Environmental Emergencies Lecture Powerpoint

Question 1

Conduction requires ___ while convection is dependent on ___

Answer 1

physical contact, wind velocity air and water vapor molecules moving around the body

Question 2

Thermoregulation mechanism of action

Answer 2

• increased body temp
• thermostat in hypothalamus activated by temp receptors
• skin blood vessels dilate so warm blood allows heat to radiate from the skin surface
• sweat glands activated increasing evaporative cooling
• when body temp decreases
• thermostat in hypothalamus activated by temp receptors
• skeletal muscle activated to begin shivering to generate heat
• skin blood vessels constrict diverting blood from skin to deeper tissues reducing heat loss from skin surface
• body temp increases

Question 3

Hyperthermia definition

Answer 3

Elevated core body temp of 38.5C or 101.3F

Question 4

Who is at risk for heat illness? (5)

Answer 4

• athletes exercising strenuously in heat
• elderly patients
• infants and children (high ratio of surface area to weight and inability to control fluid intake)
• B blockers or anticholinergics use
• dehydration due to loss

Question 5

Acclimatization definition

Answer 5

Beneficial physiological adaptations that occur during repeated exposure to the hot environment including increased sweaeting efficiency, stabilization of the circulation, ability to perform work with lower core temp and heart rate, etc.

Question 6

Heat rash (prickly heat) definition and treatment

Answer 6

Skin irritation due to blocked sweat ducts trapping sweat beneath the skin, typically found on the neck, chest, groin, in skin folds, might be papular, pustular, or vesicular, may sting or be pruritic but typically self limiting and not a problem, can be prevented by wearing loose fitting clothing, avoiding extreme heat, etc

Question 7

Heat cramps definition and treatment

Answer 7

Painful muscle cramps/spasms during or after intense exercise and sweating caused by hyponatremia and volume depletion, treated with prolonged stretching and oral sodium replacement

Question 8

Heat edema definition and treatment

Answer 8

Dependent edema from vasodilatory pooling, too much sodium can aggravate fluid retention, greater risk in rapid transiton from cold to warm climate, treatment is NOT diuretics but rather just elevate extremities and put in a cool environment

Question 9

Heat exhaustion signs and symptoms (4)

Answer 9

• early identification critical to prevent progression to heat stroke
• fatigue/malaise/weakness
• N/V/D
• in tact mental status

Question 10

Heat exhaustion lab studies (3)

Answer 10

• LFT’s (CMP)
• electrolytes (CMP)
• eval for rhabdomyolisis

Question 11

Heat exhaustion treatment options (3)

Answer 11

• move to cool area, ice packs, remove excess clothing, spray with lukewarm water, trendelenberg, etc
• gradual rehydration oral and or IV
• monitor for progression to heat stroke (patients should respond if all they have is indeed heat exhaustion)

Question 12

2 types of heat stroke

Answer 12

• exertional (young people who engage with prolonged strenuous physical activity more rapid onset)
• classic nonexertional (elderly or disabled with gradual environmental exposure)

Question 13

Heat stroke signs and symptoms (4)

Answer 13

• Elevated core temp >40.5C
• Hot dry skin
• CNS symptoms and lack of intact mental status
• NVD

Question 14

Heat stroke complications (2)

Answer 14

• high core body temp leads to multisystem damage (DIC, hepatocellular necrosis, acute kidney injury)
• cerebral hypoperfusion leads to mental status changes and can cause cereberal ischemia

Question 15

Heat stroke diagnostic studies (5)

Answer 15

• CT of head to rule out edema
• CXR
• CBC, CMP, PT/PTT
• EKG
• urinalysis (rhabdo concerns)

Question 16

Heat stroke treatment options (5)

Answer 16

• Rapid cooling measures within 30 min
• ice water immersion most effective
• antipyretics ineffective and may be harmful
• IV hydration
• admit to hospital

Question 17

2 types of cold injuries

Answer 17

• Freezing (frostbite)

- nonfreezing (chilbain or trench foot)

Question 18

Frostnip definition and treatment

Answer 18

Mildest form of peripheral cold injury, superficial nonfreezing cold injury secondary to vasoconstriction, sees pale skin with associated numbness and paresthesias but skin is still pliable***, occurs in the apical structures (ears, nose, hands, feet), treated by simple warming techniques

Question 19

Chilblains (pernio) definition and treatment

Answer 19

More severe than frostnip caused by exposure to nonfreezing temps and damp air, onset 1-5 hours of cold exposures but can be longer, develops over hours and subsides slowly over weeks, develop red to violet raised lesions (papules and nodules) most often on unprotected extremities such as fingers and toes, seen most often in middle aged women or those with chronic conditions such as raynauds, treated with local heat, gentle massage, nifedipine, corticosteroids, minimize cold exposure to prevent recurrent lesions or secondary infection

Question 20

Immersion (trench) foot definition and treatment

Answer 20

Occurs when feet are wet but not freezing for prolonged periods of time, most common in homeless and military starting with numbness and tingling pain with pruritis progressing to leg cramps and complete numbness, managed with gentle rewarming, careful washing and air drying, slight limb elevation, possible bed rest, prevented by keeping feet dry at least 8 hours a day

Question 21

Frostbite definition and its 4 degrees of severity

Answer 21

Skin and deeper structure freeze resulting in tissue injuries, water crystals disrupt cell membranes and tissue structures resulting in ischemia and death of cells, has 4 degrees of severity (hyperemia and edema, accompanied by blisters, has hemorrhagic fluid in the blisters, and comprete necrosis with gangrene)

Question 22

Frostbite management (4)

Answer 22

• do NOT start if still risk of re-freezing as this has worse outcomes
• restore core body temp first
• RAPID rewarming in a water bath until extremity has flushed appearance, once rewarming started, avoid weight bearing, very painful process
• tetanus prophylaxis

Question 23

Frostbite complications (4)

Answer 23

• compartment syndrome
• limb/digits amputaitons
• digital shortening if growth plate injured in children
• susceptible to reinjury

Question 24

Hypothermia definition

Answer 24

Body’s mech for temp regulation is overwhelmed in face of cold stressor, core temp <95 F or 35C, classified as accidental (unanticipated exposure in unprepared person), intentional (therapeutic post cardiac arrest), primary (environmental exposure) or secodnary (underlying medical issue)

Question 25

Hunter’s response

Answer 25

Paradoxical and cyclical vasodilation following initial vasoconstriction that occurs in response to cold often the fingers, toes, and face

Question 26

Hypothermia signs and symptoms (7)

Answer 26

• altered mental status, mood changes
• shivering
• flushing
• tachycardia then bradycardia
• facial edema
• hypotension
• paradoxical undressing

Question 27

Hypothermia diagnostic criteria

Answer 27

-Core body temp (rectal) may need special low temp thermometer!!!! Mild 32-35C, moderate 28-32C, severe <28C (see v-fib)

Question 28

“They’re not dead till they’re warm and dead” meaning

Answer 28

Refers to how it is required to warm body before declaring death as hypothermia can often present with v-fib, dilated pupils, lack of responsiveness, etc

Question 29

Hypothermia management (4)

Answer 29

• passive external rewarming
• minimally invasive active rewarming (IV fluids warmed)
• invasive active rewarming (bladder lavage, thoracic lavage)
• ECMO

Question 30

Contraindications to resuscitation of hypothermia

Answer 30

• cardiac arrest prior to cooling

- patient