Accidental Hypothermia. The Basics Clinical Questions Treatment.

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Transcript of Accidental Hypothermia. The Basics Clinical Questions Treatment.

  • Slide 1
  • Accidental Hypothermia
  • Slide 2
  • The Basics Clinical Questions Treatment
  • Slide 3
  • Who gets hypothermia?
  • Slide 4
  • Case: 25 M Ice climber Temp: 31 degrees
  • Slide 5
  • How would you classify this pts hypothermia? 31 degrees C
  • Slide 6
  • Mild: Core temp. 32 to 35C Moderate: Core temp. 28 to 32C Severe: Core temp. below 28C
  • Slide 7
  • Mild: 34 - amnesia and dysarthria begin 33 - ataxia and apathy develop Moderate: 32 - stupor 31 - shivering stops 30 - dysrhythmias, CO drops, insulin ineffective Severe: 28 - high risk for VF 27 - lose reflexes and voluntary movement 26 - major A/B disturbance Profound: 19 - flat EEG 18 - asystole
  • Slide 8
  • Pretend there is no history of exposurewhy else could this patient be hypothermic?
  • Slide 9
  • Differential Diagnosis Increased Heat Loss Decreased Heat Production Impaired Heat Regulation
  • Slide 10
  • What mechanisms contribute to heat loss in our patient?
  • Slide 11
  • Evaporation, radiation, conduction, convection.
  • Slide 12
  • How is the cold affecting this patient? At the body level? At the organ system level?
  • Slide 13
  • Slide 14
  • Increase HR Progressive bradycardia Ventricular Arrhythmias Asystole
  • Slide 15
  • Slide 16
  • Slide 17
  • Slide 18
  • Slide 19
  • Slide 20
  • The J Wave
  • Slide 21
  • Cold diuresis Reduced renal flow
  • Slide 22
  • Progressive depression perfusion maintained until 25 degrees 19 degrees flat EEG
  • Slide 23
  • Initial stimulation Progressive decrease CO2 retention and Acidosis
  • Slide 24
  • Case continued.
  • Slide 25
  • What is the most accurate method of measuring his temperature?
  • Slide 26
  • 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
  • Slide 27
  • Chemstrip Electrolytes Creatinine, BUN Hg, WBC, Plt Lactate EKG ABG Other: CK, fibrinogen, INR, cortisol, thyroid Blood Work
  • Slide 28
  • 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
  • Slide 29
  • How can you rewarm him?
  • Slide 30
  • 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
  • Slide 31
  • Active External Rewarming Applying heat to the skin: Warm blankets Bear Hugger Immersion warming Brokeback Hug?
  • Slide 32
  • Active Internal Rewarming Peritoneal dialysis Bladder, gastric, or colonic lavage Heated intravenous fluids Heated humidified oxygen Thoracic cavity lavage Extracorporeal blood rewarming Hemodialysis
  • Slide 33
  • 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
  • Slide 34
  • Inhaled warmed O2 Use warmed air at 45 degrees celcius Up to 2 degrees/hr*
  • Slide 35
  • Peritoneal Lavage Use Arrow peritoneal lavage kit Up to 3 degrees C/hour
  • Slide 36
  • GI and bladder rewarming 1.5-2.0 degrees/hour
  • Slide 37
  • Thoracic Cavity Lavage Up to 6 or 7 degrees/hour reported
  • Slide 38
  • Cardiac Bypass Need to consult CV surgery Up to 2 degrees/5 mins
  • Slide 39
  • Hemodialysis Up to 4.5 degrees/hour
  • Slide 40
  • Comparison of Rewarming Rates
  • Slide 41
  • Case Continued
  • Slide 42
  • Why has this patient become more hypothermic despite your warming measures?
  • Slide 43
  • Approach to rewarming Mild Hypothermia Passive External Rewarming +/- Active External Rewarming
  • Slide 44
  • Approach to rewarming Moderate Hypothermia Active External Rewarming Active Internal Rewarming
  • Slide 45
  • 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
  • Slide 46
  • 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
  • Slide 47
  • Cold and Dead? Patients with severe accidental hypothermia and cardiac arrest may benefit from resuscitation even in cases of prolonged downtime and prolonged cpr
  • Slide 48
  • The Obvious: -Decapitation -Non-compressible chest -Ice in mouth and nose -DNR order The Unreliable: -rigor or livor mortis -fixed pupils -tissue deterioration
  • Slide 49
  • 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 10, pH 250mmol/L
  • Slide 50
  • Slide 51
  • Frostbite
  • Slide 52
  • Case: In minor ER 63 M
  • Slide 53
  • Pernio Local, inflammatory, bluish-red lesions Caused by prolonged vasoconstriction Gentle drying and massaging.
  • Slide 54
  • Immersion Injury (Trench Foot)
  • Slide 55
  • Cold Injury Non-Freezing Pernio Immersion Injury Cold Urticaria Freezing Frostnip Frostbite
  • Slide 56
  • Frostnip Reversible and superficial No tissue loss Pale and discomfort and tingling
  • Slide 57
  • 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.
  • Slide 58
  • Slide 59
  • Frostbite
  • Slide 60
  • Classification
  • Slide 61
  • Treatment Remove wet clothing Rapid rewarming with warm water (40 degrees) Analgesia!! NSAIDs? Td
  • Slide 62
  • Treatment Thawing: 40 degrees Until part feels soft, erythema present Usually requires 10-30 minutes Active motion by patient
  • Slide 63
  • Treatment Post-thaw: Elevate Sterile, bulky dressing Aloe Vera? Blisters? TPA? Heparin? Abx? Hyperbaric O2?, Pentoxifylline?
  • Slide 64
  • Treatment Surgery? Admission?
  • Slide 65
  • Summary 1)Spectrum of freezing and non-freezing injuries 2)Treat by rapid rewarming 3)Aloe, ibuprofen, and Td (others are controversial)
  • Slide 66