ADVERTISEMENT
Perfusion Matters
This article appeared in the EMS World special supplement Combating the Hidden Dangers of Shock in Trauma, developed by Cambridge Consulting Group and sponsored by North American Rescue, LifeFlow by 410 Medical, and QinFlow. Download the supplement here.
You’re called to the scene of a 27-year-old male struck by a car while riding his bike. You find the patient lying unresponsive between the vehicle and a damaged lamppost. Using a backboard and inline c-spine stabilization, you move him away from the car to the adjacent ground for initial management.
You note some moaning but no response to pain or eye opening (GCS 4), scalp and facial lacerations, 3-mm pupils of equal size, bloody oral secretions but an otherwise open airway, shallow and spontaneous respirations with bilateral breath sounds, bruising over the left chest and abdomen, weak pulses, and deformity and swelling of the left thigh.
You place a c-spine collar, apply nasal cannula oxygen and end-tidal carbon dioxide (EtCO2) monitoring, and move the patient quickly to the ambulance.
Initial vital signs include a heart rate of 160 bpm, blood pressure of 72/40 mmHg, shock index (SI) of 2.3, respiratory rate of 20 breaths per minute, oxygen saturation of 94% with poor waveform, and an EtCO2 of 22 mmHg. You are approximately 10 minutes by ground from a Level 1 trauma center.
What are your immediate management priorities for this patient?
One strategy might be to minimize on-scene procedures and get the patient to the hospital as soon as possible. This approach is often advocated in prehospital trauma care, citing limited data on the value of prehospital interventions like vascular access and airway management and data suggesting prehospital procedures may increase mortality.1,2
However, several important studies confirm that, with thoughtful management, EMTs and paramedics can play a crucial role in the outcomes of these critically ill patients, particularly those with the lethal combination of hemorrhagic shock and traumatic brain injury (TBI).3–5
Initial Assessment: Hemorrhagic Shock
The patient above has multiple life-threatening injuries, including TBI, possible c-spine injury, likely multiple internal injuries, probable femur fracture, and hypotension. Markers of shock, simply defined as inadequate delivery of blood and oxygen to the major organ systems, include tachycardia, tachypnea, hypotension, elevated SI, poor skin perfusion, weak pulses, and low EtCO2.
Altered mental status is also an indicator of shock, but this may be complicated by the presence of brain injury or drug or alcohol intoxication. Although any of these markers should raise suspicion of the presence of shock, tachycardia may be the first sign of significant blood loss, even without hypotension.
The SI, which is calculated by dividing heart rate by systolic blood pressure (SBP), can be used as a quick guide to the presence and severity of shock. An SI greater than 1 is often thought to be an indicator of significant shock.6
This patient’s high SI of 2.3, along with hypotension, clearly indicates the presence of immediately life-threatening shock. His other markers of poor perfusion, including low EtCO2, weak peripheral pulses, and poor pulse oximetry waveform, validate this suspicion.
In this patient’s case the hypotension must be assumed to be from hemorrhage, likely from solid organ injury, presumed femoral fracture, and scalp and facial bleeding.
Other causes of hypotension could include spinal cord injury, tension pneumothorax, and pericardial tamponade. Of these only tension pneumothorax could be immediately addressed in the prehospital
environment.
This case helps illustrate the complexity of managing a critically ill trauma patient in the field and shows us why the traditional ABC (airway, breathing, and circulation) approach to emergency care might not lead
us to his most critical issues first and might cause harm.
The MARCH algorithm—massive hemorrhage, airway control, respiratory support, circulation, hypothermia, head injury—was first outlined in the military’s Tactical Combat Casualty Care guidelines and is now increasingly used to guide EMS trauma care. MARCH directs us to hemorrhage control as the priority in the severely injured patient.
This patient has scalp and facial lacerations that can be managed with direct pressure. He likely has significant internal bleeding, but no other controllable sources of massive hemorrhage are identified on your initial exam.
The MARCH algorithm would next prioritize airway control, and since he’s unlikely able to protect his airway, he will at some point need an advanced airway. With apnea or airway obstruction, he would need immediate intervention with at least bag-valve mask ventilation. But since he’s spontaneously breathing, definitive airway management is actually not the next most important intervention.
This patient’s combination of TBI and hypotension illustrate why the circulation first, or CAB (circulation, airway, breathing) approach may be the best framework for addressing a trauma victim with hemorrhagic
shock.7
Hypotension is this patient’s most important problem, since it will worsen his neurologic injury and complicate efforts at effective airway management. Second only to hypoxia, hypotension is the most important risk factor for peri-intubation cardiac arrest, and trauma patients with complex injuries and hemorrhage are at high risk.8,9
This is well illustrated in a recent study of combat-injured soldiers who experienced cardiac arrest shortly after intubation.10 All patients had multiple traumatic injuries and evidence of hemorrhagic shock, including
hypotension or elevated SI, and all experienced pulseless arrest shortly after intubation. None had received blood products prior to intubation, highlighting the need to “resuscitate before you intubate” in hemorrhagic shock.
The mechanisms of peri-intubation arrest are complex but likely due to a combination of vasodilation or myocardial depression from induction medications, loss of augmented venous return that occurs with
spontaneous respirations, and the application of positive intrathoracic pressure through mechanical ventilation that further reduces venous return in the setting of hypovolemia.
A second reason to prioritize circulation in this patient is his TBI. The EPIC-TBI study evaluated a bundle of EMS care for trauma patients that sought to improve outcomes for trauma patients with TBI by intentionally avoiding hypotension, hypoxia, and hyperventilation.
The EPIC-TBI authors showed:
- Treating prehospital hypotension improves outcomes and saves lives.
- Every minute of hypotension matters for these patients.
- There’s no “safe” depth or duration of hypotension in the setting of TBI.3,11–13
In fact, patients with TBI who are hypotensive in the field and remain hypotensive on arrival to the ED are 5 times more likely to die compared to those whose hypotension is corrected.14
The Treatment: Blood
So what, if anything, can you do for this patient within a short scene and transport time? You’ve applied supplemental oxygen and stopped visible hemorrhage; how do you treat his hypotension?
The preferred treatment would be to “replace what’s lost,” which is, of course, blood. Data from prehospital military and civilian studies have shown improved survival from the delivery of blood products in trauma patients in the field. As a result many EMS agencies are beginning to implement programs for whole blood administration for trauma.5,15
Not all the evidence, however, points to a clear survival benefit with administering prehospital blood products. In a recent study from the largest and most well-developed blood program, that of the Southwest
Texas Regional Advisory Council (STRAC), patients who received prehospital transfusion had improvements in vital signs and early mortality but no statistically significant difference in 24-hour mortality or in-hospital death.15
Similarly, the recent RePHILL trial from the UK showed a lack of benefit for prehospital trauma patients treated with blood products.16 This large prospective trial compared the use of normal saline to a combination of packed red blood cells (PRBCs) and lyophilized plasma in patients with trauma and suspected hemorrhagic shock (defined as systolic blood pressure less than 90 mmHg or absent radial pulse). No difference in mortality was seen between patients who received either blood products or saline. It is important to note that response and transport times were quite long in this study, with a total of 83 minutes from 9-1-1 call to hospital arrival.
Could it be that the excitement about the use of blood products in EMS is overrated? The trends toward improved outcomes in San Antonio, New Orleans, and elsewhere are encouraging, and data from military studies have certainly shown early resuscitation with blood products is helpful. Though further studies will likely help us better understand which populations are most likely to benefit, it’s clear efforts to get blood delivered closer to the point of injury are warranted.
In our patient immediate intervention for hypotension is clearly the priority based on his TBI and the risk of cardiac arrest that may result from placing an invasive airway. If blood products are available, this is a patient who needs them. However, what if your agency is among the majority of EMS systems that don’t carry blood? Should you try to begin correcting the patient’s hypovolemic shock with saline? The MARCH algorithm recommends withholding crystalloid fluids to maintain a “hypotensive resuscitation” and avoid worsening the patient’s coagulopathy and potentially disrupting clots that have formed within noncompressible torso wounds.
Many authors now advocate completely withholding all crystalloid fluids from trauma patients, going so far as to call it “poison.”17 Although there’s a physiologic rationale for this approach and the literature does support the minimization of excessive crystalloid in trauma resuscitation, it’s important to understand the origins of this recommendation and question whether crystalloid really is always “poison.”
A classic study from 1994 is often cited as evidence for withholding crystalloid in trauma patients with hemorrhagic shock.18 This trial evaluated patients in Houston with penetrating torso injuries and SBP less than 90 mmHg who were randomized to receive prehospital crystalloid bolus with continued crystalloid infusion in the trauma room, compared to normal saline and other “keep vein open” (KVO) fluids only in the control group until induction of anesthesia in the operating room (OR).
Patients in the intervention group received an average of 870 mL lactated Ringer’s (LR) prior to hospital arrival and an additional 1600 mL in the trauma bay, compared to 92 and 283 mL, respectively, in control patients. Blood products weren’t started until arrival in the OR. Hospital mortality in patients who received LR was 70%, compared to 62% in control patients.
It’s important to understand key elements of this study before using it as evidence for completely withholding crystalloid in hemorrhagic shock. The patients were mostly young males with penetrating trauma and no TBI who would therefore be more likely to tolerate a brief period of hypotension before definitive hemorrhage control. The crystalloid group received a total of 2.4 L of LR, a higher volume than would be advocated today prior to initiation of blood products. Finally, patients in both the intervention and control groups had extraordinarily high mortality, likely because they remained in shock and received no blood products until approximately 45 minutes after injury.
The lesson from this study may be that patients with penetrating trauma who receive high volumes of crystalloid, no blood preoperatively, and large intraoperative crystalloid volumes (the average in this study was 6.7 L) may have poor outcomes due to the “lethal triad” of dilutional coagulopathy, hypothermia, and acidosis induced by this approach.
So, would our patient benefit from a modest amount of fluid to address his hypotension? The EPIC-TBI study reminds us any prehospital hypotension is associated with increased mortality, especially if it’s not corrected prior to hospital arrival. The EPIC-TBI protocol specified that up to approximately 1 L of crystalloid be given to trauma patients with severe TBI and SBP less than 90 mmHg. This study included patients with multisystem trauma who may have had noncompressible torso hemorrhage—the very patients in whom we want to minimize crystalloid—and yet mortality was improved with use of modest fluid boluses to treat hypotension prior to hospital arrival.
Similarly, the RePHILL trial demonstrated the safety of a modest dose of crystalloid fluids. In both studies the average volume received was approximately 500–1000 mL.
Therefore, in our patient, after hemorrhage control and basic airway interventions, the priority should be establishing vascular access and administering enough blood or fluid to immediately raise his blood pressure, improve cerebral perfusion, and prevent the risk of worsening hypotension or cardiac arrest should invasive airway management be required.
What blood pressure should you target in this case? No firm guidelines exist, but in a patient with TBI, the minimum SBP target should be at least 90 mmHg, and likely as high as 110 mmHg. Targeting the traditional “hypotensive” resuscitation in a patient with severe TBI may result in harm.
If peripheral IV access isn’t immediately obtained in our patient, intraosseous (IO) access at the humeral head would be best given his lower-extremity injury and the likelihood of abdominal bleeding. It’s important to remember a passive approach to resuscitation in these cases may not be sufficient to improve the patient’s hemodynamics, and attention must be given to the mechanism of delivery of the blood or fluid administered, particularly when an IO or smaller-gauge IV is used and particularly with an inline fluid warmer.
Neither gravity infusion nor a pressure bag is likely to provide sufficient flow and volume of blood to correct blood pressure quickly, especially during a short transport. Therefore, use of equipment specifically intended for rapid resuscitation can improve care in these situations.
The LifeFlow infuser and QinFlow warmer represent the only available combination truly capable of providing rapid resuscitation with warmed blood products in the prehospital environment. Together these devices can deliver 1 unit of whole blood warmed to 38°C in less than 2 minutes. This allows effective resuscitation within transport times previously thought too short to allow any meaningful intervention, subsequently delivering the patient to the ED with much more stable physiology and greater chance of survival. This is particularly true in patients with severe TBI, like the patient presented in our clinical case.
Conclusion
Minutes matter when caring for trauma patients with suspected hemorrhagic shock, and EMS professionals can play an essential role in reducing mortality and improving outcomes. Despite calls for prehospital providers to minimize interventions in trauma, evidence from studies like EPIC-TBI shows early and effective prehospital care can lead to dramatically increased survival, even during short scene and transport times.
The combination of TBI and hemorrhagic shock increases the risk of death and demands the greatest urgency in management. We should maintain a high index of suspicion for shock in any trauma patient. This can usually be determined with a quick assessment of suspected injuries, obvious exam findings, and vital signs.
After managing external bleeding and providing basic airway interventions, resuscitation with warmed blood products or fluids is the next priority. For agencies that do not yet carry blood, a modest amount of crystalloid is reasonable and has been shown to save lives in patients with TBI. Even with shorter transport times, it’s possible to make a meaningful difference in this patient’s outcome.
Video: LifeFlow Demonstration
Click here to launch and watch a cadaver lab resuscitation video, courtesy 410 Medical, showing how the LifeFlow device augments the delivery of whole blood and other resuscitation fluids to deliver a brisk, calculated flow through the veinatomy (ie, 1 unit of whole blood warmed to 38°C in less than 2 minutes).
References
1. Clumpner M, Lawner B, Mehkri F. (October 2020.) Prehospital trauma management: We can do more by doing less. JEMS. Accessed March 31, 2022. www.jems.com/patient-care/prehospital-trauma-management-we-can-do-more-by-doing-less/
2. Taghavi S, Maher Z, Goldberg AJ, et al. An Eastern Association for the Surgery of Trauma multicenter trial examining prehospital procedures in penetrating trauma patients. J Trauma Acute Care Surg. 2021; 91(1): 130–40.
3. Spaite DW, Bobrow BJ, Keim SM, et al. Association of statewide implementation of the prehospital traumatic brain injury treatment guidelines with patient survival following traumatic brain injury: The excellence in prehospital injury care (EPIC) study. JAMA Surg. 2019; 154(7): e191152.
4. Sperry JL, Guyette FX, Brown JB, et al. Prehospital plasma during air medical transport in trauma patients at risk for hemorrhagic shock. N Engl J Med. 2018; 379(4): 315–26.
5. Shackelford SA, Del Junco DJ, Powell-Dunford N, et al. Association of prehospital blood product transfusion during medical evacuation of combat casualties in Afghanistan with acute and 30-day survival. JAMA. 2017; 318(16): 1581–91.
6. Geeraedts LMG, Pothof LAH, Caldwell E, et al. Prehospital fluid resuscitation in hypotensive trauma
patients: do we need a tailored approach? Injury. 2015; 46(1): 4–9.
7. Ferrada P, Callcut RA, Skarupa DJ, et al. Circulation first—The time has come to question the sequencing of care in the ABCs of trauma; An American Association for the Surgery of Trauma multicenter trial. World J Emerg Surg. 2018; 13: 8.
8. De Jong A, Rolle A, Molinari N, et al. Cardiac arrest and mortality related to intubation procedure in critically ill adult patients: A multicenter cohort study. Crit Care Med. 2018; 46(4): 532–9.
9. Chou D, Harada MY, Barmparas G, et al. Field intubation in civilian patients with hemorrhagic shock is associated with higher mortality. J Trauma Acute Care Surg. 2016; 80(2): 278–82.
10. Schwarzkoph BW, Iteen D, Auten B. Pulseless arrest after rapid sequence intubation of the massively hemorrhaged warfighter: A case series. J Spec Oper Med. 2022; 22(1): 104–7.
11. Gaither JB, Spaite DW, Bobrow BJ, et al. Effect of implementing the out-of-hospital traumatic brain injury treatment guidelines: The Excellence in Prehospital Injury Care for Children Study (EPIC4Kids). Ann Emerg Med. 2021; 77(2): 139–53.
12. Spaite DW, Hu C, Bobrow BJ, et al. Mortality and prehospital blood pressure in patients with major traumatic brain injury: Implications for the hypotension threshold. JAMA Surg. 2017; 152(4): 360–8.
13. Spaite DW, Hu C, Bobrow BJ, et al. Association of out-of-hospital hypotension depth and duration with
traumatic brain injury mortality. Ann Emerg Med. 2017; 70(4): 522–30.e1.
14. Rice A, Hu C, Bobrow BJ, et al. In-field and early hospital hypotension in major traumatic brain injury: Correlations and effects on outcome. Prehosp Emerg Care. 2022; 26(Supp 1): 109–10.
15. Braverman MA, Smith A, Pokorny D, et al. Prehospital whole blood reduces early mortality in patients with hemorrhagic shock. Transfusion. 2021; 61(Suppl 1): S15–S21.
16. Crombie N, Doughty HA, Bishop JRB, et al. Resuscitation with blood products in patients with trauma-related haemorrhagic shock receiving prehospital care (RePHILL): A multicentre, open-label, randomised, controlled, phase 3 trial. Lancet Haematol. 2022; 9(4): e250–e261.
17. Levy M. Replace what’s lost with what’s lost? Emergency Physicians Monthly. Accessed March 31, 2022. www.epmonthly.com/article/replace-whats-lost-with-whats-lost/
18. Bickell WH, Wall MJ, Pepe PE, et al. Immediate versus delayed fluid resuscitation for hypotensive patients with penetrating torso injuries. N Engl J Med. 1994; 331(17): 1105–9.
Mark Piehl, MD, MPH, is a pediatric intensivist at WakeMed in Raleigh, North Carolina, where he previously served as medical director of the WakeMed Children’s Hospital from 2009–2015. He continues to serve as a medical director for WakeMed Mobile Critical Care Services. He’s also cofounder and chief medical officer of 410 Medical, a company devoted to improving the care of critically ill patients. He’s a clinical associate professor of pediatrics in the department of pediatrics at the University of North Carolina School of Medicine, with board certifications in pediatrics and pediatric critical care medicine.
