Lesson Overview
Learning Objectives
- Use a decision framework to determine whether evacuation is urgent, non-urgent, or unnecessary
- Prepare and package patients for transport with proper hypothermia prevention and immobilization
- Construct safe improvised litters and coordinate team carries
- Activate emergency communication devices and provide rescuers with essential patient information
- Prepare a landing zone and stay safe around a helicopter
Evacuation as a Core Wilderness Medicine Skill
Evacuation is where knowledge meets judgment and creativity. In the wilderness, you have limited transport options and must work with available resources. Your decisions about evacuation urgency, method, and timing will determine whether a patient reaches definitive care in time, whether complications develop, and ultimately, the outcome. Evacuation isn't the step after the medicine. Deciding how this patient gets out—walking, litter, helicopter—is the medicine. Some patients need immediate helicopter extraction; others can walk out slowly with minimal support.
Evacuation Decision Framework
Core Principle: Urgency × Feasibility
Evacuation decisions balance two factors: how urgent is the patient's condition, and what are the practical constraints of extracting them from the wilderness? A patient with a life-threatening condition must be evacuated urgently regardless of terrain challenges. A stable patient with a minor injury might walk out or wait for weather to improve.
Evacuation Urgency Classification
| Category | Timeline | Examples | Notes |
|---|---|---|---|
| URGENT | Within hours | Life threats, deteriorating patient, hemodynamic instability, altered mental status (AMS), spine injury, severe hypothermia/heat stroke, suspected ACS/stroke, anaphylaxis, open fractures, compartment syndrome, complete amputation | Every minute matters. Activate rescue immediately. |
| NON-URGENT | Within 12-24 hours | Stable closed fractures, early infection signs, controlled bleeding, moderate environmental illness, wounds needing closure | Can transport by litter or assisted walk without immediate danger of deterioration. |
| SELF-EVACUATE / NO EVACUATION | Patient's discretion | Minor sprains (can weight bear), superficial wounds, mild GI illness, fatigue | Educate patient on red flags that would change this decision. |
Decision Factors
Patient Condition & Trend
Is the patient stable, improving, or deteriorating? Current severity is less important than trajectory. A patient who is worsening must be evacuated urgently regardless of current presentation.
Terrain & Distance
How far to definitive care? How long will transport take? Narrow passes, elevation changes, and water crossings affect evacuation time and difficulty.
Resources Available
How many trained rescuers do you have? What equipment? Do you have communication devices? Limited resources may necessitate evacuation to a designated place rather than to the nearest hospital.
Environment & Weather
Weather forecast? Daylight remaining? Cold, storm, or darkness approaching? Environmental constraints may demand faster evacuation even if distance is short.
Continuous Reassessment
Evacuation category can change. Reassess every 15 minutes in stable patients, every 5 minutes in unstable patients. A non-urgent patient who develops respiratory distress or altered mental status becomes urgent. Document serial assessments to track trends.
The wilderness is not a treatment facility. You cannot admit a patient for observation, order blood work, or escalate care. If you are uncertain whether evacuation is necessary, evacuate. It is easier to stand down a rescue that arrives at the trailhead than to request urgent rescue after dark in a storm.
Preparing a Patient for Transport
Documentation: SOAP Note for Handoff
Complete a SOAP note (Subjective, Objective, Assessment, Plan) before EMS arrives at the trailhead or helicopter lands. Include chief complaint, mechanism of injury, vital signs, treatments given, response to treatment, and your assessment of stability. This documentation informs receiving providers and ensures nothing is missed in handoff.
Hypothermia Prevention During Transport
Immobility combined with shock, pain, and environmental exposure accelerates hypothermia. Aggressive insulation is essential, even in moderate weather.
Ground Insulation
Use 3-4 layers of insulation between patient and ground (sleeping pads, sleeping bags, packs, vegetation). Do NOT allow the patient to lie directly on cold ground or snow.
Vapor Barrier
Wrap the patient in plastic sheeting or garbage bags to trap warm air. This creates a "vapor barrier" that prevents evaporative heat loss and wind exposure.
Head Coverage
Heat loss is proportional to exposed surface area—the head is roughly 10% of the body's surface, not the 30-40% of popular myth. Cover it anyway: the head is well-perfused, often left exposed, and one of the easiest areas to insulate. A wool hat, balaclava, or improvised headwear meaningfully reduces overall heat loss.
External Heat Sources
Hot water bottles filled with warm (not boiling) water and placed against the groin, axillae (armpits), and neck can provide external warmth. Insulate the bottles so they don't burn skin.
Insulating Shell
Wrap the patient in sleeping bags and additional clothing/blankets to create an insulating shell.
Litter Securing Procedure
Once a patient is placed in a litter, secure them properly to prevent falls and shifting during transport.
Padding & Positioning
- Pad all bony prominences: occiput (back of head), sacrum, heels, elbows
- Position per injury type (see table below)
Strapping Protocol
- Chest strap: Above the nipple line to allow breathing
- Waist/hip strap: Secures pelvis
- Thigh straps: Prevent sliding
- Arms: Padded and secured at sides or across chest
- Head: Padding on both sides (rolled sleeping pads) prevents lateral movement
Always reassess ABCs after packaging. Confirm airway is patent, breathing is adequate, and circulation is present before beginning transport.
Transport Position Table
| Condition | Recommended Position |
|---|---|
| Unconscious, no mechanism for spine injury | Recovery position (lateral with head tilted back to maintain airway). When in doubt, treat as a spine injury. |
| Spinal precautions | Supine with neutral spine, secured on spine board in litter |
| Respiratory distress | Semi-recumbent (head elevated ~45°) to ease breathing |
| Shock | Supine (flat)—do not elevate the legs; insulate above and below, heat sources at the trunk |
| Nausea/vomiting risk | Recovery position or semi-lateral to prevent aspiration |
| General comfort (no specific concern) | Position of comfort per patient preference |
Medication Monitoring
Document all medications given: drug name, dose, time, route (swallowed, chewed, inhaled, auto-injector), and patient response. This documentation is critical for receiving providers and prevents dangerous medication duplication.
Vital Sign Monitoring During Transport
Reassess vital signs every 5 minutes in unstable patients, every 15 minutes in stable patients. Document serial vitals to show trend. Any change in mental status, breathing, heart rate, or perfusion warrants increased monitoring frequency and assessment of whether evacuation urgency needs upgrading.
Improvised Litter Construction
When Improvised Litters Are Needed
Helicopter evacuation is unavailable, the distance to trailhead is long, or the patient is unable to walk despite assistance. Improvised litters are essential wilderness skills when commercial stretchers are not available.
A floppy litter is uncomfortable for the patient and exhausting for rescuers. Aim for a structure that maintains patient support without sagging.
Improvised Litter Methods
| Method | Materials | Pros | Cons |
|---|---|---|---|
| Jacket + Poles | 2-3 jackets, 2 sturdy poles (branches, ski poles, ice axes) | Easy, uses common materials, good for moderate distances | Less rigid, limited for larger patients |
| Tarp/Poncho Litter | Tarp or poncho, 2 rigid poles | Very strong, large surface area, good for rough terrain | Requires tarp; can be heavy |
| Two Backpack Litter | 2 large packs, poles lashed through pack frames or straps | Sturdy, good padding from pack frames, commonly available materials | Heavier than other options |
| Blanket/Sleeping Bag Roll | Sleeping bag or blanket, poles inserted through sides | Excellent insulation, quick to construct, light | Less rigid, limited for long distances |
Carrying Team Coordination
Optimal Team Size
- Ideal: 6 carriers (2 at head, 2 at middle/waist, 2 at feet) distribute weight and allow symmetrical lifting
- Minimum: 4 carriers (head and foot ends each have 2 carriers on opposite sides)
Command System
One team leader positioned at the head gives clear verbal commands: "Prepare to lift," "Lift," "Step," "Halt." This synchronizes movement and prevents injury.
Rotation
Rotate carriers every 10-15 minutes to prevent fatigue and maintain litter stability. Tired rescuers make mistakes and risk dropping the litter.
Pace and Communication
- Maintain steady, slow pace—speed is impossible on uneven terrain and increases risk of falls
- Communicate obstacles in advance: "Rock on right," "Step down," "Creek crossing ahead"
- Keep one person dedicated to monitoring patient comfort and stability during transport
Narrow Trail Technique
On single-file trails, carriers can use staggered foot placement (one foot on each side of the trail, alternating) to allow the litter to pass through narrow sections. This is more challenging and requires practice.
One-Rescuer Carries (Short Distances Only)
For short evacuations (injured person near shelter or campsite), a single rescuer can carry a patient using appropriate technique. Solo carries are only for patients with no suspected spine injury, and only when immediate danger forces movement. An unconscious patient carried over the shoulder cannot be airway-monitored—treat these carries as a last resort:
- Fireman's carry: For unconscious or larger patient—patient is draped over rescuer's shoulders
- Cradle carry: For small patient or short distance—patient held across rescuer's chest and arms
- Walking assist: For alert ambulatory patient—patient's arm around rescuer's neck, rescuer's arm around patient's waist
Helicopter Considerations
When helicopter evacuation is anticipated, confirm litter orientation with the rescue team. Litters must be loaded into aircraft in the direction the aircraft is positioned—typically feet first. Ensure your litter design allows this loading orientation.
Emergency Communication in the Wilderness
Communication Device Comparison
Cell Phone
Pros: Everyone has one. Cons: Coverage gaps, battery drain. Tips: Elevate phone, try 911 even with no bars (may reach any tower), text may succeed when calls fail.
Satellite Communicator (Garmin InReach, SPOT)
Pros: 2-way messaging anywhere, GPS tracking. Cons: Requires subscription, slower SOS response than voice.
PLB (Personal Locator Beacon)
Pros: Free monitoring via COSPAS-SARSAT, no subscription, globally monitored by rescue authorities. Cons: 1-way only (no communication back), cannot cancel easily once activated.
Satellite Phone
Pros: Voice communication anywhere. Cons: Expensive, less portable, slower connection.
MIST Report: Essential Information for Rescuers
When contacting emergency services, provide the MIST report format plus critical logistics:
- M = Mechanism of Injury: How did the injury happen? Fall, avalanche, lightning, animal attack?
- I = Injuries Found: Chief complaint and identified injuries. "Open femur fracture, ankle swelling, intact neurovascular."
- S = Signs and Symptoms: Vital signs, mental status, pain level, relevant history (diabetic, allergies, medications).
- T = Treatment Given So Far: Fluids, medications, splinting, wound care. "Bandaged wound, splinted ankle, gave aspirin."
- PLUS: Exact GPS Coordinates (if you have GPS device)
- PLUS: Number of Patients and Number of Rescuers on scene
- PLUS: Resources Available (litter, communication device, medical equipment)
- PLUS: Weather Conditions and Forecast
- PLUS: ETA to Trailhead if you are self-evacuating
Helicopter Landing Zone Preparation
Minimum Clear Area
100 × 100 feet (30 × 30 meters) of relatively flat terrain, clear of debris, branches, or loose material that could be sucked into rotors or blow into faces.
LZ Marking
- Mark with an X pattern visible from the air using bright colors (surveyor tape, sleeping bags, packs)
- Remove hats and loose items that will blow in rotor downwash
- Keep all bystanders back 200+ feet from LZ
Signaling
- Arms raised in Y shape: "Yes, land here"
- One arm down, one arm up (L shape): "No, do not land"
Safety Considerations
- NEVER approach the helicopter from the rear—the spinning tail rotor is nearly invisible and lethal. Approach only from the front or side, within the crew's line of sight, and only after the crew signals you to approach. Stay low and secure loose items.
- The signaler stands at the edge of the LZ with their back to the wind—the aircraft lands into the wind, facing the signaler
- No fires or smoke downwind of LZ
- Patient loading: follow crew instructions exactly; they manage loading procedures
Device Testing & False Activations
Test your communication device before every trip to confirm battery and function. Know the difference between SOS/emergency buttons and non-emergency messaging. False activations trigger expensive rescue operations with serious legal consequences. Never activate an emergency device as a test in the field.
It is easier to stand down a rescue that arrives at the trailhead than to launch one after dark in a storm. When in doubt about evacuation necessity, alert rescuers early. Provide your location and situation, and let them advise whether formal rescue is needed.
Scenario-Based Learning
Setting: A climber falls 15 feet in a slot canyon and sustains an obvious open femur fracture. You are 8 miles from the trailhead, it is 3 PM, and you have 4 hours of daylight. You have a satellite communicator, a first aid kit, two sleeping pads, and 3 other group members.
Questions to Consider:
- What is the evacuation urgency?
- What do you do in the next 10 minutes?
- Do you self-evacuate or call for rescue?
- Urgency: URGENT. Open fracture = contaminated bone, major hemorrhage risk, shock risk, high pain. Cannot wait.
- Next 10 minutes:
- Control any bleeding (direct pressure, pressure dressing). If bleeding is arterial and uncontrolled, apply a tourniquet on the thigh 2-3 inches above (proximal to) the bleeding site—or "high and tight" near the groin if the wound's full extent is unclear. Never place a tourniquet below the wound.
- DO NOT reduce fracture. Support in position found.
- Irrigate exposed bone and wound gently with clean water; cover with loose sterile dressing.
- Splint femur using sleeping pads, clothing, or improvised splint. Immobilize from hip to ankle.
- Assess neurovascular distal to fracture: pulses, capillary refill, sensation, color. If the foot below the injury is pulseless or numb, the evacuation is EMERGENT.
- Nothing by mouth—this patient may need surgery, and shock is a real risk.
- Evacuation decision: DO NOT attempt litter carry over 8 miles with 3 rescuers. This is extremely difficult terrain, patient is severely injured, and risk of further injury during transport is high. Activate satellite communicator immediately: "Open femur fracture, 8 miles from trailhead, 4 adults, urgent evacuation needed. GPS: [coordinates]. Patient immobilized, bleeding controlled, needs helicopter or SAR with additional personnel."
- While waiting for rescue:
- Monitor vital signs every 5 minutes—shock is a major risk
- Hypothermia prevention critical: ground insulation, vapor barrier, head coverage
- Pain management without medication: good splinting, padding, and gentle handling. Do NOT give NSAIDs when significant bleeding is a concern, and this patient is nothing-by-mouth. Local wound care only (not suturing).
- Maintain warmth and comfort as best as possible
- Document SOAP note: mechanism, vital signs, treatments given, patient response
- Helicopter arrival: Clear LZ, mark with X, follow crew instructions for loading.
Setting: Day 5 of a 7-day river trip. A 58-year-old participant develops crushing chest pain radiating to the left arm with diaphoresis. No satellite communicator. You have a PLB. Nearest takeout is 2 days by river.
Questions to Consider:
- What is your field assessment and treatment?
- How do you call for help?
- What packaging decisions are important?
- Field Assessment: OPQRST for chest pain: Onset 30 min ago, Provocation none, Quality crushing, Radiation left arm, Severity 8/10, Time ongoing. Associated: diaphoresis (sweating), anxiety, possible shortness of breath. SAMPLE: History hypertension, takes aspirin and lisinopril, last ate 2 hours ago. Vital signs: BP elevated, HR elevated, RR elevated.
- Strong cardiac presentation: Treat as acute coronary syndrome (ACS) pending hospital evaluation.
- Field treatment:
- Give aspirin 325 mg, CHEWED (if no contraindications—not allergic, no GI bleed history)
- Position of comfort—most cardiac patients prefer sitting up slightly
- Nothing further by mouth after the aspirin
- Monitor vital signs closely
- Calling for help: Activate PLB immediately. PLB triggers COSPAS-SARSAT satellite monitoring—rescue authorities worldwide will be notified within minutes. Your location is transmitted automatically. Remember: a PLB is one-way—rescuers cannot message you back. The rescue coordination center will contact the beacon's REGISTERED emergency contacts for trip details, which is why beacon registration and leaving a trip plan with someone at home matter so much. Do NOT wait to see if symptoms improve.
- Packaging for evacuation:
- Semi-recumbent position (head elevated ~45°) for comfort
- Warm insulation
- Monitor ABCs and vitals every 5 minutes—cardiac event could deteriorate rapidly
- Prepare for helicopter extraction if rescue arrives
- Do NOT paddle out: Physical exertion increases cardiac demand and oxygen need. Wait for rescue.
- Serial assessment: Any change in mental status, respiratory distress, loss of consciousness, or cardiac arrest changes immediate priorities and requires escalation of supportive care.
Knowledge Check
10 questions. Pick an answer to get immediate feedback. Answer order is shuffled each attempt, and your best score is saved on this device.
Lesson Summary
Key Takeaways: Evacuation & Transport
- Evacuation urgency is determined by patient condition trend, terrain, resources, and environment.
- Hypothermia prevention during transport includes ground insulation, vapor barrier, head coverage, and external heat sources.
- Rigid improvised litters can be constructed from jackets, tarps, backpacks, or sleeping bags.
- Carrying teams should have 4-6 rescuers and rotate every 10-15 minutes to prevent fatigue.
- Satellite communicators and PLBs extend reach beyond cell coverage; test devices before every trip.
- MIST reports provide rescuers with essential information; include GPS coordinates and logistics.
- Helicopter landing zones must be 100×100 feet, clear, and marked; never approach from the rear—approach from the front or side only after the crew signals.
- Alert rescue early rather than late—it is easier to stand down than to launch in darkness or storm.
Glossary of Terms
- Urgent Evacuation
- Patient has a life-threatening condition or is deteriorating; must reach definitive care within hours.
- Non-Urgent Evacuation
- Patient is stable but needs medical evaluation within 12-24 hours; transport by litter or assisted walk is acceptable.
- Patient Packaging
- The process of preparing a patient for transport, including padding, strapping, insulation, and positioning.
- MIST Report
- Standardized communication format: Mechanism, Injuries, Signs/symptoms, Treatment—provides rescuers with essential information.
- PLB (Personal Locator Beacon)
- One-way emergency beacon monitored by COSPAS-SARSAT; no subscription, no communication back, globally monitored.
- Satellite Communicator
- Two-way messaging device that works anywhere; requires subscription; allows communication with rescue coordinators.
- Landing Zone (LZ)
- Designated clear area for helicopter evacuation; minimum 100×100 feet, marked with X pattern.
- Search and Rescue (SAR)
- Organized rescue operation involving multiple rescuers, equipment, and coordination with emergency authorities.
- Improvised Litter
- Emergency stretcher constructed from available materials (jackets, tarps, packs, branches) for patient transport.
- SOAP Note
- Documentation format: Subjective (history), Objective (vitals/findings), Assessment (diagnosis), Plan (treatment).
- Hypothermia Prevention
- Strategies to maintain body temperature during transport: ground insulation, vapor barrier, head coverage, external heat.
- Litter
- Stretcher or carrying device used to transport an immobilized or non-ambulatory patient.
Wilderness Medicine: Beyond First Aid (7th ed.) - William Forgey
COSPAS-SARSAT: cospas-sarsat.int (PLB information)
Wilderness Medical Society Guidelines: wms.org
Leave No Trace Principles: lnt.org
Two things worth carrying out of this lesson: exhaust your communication options before you spend people—a satellite message is cheaper than a six-person carry. And remember that the evacuation decision is part of the medicine. How this patient gets out matters as much as what you did for them on the ground.