PA - Environmental Emergencies Guest Lecture - CM, 11/18
How is frostbite graded?
1 - Normal/absence of cyanosis 2 - frost nip - cyanosis on distal phalanges 3 - superficial frostbite - cyanosis up to MP 4 - deep frostbite - cyanosis proximal to MP joint
What describes the incidence of near drowning?
3 age related peaks - Toddlers (<5), adolescent-young adults (15-25y/o), elderly (bathtubs) Assoc. w/ trauma and MC in warm, freshwater More cold water survivors
How is heat stroke tx?
ABCs Cardiac monitoring + IV line established Immediate cooling measures Continuous monitoring of core temp High flow O2 IV fluids (NS/LR) Avoid shivering w/ benzodiazepines ICU for monitoring
How is hypothermia managed?
ABCs Rewarming - O2 and IV fluids should be warmed (passive=removal of wet/cold clothing, active external = heated blankets/packs, active core = warmed fluids/O2, etc) Heart/lung/renal labs
What are s/sx of near drowning?
Abdominal distension Bluish skin of face/lips Chest pain Cold skin + pale appearance Confusion Cough w/ pink, frothy sputum Irritability Lethargy No breathing Restlessness Shallow/gagging respirations Unconsciousness Vomiting
How are early stages of miliaria rubra tx?
Antihistamines / chlorhexidine cream
How is the profunda stage of miliaria rubra tx?
Antistaphylococcal abx + 1% salicylic acid
What defines wet drowning?
Aspiration of fluid/foreign material E.g. Pt has inhaled water which interferes w/ respiration + causes circulatory system to collapse
What are non-freezing cold injuries?
Chilblains + trench foot
What characterizes hyperthermia?
Core body temp >96.8-99.5F (above normal) Neonates/elderly, rigorous athletes, and military recruits most at risk Entirely preventable
What characterizes heat exhaustion?
Core body temp elevation to febrile state d/t heat exposure w/ inadequate water/salt intake No significant CNS dysfunction
What characterises hypothermia?
Core body temperature <35C/95F Dec. respiratory drive (depressed cough + reflex) Dilated pupils + slowed reflexes Cold diuresis d/t impaired renal fxn (significant volume loss) Osborn J waves on ECG PR, QRS, and QT prolongation
What defines drowning?
Death as a result of suffocation after submersion in water
What are s/sx of heat stroke?
Dizziness Weakness Confusion Emotional lability Blurry vision Convulsions Delirium Collapse
How is heat edema tx?
Elevation of extremities, finding a cooler environment
How should temperature always be measured in emergent cases?
Esophageal, rectal, or bladder probe
What describes mild hypothermia?
Excitatory phase occurring around 32-35C (89.6-95F)
What defines first degree frost bite?
Frost nip Partial skin freezing Erythema Mild edema Lack of blisters Complaints of burning + stinging followed by throbbing
What defines 2nd degree frost bite?
Full-thickness skin freezing Edema Clear blisters developing w/in 24 hrs (may form eschar, but sloughs off) Complaints of numbness followed by aching + throbbing
What is radiation?
Heat loss from body to surrounding atmosphere
What is conduction?
Heat loss through direct contact w/ solid surface
What is evaporation?
Heat loss through drying of moisture on skin
What is convection?
Heat loss through local air currenst
What are heat-related injuries?
Heat stroke Heat syncope Heat exhaustion Heat cramps
What electrolyte imbalances can occur in freshwater near drowning?
Hemolysis + hyponatremia
What electrolyte imbalances can occur in salt water near drowning?
Hypernatremia + hyperkalemia
What are cold related injuries?
Hypothermia Frostbite Chilblains Trench foot
What characterizes chilblains (pernio)?
Inflammatory skin changes caused by chronic intermittent exposure to cold, damp environments w/o actual freezing of tissue Red/purple papular lesions that are painful/pruritic w/ mild edema + crusting MC in young people in cold climates (esp. young + middle aged women)
What characterizes frostbite?
Injury from tissue freezing _ formation of ice crystals in tissue followed by reperfusion of frozen tissues resulting in progressive microvascular thrombosis + tissue damage Occurs MC below -20C (-4F) Wind exposure inc. risk, MC involving distal extremities, nose, and ears
What is the MCC of fever presenting in pediatric Pts at the ER?
Insufficient antipyretics
What defines 3rd degree frost bite?
Involves deeper subdermal plexus Hemorrhagic blisters Necrosis of skin + underlying tissue Blue-gray discoloration + mottling "block of wood" sensation Burning/throbbing/shooting pains
What defines 4th degree frost bite?
Involves subq, muscle, tendon, and bone Little edema of injured area Mottle skin w/ non-blanching cyanosis Mummification Deep aching joint pain
Which blisters are preferential in frostbite?
Large, clear blebs that extend to the tips of digits
What defines dry drowninng?
Laryngospasm/airway obstruction which causes hypoxemia + CNS insult E.g. Airway closes up d/t spasms caused by presence of water
What characterizes heat stroke?
Life threatening medical emergency CNS dysfunction w/ core body temperature >40C(104F) Classic + exertional forms
What characterizes heat syncope?
Light-headedness, pale/sweaty skin, weak pulse, mildly elevated core temp caused by volume depletion, peripheral vasodilation, and dec. vasomotor tone
What characterizes near drowning?
Mental status ranges from normal-comatose Hypothermia w/ cold water/prolonged submersion Noncardiogenic pulmonary edema Rales/wheezing/rhonchi in lung fields
What are lab findings of near drowning?
Metabolic acidosis common Electrolyte abnormalities CXR normal or w/ pulmonary edema/infiltrates
What characterizes heat rash?
Miliaria rubra Maculopapular eruption located over clothed areas of the body (prickly heat) Red + itchy in early stages Whitish papular + vesicular rash in blockage of pores (profunda stage)
Who is at inc. risk for cold injuries?
Military personnel Outdoor workers Homeless
Which blisters have the worst prognosis in frostbite?
Mottled, violaceous, or hemorrhagic proximal blisters
What is important to understand regarding dysrhythmias and hypothermia?
Often revert spontaneously w/ rewarming
What is important to understand regarding chilblain recurrence?
Once a body part has been affected, it is more susceptible to reinjury
What characterizes trench foot?
Outdoorsmen, military, homeless at greater risk Caused by prolonged immersion in cool/cold water + mud Pale, mottled anesthetic, pulseless appearing foot
What characterizes heat cramps?
Painful muscle spasms occurring MC during exercise Common during athletic events w/ hx vigorous activity immediately preceding Heavy sweating Core body temp normal/slightly elevated
How is near drowning tx?
Prehospital care ED care Submersion event algorithm Prevention - learn to swim, proper monitoring, avoid dangerous waters, etc
What occurs when body temp falls below 30C-32C (86-89.6F)?
Progressive slow down of bodily functions + cessation of shivering
By what processes does heat exchange from the body to the environment?
Radiation Evaporation Conduction Convection
How is frostbite tx?
Rapid rewarming - thaw until flush appears (20-30min) Pain Rx required Tetanus immunization booster Bed rest w/ affected parts elevated + uncovered at room temp AVOID DRY HEAT - does not affect deep tissues Prophylactic abx Protect skin blebs from physical contact (clear blisters may be aspirated) Amputation consideration only after tissue determined necrotic
How is heat exhaustion tx?
Rest Evaporative cooling IV/oral rehydration
How are heat cramps tx?
Rest Oral electrolyte solution Massaging involved muscle
How is heat syncope tx?
Resting in cool place IV/oral rehydration
How is trench foot tx?
Rewarming Air drying Elevation of foot Prevention (properly fitting footwear + changing socks)
How is chilblains tx?
Rewarming + protective clothing 1st line Nifedipine 20mg TID Avoid cold climates
What characterizes heat edema?
Self-limited condition of mild swelling of dependent extremities occurring in first few days of exposure to new hot environment Normal core body temp
What defines near drowning?
Survival, at least temporarily, after suffocation in water
What are lab findings of heat stroke?
Tachycardia Elevated body temp AMS Ataxia Hyperventilation Elevated BP --> hypotension Elevated BUN Dec. glucose/sodium Elevated CK Clotting abnormalities Leukocytosis
What Rx are indicated for hypothermia management?
Thiamine 100mg IV/IM (suspicion of ETOH) Glucose 50-100mL IV D50W if low Hydrocortisone + IV thyroxine if suspect adrenal insufficiency/hypothyroidism
How does dysrhythmia occur in hypothermia?
Upon reaching body temp <30C, sinus bradycardia progresses to afib w/ a slow ventricular response on to v fib and asystole
What is important to remember regarding submersion victims?
Victims are not dead until "warm + dead"