Accidental Hypothermia

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Accidental Hypothermia

description

Accidental Hypothermia. The Basics Clinical Questions Treatment. Who gets hypothermia?. Case: 25 M Ice climber… Temp: 31 degrees. How would you classify this pt’s hypothermia?. 31 degrees C. Mild: Core temp. 32 to 35ºC Moderate: Core temp. 28 to 32ºC Severe: Core temp. below 28ºC. - PowerPoint PPT Presentation

Transcript of Accidental Hypothermia

Page 1: Accidental Hypothermia

AccidentalHypothermia

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The Basics

Clinical Questions

Treatment

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Who gets hypothermia?

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Case:

25 M Ice climber…

Temp: 31 degrees

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How would you classify this pt’s hypothermia?

31 degrees C

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Mild: Core temp. 32 to 35ºC

Moderate: Core temp. 28 to 32ºC

Severe: Core temp. below 28ºC

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Mild:34 - amnesia and dysarthria begin33 - ataxia and apathy develop

Moderate:32 - stupor31 - shivering stops30 - dysrhythmias, CO drops, insulin ineffective

Severe:28 - high risk for VF27 - lose reflexes and voluntary movement26 - major A/B disturbance

Profound:19 - flat EEG18 - asystole

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Pretend there is no history of exposure…why else could this

patient be hypothermic?

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Differential Diagnosis

Increased Heat Loss

Decreased Heat

Production

Impaired Heat Regulation

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What mechanisms contribute to heat loss in our patient?

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Evaporation, radiation, conduction, convection….

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How is the cold affecting this patient?

At the body level?

At the organ system level?

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QuickTime™ and a decompressor

are needed to see this picture.

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Increase HR

Progressive bradycardia

Ventricular Arrhythmias

Asystole

QuickTime™ and a decompressor

are needed to see this picture.

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The J Wave

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Cold diuresis

Reduced renal flow

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Progressive depression

perfusion maintained until 25 degrees

19 degrees flat EEG

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Initial stimulation

Progressive decrease

CO2 retention and Acidosis

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Case continued….

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What is the most accurate method of measuring his

temperature?

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Rectal temperature (insert to 15 cm)- ? Accurately reflect brain/heart temperature- Influenced by adjacent frozen stool- lags behind core temperature changes

Oral- Often do not measure below 34 degrees C.

Tympanic- accurately reflect hypothalamus if true tympanic

Axilla- easily affected by external factors

Esophogeal (insert to 24 cm)-can be affected by warm airway temperature in tubed patient

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ChemstripElectrolytesCreatinine, BUNHg, WBC, PltLactateEKGABG

Other: CK, fibrinogen, INR, cortisol, thyroid

Blood Work

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Chemstrip:-Insulin ineffective below 30 degrees -persistent elevation despite rewarming signals secondary cause

Hct:-Increases 2% for every drop by 1 degree C-Beware of the hypothermic patient with a normal/low hematocrit

ABG:-Historically controversial-Use uncorrected values

Blood Work

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How can you rewarm him?

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Passive External Rewarming (PER)

• Providing blankets• Moving to a warm environment• Heated IV fluids/oral fluids

**pt must be able to produce their own heat

***slow rise in temperature

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Active External Rewarming

• Applying heat to the skin:

– Warm blankets– Bear Hugger– Immersion warming– Brokeback Hug?

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Active Internal Rewarming

• Peritoneal dialysis• Bladder, gastric, or colonic lavage• Heated intravenous fluids• Heated humidified oxygen• Thoracic cavity lavage• Extracorporeal blood rewarming• Hemodialysis

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Recipe:

Warmed NS

1) Place 1L NS in 650 W microwave

2) Cook on high for 120s, turning and shaking it once at midcycle

3) Agitate before infusion

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Inhaled warmed O2

• Use warmed air at 45 degrees celcius

• Up to 2 degrees/hr*

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Peritoneal Lavage

• Use Arrow peritoneal lavage kit

• Up to 3 degrees C/hour

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GI and bladder rewarming

• 1.5-2.0 degrees/hour

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Thoracic Cavity Lavage

Up to 6 or 7 degrees/hour reported

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Cardiac Bypass

• Need to consult CV surgery

• Up to 2 degrees/5 mins

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Hemodialysis

• Up to 4.5 degrees/hour

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Comparison of Rewarming Rates

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Case Continued

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• Why has this patient become more hypothermic despite your warming measures?

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Approach to rewarming

Mild Hypothermia

Passive External Rewarming

+/- Active External Rewarming

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Approach to rewarming

Moderate Hypothermia

Active External Rewarming

Active Internal Rewarming

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Approach to Rewarming

Severe Hypothermia

Level 1 callout

If Stable, treat as moderate but be prepared for ecmo

If Unstable, ACLS and prepare for ecmo

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ACLS guidelines?BLS:

-prevent heat loss, rewarm-mild AH = passive rewarming-moderate AH = AER-Severe + Stable = AER or AIR-Severe + Unstable = bypass or AIR-Do not withhold ABC’s to rewarm

ACLS:-If in VF or pulseless VT, attempt defibrillation-“Might be reasonable to perform further defibs-“Might be reasonalbe to administer vasopressor”

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Cold and Dead?

“Patients with severe accidental hypothermia and cardiac arrest may benefit from resuscitation even in

cases of prolonged downtime and prolonged cpr”

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The Obvious:-Decapitation

-Non-compressible chest-Ice in mouth and nose

-DNR order

The Unreliable:-rigor or livor mortis

-fixed pupils-tissue deterioration

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Rosens:“Significant predictors of outcome”

asphyxia, prehospital arrest, low or no BP, high BUN, need for intubation in ER

Literature:

Mt. Hood: only survivors had signs of life on scene, temps were above 20 degrees, K < 7Mair et al. 1994: K > 10, pH < 6.5,

Others: fibrinogen <50mg/dL, ammonia >250mmol/L

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Frostbite

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Case:

In minor ER

63 M

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Pernio

• Local, inflammatory, bluish-red lesions

• Caused by prolonged vasoconstriction

• Gentle drying and massaging.

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Immersion Injury (Trench Foot)

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Cold Injury

Non-Freezing

• Pernio• Immersion Injury

• Cold Urticaria

Freezing

• Frostnip• Frostbite

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Frostnip

Reversible and superficial

No tissue loss

Pale and discomfort and tingling

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Case:

27 F Car broke down on a rural road.Decided to walk out

While walking through wooded area, she gets lost, at one point ending up knee deep in a stream.

She wanders through the forest for 12 hours lost.

Eventually she is spotted by a hunter who calls EMS.

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Frostbite

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Classification

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Treatment

• Remove wet clothing• Rapid rewarming with warm water (40

degrees)• Analgesia!!• NSAID’s?• Td

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Treatment

• Thawing:– 40 degrees– Until part feels soft, erythema present– Usually requires 10-30 minutes– Active motion by patient

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Treatment

• Post-thaw:– Elevate– Sterile, bulky dressing– Aloe Vera?– Blisters?– TPA?– Heparin?– Abx?– Hyperbaric O2?, Pentoxifylline?

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Treatment

• Surgery?

• Admission?

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Summary

1) Spectrum of freezing and non-freezing injuries

2) Treat by rapid rewarming

3) Aloe, ibuprofen, and Td (others are controversial)

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