-type blood tubing should be the standard tubing used when rapid infusion of crystalloid, albumin, or blood products are desired in the field. 
2. Needleless IV adapters (commonly known as “saline locks,” “caps,” or “PRN adapters”) have become ubiquitous since the 1990s and allow for easy medication pushes and tubing changes. However, they are also a dramatic impendence to infusion rates. They have been shown to substantially decrease flow rate of fluid, even when attached to larger catheters.^8-9 They should always be removed if rapid infusion is desired.
3. A short length of extension tubing is often provided with needleless IV adapters. Some organizations purchase microbore or minibore diameter tubing, which decreases the volume contained with the line. This is aimed at pediatrics and oncology (chemotherapy) in particular, providing a decreased volume for medication to remain in tubing outside of a patient. However, the internal diameter of this tubing approximates 20-gauge or smaller depending on manufacturer, negating the benefit of a larger catheter even if the needleless adapter is removed. To prevent inadvertent flow restriction, ambulance services should consider not stocking microbore or minibore tubing/extension sets except for limited use in pediatrics (if at all). If an extension set is used in a patient requiring rapid infusion, it should be of standard bore at a minimum. Several companies produce large-bore (5 mm ID or larger) “trauma tubing” extension sets. 
4. Intraosseous (IO) lines require a rapid initial flush under pressure to provide maximal flow rate.¹⁰ A 10 mL syringe of fluid should be injected rapidly in 2 mL aliquots to displace the bone and marrow from the needle and allow for maximal flow.
5. Infusion tubing should be connected directly to the IO needle. The extension set that comes with one popular brand of IO needle has a permanently attached needleless adapter and will slow flow rates significantly.
6. Shorter length and greater diameter are the factors which increase flow in peripheral IV catheters. 14- and 16-gauge peripheral IV catheters are commonly stocked in ambulances, but 12-gauge peripheral IV catheters have been shown as feasible in the prehospital setting and could be considered, particularly in the External Jugular (EJ) vein.¹¹ The increased length (three inches) of the currently available 12-gauge IV catheter is outweighed by its diameter in increasing flow.
7. The EJ was long the standby of paramedics in resolving difficult vascular access situations. It has recently been eschewed in favor of IO access. However, in the setting of need for rapid infusion — the EJ provides a potential opportunity for large-bore peripheral access when other sites fail or are not available.
8. Teleflex still provides a 6F (14.4 gauge) peripheral IV catheter called the Peripheral Emergency Infusion Device (EID), that uses a guidewire and dilator to more easily allow large-bore peripheral access in collapsed veins. The same manufacturer provides the Rapid Infusion Catheter (RIC), a guidewire exchange kit that allows for a 20-gauge IV catheter to be placed in a collapsed vein and “upsized” to a 7F (13.3 gauge) or 8.5F (approx. 11.8 gauge) catheter. The authors’ anecdotal experience is that the 8.5F device may be too large for some veins.
9. Those paramedics with ability to place peripheral IV’s under ultrasound guidance should consider this when obtaining venous access is particularly difficult. The longer IV catheters required for access of deep veins (often 1.75″ or 2.25″) have a lower flow rate than shorter IV catheters, but will generally provide a greater flow rate than an IO line. 
10. EMS physicians and specially-trained paramedics may wish to consider central venous access and/or venous cutdown in special circumstances. 

Following these best practices allows SAFD EMS and UTHSCSA OMD to fully put into practice the concepts of damage control resuscitation by infusing the patient at point-of injury with the life-saving treatment of whole blood with the most rapid infusion techniques available.

Disclaimer: The view(s) expressed herein are those of the author(s) and do not reflect the official policy or position of Brooke Army Medical Center, the U.S. Army Medical Department, the U.S. Army Office of the Surgeon General, the Department of the Army and Department of Defense, or the U.S. Government.

Disclosures: The authors have nothing to disclose. The authors have no financial interest in, nor receive payments from any medical device manufacturers or distributors.

References

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10. Teleflex. Arrow EZ-IO Instructions for Use.
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