Lecture 7: Environmental Emergencies (Elkins) Flashcards
What is heat illness?
Inabiity to regulate body temperature adequately
What characterizes Heat Edema & how do you tx?
- Mild swelling of extremities
- Tx: Self-limiting, just rest, ice, elevate, drink water
Cutaneous and muscular vasodilation redistributes intravascular volume to the periphery of the body. Volume loss and prolonged standing (pooling in the lower extremities) also contribute to the development of inadequate central venous return and insufficient cerebral perfusion.
What is heat syncope and what is the clinical presentation?
- Heart syncope is syncope after exerting yourself in the heat.
- NORMAL CORE TEMP
- Skin will be cool, sweaty; weak pulse, transient hypotension
2 pathophysiologic processes:
vasodilation of the skin and muscles redistributes intravascular volume to the periphery of the body
volume depletion in addition to prolonged standing leads to inadequate cardiac return and cerebral perfusion
How do you manage heat syncope?
- R/o other possible causes
- Lie supine, elevate legs, cool externally and rehydrate IV/PO
Get them out of the heat and rehydrate.
What are heat cramps and the clinical presentation?
- Painful muscle spasms of abd + ext due to salt depletion
- NORMAL or SLIGHTLY ELEVATED CORE TEMP
- +/- muscle fasciculations
- Skin can be anything (dry or moist, cool or warm)
What would you see on labs for heat cramps if you decided to order them?
Rarely indicated.
- Low to normal Na
- Low to normal K
- Low to normal Mg
Just a little lyte depletion
I think of bananas for cramps, so cramps = electrolyte issue
Management of heat cramps?
- Remove from heat, externally cool
- Oral electrolytes (pedialyte/gatorade) or IV NS
- Replace K and Mg PRN
Discharge home and rest for 1-3 days.
What characterizes Heat Exhaustion?
Inability to maintain adequate CO
Will lead to heat stroke if no intervention!
Running on Empty, no output
What are the two underlying types of heat exhaustion?
- Hypernatremic (Primary water loss): LACK OF WATER
- Hyponatremic (Primary salt loss): Only getting free water instead of water + lytes
How does heat exhaustion present clinically?
- Mild core temp elevation up to 104F
- Diaphoresis, HA, N/V, malaise, weakness
- Cramps, dizziness, +/- dark urine
- Tachy, hypotensive
- NO EVIDENCE OF CNS DYSFUNCTION (Key distinguishing from heat stroke)
What is a key feature of the clinical presentation that suggests heat exhaustion over heat stroke?
No evidence of CNS dysfunction
What UA finding suggests subclinical rhabdomyolysis?
- UA showing blood
- Microscopy showing little to no RBCs
If a patient presents with suspected heat exhaustion, what will your workup include?
- BMP
- UA
- CK
- LFTs
- ABG
- EKG
Rhabdo + lyte abnormalities
What are the management steps for heat exhaustion?
- Remove from heat
- Externally cool
- PO lytes if they can
- If not, IV NS or LR.
- If primarily marked hyponatremic due to water intoxication, use hypertonic NS
When would you admit for heat exhaustion?
- Mod-severe
- Cormorbid illnesses
- Old af or young af
- Lab abnormalities
- Social concerns
What is the underlying mechanism that characterizes heat stroke?
Dysfunction of heat regulation, leading to hyperthermia & end-organ damage
What tissues and cells are MOST SENSITIVE to heat stress?
- Neural tissue (Brain)
- Hepatocytes (Liver)
- Nephrons (Kidney)
- Vascular endothelium (blood vessels)
Brain, liver, kidney, blood
Define hyperthermia
Core body temp > 104F or 40C
What are the two types of heat stroke?
- Exertional (rapid)
- Non-exertional (slow)
What are the primary S/S that suggest heat stroke over anything else?
- Confusion
- Seizure
- Delirium
- Ataxia
- Coma
Neuro!
What life-threatening condition can heat stroke cause?
DIC
What would you order in a workup for heat stroke?
- CBC, PT/PTT (DIC)
- CMP
- Phosphate (hypo occurs due to renal dysfunction)
- UA
- CK
- EKG
- CXR
UA findings include protein, myoglobin, and tubular casts.
UA can be concentrated with protein due to kidney leakage.
What is the first step in managing heat stroke?
RAPID COOLING
- Ice water submersion (preferred)
- Disrobe/spray water + fan blowing
- Cooling blanket with ice packs over great vessels
If a patient is shivering severely in heat stroke, what can you give them?
IV BZD
What is the preferred temperature monitoring technique for heat stroke?
Rectal until its down to 102F
If Rapid cooling & IV BZDs all fail for heat stroke, what is your last resort?
Internal lavage
What is ideal Urine Output in Heat stroke?
50-100 mL/h
Adjust IV fluids PRN to reach this.
Bolus 1-2L if hypotensive or rhabdo
When would you ventilate/intubate in heat stroke?
Significant AMS
When do you admit to ICU for heat stroke?
- Hemodynamic instability
- Severe LFTs
- Rhabdo
Everyone else to med-surg
Heat stroke always requires admit then?
What are the unfavorable prognostic signs for heat stroke?
- Extreme hyperpyrexia (> 42C/107.6F)
- Persistent coma after cooling
- Markedly elevated LFTs
- Hyperkalemia + extensive rhabdo
How does mild frostbite present prior to re-warming?
- Paresthesias
- Pruiritis of tissue involved
- Loss of sensation and fine motor control
How does mod-severe frostbite present prior to re-warming?
- Decreased ROM
- Blister formation
- Edema
- Tissue appears white
- Firm/hard
- Cool to touch
How does frostbite present once you have rewarmed them?
- Stinging/burning/aching/throbbing/tender
- Tissue discoloration + loss of elasticity and mobility
- Profound edema, hemorrhagic blisters, necrosis, gangrene
Describe the 4 degrees of frostbite.
- Erythema & edema, no blister, skin peeling
- serous blister
- Necrosis, hemorrhagic blister, SQ involvement
- Full-thickness down to bone, dry, black, mummified eschar, ded
What are the 2 things to remember when treating frostbite initially?
- Treat systemic hypothermia first
- If you’re gunna rewarm, you gotta do it completely!
How do you rewarm frostbite?
Rapid rewarming in circulating water at 98.6F-102.2F
Can give NSAIDs cause it might hurt
15-60 minutes, until skin turns red-purple and pliable. Air dry.
After you rewarm some frostbitten fingers, what is next for wound care?
- Keep sterile
- Topical aloe vera Q6h
- Debridge in whirlpool if dead tissue
- Splinting to prevent contracture
- Elevate extremity to lessen edema
- Update tetanus
Aloe vera helps with collagen recomposition.
When can you send frostbite home?
Only with a limited 1st degree injury.
Everything else needs admit
Define hypothermia
Core body temp < 35C/95F
Rectal, bladder, or esophageal thermometer
What usually causes primary hypothermia?
Out in the cold after drugs/alcohol use
Who is most at risk for impaired shivering?
- Age extremities
- Malnutrition
- Physical exhaustion
- Neuromuscular dz
How do cardiac arrhythmias progress in hypothermia?
- Bradycardia
- Afib with slow response
- VF
- Asystole
Usually around HT 3, which is < 28C
What are the 4 levels of hypothermia?
- Mild 32-35C
- Moderate 28-32C
- Severe < 28C
- Pretty much dead < 24C (no vitals left)
First step in managing hypothermia 1 & 2
Warm em up
How is HT 1 managed?
- Warm em up
- Active movement
- Warm oral sugary drinks
How do we manage HT 2?
- Full rewarming via blankets
- Warmed IV fluids
How do we manage HT 3?
- Airway management
- Rewarming can treat rhythms besides VF
- Defibrillate once prior to rewarming if in VF
What is the ideal rewarming method for HT 3?
ECMO
How do we treat HT 4?
Cardiac arrest protocol (CPR, airway)
What is the coma cocktail for HT 4?
- Dextrose 50 mL
- Thiamine 100 mg
- Naloxone 2g
3 harmless things
How would you treat hypothyroidism in HT 4?
- Levothyroxine 400 mcg
- Hydrocortisone 100 mg
Double hydrocortisone for hypoadrenalism.
What criteria must be met to NOT admit someone for hypothermia?
- No comorbidities
- No AMS
- Core temp must be > 34C
What is the MC type of sting reaction?
Localized reaction from a bee string
- Small, pruiritic, painful, erythematous, edematous lesion due to venom.
- Sometimes > 5 cm
How do fire ant stings present?
- Sterile pustule over 6-24h
- Can cause necrosis or scarring
How many stings usually are needed for a more systemic/toxic reaction?
> 50 stings
How does a systemic/toxic reaction present?
Wasp, bees, ants
- N/V/D with urticarial lesions distant from sting site
- Only lasts around 48h
How quickly does anaphylaxis occur?
Usually 15 mins, but can take up to 6 hours
When do you do lab evals for stings?
Systemic or anaphylactic rxn (but save their life first)
What 5 drugs are used for anaphylaxis?
- Epi 1:1000 (0.5mg max in kiddos)
- IV methylprednisolone 2mg/kg
- IV Diphenhydramine 1mg/kg
- IV Famotidine 0.5mg/kg
- Nebulized albuterol (bronchospasms)
For a systemic sting reaction, what drugs are most appropriate?
- Methylprednisolone
- Diphenhydramine
- Famotidine
Aka don’t use epi
How do you remove a stinger?
Scrape it
When do you admit for systemic sting reactions?
- Child
- Elder
- Comorbidities
- 50+ stings
- Prolonged rxn (guessing over 48h?)
How do you observe/discharge a healthy patient with a systemic sting reaction?
- 6 hours of obs with NO rebound symptoms
- Repeat labs before d/c
- Rx them an EpiPen
- F/u with an allergist
What is the only systemically toxic scorpion in the US and where is it found?
Bark scorpion in the Southwest
Most deadly to kiddos
How does a scorpion sting present?
- PAINFUL, but no initial erythema/swelling
- tap sign of light percussion causes immense pain
- Neuromuscular excitation
- CV toxicity
How do we manage a normal scorpion sting?
- Pain Meds
- BZDs for motor control
What is the antivenom for scorpion stings and what are the main SE?
Anascorp
- N/V
- Pyrexia
- Rash
- Pruiritis
What snakes are pit vipers?
- Rattlesnakes
- Copperheads
- Water moccasin
Triangle shaped head with heat sens depression pit between eyes
They have cytotoxic venom
Clinical hallmark of a pit viper bite
- Fang marks
- Pain
- Edema
- Hemorrhage
- Necrosis
30minutes to 12 hrs
After 12 hrs of no S/S = DRY bite
What do we do to a snake bite?
- Immobilize bitten extremity (no constriction bands proximal)
- Serial wound eval Q30mins
- Mark area to monitor edema
When do we give CroFab?
Pit viper bites in which the envenomation will be worse than the SEs of the antivenom.
What are the risks and SEs of CroFab?
- Urticaria, rash, nasuea, pruiritis, back pain
- HSR occurs in 5-19% of pts
- Recurrent coagulopathy still occurred in 50%
Who gets ICU admit for snake bites?
- Severe
- Used CroFab
Generally, when you do see high altitude sickness? (altitude)
> 1500 m or 4800 ft
Pretty much a mile
How does the body adjust for hypoxia?
- Increased RR
- Increased Bicarb excretion
- Increased sympathetics
- Increased oxygen carrying capacity
How does acute mountain sickness present?
Hangover within 48h of rapid ascent.
How do you tx acute mountain sickness?
- Stop ascending
- Descend if no improvement (300-1000m)
- Low-flow O2
- Tylenol for HA, Zofran for N/V
What would suggest a moderate presentation of acute mountain sickness and what can we do for it?
- No improvement in 36 hrs after ceasing ascent.
- Hyperbaric O2
- Acetazolamide + Dexamethasone
Acetazolamide is also a prophylaxis for acute mountain sickness.
1 day prior to ascent, 2 days after reaching max altitude.
What characterizes High Altitude Pulmonary Edema?
Extension of untreated acute mountain sickness
- MCC of death, can be fatal in hours.
- Hypoxic vasoconstriction
- Elevated right heart pressures
- Noncardiogenic Pulmonary Edema
How does High Altitude Pulmonary Edema present?
- 2-4 days after ascent
- Decreased exercise capacity is initial symptom
- 2 of the following must be present:
Dyspnea at rest, cough, rales, tachypnea, weakness, decreased performance, chest tightness, tachycardia, signs of pulmonary HTN
How do you manage HAPE?
- Immediate descent is #1 tx
- Supplemental O2 > 90%
- Hyperbaric O2
- PDE5 inhibitors or nifedipine to vasodilate (The least preferred options)
Sildenafil, tadafil, nifedipine, which can also be used prophylactically
Discharge criteria for HAPE (3)
- > 90% O2 on RA
- Symptom resolution
- Improved CXR
What characterizes high altitude cerebral edema?
End-stage of AMS or HAPE.
How does HACE usually begin?
A history consistent with AMS, but S/S of increased ICP.
MRI will show cerebral edema
Management of HACE
- Supplemental O2 > 90%
- Immediate descent vs hyperbaric O2
- Dexamethasone 8mg, then 4mg Q6h
- Admit anyone symptomatic for >2h after descent.
Why is aspirating water bad
Washes out your surfactant causing V/Q mismatch
How does near drowning present?
- Pulmonary injury
- ARDS
- Water aspiration
- Multiorgan failure if prolonged hypoxia
- Hypothermia (EVEN IF WATER WAS WARM)
< GCS 13 = do more stuff
MCC of fire-related death
Smoke inhalation
What are the 3 ways inhaling can injure you?
- Thermal (it is hot af and burns you)
- Particulate matter (bronchospasm and edema)
- Toxic gases (CO or hydrogen cyanide)
Management of inhalation injuries
- Humidified 100% O2 via mask
- ET intubation
- Bronchodilators
- Pulmonary toilet
What is pulmonary toilet?
- Suctioning
- Chest physiotherapy
- Nasotracheal suction
- Bronchoscopy
- Incentive spirometry
- Use of analgesics
- Prone positioning
How does CO poisoning present?
- FLS
- Ha
- Dizziness
- Vision changes
- Confusion
- Multiple ppl from the same residence will have the exact same presentation
CO has much higher affinity for Hgb than O2.
How do you evaluate CO poisoning?
- CO-oximetry (cannot use pulse ox)
- Carboxyhemoglobin elevation
- ABGs
Management of CO poisoning
- High flow O2
- Hyperbaric O2 if severe
Severe: LOC, AMS, MI, Focal neuro deficit, or preggo.
DO NOT WAIT FOR CONFIRMATION
When can you d/c someone home with CO poisoning? (asymptomatic vs moderate vs severe)
- Asymptomatic: Safe home + was not a SI
- Mod (HA/N/V): Obs for 4 hrs with 100% O2
- Severe: Admit and consult with hyperbaric specialist
What is the rule of 9s for burns?
- Head 9%
- Front torso 18%
- Back torso 18%
- Arms 9%
- Groin 1%
- Legs 18%
Primarily used for 2nd and 3rd degree burns
How do we grade burns?
Depth
- Superficial partial
- Deep partial
- Full thickness
What are the alternative methods to Rule of 9s for burns?
- Lung and browder (infants and children)
- Palmar (dorsal palm is 1%, use for small burns)
How do we manage burns?
- Vitals and monitor airway
- Opiates for pain
- Urinary cath for I&Os (0.5-1mL/kg/hr)
- IV LR via 2 IVs via parkland formula
What is the Parkland formula?
Must know!
- LR 4 mL x wt in kg x % BSA burned over initial 24h.
- Give 1st half over 8h from onset.
- Give 2nd half over 16h.
- Example: 4 mL * 70kg * 40% burn = 11,200 mL over 24h.
If child, use 3 mL instead.
For minor burns, how do we manage them wound care wise?
- Mild soap & water
- Drain/debride bullae > 2cm or over joints & give silvadene
- See PCP after
How do we manage mod-severe burns?
- Moderate: Sterile sheets + admit
- Severe: Send to burn center
How do acid burns on skin present?
- Coagulation necrosis leading to eschar formation that limits the extent of damage
- Partial-thickness with erythema & erosion.
Only exception is hydrofluoric acid, which penerates deeply!!!!!!!!
How does an alkali burn on the skin present?
- Liquefaction necrosis
- Deeper damage
- Full-thickness, pale
- Leathery and slippery
aLkali Liquefies
How do we manage chemical burns?
- Remove clothes
- Tap water
- Elemental metals require mineral oil to prevent exothermic burns
- Poison control
- The usual
Metals: Na, Lithium, Ca, Mg
What are the two types of electrical injuries and MC demographic?
- High voltage: adults & > 1000V (powerlines)
- Low voltage: kids & < 1000V (house)
What are the 3 ways electricity causes injury?
- Direct damage (cardiac)
- Thermal damage (burns + rhabdo)
- Mechanical damage (fall or tetanic muscle contraction)
Management of an electrical injury
- Airway
- EKG
- Treat as blunt force trauma
- IVF with ideal UO of 2 ml/kg/h
- Treat everything as usual
When can you discharge an electrical injury?
- Low voltage
- Asymptomatic
- Normal PE
- Normal EKG
Must meet everything
Whats the usual danger with stuff like tasers and stun guns?
- Pain
- Muscle contraction
- Incapacitated
Just manage like blunt trauma or ingestion
What is the MCC of death when it comes to lightning injury?
Cardiac arrest
What is the pathognomic sign of a lightning injury?
Feathering or fern-shaped burns
What is dysbarism?
Complications associated with changes in ambient pressure or breathing compressed gases
Barotrauma
Decompression sickness
What characterizes middle ear barotrauma due to descent?
Rupture/bleeding of TM
What characterizes inner ear barotrauma due to descent?
- Rupture of round or oval window
- Tinnitus
- SN hearing loss
- Vertigo
What characterizes sinus ostia occulsion due to descent?
Bleeding from sinus cavity
What are the various presentations of barotrauma due to ascent?
- Lung overinflation
- Pneumomediastinum
- SQ emphysema
- Pneumothorax
- Cerebral arterial gas embolism
What causes decompression sickness?
Release of nitrogen gas bubbles from plasma during ascent
Classic situation of decompression sickness
Scuba diver who then goes on a flight
Describe each type of decompression sickness
- Minor: deep aching pain in elbows and shoulders
- Cardio/Neuro: Spinal cord embolism in scuba diving, cerebral gas embolism in flights, fatigue, ataxia, spinal paralysis, etc
Management of Barotraumas
- Middle ear: Decongestants/analgesics, refer for TM rupture
- Inner ear: Rest with head upright, refer
- Pneumothorax: needle decompression
Management of decompression sickness
- 100% O2 via mask for 2h
- Crystalloids IV
- Hyperbaric O2 for recompression
