# Tactical and Austere Environment Medicine

## Introduction

Tactical and austere environment medicine encompasses the delivery of emergency care in settings where standard resources, infrastructure, and evacuation options are limited or absent. This includes tactical law enforcement operations (TEMS), wilderness and remote environments, military combat casualty care, and humanitarian disaster zones. Emergency physicians increasingly serve as medical advisors and providers in these contexts, requiring adaptation of standard protocols to resource-constrained realities.

## Tactical Emergency Medical Support (TEMS)

### Phases of Tactical Care

| Phase | Threat Level | Key Interventions | Do NOT Attempt |
|-------|-------------|-------------------|----------------|
| Care Under Fire (CUF) | Active hostile threat | Tourniquet, direct pressure, move to cover | Airway management, IV access |
| Tactical Field Care (TFC) | Threat mitigated, no evacuation | MARCH assessment, cricothyrotomy, chest seal, needle decompression, IV/IO, TXA, blood products | — |
| Tactical Evacuation (TACEVAC) | During transport | Reassess all interventions, tourniquet conversion, blood products, pain management, documentation | — |

Care Under Fire (CUF) is provided while under active hostile threat and is limited to self-aid and buddy-aid. Tourniquet application is the primary intervention, using only direct pressure and tourniquets. The casualty should be moved to cover, and the threat must be suppressed before attempting complex interventions. Airway management and IV access should not be attempted during CUF.

Tactical Field Care (TFC) occurs once the threat is mitigated but evacuation is not yet available. It follows a systematic MARCH assessment: Massive hemorrhage, Airway, Respiration, Circulation, and Hypothermia/Head injury. Interventions include advanced airway management (cricothyrotomy if indicated), chest seals, needle decompression, IV or IO access, tranexamic acid (TXA) administration, and fluid resuscitation with blood products when available.

Tactical Evacuation Care (TACEVAC) is provided during transport to a higher level of care. All interventions are reassessed, and there is a transition from field-expedient to more definitive measures. Tourniquet conversion to wound packing may be considered if transport time permits. Blood product resuscitation, pain management, and documentation occur during this phase.

<image>Illustration of the MARCH algorithm for tactical field care showing sequential assessment steps: Massive hemorrhage control with tourniquet, Airway with jaw thrust, Respiration with chest seal application, Circulation with IV access, and Hypothermia prevention with blanket wrap</image>

### TEMS Team Structure

Tactical physicians and tactical paramedics are embedded within law enforcement special operations teams. Medical threat assessments are conducted pre-mission to anticipate likely injury patterns. Medical planning includes establishing casualty collection points, evacuation routes, and hospital notification procedures.

## Hemorrhage Control in Austere Settings

### Tourniquet Use

The CAT (Combat Application Tourniquet) and SOFTT-W are the standard devices. During CUF, the tourniquet is applied high and tight on the extremity, with reassessment and narrowing of placement during TFC. Tourniquet time of up to 2 hours is generally safe, and prolonged application up to 6 hours has been survived with limb salvage. Junctional hemorrhage (groin, axilla, neck) cannot be controlled with standard tourniquets and requires junctional tourniquets (such as JETT or SAM Junctional Tourniquet) or wound packing with hemostatic agents.

### Hemostatic Agents

Combat Gauze (kaolin-impregnated) is the standard hemostatic dressing and is packed tightly into the wound with direct pressure held for 3 minutes. Chitosan-based dressings (Celox) are an alternative that provides clotting factor-independent hemostasis. The wound packing technique involves identifying the source, packing gauze directly into the wound cavity, and applying sustained pressure.

## Airway Management in Austere Environments

Surgical cricothyrotomy is the definitive austere airway when oral intubation fails or is not feasible. Bougie-assisted cricothyrotomy improves first-pass success. Supraglottic airways (iGel, King LT) are appropriate temporizing measures. An unconscious patient with a patent airway should be placed in the lateral (recovery) position, which is especially important when evacuation is delayed.

## Chest Trauma Management

Tension pneumothorax is the second leading cause of preventable death on the battlefield. Needle decompression is performed with a 14-gauge, 3.25-inch catheter at the 2nd intercostal space, midclavicular line, or the 4th to 5th intercostal space at the anterior axillary line. Vented chest seals (HyFin, SAM) are preferred to prevent tension physiology. Finger thoracostomy may be performed in the field by trained providers when tube thoracostomy equipment is unavailable.

<image>Step-by-step illustration of surgical cricothyrotomy technique in an austere setting showing landmark identification, vertical skin incision, horizontal membrane incision, bougie insertion, and tube placement</image>

## Wilderness Medicine Considerations

### Environmental Emergencies

Hypothermia management focuses on preventing further heat loss with vapor barriers and insulation, avoiding rough handling (which risks cardiac dysrhythmia), and rewarming with body-to-body contact, warm IV fluids, and chemical heat packs to the axillae and groin. For altitude illness, descent is the definitive treatment, acetazolamide prevents AMS, dexamethasone treats HACE, and nifedipine or sildenafil addresses HAPE. Envenomation management involves identifying the species when safe, immobilizing the affected extremity, avoiding tourniquets, incision, or suction, and recognizing that antivenom is the definitive treatment. For drowning and submersion injuries, oxygenation is prioritized, cervical spine precautions are reserved for cases where the mechanism suggests injury, and hypothermic drowning victims may have prolonged resuscitation windows.

### Improvised Medical Care

Improvised splinting uses SAM splints, trekking poles, or sticks with padding. Wound irrigation with clean potable water is acceptable when sterile saline is unavailable, using high-pressure irrigation with a syringe and splash guard. Improvised litters can be constructed from backpacks, tarps, or poles for patient evacuation over terrain.

## Prolonged Field Care (PFC)

When evacuation is delayed beyond the "golden hour," providers must deliver sustained critical care in the field. Prolonged field care guidelines published by the Joint Trauma System address ventilator management, vasopressor use, blood product administration, and surgical interventions in prolonged casualty scenarios. Point-of-care testing (iSTAT, handheld ultrasound) extends diagnostic capability. Telemedicine consultation with remote physicians is possible when satellite or cellular communication is available.

<image>Diagram of a prolonged field care setup in an austere environment showing portable monitoring equipment, blood product cooler, IO access, improvised warming system, and satellite communication device</image>

## Medical Planning and Risk Mitigation

Medical threat assessment evaluates anticipated injuries, environmental hazards, and available resources before operations or expeditions. Medical kits are mission-tailored, with TEMS kits differing from wilderness medicine kits. Casualty evacuation planning (CASEVAC/MEDEVAC) identifies primary and alternate evacuation platforms, landing zones, and receiving facilities. Training requirements include regular skills maintenance for low-frequency, high-acuity procedures such as cricothyrotomy, chest decompression, and junctional hemorrhage control.

## Clinical Pearls

In tactical care, hemorrhage control takes precedence over airway management, inverting the traditional ABCDE approach. Tourniquets save lives and are safe for at least 2 hours; there should be no hesitation to apply one for life-threatening extremity bleeding. Tension pneumothorax is a clinical diagnosis in the field and should be treated empirically with needle decompression or finger thoracostomy if clinical suspicion is high. The surgical cricothyrotomy is the gold standard austere airway, and all emergency physicians should maintain procedural competency. Prolonged field care is an expanding discipline as military and civilian austere operations increasingly face delayed evacuation scenarios.

## References

1. Butler FK, et al. "Tactical Combat Casualty Care: Transitioning Battlefield Lessons Learned to Other Austere Environments." *Wilderness & Environmental Medicine*. 2017;28(2S):S12-S17.
2. Joint Trauma System. *Tactical Combat Casualty Care (TCCC) Guidelines*. 2023.
3. Auerbach PS, et al. *Auerbach's Wilderness Medicine*. 7th ed. Elsevier; 2017.
4. Schauer SG, et al. "Prehospital Blood Product Transfusion in Civilian and Military Settings." *Journal of Trauma and Acute Care Surgery*. 2020;88(5):e130-e136.