Royal College: Emergency Medicine > Environmental > Flashcards

Environmental Flashcards

This deck covers Chapters 131-138 in Rosens, comprising all of environmental medicine. (58 cards)

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1
Q

What is Henry’s Law?

A

Henry’s Law

  • ep = ekc
  • Henry’s hovers

The amount of gas in solution is proportional to the pressure of the gas above the solution

Relevant in:

  • DCS I/II
  • Coca cola!
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2
Q

What are heat cramps? Name 4 professions at risk for this.

A

Cramps of most worked muscles after exertion

Copious sweating during exertion, then hypotonic replacement

Treat with salt solutions (Gatorade, IV NS)

At-risk professions:

  • Athletes
  • Roofers
  • Steelworkers
  • Coal miners
  • Field workers
  • Boiler operators
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3
Q

List 5 indications for active rewarming.

A
  1. Cardiovascular instability
  2. Moderate hypothermia
  3. Failure of passive rewarming
  4. Endocrinologic insufficiency
  5. Trauma/Toxicologic vasodilation
  6. Secondary hypothermia impairing thermoregulation
    * This is when illness sets a lower set temperature
    * Opposite of fever, when higher set point set
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4
Q

List 10 factors that predispose you to HYPOTHERMIA.

A

Decreased Heat Production

  • Endocrine (DM, Hypothyroidism, Hypoglycemia)
  • Inactivity
  • Extremes of age (limited muscle to shiver)

Increased Heat Loss

  • Environmental exposure
  • Skin damage
  • Ethanol (vasodilation)
  • Iatrogenic (active cooling vs no blankets)

Impaired Thermogenesis

  • Toxins (TCAs, SSRIs, Antipsychotics)
  • CNS lesions
  • Spinal cord injury
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5
Q

What changes are made in ACLS with hypothermic arrest?

A
  • Pulse checks last 30 seconds
  • Max 3 shocks until >30 degrees
  • Avoid medications until >30 degrees
  • Some give Epi x3 max
  • Actively rewarm patient
  • Continue CPR/Rewarming until 32 degrees
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6
Q

What is Dalton’s Law?

A

Dalton’s Law

  • Ptotal = P1 + P2 + P3 + P…
  • Dalton’s divides

The pressure in a mixture of gases is equal to the partial pressure of the proportion of gases in the mixture

Relevant in:

  • Altitude medicine
  • O2/N2 toxicity
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7
Q

List 10 risk factors for heat illness.

A

Increased Heat Production

  • Exercise
  • Sympathomimetics
  • Fever
  • Delirium
  • Hyperthyroidism

Decreased Heat Loss

  • Drugs
  • Skin disease
  • Occlusive clothing

Impaired Heat Sensing

  • Hypothalamus injury
  • Atherosclerosis
  • Diabetes
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8
Q

List tissues in the order of increasing resistance to electric current:

A
  • Nerves
  • Blood
  • Mucous membranes
  • Muscle
  • Dry skin
  • Tendon
  • Fat
  • Bone
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9
Q

What is Charle’s Law?

A

Charles’s Law

  • V1/T1 = V2/T2
  • Charles is Colder

At constant pressure, as volume increases, temperature increases.

Relevant in:

  • Altitude medicine
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10
Q

How does High Altitude Pulmonary Edema (HAPE) present? Treated? Prevented?

A

High Altitude Pulmonary Edema

Symptoms

  • SOB at rest, cyanosis
  • Cough, Rales
  • Tachypnea, Tachycardia

Treatment

  • Mild - bed rest
  • Moderate - oxygen
  • Severe - descent/HBOT + Nifedipine 30mg q12h
  • Consider sildenafil/tadalafil if can’t leave
  • Consider Dex/Acetazolamide

Prevention

  • Gradual ascent (500 m/day)
  • Nifedipine 30 mg q12h
  • Acetazolamide (Not evidence-based)
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11
Q

List two effects of temperature on ABG results.

A

Sample warmed before analyzed in lab

Warming causes increased partial pressure of gases (Charles)

  1. Higher O2 than patient
  2. Higher CO2 than patient
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12
Q

What is malignant hyperthermia? How do you treat it?

A

Ryanodine receptor mutation

  • Autosomal dominant
  • Causes an uncontrolled increase in skeletal muscle metabolism
  • Hypercatabolic
  • Hyperthermic
  • Tachypneic
  • Tachycardia
  • Rigidity
  • Rhabdo
  • HyperK
  • Acidosis

Treatment

  • Dantrolene 2.5 mg/kg
  • 100% oxygen
  • Cool
  • Treat rhabdo, hyperK, acidosis
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13
Q

Define:

  • Frostnip
  • Frostbite
  • Trench foot/Immersion Foot
  • Chilblains
A
  • Frostnip
  • Superficial cooling injury without tissue loss
  • Frostbite
  • Cold injury with tissue loss
  • Trench foot/Immersion Foot
  • Cold injury from near freezing in wet environment
  • Chilblains
  • Cold injury from chronic dry cold
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14
Q

What are 6 factors that determine electrical burn severity?

A
  • Type of Circuit (AC/DC)
  • Duration
  • Resistance of tissue
  • Voltage
  • Amperage
  • Pathway
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15
Q

How much water do you need to aspirate to interfere with surfactant integrity?

How much water do you need to aspirate to cause intravascular abnormalities?

A
  • Surfactant = 1-3 mL/kg
  • Vascular = 11 mL/kg
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16
Q

How does the body physiologically adapt to altitude?

A
  1. Hypoxic ventilatory response
    * Medullar chemoreceptors sense lower PaO2 and stimulate hyperventilation. Resp alkalosis causes bicarb diuresis.
    * Takes 1 week
  2. Cardiovascular
    * Increased CO/HR/SVR
  3. Hematologic
    * Increased EPO causes more RBC mass
  4. Increased 2,3-DPG
    * Causes rightward shift in oxygenation curve
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17
Q

List 8 indications for prolonged telemetry in electrical injury.

A
  1. Cardiac arrest
  2. ECG changes
  3. Arrhythmia
  4. LoC
  5. Chest pain
  6. Hx cardiac disease
  7. Cardiac risk factors
  8. Hypoxia
  9. Severe injuries
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18
Q

What is Pascal’s Law?

A

Pascal’s Law

  • Delta P = pg(delta H)
  • Pascal’s pushes (equally)

A pressure applied to any part of a liquid is transmitted equally throughout. Think tube of toothpaste.

Relevant in:

  • Inner/Middle ear barotrauma
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19
Q

List 5 poor prognostic factors in drowning victims.

A
  1. Hypoxia
  2. Age <3
  3. Submersion >5 min
  4. GCS 3
  5. Unreactive pupils
  6. Asystole
  7. Ongoing CPR
  8. CPR delay >10 min after rescue
  9. Severe acidosis
  10. Hypothermia
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20
Q

What is Joule’s Law?

A

Joule’s Law: P = VI

  • P = Power (Watts)
  • V = Potential (Volts)
  • I = Current (Amps)
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21
Q

List 10 factors that predispose you to frostbite.

A

Physiologic

  • Acclimatization
  • Dehydration
  • Over-exertion
  • Trauma
  • Skin diseases
  • Hypoxia
  • Diaphoresis

Mechanical

  • Wet clothing
  • Immobility
  • Inadequate insulation

Psychological

  • Mental status
  • Fear
  • Attitude
  • Fatigue
  • Peer pressure
  • Hunger
  • Drugs/Alcohol

Environmental

  • Temperature
  • Humidity
  • Wind Chill
  • Duration of contact
  • Altitude

Cardiovascular

  • Hypotension
  • Raynaud’s
  • Anemia
  • Sickle Cell
  • Diabetes
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22
Q

List 4 diving disorders requiring HBOT.

A
  1. DCS I
  2. DCS II
  3. AGE
  4. CO poisoning
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23
Q

List 5 mechanisms of heat loss.

A
  1. Convection
  2. Conduction
  3. Radiation
  4. Evaporation
  5. Respiration
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24
Q

Name 5 indications to terminate resuscitation in hypothermic arrests.

Study These Flashcards
A
  1. DNR
  2. Obvious death (other injuries, decapitated, etc.)
  3. Conditions unsafe (EMS)
  4. Temp >32 degrees + Asystole
  5. Avalanche burial >35 min
  6. K >12 mmol/L
25
What is the most effective method of cooling in the **ED**?
Tepid water fanning (Evaporative) Ice water immersion
26
What is the earliest indicator of **significant radiation exposure** following whole-body radiation?
Vomiting within 1 hr Lymphocytes \<500 at 48h
27
List 5 mechanisms for **lightning strike injury**.
* Ground current (50%) * Side flash (30%) * Upward streamer (10%) * Direct strike (5%) * Contact injury (5%) * Blunt injury (unknown)
28
Outline the **freezing injury cascade**.
**Pre-freeze Phase** * Loss of sensation * Increased blood viscosity **Freeze-Thaw Phase** * Intracellular dehydration * Extracellular ice crystal formation **Vascular Stasis and Progressive Ischemia** * Microvascular thrombosis * Tissue ischemia
29
**Differentiate** DCS from AGE.
**DCS** * Dependent on the dive profile * Progressive onset * Spinal symptoms * Limb weakness * Paresthesias * Urinary retention * Headache **AGE** * Independent of dive profile * Caused by rapid ascent * Rapid onset * Cerebral symptoms * Headache * LOC * Seizures * Cardiac arrhythmia/arrest
30
# Define: * Drowning * Submersion Victim * Immersion syndrome
**Drowning** * Respiratory impairment from submersion in liquid **Submersion Victim** * Submersion distress requiring transport to hospital **Immersion Syndrome** * Cardiac syncope after contact with water \>5 degrees colder than you
31
What are the 2 types of **heat exhaustion**? How do you diagnose these? Treatment?
**Types** * Water depletion (dehydration/hypovolemia) * Salt depletion (hypotonic replacement of sweat) **Diagnosis** * NORMAL ALERTNESS (otherwise heatstroke) * Fatigue, headache * Tachycardia/Hypotension * Rule out other illness (sepsis, etc.) **Treatment** * Rest, cool, IVF
32
What is the pathophysiology of **DCS**?
* Nitrogen bubbles form in blood during ascent * Bubbles cause an inflammatory response * Bubbles cause obstruction leading to ischemia/hypoxia * Nitrogen is very fat-soluble = CNS vulnerable (myelin)
33
What is the minimum observation time for **submersion victims**? List 4 discharge criteria that must be met.
6 hours 1. Normal SpO2 2. Normal CXR 3. Normal ABG 4. No symptoms
34
Outline a rewarming protocol to use in the ED for **frostbite**.
**Pre-thaw** * Assess pulses * Avoid friction massage * Stabilize core temperature * Rehydrate **Thaw** * IV Ketorolac/Opiates PRN * Advil 600 mg q6h * Immerse in 37-39 degree water, gentle circles **Post-Thaw** * Dry and elevate * Aspirate clear vesicles * Leave hemorrhagic vesicles * Consider tPA/Td/ABx
35
# Compare and Contrast: DCS I and DCS II
**DCS I** * MSK/Skin/Lymphatics involved * Periarticular pain in UE/LE (diagnostic if gone with BP cuff) * Cutis marmorata (patchy cyanotic marbling of skin) * Extremity edema from lymphatic obstruction **DCS II** * Any organ system involved * Any of the above plus: * Spinal Cord * Patchy motor/sensory deficits * Brain * H/A, diplopia, inappropriate behavior * Inner Ear * Vertigo, Nystagmus, N/V * Lung * SOB, CP, cough
36
List 4 types of **radiation** and their degree of penetration.
1. Alpha particles - Epidermis 2. Beta particles - 8 mm 3. Gamma rays - deep 4. Neutrons - deep
37
How does **High Altitude Cerebral Edema** (HACE) present? Treated? Prevented?
**High Altitude Cerebral Edema** **Symptoms** * Severe H/A, **Ataxia**, N/V, Seizures, **Altered LOC** **Treatment** * Immediate descent * Dexamethasone * HBOT * Oxygen * ICP management **Prevention** * Gradual ascent (500m/day) * Acetazolamide
38
**Differentiate** the following: * Middle ear barotrauma * Inner ear barotrauma * Alternobaric vertigo
**Middle ear barotrauma** * Ear pain during DESCENT * Slight transient vertigo * Hearing loss (CONDUCTIVE) * Unilateral facial paralysis **Inner ear barotrauma** * Ear pain during DESCENT * Vertigo/Nausea * Hearing loss (NEURAL) * Nystagmus, Ataxia, Romberg + **Alternobaric vertigo** * Ear pain during ASCENT * Nausea * TM injury with transient hearing loss * Nystagmus
39
What is **'let go' current** for men/women/children? What current causes respiratory arrest from diaphragm tetany?
**Let Go** * 9 mA = Men * 7 mA = Women * 4 mA = Children **Respiratory Arrest** * 20-50 mA
40
When do most cases of **AGE** become symptomatic?
Within 10 minutes of surfacing
41
What are three options for the internal decontamination of **radioactive poisoning**?
1. **Chelating** * DTPA, Prussian blue, D-Penicillamine 2. **Blocking** * Potassium iodide 3. **Bronchopulmonary lavage** * For inhaled exposures
42
List 6 risk factors for **drowning**.
1. Age 2. Male 3. Black 4. Alcohol 5. Time (Weekends/Summer/Daytime) 6. Seizure disorder 7. Long QT 8. Autism
43
List 5 types of **electrical burn**.
1. Direct contact 2. Indirect contact 3. Electrothermal heating 4. Arc (most destructive) 5. Flame 6. Flash
44
Compare exertional and classic **heat stroke**.
**Exertional** * Usually younger, healthier people who exercised * Diaphoresis * Sicker * Rhabdo, DIC, AKI, Lactic acidosis **Classic** * Older, sedentary, comorbid * Anhidrosis * Mild coagulopathy, CK, oliguria, mild acidosis
45
What are the recommendations for **flying after diving**?
* \<2h diving = wait 12 hours * Multiple day/Unlimited diving = wait 24 hours * Patients post-HBOT = wait 72 hours
46
List the signs/symptoms of mild/moderate/severe/profound **hypothermia**.
**Mild (32-35 degrees)** * Shivering * Ataxia **Moderate (28-32 degrees)** * Less shivering * Stupor * Bradycardia/Hypotension * Atrial fibrillation **Severe (20-28 degrees)** * VF * Acidemia * Severe hypotension/bradycardia * No motor response or reflexes **Profound (\<20 degrees)** * Flat EEG * Asystole * ~14 degrees is lowest survival
47
**Differentiate** active vs passive rewarming.
**Passive rewarming -** providing insulation and changing the ambient temperature of the environment to preserve and encourage heat generation. * Eg. blankets, increasing ambient temperature **Active rewarming** - adding heat directly to the patient to increase the temperature of tissues. * Eg. warmed oxygen, warm IVF, warm lavage, HD, ECMO
48
List 4 **chronic conditions** which are contraindicated to climb to altitude.
1. CHF 2. COPD 3. Pulmonary HTN 4. Sickle cell
49
What is **heat stroke**?
* Exposure to heat stress * Severe CNS dysfunction * Temp usually \>40 degrees * LFTs markedly elevated
50
Give a DDx of three things depending on **diving illness**: * On Descent? * At Depth? * On Ascent?
**On Descent** * Middle ear barotrauma * Inner ear barotrauma * External ear barotrauma * Facial barotrauma * Sinus barotrauma **At Depth** * Nitrogen narcosis * Oxygen toxicity * CO poisoning * Hypothermia **On Ascent** * DCS I * DCS II * AGE (Arterial gas embolism) * ABV (Alternobaric vertigo) * GI barotrauma * Barodentalgia * Pneumothorax * Pneumomediastinum * Pulmonary hemorrhage
51
List 6 **risk factors** for DCS and 3 for AGE.
**DCS** * Fatigue * Dehydration * Fever * Hypothermia * Obesity * Strenuous exercise **Obese** people **Exercise**, which makes them **fatigued**, **dehydrated**, and **febrile**. * Dive profile * Diving at altitude * Flying after diving * PFO * Smoking * Alcohol **AGE** * COPD (less lung surface to absorb bubbles) * Emphysema * Mucus plugging * PFO
52
What is **Boyle's Law**?
**Boyle's Law** * P1V1 = P2V2 * Boyles get Bigger (under pressure) At a constant temperature, as volume increases pressure decreases **Relevant in:** * Scuba diving * Air transport
53
How does **Acute Mountain Sickness** (AMS) present? Treated? Prevented?
**Acute Mountain Sickness** **Symptoms** * Headache, nausea, fatigue, insomnia * HACE if cerebellar symptoms * HAPE if SOB at rest **Treatment** * Stop ascending * Acetazolamide for moderate cases * Dexamethasone for severe cases * Symptomatic control for headache **Prevention** * Gradual ascent (500m/day) * Avoid alcohol/smoking * High carb diet
54
Name 3 **extracorporeal rewarming methods**.
1. **Venovenous circuit** * No oxygenation support * 2-3 degrees/hour 2. **Hemodialysis** * Stabilizes electrolyte/toxicologic issues * 2-3 degrees/hour 3. **Continuous AV rewarming circuit** * Femoral catheters * No perfusionist needed * 3-4 degrees/hour 4. **Cardiopulmonary bypass (ECMO)** * Full Circulatory/Oxygenation support * Requires anticoagulation/perfusionist * 9-10 degrees/hour
55
List 5 treatment priorities in managing **heat stroke**.
1. ABCs, MOVID 2. Rapid cooling 3. Fluids 4. Benzos to stop shivering 5. Urine alkalinization for rhabdo 6. Avoid shocks until myocardium cooled, if possible
56
List 10 sequelae of **frostbite**.
**Pain** 1. Phantom pain 2. Chronic pain **Sensation** 1. Hypesthesia 2. Dysesthesia 3. Paresthesia 4. Anesthesia 5. Cold intolerance 6. Heat intolerance **Autonomic Dysfunction** 1. Raynaud's syndrome 2. Hyperhidrosis **MSK** 1. Atrophy 2. Rhabdomyolysis 3. Compartment syndrome 4. Stricture 5. Necrosis 6. Amputation **Dermatologic** 1. Edema 2. Lymphedema 3. Chronic ulcers 4. Cancer 5. Hair/Nail deformities **Miscellaneous** 1. Core temperature after drop 2. ATN 3. Electrolyte abnormalities 4. Gangrene 5. Sepsis
57
Define mild, moderate, severe, and profound **hypothermia**.
* Mild = 32-35 degrees * Moderate = 28 -32 degrees * Severe = 20-28 degrees * Profound = \<20 degrees
58
What is the **General Gas Law**?
**General Gas Law** P1V1/T1 = P2V2/T2 Combination of Boyle's and Charle's Law
Royal College: Emergency Medicine
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