Prehospital Trauma Compendium: Fluid Resuscitation in Trauma – a Position Statement and Resource Document of NAEMSP

How should EMS providers manage fluid resuscitation in prehospital trauma care? NAEMSP’s 2024 position statement recommends isotonic crystalloids as the preferred prehospital fluid, supports permissive hypotension in non-TBI patients, warns against large-volume crystalloid resuscitation, and calls for better standardized trauma education across EMS systems.

TL;DR

• Isotonic crystalloids remain the go-to fluid for prehospital trauma — colloids and hypertonic saline show no survival benefit and may cause harm.
• Permissive hypotension is associated with improved survival in hemorrhagic shock without TBI, but patients with traumatic brain injury need a systolic blood pressure target of ≥110 mmHg.
• Large-volume crystalloid resuscitation (over 2 liters) is associated with coagulopathy, increased transfusion requirements, and higher mortality.
• EMS education on trauma fluid management is inconsistent across states, and clinical uptake of updated guidelines remains slow — a standardized curriculum is overdue.

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Fluid resuscitation in trauma sounds straightforward until a provider is standing over a hypotensive patient and has to decide: how much, how fast, what kind, and whether giving fluid right now helps or hurts. Those decisions happen every shift, and the evidence behind them has shifted significantly in the last decade.

NAEMSP published a position statement in late 2024 that consolidates the current evidence on prehospital crystalloid use in trauma. It covers fluid choice, hemodynamic triggers, warming strategies, potential harms, and — importantly — the education gaps that still leave providers making resuscitation decisions based on outdated training. For field providers and medical directors, this is one of the most operationally relevant position statements published in recent years.

What Did NAEMSP Set Out to Address?

The position statement tackled a deceptively simple question: how should EMS clinicians use crystalloid fluids in prehospital trauma resuscitation? Most agencies only carry crystalloids. Blood product programs are growing but still limited by supply, logistics, and cost. So crystalloid management remains a core clinical skill for the vast majority of prehospital providers.

The authors reviewed 68 papers across five content areas: preferred fluid choice, physiologic triggers for resuscitation, warmed fluid use, potential harms of fluid administration, and educational gaps. The search strategy pulled from roughly 1.9 million trauma articles, 100,000 EMS articles, and 650,000 crystalloid-related publications before narrowing to 885 unique articles for screening.

Which Crystalloid Should EMS Use — Normal Saline or Lactated Ringer’s?

NAEMSP recommends isotonic crystalloid solutions as the preferred fluids for prehospital trauma management. However, the statement is deliberately agnostic about which isotonic crystalloid — normal saline versus lactated Ringer’s versus Plasma-Lyte — should be the universal choice. The specific selection, per the statement, “may be driven by medication compatibility and other operational issues.”

Operationally, normal saline is compatible with more medications for concurrent administration because of its relatively simple composition. Buffered solutions like lactated Ringer’s and Plasma-Lyte, on the other hand, showed a 1.1% reduction in the composite outcome of death, new dialysis, or persistent renal dysfunction in the landmark SMART trial of over 15,000 critically ill patients. The concurrent SALT-ED trial found no difference in hospital-free days among noncritically ill patients.

One finding that should catch the attention of any provider working neurotrauma: a secondary analysis from a prospective prehospital observational trial found increased all-cause mortality in TBI patients who received lactated Ringer’s compared to normal saline. No difference was found among patients without TBI. For systems running high volumes of TBI calls, that finding alone justifies reviewing current fluid stocking practices.

Colloids and hypertonic solutions are effectively off the table. Multiple RCTs and meta-analyses reviewed in the statement found no survival benefit for hypertonic saline, hypertonic saline with dextran, or synthetic colloids compared to isotonic crystalloids. Worse, synthetic colloid use at volumes greater than 1 liter was associated with increased risk of renal failure and need for dialysis. Hypertonic solutions with dextran were associated with worsened coagulopathy and hyperfibrinolysis.

When Should Providers Give Fluid — and How Much?

This is where the position statement pushes hardest against legacy training. The short version: permissive hypotension is reasonable in hemorrhagic shock patients without TBI, and large-volume crystalloid resuscitation should be generally avoided.

Permissive hypotension — maintaining blood pressure lower than normal physiologic levels during hemorrhagic blood loss — aims to preserve vasoconstriction, maintain organ perfusion, and prevent dilutional coagulopathy. The statement cites a systematic review and meta-analysis indicating that permissive hypotension strategies confer mortality benefits and reduce blood loss and transfusion requirements prior to definitive hemorrhage control.

In practice, that means targeting mental status and presence of distal pulses rather than chasing a specific systolic number. Some resources still suggest using MAP of 50 mmHg or SBP of 70–90 mmHg as triggers, with boluses of 100–200 mL at a time. However, the position statement notes that many authors argue defining hypotension at higher blood pressures is more appropriate, especially in elderly patients — one registry study found mortality increases begin at SBP below 110 mmHg, and blood pressure thresholds associated with survival increase with age.

On volume: targeted resuscitation with smaller volumes is associated with improved outcomes. Large-volume resuscitation — more than 2 liters — is frequently linked to coagulopathy, increased transfusion requirements, and increased mortality. One study found that receiving more than 500 mL of prehospital crystalloid was associated with increased mortality and coagulopathy in severely injured patients who were not hypotensive. Giving fluid to patients who do not have hypotension may itself cause harm.

Calling every hypotensive trauma patient a candidate for wide-open crystalloid is outdated practice. The evidence has moved past that, and protocols should reflect it.

How Does Traumatic Brain Injury Change the Resuscitation Strategy?

Significantly. The position statement draws a clear line: avoiding or correcting hypotension in polytrauma patients with TBI may be a higher priority than restricting fluid use.

Current prehospital TBI guidelines recommend a minimum SBP target of ≥110 mmHg in adults, with recent evidence suggesting that hypotension has a dose-and-duration-response effect on mortality. One registry study found a linear association between degree of hypotension and mortality risk in TBI patients, with no distinct inflection point or safe threshold.

Spinal cord injury adds another layer. Patients with acute spinal cord injuries require MAP goals of ≥85 mmHg to maintain adequate spinal cord perfusion, and the statement recommends isotonic crystalloids for prehospital treatment of hypotension in these cases.

For field providers, this creates a genuine clinical tension. The same fluid being restricted in a hemorrhagic shock patient without head injury may be the fluid that needs to be pushed more aggressively in a polytrauma patient with TBI. Recognizing that distinction — and acting on it — is where training either holds up or falls apart.

Does Warming Prehospital IV Fluids Actually Matter?

The statement recommends developing processes to minimize the use of non-warmed IV fluids, though it frames this as “reasonable” rather than mandatory — reflecting the limited direct evidence.

Even mild hypothermia is associated with increased morbidity and mortality in trauma patients, including increased transfusion requirements and development of ARDS. Prehospital hypothermia compounds an already bad situation. One prospective study found that infusion fluid temperature below 21°C was a risk factor for hypothermia at hospital arrival.

However, the position statement is honest about the limitations. In healthy adults, a 2-liter bolus of room-temperature crystalloid decreases body temperature by only 0.3°C. Actively rewarming a hypothermic patient using warmed IV fluids would require prohibitively large — and probably harmful — volumes of fluid. The primary role of warmed fluids in the prehospital setting is preventing further heat loss, not actively rewarming.

Commercial battery-powered warming devices outperform improvised methods (hand warmers, MRE heaters, vehicle defrosters) but performance varies by device, flow rate, and input temperature. Insulating IV tubing between the warmer and the patient reduces temperature loss. A simple infrared thermometer can monitor fluid temperature if needed.

Agencies operating in cold environments should treat fluid warming as a standard practice, not a nice-to-have. The technology exists. The evidence supports it. The operational barrier is usually just procurement and protocol updates.

What Are the Actual Harms of Crystalloid Resuscitation?

The position statement dedicates significant attention to this — and it should. The “trauma triad of death” (hypothermia, coagulopathy, acidosis) is well known conceptually but, per the authors, “inadequately relayed” in education.

Normal saline administration is associated with hyperchloremic metabolic acidosis, which can impair the clotting cascade and worsen post-trauma bleeding. Balanced fluids like lactated Ringer’s and Plasma-Lyte appear more effective at maintaining acid-base status. Yet balanced solutions have less tonicity than normal saline and were associated with increased mortality in TBI patients in one analysis.

Any IV fluid — regardless of type — may contribute to dilutional coagulopathy. The volume of crystalloid received is an independent predictor of trauma-induced coagulopathy. At the same time, the statement acknowledges confounding: observed coagulopathy may reflect injury severity rather than iatrogenic harm. Coagulopathy frequently occurs early after trauma, before any prehospital fluids are given.

Withholding fluids also carries risk. In the Prospective Observational Multicenter Massive Transfusion Study of 1,200 patients, receiving fluid resuscitation prior to hospital arrival was associated with increased survival. Severe organ hypoperfusion may result if no fluids are given at all. An animal study found that while hypotensive resuscitation maintained organ perfusion, complete withholding of fluids decreased it.

The position is clear: universal large-volume resuscitation and universal withholding of fluids may both be harmful. The answer is individualized, targeted resuscitation — which demands better training than most providers currently receive.

How Should Providers Reduce the Need for IV Fluids?

This section of the statement reinforces what should already be first-line practice: hemorrhage control. Tourniquets, wound packing, pressure dressings — these are the interventions that reduce the need for crystalloid in the first place. Fracture immobilization and pelvic binders also play a role.

Prehospital tranexamic acid (TXA) administration leads to clot stabilization and is associated with decreased mortality and reduced need for massive transfusion, per the CRASH-2 trial. Clot stabilization may also prevent the mechanical clot displacement and rebleeding that aggressive fluid resuscitation can cause — though the statement notes this specific interaction has not been studied.

Prompt transport matters. Scene times under ten minutes are encouraged when surgical management is likely, such as in penetrating trauma or major hemorrhage. In those cases, delaying IV access and fluid administration is reasonable. Conversely, prolonged extrication or transport times may make prehospital fluids necessary to maintain perfusion.

Why Is EMS Trauma Fluid Education Still This Inconsistent?

The position statement calls for development of a standard trauma resuscitation curriculum for prehospital providers. The authors found that state-level EMS protocols are highly variable in recommendations on when to give IV fluids, how much to give, and what type is preferred.

Common prehospital trauma courses — PHTLS, ITLS, TECC, TCCC — share several themes: hemorrhage control, blood products, fluid options, permissive hypotension, and physiologic markers. However, the authors found that these courses “fail to sufficiently emphasize the superiority of physiologic indicators of perfusion over any SBP goal.” Numeric BP targets have changed in recent years, but clinical practice uptake is slow. One study found that practice patterns in tactical combat casualty care had not meaningfully changed five years after guidelines encouraged blood products over crystalloids.

EMS providers are still being taught — or are still defaulting to — outdated resuscitation approaches because there is no standardized curriculum that translates the current evidence into consistent field practice. This is a system-level failure, not an individual provider failure. Medical directors and training officers have a responsibility to close this gap.

Prehospital Fluid Resuscitation: How Does This Look on a Call?

A typical case might involve: a 45-year-old male, motorcycle collision, obvious femur deformity, tender abdomen, altered mental status. SBP on scene is 82 mmHg by automated cuff. No signs of head injury.

Based on this position statement, the approach involves isotonic crystalloid in small boluses — 100 to 200 mL — targeting return of distal pulses and improved mental status rather than a specific BP number. Large-volume resuscitation would increase coagulopathy risk and transfusion requirements. Hemorrhage control measures — splinting the femur, pelvic binder if indicated — are the primary interventions. Prompt transport to a trauma center takes priority over establishing fluid resuscitation in the field when transport times are short.

Now change one variable: add a witnessed loss of consciousness and unequal pupils. The resuscitation target shifts — SBP ≥110 mmHg becomes the goal to maintain cerebral perfusion, and fluid restriction takes a back seat to preventing secondary brain injury. Same patient, different physiology, different strategy. The ability to make that distinction in real time is what evidence-based training produces.

Limits of the Evidence

The position statement is transparent about its constraints. Much of the evidence base comes from registry studies and retrospective analyses, which are subject to confounding by indication — sicker patients receive more fluid, making it difficult to isolate the fluid itself as a cause of poor outcomes. The authors explicitly acknowledge this limitation.

Pediatric-specific evidence is sparse, with similar associations observed between high-volume resuscitation and worsened outcomes but the same methodological limitations as adult literature. No specific ideal volume for fluid resuscitation has been established. Future monitoring technologies — prehospital ultrasound, serial lactate, ECG waveform analysis — need further evaluation before recommendation. Additionally, the literature search was conducted in October 2022, meaning studies published after that date are not captured.

Bottom Line

EMS systems should update protocols and training now to reflect individualized, targeted fluid resuscitation — including permissive hypotension for non-TBI hemorrhagic shock, SBP ≥110 mmHg targets for TBI, and hard limits on large-volume crystalloid administration — because the evidence no longer supports reflexive fluid boluses or blanket withholding.

References

McMullan J, Curry BW, Calhoun D, Forde F, Gray JJ, Lardaro T, Larrimore A, LeBlanc D, Li J, Morgan S, Neth M, Sams W, Lyng J. Prehospital Trauma Compendium: Fluid Resuscitation in Trauma – a Position Statement and Resource Document of NAEMSP. Prehospital Emergency Care. Published online December 10, 2024. https://doi.org/10.1080/10903127.2024.2433146