1. Eric Anderson, MD MBA FACEP
Director of Clinical Operations
Cleveland Clinic Emergency Department

2. Learning Objectives Identify cold temperature injuries of extremities
Identify hypothermic syndromes as body temperature decreases
Apply rewarming techniques for extremities and for hypothermia
Discuss principles and therapy in therapeutic hypothermia

3. Cold Induced Injuries Non-Freezing Tissue Injury
Chilblains
Immersion foot (Trench foot)
Tissue Freezing Injury
Frostbite
Hypothermia

4. Chilblains
Usually in pts with an underlying vasculitis after repeated exposure to dry above freezing cold temps
Erythema, edema, pruritus, burning sensation
Rarely ulcerations, bullae
Hands, feet, pretibial areas
Sx occur hrs after cold exposure

5. Chilblains

6. Chilblains

7. Immersion Foot

8. Immersion foot (trench foot)
Typically results from constant exposure of skin to moisture, worse with cold and wet.
Often seen in homeless who wear wet shoes and socks for days or weeks at a time.
Numbness, pain
Foot is cool and erythematous and edematous
Distinction between immersion foot and post thaw phase of frostbite may be difficult so detailed Hx is essential.

9. Immersion foot

10. CHART 2-FUNGAL DISEASE FOOT AND BOOT AREA

11. Trench foot time to disability-military

12. Diagram of Normal Skin

13. Slide of Normal Skin

14. Histopathologic findings in Immersion Foot

16. Frostbite Freezing of tissue Similar classification as burns
First degree
Second degree
Third degree
Fourth degree

17. Frostbite Classification
Severity
symptoms
First degree partial thickness
Stinging, burning
Possible throbbing and aching
Possible hyperhidrosis Violaceous/hemorrhagic blisters
Skin necrosis, blue gray skin
Second Degree: Full thickness
Erythema, edema
Blisters may desquamate and form blackened eschar,
numbness
Third Degree: Involves s.q. tissue
Initially insensate: later burning, throbbing shooting pain, aching
Violaceous/hemorrhagic blisters

18. Frostbite Classification (2)
Severity
Symptoms
Fourth Degree: Involves muscle, tendon and bone.
Little edema
Skin Initially mottled, deep red or cyanotic
Later (weeks to months) dry, black, mummified
Possible joint discomfort.

19. First Degree (Frostnip)
Mildest form
Numbness, pain, pallor, paresthesias
Mild edema may develop
No blister development
Typically Affects - fingers, nose, toes
Usually resolves in 30 min
Prognosis is excellent for full recovery

20. Second Degree Frostbite
Involves freezing of the full thickness of skin (epidermis and dermis)
Substantial Edema develops 3-4 hrs after rewarming
Clear Blisters develop 6-24 hrs after rewarming may extend to fingertips days later may desquamate and form hard black eschars
Pt co numbness, aching, throbbing
Prognosis is good

21. Frostbite

22. Third Degree Frostbite
Freezing of skin and s.q. tissues
Pt says feels like a block of wood
Rewarming throbbing then shooting pain
Hemorrhagic blisters and skin necrosis later develop
Blue-grey skin discoloration
Prognosis is often poor

23. Frostbite Bullae

24. Fourth Degree Frostbite
Freezing of skin, muscle, tendon, bone
Min, edema forms after rewarming
Skin - mottled, non-blanching, cyanosis
Later forms black mummified eschar
Vesicles if they form are late, small, hemorrhagic do not extend to fingertips
Pt may complain of deep achy joint pain
Prognosis extremely poor

25. Frostbite

26. Difficulties in Classifying Frostbite
Difficult early in clinical course
Often requiring several days to more accurately classify – blister, edema development
Many simply classify as superficial or deep initially
Hx helps - duration of exposure, temp, wind, precipitation, clothing, ETOH, drugs, med illnesses

27. Frostbite Evolution

28. Frostbite

29. Factors Increasing Risk of Frostbite
Environmental
Temperature
Wind
Wetness
Clothing, gloves, vs. mittens
Contact with cold objects or volatile liquids
Duration of exposure to cold
Altitude, Hypoxia

30. Factors Increasing Risk of Frostbite
Age, race, underlying medical conditions, gender
Behavioral- mental status, ETOH, Drugs, etc
Cold acclimatization
Dehydration
Smoking
Use of protective ointments
Prolonged stationary posture, Constrictive clothing (tight boots)
Inappropriate or wet clothing

31. Factors Increasing Risk of Frostbite
Health related / Physiologic
Reynaud phenomenon
Cold induced vasodilation reactivity
Peripheral vascular disease or neuropathy
Diabetes
Vasoconstrictive drugs
Previous cold injury
Psychiatric disorder or altered mental status

32. Body parts affected by Frostbite
Head 33-39%
Hands 20-28%
Feet 15-25%
Civilian studies report head > extremities
Military studies report extremities > head

33. Frostbite Treatment in the Field
Avoid refreezing
Elevate affected Limb
Transfer to ED – scoop and run, will not save limb on site.
In remote rural site: initiate Rx for and check for hypothermia

34. Frostbite Treatment - ED
Place in ext in warm circulating water 40-42C ( F)
Apply topical Aloe Vera cream q 6 h
No blister or soft tissue debridement acutely
Local care
Tetanus immunization
Analgesia
Ibuprofen in divided doses
Abx Rx controversial - topical Bacitracin is as good as IV Penicillin

35. Frostbite treatment long term
Surgical interventions
Tissue debridement vs. amputation
Allow weeks to months for viable vs. non-viable tissue to become clinically evident.
“Frostbite in January, Amputate in June.”

36. Prevention of Frostbite
Avoidance of exposure in very cold weather
Avoidance of ETOH or Drugs when you must be outside
Layered clothes
Mittens are warmer than cloves
Keep hands and feet DRY
Get to warmth or avoid further cooling if possible

37. Prevention of Frostbite (2)
Good fitting (NOT tight) boots - insulated
Layered socks
Keep Feet and boots DRY
Avoid Freeze – Thaw – Freeze
If frostbite leave frozen until definitively thawed.
Keep well hydrated
Situational awareness of what is around you and how things can go wrong and how to fix it

38. Hypothermia Normal Human temp 98.6 F (37 C)
Hypothermia <95 F (35 C)
Medically induced 93 F (33C)
Mild F (32-35 C) Excitation stage (responsive)
Moderate (28-32 C) Slowing stage (adynamic)
Severe <86 F (28 C) Shivering stops

39. Mechanisms of Heat Loss
Radiation – loss of heat to cooler environment, 60% of normal heat loss
Conduction – direct contact with a cool object, 10-15% of normal heat loss
Convection – cool air/water currents
Evaporation – liquid (usually sweat or water) evaporates from skin (0.58 kcal/ml)
Respiration – cool air exchange in lungs

41. Mechanisms of Thermal Homeostasis
Preoptic anterior hypothalamus
Immediate response via autonomic nervous system
release of norepinephrine to increase muscle tone, shivering, increase basal metabolic rate
Skin thermoreceptors cause direct vasoconstriction
Delayed control is mediated via the endocrine system
Prolonged cold stimulates the thyroid axis to increase basal metabolic rate.

42. Mechanisms of Thermal Homeostasis
Behavioral changes
Avoid cold
Seek heat source
Clothing
Hot food

43. Medical Conditions Predisposing to Hypothermia
Hypothyroidism
Adrenal insufficiency
Hypoglycemia
Hypothalamus lesions – stroke, bleed
Sepsis – a poor prognostic sign

44. Skin Conditions that Predispose to Hypothermia
Acute Extensive burns
Psoriasis
Erythrodermas
Any skin condition that causes uncontrolled vasodilation

45. Risk factors for Hypothermia
Age
Elderly
Neonates
Outdoor exposure
Occupational
Sports, recreational
Inadequate clothing
Temp
Wind
Precipitation
Drugs, intoxicants
ETOH
Barbiturates
Phenothiazines
Anesthetics
Neuromuscular blockers

46. Risk Factors for Hypothermia
Neurologic
Stroke
Hypothalamic disorders
Parkinson's Dz
Spinal cord injury
Immobility
Multisystem
Malnutrition
Sepsis
Shock
Hepatic or Renal failure
Endocrine
Hypothyroid
Adrenal insufficiency
Hypoglycemia

47. Physiologic changes associated with Hypothermia
Mild 32-35C ( F)
Mod 28-32C
( F)
Severe <28C, (<82.4F)
C-V
Tachy, elev BP, incr CO, incr SVR
Brady, conduction delay,
Osborne waves,Decr CO, incr SVR
Brady, decr BP, AV block, vent, atrial dysrhy, Asystole, Paradox vasodilation, decreased CO
Respir
Tachypnea, decr Min vent, bronchospasm
Hypovent, respir acidosis, risk of aspiration
Hypovent, apnea, ARDS, pul edema
Resp acidosis
Neuro
Confused, amnesia, apathy, shivering, ataxia, incoordination
Decr LOC, decr shivering, joint rigidity, sluggish pupils, decr reflex
Unresponsive,
Fixed pupils, no neuro sx of life

49. J waves on the ECG

50. Normal ECG Pattern

51. Normal ECG Pattern

52. J waves on the ECG

53. Situational Awareness

54. Get the History of exposure
How long
Wet or Dry
Clothes
Environmental temps, wind, exposed exts
ETOH, illicit drugs
Trauma, submersion
Therapeutic drugs - insulin

55. Field Treatment of Hypothermia
Remove from cold
Gentle handling of pt
Warm on the way into shelter if possible
Passive rewarming – dry blankets, cover head
Passive external rewarming warm blankets, warm air, electric blankets, Bair Hugger
Active simple core rewarming – warm po fluids, warm IVF, warm humidified O2

58. ED Treatment of Hypothermia
Confirm hypothermia
Gentle handling
Rewarming
Asses for complicating trauma, medical, tox, condition
Asses for complications of hypothermia
Asses for prior medical conditions

59. Methods of rewarming
Passive – dry blankets, cover head, pt heat up by himself
Active external –
Warmed (electric) blankets C/hr
warm forced air C/hr
radiant heat
place pt in warm water fastest heat transfer 2-4C/hr

60. Bair Hugger

61. Methods of rewarming (2)
Active simple core rewarming C/hr
Warmed IVF
Warmed po fluids
Heated humidified O2

62. Rewarming device RES-Q-AIR model Ht-1000

63. Methods of rewarming (3)
Active Invasive Core rewarming
Body cavity lavage
stomach, bladder, colon
Peritoneum, Hemithorax
Open mediastinal Irrigation
Extracorporeal circulation
Hemodialysis
A-V rewarming
Cardiopulmonary bypass

64. Complications of rewarming

65. Complications of rewarming
Do not use lactated ringers – cold liver cannot metabolize lactate
Most cardiovascular meds for resuscitation are less effective or ineffective in severe hypothermia
Do not use sq or IM admin of meds – absorption is erratic due to vasoconstriction
Must use appropriate low reading thermometers

67. Disposition
Healthy pts with mild hypothermia may be D/C if social situation allows
Pts with mod & severe hypothermia admit
Transfer if hospital is not capable of managing a hypothermic pt
Always handle these pts gently
NOT DEAD UNTIL WARM AND DEAD IS DEBATED BY ACTUAL PRACTITIONERS

68. Therapeutic Hypothermia cooling methods EMCools Cooling Blanket

69. Therapeutic Hypothermia
Cooling post arrest pts to 32-34C ( F)
May have added benefit when added to PCI
Decreased cellular metabolism, decreased accumulation of toxic metabolites
Not indicated for conscious pts with spont return of circulation
Not indicated for Arrest >25 min

70. Results of Hypothermic treatment

71. Indications for Therapeutic Hypothermia
American Heart Association (AHA)
European Resuscitation Council (ERC)
Mild therapeutic hypothermia for unconscious adult with Return of Spontaneous Circulation (RSC) after out of hospital ventricular fibrillation arrest.
Comatose pt who are going to be paralyzed with secure airway

72. Indications for Therapeutic Hypothermia
AHA
Therapeutic Hypothermia may be beneficial for non-ventricular fibrillation arrest and for in-hospital arrest.

73. Literature on Post-arrest Hypothermia
In favor
Mortality reduced from 78% to 50% (Gaieski)
Increase survival with good Neuro outcome from 34 to 53%(Holzer)
PCI following arrest, cooling improved survival (Knafelj,Schefold)
Against
Non-ventricular fib arrest pts has poor outcome and cooling did significantly change outcome (Oddo)
Non-ventricular fib arrest had a poorer outcome with cooling (Kim)
Gaieskin et al. Resuscitation 2009;80(4), Holzer et al Stroke 2006;37(7),
Knafeli et al Resuscitation 2007;74(2), Schefold et al Int J Cardiol 2009;132(3)
Oddo et al. Crit Care Med 2008;36(8), Kim et al Circulation 2007;115

74. Generally accepted principals of Therapeutic Hypothermia
The longer the time before RSC the worse the prognosis (thus pts in non v. fib arrest do so poorly)
After min outcomes are poor (Oddo)
< 25 min 66% survival
> 25 min 3.1% survival
Start cooling as soon as possible after RSC
Cooling method is not as important as cooling
Oddo et al. Crit Care Med 2006;34(7)

75. Controversies in Therapeutic Hypothermia
Use in non-V. Fib arrest
Use in children and elderly
Use in pregnancy

76. Methods to induce cooling
Ice cold IVF - 30 cc/kg
Ice packs - neck, axilla, inguinal areas
Cooling blankets
Non-invasive cooling surface devices
Cool: bladder, gastric, colonic lavage
Endovascular cooling device
Wet clothing
Pharmacologic prevention of shivering

77. Therapeutic Hypothermia cooling methods Arctic Sun Temperature Management System by Medivance

78. Therapeutic Hypothermia cooling methods Criticool

79. Therapeutic Hypothermia cooling methods Coolguard 3000 device and Icy Catheter by Zoll Medical Corg

80. Timing of cooling methods
Endovascular cooling
Time to start 150 min
Median cooling rate 1.1C(2F)/hr
Provides more precise control, less overshoot of temp
More expertise, equipment and cost needed
Surface cooling
Time to start 75 min
Median cooling rate 1.1C(2F)/hr
Less control of degree of cooling, more chance for overshoot
Less expensive can be started on site by EMS

81. Complications of Therapeutic Hypothermia
Cardiac Dysrhythmia 6%
Hyperkalemia – not clinically important
Hyperglycemia – decreased insulin from cool pancreas
Infection – not statistically significant
Hemorrhage 3%
European Resuscitation Council, Hypothermia After Cardiac Arrest study Group.
Crit Car Med 2007;35(4)

82. Future EMS Applications
Need to develop SOPs for cooling post arrest pts
Initiate cooling in the field in resuscitated pts
Carry cooling equipment
Protocols with EDs for smooth transition of care
Transfer cooled pts to cardiac cath lab

83. Potential Benefits of Therapeutic Hypothermia
Therapeutic hypothermia increases the chance of good neuro outcome in v.fib arrest with RSC
Odds ratio of 1.4 for good neuro outcome (Arrich)
An additional 776 to 5171 pt/yr would survive with good neurologic outcome(Majersik)
ICU LOS shortened (Storm, Hay)
Majersik et al. Resuscitation 2008;77, Arrich J. Crit Care Med 2007;35(4)
Storm et al. Crit Care Med 2008:12(3). Hay et al. Anaesthesia 2008:63.

84. Present Realities of Therapeutic Hypothermia
Use by U.S. Physicians 23-26%
Use by U.S. EM physicians 16%
Huge potential for increased use
Great opportunity for growth in EMS

85. Therapeutic Hypothermia cooling methods EMCools Cooling Blanket

86. Eric Anderson, MD MBA FACEP
Director of Clinical Operations
Cleveland Clinic Emergency Department

87. Systemic Effects of Hypothermia

88. Cold Injuries Eric Anderson, MD MBA FACEP
Director of Clinical Operations
Emergency Department Cleveland Clinic