Environmental Flashcards

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1
Q
Water rescue
Submersion or immersion without evidence of respiratory impairment
Nonfatal drowning
Process of drowning interrupted
Fatal drowning
Death from drowning
All other terms should be avoided
A

Drowning Definitions

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2
Q
One of top two leading causes of accidental death in children
2/3 of deaths are age < 30
 Young children 
Inability to swim
Surveillance 
Fencing and locks
Pools, bathtubs
Curiosity, play
   Teens and adults
Seizures
Alcohol
Associated trauma
Inability to swim
Exhaustion
Scuba
A

Epidemiology of Drowning

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3
Q

Bradycardia, apnea
Shunting of blood to CNS
Decreased metabolism
Children > adults

A

Mammalian diving reflex (sudden cold water immersion)

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4
Q

Primary factor is duration of immersion
Also water temperature, age, associated trauma, associated dysbaric problems, bystander CPR, water contamination
If submerged < 60 minutes and no obvious physical signs of death – initiate CPR
Not all patients need admission
Good oxygenation, scattered rales
Can discharge
All others should be admitted

A

Drowning Survival Factors

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5
Q

The amount of gas dissolved in a liquid is proportional to the partial pressure of the gas in contact with the liquid

A

Henry’s Law:

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6
Q

Partial pressure of a gas increases with increasing pressure
Both above - Decompression Sickness and Nitrogen Narcosis

A

Dalton’s Law:

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7
Q

The volume of a gas varies inversely with the pressure

Squeeze Syndromes and Barotrauma

A

Boyle’s Law

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8
Q
Asthma
COPD
Seizures
Sinus and ear disease
Syncope
Panic disorder
Vertigo
Poor training
A

SCUBA DivingContraindications

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9
Q

Disorders of descent (Boyle’s Law)
Squeeze Syndromes
Barotitis Media: “Ear squeeze”
Pain from pressure on the TM, due to inability to equalize pressure (blocked Eustachian tube)
TM can rupture with severe vertigo, N&V
Treatment: Nasal decongestants, maneuvers to open Eustachian tube (Valsalva, et al.)
Other squeeze syndromes: Sinus squeeze, facemask squeeze, eye squeeze, suit squeeze, lung squeeze

A

Barotrauma from Diving

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10
Q

Due to blockage of external auditory canal by cerumen or ear plugs

A

External ear barotrauma

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11
Q

Hemorrhage or rupture of the inner ear round window with sensorineural hearing loss = labyrinthine window rupture
Severe vertigo, N/V, tinnitus, nystagmus, ataxia
Referral to ENT

A

Inner ear barotrauma

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12
Q

Rapid uncontrolled ascent (Boyle’s Law)
Dropped weight belt
BC malfunction
Panic and charge to the surface
Expansion of unvented lung gases on ascent results in a “burst lung”
Must exhale on ascent to “vent” the expanded gases
Clinical presentation
PTX, pneumomediastinum, pneumopericardium
Hemothorax from injured lung
Arterial gas embolism can occur (rarer)

A

Pulmonary Barotrauma Pulmonary Over Pressurization Syndrome

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13
Q

Pulmonary overpressurization causes alveolar gas to enter systemic circulation
Air emboli in coronary, cerebral and retinal arteries
Sudden and dramatic symptoms often with focal neuro findings
Presents on surfacing or within 10 minutes
Unlike decompression sickness, which occurs gradually
ALOC is the rule and seizures are common
Dive chamber “stat” for treatment

A

Arterial gas embolism or AGE (high morbidity and mortality)

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14
Q

A disorder at depth from breathing compressed air
High concentrations of nitrogen are neurotoxic
Symptoms
Euphoria
Confusion
Disorientation
Poor judgment – may result in drowning
Diminished motor control
Treatment is controlled ascent to decrease the amount of dissolved nitrogen in the brain

A

Nitrogen Narcosis

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15
Q

A disorder of ascent (gas comes out of solution)
At depth, increased amounts of nitrogen dissolve in blood and tissues
Ascending too quickly causes nitrogen bubbles to form in blood and tissues
Length and depth of dive are the primary determinants of risk
Obesity is a risk factor (nitrogen is lipid-soluble)
A spectrum of illnesses depending on location and severity
Two categories: I and II (II is more serious)
Treatment: Recompression in a chamber

A

Decompression Sickness

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16
Q

Affects musculoskeletal, skin, lymphatics
“The Bends” or “Caisson’s Disease”
Periarticular pain (especially elbows and shoulders) in 70% of all cases
Pruritus, erythema, skin marbling (“cutis marmorata”) from venous stasis
Intravascular nitrogen bubbles cause a wide variety of presentations

A

Type I Decompression Sickness

17
Q

Central nervous system decompression sickness
High CNS concentration of nitrogen
Prickly sensations in the limbs
Low back and abdominal pain
Spinal DCS: Limb paresthesias, weakness
Dermatome sensory distribution is common
Incontinence, priapism
Headache, diplopia, dysarthria, inappropriate behavior
LOC is rare
Differs from arterial air embolism where is is common
Symptoms develop gradually hours after surfacing (unlike arterial gas embolism)

A

Type II Decompression Sickness

18
Q

DCS of the lungs = “The chokes”
Decompression shock = Vasomotor DCS
DCS involving cerebellum or inner ear = “The staggers”
Symptoms the same as inner ear barotrauma
Cause: Gas bubbles in inner ear or cerebellum

All decompression syndromes develop slowly

A

Type II Decompression Sickness

19
Q

Occurs on ascent
Caused by unequal middle ear pressures
Transient vertigo, nausea

A

Alternobaric vertigo

20
Q

Air trapped in a dental cavity expands on ascent, causing tooth pain

A

Barodontalgia (squeeze and reverse squeeze)

21
Q

Serious problems are rare
Eructation, flatulence, bloating, abdominal cramps
Avoid carbonated beverages and gas-generating foods prior to diving

A

Gastrointestinal barotrauma

22
Q

Pulmonary over pressurization syndrome
Air embolism - sudden
Decompression illness - gradual

A

Disorders of diving ascent

23
Q
Squeeze syndromes
Nitrogen narcosis (at depth)
A

Disorders of diving descent

24
Q

Recompression is the definitive treatment for decompression sickness and arterial gas embolism
Have a low threshold for treatment of DCS
Delayed onset of symptoms is common
More subtle symptoms may develop after treatment of major symptoms
Minor symptoms may progress
May recompress up to 14 days after symptom onset

A

Recompression Therapy

25
Q

Commercial planes pressurized to 5,000-8,000’
May exacerbate all symptoms of decompression sickness
May result in new symptoms of decompression sickness for divers without any symptoms initially
Is why diving discouraged for 24 hours prior to flying
No flying for 3-7 days post-treatment of DCS-1
No flying for 1 month post-treatment of DCS-2

A

Diving Risks associated with flying

Commercial planes pressurized

26
Q

Type I: Pulse of pressure (barotrauma)
Type II: Flying debris (penetrating trauma)
Type III: Flying humans (deceleration impact)
Type IV: Toxic gases, radiation, burns

A

Blast Injury Classification

27
Q

Ear: TM rupture, ossicle disruption
Lung: Pneumothorax, air emboli
GI: Hollow viscus rupture
CNS: Concussion, air emboli

A

Top 4 organs

Type I blast injuries

28
Q

Pathophysiology of high altitude illness
Hypoxia-induced over perfusion and increased hydrostatic pressure with capillary leak
Increased sympathetic activity

A

High-Altitude Illness

29
Q
Manifestations
Acute Mountain Sickness (AMS)
High Altitude Cerebral Edema (HACE)
High Altitude Retinopathy (HAR)
High Altitude Pulmonary Edema (HAPE)
High Altitude Flatulent Expulsion (HAFE)

Factors influencing development
Rate of ascent and final altitude
Physiology, acclimation, hydration
Sleeping at altitude (ventilation decreases)

A

High-Altitude Illness

30
Q

Prior history of altitude illness
Residence at an altitude below 900 meters
Pre-existing cardiopulmonary conditions
R to L cardiac shunts (listen for a heart murmur) and intrapulmonary shunts
Pre-existing pulmonary hypertension / mitral stenosis
Exertion (physical fitness is not protective)
Women and age >50 have a lower incidence

A

High-Altitude Illness risk factors

31
Q

Common with rapid ascent to 8-10,000 feet
Headache, nausea, fatigue, insomnia +/- GI sx
Worse with drugs, alcohol, sedatives, and any respiratory depressant
Prophylaxis: Acetazolamide (carbonic anhydrase inhibitor)
Renal bicarbonate diuresis and metabolic acidosis
Increases respiratory drive
Increases oxygenation since less sleep-related hypoventilation
Avoid in sulfa allergy
Can cause paresthesias
Treatment: Steroids, oxygen, descent

A

Acute Mountain Sickness

32
Q

Responsible for most altitude-related deaths
Most commonly on the second night at altitude
Resting tachypnea and tachycardia
Most patients also have acute mountain sickness
Fever / rales / pink sputum
Normal heart size
Non-cardiogenic heart failure
Severe hypoxemia and respiratory alkalosis

A

High-altitude pulmonary edema (HAPE)

33
Q
Environmental causes
HAPE
Thermal injury
Drowning
Other causes
Toxins: ASA, phenobarbital, CO, opioids
Strangulation
Fat emboli, amniotic fluid emboli
A

Non-CardiogenicPulmonary Edema

34
Q

Improve oxygenation with supplemental oxygen
If rapid reversal does not occur (failure to increase oxygen saturation to above 90% within five minutes) descent is mandatory
Portable hyperbaric chamber is another option
Noninvasive ventilation may help
Nifedipine to treat pulmonary hypertension
Consider inhaled beta-adrenergics for wheezing
Dexamethasone and/or tadalafil MAY be helpful in HAPE (some recent debate exists here)

A

Treatment of HAPE