01Approach to the Critical Patient/attcp53

Immediate priorities

›Stabilization and triage

›Airway compromise

›If depressed mental status, airway protection

›If aspiration risk, suction and positioning

›Breathing compromise

›If hypoventilation, assisted ventilation

›If hypoxia, supplemental oxygen

›Circulation compromise

›If shock, isotonic crystalloid bolus and reassessment

›If dysrhythmia, ACLS pathway

›Hypothermia screening and management

›Core temperature measurement

›If moderate to severe hypothermia, active core rewarming and continuous monitoring

›Concurrent trauma and cold injury coassessment

›If polytrauma, trauma pathway and imaging

›If compartment syndrome concern, urgent surgical consultation

Limb threat assessment

›Limb viability and time sensitivity

›Time from cold exposure to rewarming

›Time of freezing

›Any refreezing episodes

›After rewarming perfusion assessment

›Capillary refill

›Doppler signals

›Sensation and motor function

›If absent perfusion after rewarming, urgent burn or vascular consultation

›Thrombolysis or vasodilator candidacy window assessment

02History/hx65

Key history elements

›Exposure and timeline

›Duration of cold exposure

›Continuous exposure duration

›Intermittent exposure

›Wet exposure

›Immersion

›Sweating under clothing

›Wind exposure

›Wind chill context

›Inadequate insulation

›Rewarming attempts

›Method used

›Any refreezing after rewarming

›Symptoms and functional impact

›Numbness

›Persistent after rewarming

›Paresthesia

›Pain

›During rewarming

›Persistent pain after rewarming

›Color change

›Pallor

›Cyanosis

›Erythema after rewarming

›Swelling and stiffness

›Limited ROM

›Loss of grip or ambulation

03Physical Exam/exam42

General and systemic

›System assessment

›Core temperature status

›Hypothermia category

›Shivering presence

›Hemodynamic status

›Heart rate and rhythm

›Blood pressure trend

›Mental status

›Confusion

›Intoxication signs

›Coexisting cold injury

›Hypothermia features

›Nonfreezing cold injury features

Local extremity exam

›Affected part exam

›Skin appearance

›Waxy or wooden feel

›Mottling

›Cyanosis

›Blister characterization

›Clear blisters

›Hemorrhagic blisters

›Perfusion

›Capillary refill after rewarming

›Doppler arterial signals

›Sensation

›Light touch

04Differential Diagnosis/ddx37

Primary and mimics

›Cold injury differential

›Frostnip

›ICD-10 T33.0 to T33.9 for superficial freezing injury by site

›SNOMED CT concept: Frostnip

›Frostbite

›ICD-10 T33 and T34 series by site and depth

›SNOMED CT concept: Frostbite

›Nonfreezing cold injury

›Trench foot

›Chilblains

›Cold induced urticaria or vasospasm

›Raynaud phenomenon

›Acrocyanosis

›Vascular and ischemic mimics

›Acute limb ischemia

›Embolic occlusion

›Thrombosis in situ

›Severe peripheral arterial disease exacerbation

›Critical limb ischemia

›Vasculitis

›Small vessel vasculitis

›Cryoglobulinemia

›Dermatologic and infectious mimics

›Cellulitis

›Warmth and erythema predominance

›Necrotizing soft tissue infection

›Rapid progression

05Laboratory Tests/lt42

Initial labs and indications

›Baseline laboratory evaluation

›Point of care glucose

›Hypoglycemia as hypothermia mimic

›Hyperglycemia in diabetes and stress response

›Complete blood count for infection or hemoconcentration

›Leukocytosis interpretation with stress response

›Hemoconcentration with dehydration

›Electrolytes and renal function

›Potassium disturbances in hypothermia

›Creatinine for contrast planning

›Creatine kinase for muscle injury and rhabdomyolysis

›Trend for crush or prolonged cold immobilization

›AKI risk stratification

›Liver enzymes if systemic hypoperfusion concern

›Shock liver consideration

›Alcohol related injury

›Coagulation studies if thrombolysis considered

›INR

›aPTT

›Pregnancy test when applicable

›Medication safety planning

›Radiation planning

›Blood gas if significant hypothermia or respiratory compromise

›pH and PaCO2

›Lactate as perfusion marker

Thrombolysis readiness labs

›Thrombolysis and vasodilator pathway labs

06Diagnostic Tests/dt38

Scoring Systems

›Prognostic scoring and staging

›Cauchy clinical grading

›Grade 1

›Distal phalanx involvement only

›No cyanosis after rewarming

›Grade 2

›Intermediate phalanx or more proximal involvement

›Cyanosis limited to distal segment

›Grade 3

›Proximal involvement with persistent cyanosis

›Hemorrhagic blisters possible

›Grade 4

›Extensive proximal involvement

›Likely tissue loss

›Use of grade for therapy selection

›If grade 2 to 4, consider iloprost pathway

›If grade 3 to 4 with absent perfusion, consider thrombolysis pathway

MRI

›MRI role

›Soft tissue viability assessment

›Deep tissue necrosis extent

›Osteomyelitis evaluation in delayed presentations

›Limitations

›Limited acute prognostic value early

›Availability and time constraints in ED setting

CT

›CT role

07Disposition/dispo26

Level of care and referral

›Disposition planning

›Admission indications

›Deep frostbite suspected

›Persistent absent perfusion after rewarming

›Significant hypothermia

›Rhabdomyolysis risk or AKI

›Uncontrolled pain

›Infection concern or immunocompromise

›Specialty consultation triggers

›Burn center consultation for deep frostbite or multi digit involvement

›Vascular or interventional radiology for perfusion deficits and thrombolysis consideration

›Orthopedics or hand surgery for severe involvement

›Transfer criteria

›Candidate for iloprost or thrombolysis not available locally

›Need for advanced imaging or surgical capability

›Discharge criteria

›Frostnip or superficial frostbite only

›Normal perfusion after rewarming

›Reliable follow up and wound care capacity

Follow up

›Follow up and monitoring

›Early recheck within 24 to 72 hours for progression

›Perfusion reassessment

›Blister evolution

›Longer term follow up

›Tissue demarcation monitoring over weeks

›Rehab and ROM therapy planning

08Treatment/t106

Rewarming and immediate care

›Core and local rewarming

›Rapid water bath rewarming for frozen part

›Water temperature 37 to 39 C

›Duration 15 to 30 minutes

›Continue until tissue pliable and erythematous

›Prevent refreezing

›Warm environment and insulation

›Avoid re exposure until definitive warming assured

›Analgesia during rewarming

›Opioid analgesia if severe pain

›Regional anesthesia consideration for extensive injury

General measures and wound care

›Supportive and local care

›Gentle handling and protection

›Bulky dry dressings

›Elevation to reduce edema

›Blister management

›Clear blisters

›Debridement consideration in burn specialist pathway

›Infection risk and dressing planning

›Hemorrhagic blisters

›Leave intact in most protocols

›Specialist guided debridement if needed

›Topical therapy

›Aloe vera every 6 hours if available

›Nonadherent dressings

›Tetanus prophylaxis

›If immunization not up to date, tetanus vaccination

›If high risk wound and unknown status, tetanus immune globulin

Anti inflammatory and antiplatelet strategy

›NSAID based prostaglandin inhibition

›Ibuprofen

›12 mg/kg/day by mouth divided every 6 to 8 hours

›Maximum 2400 mg/day

›Continue until healing or demarcation

›If NSAID contraindicated, specialist directed alternative

›GI bleed risk

›Renal dysfunction

Infection management

›Antibiotic strategy

›No routine prophylactic antibiotics for uncomplicated frostbite

›Low infection rate without necrosis

›Focus on wound care and monitoring

›If cellulitis or infected necrosis, antibiotics per local SSTI guidance

›MRSA risk assessment

›Culture if purulence

Thrombolysis and vasodilator therapy

›Reperfusion targeted therapies for deep frostbite

›Candidate selection after rewarming and perfusion assessment

›Deep frostbite with absent distal perfusion

›Significant digit or limb involvement

›Contraindications screening for thrombolysis

›Active bleeding

›Recent stroke

›Recent major surgery

›Intracranial pathology

›Iloprost pathway

›Indication pattern

›Cauchy grade 2 to 4 within 48 hours of injury

›Persistent ischemia after rewarming

›Dosing and administration

›Initiate iloprost IV 0.5 ng/kg/min

›Titrate every 30 minutes to 2 ng/kg/min as tolerated

›Duration 6 hours daily

›Course 5 to 8 days

›Monitoring

›Blood pressure every 15 minutes during titration

›Headache and flushing as dose limiting effects

›Evidence level labeling

›Consensus guideline support for grade based use

›ACEP Level C style evidence statement

›Thrombolysis pathway with alteplase

›Indication pattern

›Deep frostbite with absent perfusion after rewarming

›Presentation within 24 hours of injury when feasible

›Example institutional protocol framework

›Catheter directed alteplase

›Initiate alteplase 0.5 mg/hour per affected limb vascular territory

›Titrate up to 1 mg/hour based on perfusion response and bleeding risk

›Typical duration 6 to 24 hours

›Concurrent heparin infusion

›Initiate heparin 500 units/hour

›Titrate to aPTT target per institutional protocol

›Monitoring

›Neuro checks every 1 to 2 hours

›Hemoglobin and fibrinogen every 6 hours

›Systemic alteplase

›Use only with specialist protocol if catheter access unavailable

›Bleeding risk higher than catheter directed approach

›Post thrombolysis antithrombotic plan

›Transition plan per consultant

›Ongoing perfusion checks

›Evidence level labeling

›Class IIb recommendation style for selected patients in specialized centers

›ACEP Level C style evidence statement

›Adjunctive therapies not routinely recommended

›Hyperbaric oxygen

›Insufficient evidence for routine use

›Consider only in specialist driven protocol

Surgical and delayed care principles

›Surgical timing and tissue demarcation

›Early amputation avoidance

›Demarcation over weeks typical

›Early surgery increases tissue loss risk

›Early surgery exceptions

›Wet gangrene

›Sepsis source control

›Compartment syndrome

›Escharotomy or fasciotomy

›If compartment syndrome, urgent decompression

›If circumferential constriction with perfusion compromise, specialist decision

09Special Populations/sp36

Pregnancy

›Pregnancy considerations

›Maternal hypothermia risk prioritization

›Active core rewarming when indicated

›Fetal monitoring coordination when viable gestation

›Medication considerations

›NSAID avoidance in later pregnancy context

›Opioid analgesia risk benefit discussion

›Thrombolysis and iloprost

›Specialist consultation mandatory

›Maternal bleeding risk assessment

›Disposition bias toward observation or admission

›Lower threshold for monitoring

›Coordination with obstetrics

Geriatric

›Geriatric considerations

›Higher comorbidity burden

›Peripheral arterial disease prevalence

›Anticoagulant and antiplatelet use

›Medication dosing and toxicity

›NSAID renal and GI risk

›Opioid delirium risk

›Lower threshold for admission

›Hypothermia complications

›Social support limitations

Pediatrics

›Pediatric considerations

›Faster heat loss physiology

10Background/b36

Epidemiology

›Epidemiologic context

›High risk settings

›Outdoor recreation and occupational exposure

›Unsheltered homelessness

›Common sites

›Fingers and toes

›Nose and ears

›Risk modifiers

›Wind and wet exposure

›Tight footwear and impaired circulation

Pathophysiology

›Mechanisms of injury

›Ice crystal formation and cellular injury

›Extracellular ice leading to osmotic shifts

›Cellular dehydration and membrane damage

›Microvascular dysfunction

›Endothelial injury

›Thrombosis and no reflow

›Reperfusion injury

›Inflammatory mediator release

›Progressive tissue necrosis after rewarming

›Blister fluid mediator content

›Thromboxane and prostaglandins contribution

›Rationale for NSAID and aloe vera use

Therapeutic Considerations

›Rationale for key therapies

›Rapid rewarming

11Patient Discharge Instructions/pdi23

copy discharge instructions

›Discharge instructions

›Wound care

›Keep area clean and dry

›Nonadherent dressing changes daily or if wet

›Elevation when resting

›Activity

›Protect from pressure and friction

›Avoid smoking or nicotine

›Pain control

›Ibuprofen as directed if safe

›Avoid excess heat sources

›Avoid refreezing and cold exposure

›Warm clothing and gloves

›Avoid outdoor exposure until healed

›Return to ED now for red flags

›Increasing pain not controlled

›New numbness or weakness

›Skin turning black or rapidly worsening discoloration

›Spreading redness, pus, fever, or chills

›Blisters rapidly increasing or foul odor

›Follow up

›Recheck in 24 to 72 hours

›Burn or hand specialist follow up if blistering or fingertip involvement

12References/r16

Clinical guidelines and evidence sources

›Frostbite guidance sources

›Wilderness Medical Society clinical practice guidelines on prevention and treatment of frostbite

›Rapid rewarming 37 to 39 C recommendation

›Ibuprofen for prostaglandin inhibition recommendation

›American Burn Association referral principles for complex extremity injury care

›Burn center involvement for deep frostbite and multi digit injury

›Transfer considerations for limb salvage therapies

›Specialty consensus on thrombolysis for selected deep frostbite in specialized centers

›Time window based selection

›Bleeding risk and monitoring requirements

›ACEP Level C evidence style labeling for frostbite therapies commonly based on consensus and observational data

›Iloprost use in selected grade based cases

›Thrombolysis in selected deep frostbite cases

›Class IIb recommendation style statement for thrombolysis in selected patients when expertise available

›Benefit may exceed risk in carefully selected cases

›Shared decision making and specialist oversight

Evidence & Review

Evidence & Review