04/22/23 Ken Zafren, MD FACEP Hypothermia Guidelines

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Revised Cold Injuries and Cold Water Near Drowning Guidelines

Ken Zafren, MD, FACEPEMS Medical Director,State of Alaska

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The State of Alaska Cold Injuries and Cold Water Near Drowning Guidelines Developed in 1988 by an expert

panel Revised in 1996 Expert panel revision - Sitka 2002 Revised edition in progress

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Overview of Guidelines General points Hypothermia Cold water near drowning Frostbite New section on avalanche rescue

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Introduction Guidelines - not absolute rules Designed as a reference, not a

teaching document

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Multilevel guidelines

General points General public First Responder / EMT-I EMT-II EMT-III / Paramedic Small/Bush Clinic Hospital

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Hypothermia -General Points

Core temperature best measured as esophageal temperature if possible

Epitympanic temperature second choice

Rectal temperature third choice

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Hypothermia -General PointsWhy esophageal temperature?

Best reflection of core temperature Reflects cardiac temperature Relatively non-invasive Technology widely available Patient remains covered

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Hypothermia -General PointsEpitympanic temperature

Reflects carotid artery temperature Non-invasive Technology not yet widely

available in USA

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Hypothermia -General PointsRectal temperature

Does not reflect core temperature very well

Lags core temperature during rewarming

Requires disrobing patient

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Hypothermia - General PointsOrthopedic injuries Splint with caution in frostbitten

limbs to prevent further damage; frostbitten skin is damaged skin.

Align fractures/dislocations in neutral position. This gives the best chance of preserving neurovascular and other structures.

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Hypothermia - General PointsOrthopedic injuries

Do not reduce frozen extremities to prevent further damage.

Splints should not be constrictive in order to allow for postinjury swelling.

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Hypothermia - General Points

Warm oral and IV fluids to at least body temperature to prevent further cooling.

Give IV fluids as boluses (especially for field use).

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Hypothermia - General PointsWhy IV fluid boluses? Less likely to freeze than

continuous infusions Better titration to effect

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Hypothermia - General Points

Chemical heat packs ineffective for warming

Can be used on hands or feet to prevent frostbite

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Hypothermia - General Points

Positive attitude is important Assume the patient can be

resuscitated even if they appear to be beyond help

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Hypothermia - General PointsContraindications to CPR New temperature cutoff - core

temperature 10°C/50°F Rescuers exhausted or in danger

or CPR cannot be maintained throughout transport to a medical facility

Transportation available within 3 hours

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Hypothermia - General PointsContraindications to CPR - new cutoff New temperature cutoff - core

temperature 10° C / 50° F Survival has now been

documented to core temperature of 13.7° C / 56.7° F

Routine use of 10° C / 50° F in surgery

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Hypothermia - General PointsContraindications to CPR Rescuers exhausted or in danger

or CPR cannot be maintained throughout transport to a medical facility

If CPR is begun any perfusing rhythm will probably be lost; stopping CPR once begun is therefore likely to be fatal

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Hypothermia - General PointsContraindications to CPR Transportation available to critical

care within 3 hours Hypothermic patients can survive

for up to 3 hours with pulse and blood pressure which are difficult to detect.

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Hypothermia - General PointsCPR Apneic pulseless patient - ventilate

for 3 minutes before CPR to increase VF threshold

Ventilation may increase heart rate, blood pressure

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Hypothermia - General PointsCPR

Apneic pulseless patient - decision to start CPR based on time to critical care

<3 hours: ventilate (intubate, if possible), prevent heat loss

>3 hours: chest compressions and ventilate for 30 minutes, attempt to rewarm

CPR cannot be done in a litter

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Handle hypothermic patients gently to prevent Ventricular Fibrillation

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Hypothermia - General PointsAssessment Check for cardiac activity for at

least 60 seconds Automatic External Defibrillator

(AED) may be used to detect cardiac activity - signal to shock indicates V Tach or V Fib

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Hypothermia - General PointsAssessment New classification for severity of

hypothermia Follows International Commission

for Alpine Rescue, Winnepeg consensus guidelines

Correlates core temperature with observable findings

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Classifications of level of hypothermia

Core temp Thermoregulatorystatus

S & S Classifications

37 oC Cold sensationshivering

Normal

35-32 oC Control andresponses fullyactive

Physicalimpairment finemotorGross motor

MentalimpairmentComplexSimple

mild

32-28 oC Responsesattenuatedextinguished

-30 degreesshivering shopsloss of consciousness

moderate

Below 28 oC Responses absent RigidityVital signs reduced or absentRisk of VF (rough handling)

Below 25 oC Spontaneous ventricular fibrillationCardiac arrest

Severe

Red text are major thresholds between stages

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Hypothermia stages Mild 32-35°C (90-95°F) Moderate 28-32°C (82-90°F) Severe <28°C (<82°F) Ideally based on esophageal

temperature Becoming standard classification

worldwide

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Hypothermia - General PublicMild Hypothermia Patient is cold Vigorous shivering Alert May be ambulatory

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Hypothermia - General PublicTreatment

Remove wet clothes only with shelter

Vapor barrier Cover head and neck

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Hypothermia - General PublicTreatment

Shivering is an important method to increase heat production

Sugar containing fluids are more beneficial than hot drinks

Special importance if medical care delayed

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Hypothermia - General PublicTreatment

Mild exercise such as walking may be helpful after the patient is dry and has eaten

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Hypothermia - General PublicTreatment

Mild exercise such as walking may be helpful after the patient is dry and has eaten. If the patient is exhausted, exercise cannot be maintained and the patient will lose the ability to increase body heat (primarily by shivering)

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Hypothermia - General Public Moderate-Severe Treatment Handle gently Do not rub or manipulate

extremities

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Hypothermia - General Public Moderate-Severe (with life signs)Treatment Handle gently Do not rub or manipulate

extremities Do not allow to sit or stand Do not put in shower or bath No exercise

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Hypothermia - General Public Moderate-Severe (without life signs)Treatment Handle gently Check pulse for at least 60

seconds CPR if not contraindicated

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Hypothermia -First Responder EMT-I

Same as general public with additions

Oxygen, if used, should be heated and humidified

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Hypothermia -First Responder / EMT-I

Insulate patient - sleeping bag Cover head and neck Rewarming axilla, trunk, groin Hot shower/bath okay only for mild

hypothermia

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Hypothermia - EMT-II

Same as EMT-I with additions Most patients need volume IV fluid should be normal saline -

250 cc boluses, repeated as needed to treat tachycardia

Heat fluid to 104-108°F (40-42°C) Consider glucose, naloxone

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EMT-IISevere hypothermawith signs of life Measure core temperature

(esophageal is preferred)

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EMT-IISevere hypothermawithout signs of life Ventilate and pre-oxygenate 3

minutes before intubating Intubate Do not hyperventilate One set of defibrillations if core

temperature is less than 30°C (86°F)

Further attempts above 30°C

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EMT-III / ParamedicSevere hypothermawithout signs of life Same as for EMT-II No ACLS drugs No CPR if any rhythm on monitor

other than VF/VT

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Hypothermia - HospitalGeneral Points Treat to level of ability Transfers follow usual guidelines May be better to bypass

community hospital for one with cardiac bypass capability

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Hypothermia - HospitalGeneral Points Consider transfer of patient with

core temp <20° C (68° F) Consider bypass if BP<60 systolic Stabilize patient before transport

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Hypothermia - HospitalGeneral Points

Suggestions for evaluation and treatment

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Hypothermia - HospitalGeneral Points Esophageal temperature and end

tidal CO2 monitoring IV fluids must be heated. Heated, humidified oxygen, if

available Avoid sedation to depress

shivering

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Hypothermia - HospitalGeneral PointsRewarming methods Passive external rewarming Active external rewarming Active core rewarming

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Hypothermia - HospitalGeneral PointsActive internal rewarming Peritoneal lavage AV Rewarming Cardiopulmonary bypass Venous heat-exchange catheter

(possible future technology)

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Hypothermia - HospitalGeneral PointsActive internal rewarming Slow rewarming prior to adequate

ventilation

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Hypothermia - HospitalGeneral PointsCardiac rhythm disturbances Supraventricular dysrhythmias are

innocent V Tach and V Fib - one round of

shocks until 30°C (85°F) Drugs ineffective

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Hypothermia - HospitalGeneral PointsInsulinConsider insulin during rewarming.

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Hypothermia - HospitalWhen to stop resuscitation? Core temperature not improving

despite aggressive rewarming Serum potassium >10 with

associated asphyxia (near drowning, avalanche)

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Cold Water Near DrowningGeneral Points Use of PFDs with thermal

protection mandatory for emergency responders

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Cold Water Near DrowningGeneral Points Submersion - head under water Immersion - head out of water

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Cold Water Near DrowningGeneral Points Hypothermia not the main problem Cardiac, pulmonary and

coagulation problems are key Rewarming to raise temperature to

make defibrillation more effective

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Cold Water Near Drowning - General Public Neck protection if possible injury Activate EMS system Start CPR if patient pulseless after

pulse check of 60 seconds Heimlich maneuver only for solid

foreign body obstruction

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Cold Water Near Drowning - First Responder / EMT-I Similar to General Public

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Cold Water Near Drowning - EMT-II Similar to EMT-I Saline lock or TKO (no fluids)

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Cold Water Near Drowning - EMT-III / Paramedic Similar to EMT-II Assess for possible

cardiopulmonary bypass

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Cold Water Near Drowning - Hospital

IV fluids only if volume depleted Cardiopulmonary bypass no longer

recommended

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Cold Water Near Drowning - Hospital Active external rewarming as

indicated by core (esophageal) temperature.

Keep patients at 32-33° C to protect the brain.

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Cold Water Near Drowning - Hospital Agressive cerebral resuscitation

(IVP monitoring, diuretics, barbiturates) no longer recommended.

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Frostbite

No significant changes in prehospital care

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Frostbite

Temperature for thawing 38-40°C (100-107°F). The lower end is preferred.

Stop thawing when tips of digits flush.

Recommendations for wound care.

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Frostbite

Fasciotomy guided by compartment pressures (>37-40 mm Hg) and clinical judgment

Antibiotics necessary only for deep infection

General care recommendations

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Frostbite

Orthopedic guidelines Guidelines for disposition Sample admitting orders

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Avalanche rescue

Similar to cold water near drowning Importance of asphyxiation

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Avalanche Rescue

Rapid extrication to 35 minutes to prevent asphyxia

Gentle extrication after 35 minutes to prevent ventricular fibrillation in hypothermic patient

Check for air pocket

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Avalanche Rescue

Rapid extrication to 35 minutes to prevent asphyxia

Patients extricated in less than 35 minutes are unlikely to be hypothermic, but will die of asphyxia without an adequate air pocket.

An air pocket is any space in front of the nose or mouth, no matter how small.

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Avalanche Rescue

Gentle extrication after 35 minutes to prevent ventricular fibrillation in hypothermic patient

Patients extricated after 35 minutes who are still alive will have an air pocket.

They are at risk for hypothermia.

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Avalanche Rescue

Rapid extrication to 35 minutes to prevent asphyxia

Gentle extrication after 35 minutes to prevent ventricular fibrillation in hypothermic patient

Check for air pocket

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Avalanche Rescue

CPR/ACLS for 30 minutes for burials less than 35 minutes or core temp >32°C

No CPR/ACLS for burials longer than 35 minutes or core temp <32°C if no air pocket

CPR/ACLS for burials longer than 35 minutes or core temp <32°C with air pocket