Environmental Flashcards

This deck covers Chapters 131-138 in Rosens, compromising all of environmental medicine.

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.

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/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 coagulatopathy, 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
Define 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. Hyperhydrosis **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