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Transcript of Accidental Hypothermia
Who gets hypothermia?
25 M Ice climber
Temp: 31 degrees
How would you classify this pts hypothermia?31 degrees C
Mild: Core temp. 32 to 35C
Moderate: Core temp. 28 to 32C
Severe: Core temp. below 28C
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
Pretend there is no history of exposurewhy else could this patient be hypothermic?
Differential DiagnosisIncreased Heat LossDecreased Heat ProductionImpaired Heat Regulation
What mechanisms contribute to heat loss in our patient?
Evaporation, radiation, conduction, convection.
How is the cold affecting this patient?
At the body level?
At the organ system level?
The J Wave
Reduced renal flow
perfusion maintained until 25 degrees
19 degrees flat EEG
CO2 retention and Acidosis
What is the most accurate method of measuring his temperature?
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
ChemstripElectrolytesCreatinine, BUNHg, WBC, PltLactateEKGABG
Other: CK, fibrinogen, INR, cortisol, thyroid
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
How can you rewarm him?
Passive External Rewarming (PER)Providing blanketsMoving to a warm environmentHeated IV fluids/oral fluids
**pt must be able to produce their own heat***slow rise in temperature
Active External RewarmingApplying heat to the skin:
Warm blanketsBear HuggerImmersion warmingBrokeback Hug?
Active Internal RewarmingPeritoneal dialysis Bladder, gastric, or colonic lavage Heated intravenous fluids Heated humidified oxygen Thoracic cavity lavage Extracorporeal blood rewarming Hemodialysis
Place 1L NS in 650 W microwaveCook on high for 120s, turning and shaking it once at midcycleAgitate before infusion
Inhaled warmed O2Use warmed air at 45 degrees celciusUp to 2 degrees/hr*
Peritoneal LavageUse Arrow peritoneal lavage kit
Up to 3 degrees C/hour
GI and bladder rewarming1.5-2.0 degrees/hour
Thoracic Cavity LavageUp to 6 or 7 degrees/hour reported
Cardiac BypassNeed to consult CV surgery
Up to 2 degrees/5 mins
HemodialysisUp to 4.5 degrees/hour
Comparison of Rewarming Rates
Why has this patient become more hypothermic despite your warming measures?
Approach to rewarming
Passive External Rewarming
+/- Active External Rewarming
Approach to rewarmingModerate Hypothermia
Active External Rewarming
Active Internal Rewarming
Approach to RewarmingSevere Hypothermia
Level 1 callout
If Stable, treat as moderate but be prepared for ecmo
If Unstable, ACLS and prepare for ecmo
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 ABCs to rewarm
ACLS:-If in VF or pulseless VT, attempt defibrillation-Might be reasonable to perform further defibs-Might be reasonalbe to administer vasopressor
Cold and Dead?Patients with severe accidental hypothermia and cardiac arrest may benefit from resuscitation even in cases of prolonged downtime and prolonged cpr
The Obvious:-Decapitation-Non-compressible chest-Ice in mouth and nose-DNR order
The Unreliable:-rigor or livor mortis-fixed pupils-tissue deterioration
Rosens:Significant predictors of outcomeasphyxia, 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 250mmol/L
In minor ER
PernioLocal, inflammatory, bluish-red lesions
Caused by prolonged vasoconstriction
Gentle drying and massaging.
Immersion Injury (Trench Foot)
PernioImmersion InjuryCold UrticariaFreezing
FrostnipReversible and superficial
No tissue loss
Pale and discomfort and tingling
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.
TreatmentRemove wet clothingRapid rewarming with warm water (40 degrees)Analgesia!!NSAIDs?Td
TreatmentThawing:40 degreesUntil part feels soft, erythema presentUsually requires 10-30 minutesActive motion by patient
TreatmentPost-thaw:ElevateSterile, bulky dressingAloe Vera?Blisters?TPA?Heparin?Abx?Hyperbaric O2?, Pentoxifylline?
SummarySpectrum of freezing and non-freezing injuries
Treat by rapid rewarming
Aloe, ibuprofen, and Td (others are controversial)
Thanks to Kyle Mclaughlin for help with his experiences, cases, and knowledge.
As opposed to therapeutic hypothermia
Not too uncommon around these parts - In fact, Dr. McLaughlin has a few stories hell be able to share with us as we go along..
Weather records in Canada: mount logan -77.5, snag, yukon -63, fort vermillion, ab -61.1, Calgary -45
We only have an hour so Ill keep it brief wherever possible.
There will be a handout (made by Kyle) that I will send out. Also, any further questions and Im happy to provide you with the references.
I also have a short video from the USC series for anyone who is interested.
Youll find a whole table in Rosens about this but just keep in mind the basics:
Essentially: Extremes of age, intoxication/behavioural, and co-morbids
Old people because: chronic disease (which interfere with heat production and conservation), medications, social isolation, older homes, Young because: larger SA to V ration, relatively smaller subcutaneous tissue layer, inefficient shiveringNeonates: no behavioural defense, Etoh/Behavioural: name says it. They lack the behavioural mechanism to leave the cold or bundle up.
Decrease heat productionIncrease heat lossImpaired thermoregulationOther miscellaneous statesKyle, Id like you to give the history on this guy right up to the point where EMS get his initial temp.that will lead into the first question about classification and the subsequent questions about differential and expected symptoms at given temps. After that well give more info
25 yo Ice climber at Johnston Canyon- ground level fall and submerged under ice this past Nov. unable to free self from under ice but able to find air pockets and under water caves to breath in. Made decision to leave one-way caves twice back under the ice. Partially submerged for 20-25 minutes. Breaks a small hole in ice and passerby's descend a rope from 5 meters up - patient flops on top of ice. EMS arrive and bystanders have covered patient in jackets. Patient altered and not shivering. EMS strip him down, place in bag and crack neonate warming pads. By the time he arrives in Banff- rectal temp 31, shivering, alert, GCS 15, in rapid A. Fib. Warmed to 37 over 5 hours with bear hugger and warm fluids. Still in A. Fib with rate 150-160 Asymptomatic. Cardioverted to normal sinus. Home after Psych has seen for expected PTSD.Key points: Management at scene- directing EMS to remove cold clothes and actively warm if not shivering.-arrhythmias: most will resolve with warming, expect any type, Osborne J waves are classic.This may help in terms of standardizing your lingo but also correlates with their clinical presentation
Slide of the degrees celcius with corresponding clinical presentation:
In more simplified terms:In the mild phase, the body is compensating for the heat loss by producing/conserving more heatIn the moderate phase, protective/compensatory measures begin to fail and clinical signs begin to developIn the Severe phase, the patient is grossly unstableIn the Profound phase, the patient is dead
DIFFERENTIAL DIAGNOSIS In