HOT / COLD/ ALTITUDE Flashcards

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1
Q

Exercise related causes of unwell athlete

A

Exertional Heat stroke
Exercise related Hyponatremia
Hypothermia

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2
Q

General Management of Unwell athlete

A
A - Airway
B - Breathing
C - Circulation and temperature
D - Disability (AVPU, PEARL, CGG)
E - Environment
F - Fluid status
G - Glucose and sodium
H - History, incl site of collapse
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3
Q

Exertional Heat Exhaustion

A

Inability to continue exercise
Can happen in all temperatures but more common in hot; dehydration, esp after running

Patho

  • Heat and dehydration => tachycardia, central fatigue and peripheral vasodilation
  • Peripheral vasodilation => hypotension, CV insufficiency + blood pooling
  • Blood pooling further worsens hypotension and reduces heat transfer to periphery

S&S
Sweaty, pale/ashen. Headache. Dizziness. N&V. Muscle fatigue. - reduced coordination and cramps, weakness

ABCDEFGH
B - Tachypnoea
C - Tachycardia, Postural hypotension
E - <40 degrees
F - normal or dry
H - likely collapse after cessation of exercise
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4
Q

How do you differentiate between EHE and EHS?

A

Core body temp

Mental function

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5
Q

Exertional Heat Stroke

A

Predisposing Factors
Strenuous exercise, hot-humid environment, poor acclimatization, poor physical fitness

Patho
Core temperature reaches >40 causing cellular membrane damage and disrupting the cellular energy systems. This causes cell and organ dysfunction and subsequently failure. Multiple system involved - brain, liver, kidneys, heart, muscle. GI

Tachycardia. May or may not be sweating. Altered mental state (confusion/disorientation → seizures → coma). Irrational behavior. Vomiting. Diarrhoea. Post episode do not recall last 35-45min.

ABCDEFGH
B - Tachypnoea
C - Hypotensive, tachycardic
D - Altered mental state
E - Rectal temp >40
F - Exercise induced hyponatremia => fluid retention, puffy
H - During event, can also occur after
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6
Q

EHS Treatment

A

MEDICAL EMERGENCY - ACTIVE COOLING ASAP

  • Remove excessive clothing
  • Ice baths and fans
  • Ice packs: 2 at neck, 2 under armpits, 2 on groin
  • PO fluids
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7
Q

Exercise Associated Muscle Cramps

A

Painful spasms of skeletal muscle
common after long, high intensity sports

Risk factors
Dehydration, large sweat Na loss, exercise induced muscle fatigue

Rx
Rest, stretching, oral Na-containing foods and fluids

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8
Q

Prevention of heat related problems

A

Good schedule of events, activity modification and appropriate clothing
Heat acclimatisation e.g. heat baths
Hydration and nutrition

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9
Q

Normothermia

A

35-39

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10
Q

Mild hypothermia

& physiological response

A

33-35

Maximal shivering
Dysarthria, amnesia, poor judgment

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11
Q

Moderate hypothermia

& physiological response

A

29-32

Shivering ceases
Stupor, arrhythmias, unconsciousness

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12
Q

Severe hypothermia

& physiological response

A

<29

VF
Loss of reflexes and voluntary motion, acid-base distur

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13
Q

Physiological responses to cold

A
  1. Peripheral vasoconstriction

2. Skeletal muscle contraction (voluntary modified behaviour)

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14
Q

Mechanisms of hypothermia

A

decreased heat production
increased heat loss
impaired thermoregulation

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15
Q

Aetiology of decreased heat production

A

Training
Inactivity, fatigue, energy depletion

Endocrine
Hypothyroidism, hypopituitarism, hypoglycaemia

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16
Q

Aetiology of increased heat loss

A

Training
Immersion, rain, wet clothing, wind, low body fat

Erythroderma
Burns, psoriasis, sunburn

17
Q

Aetiology of impaired thermoregulation

A

Peripheral failure
Spinal cord transection
Trauma
Neuropathies

Central failure
CNS lesion
Cerebrovascular Accident
Subarachnoidhaemorrhage
PD
Hypothalamic dysfunction
Drug and alcohol abuse
18
Q

Trenchfoot

A

Non-freezing injury - 0-15 degrees; prolonged exposure (12hr-4d)

Swollen, erythematous 
Red -> pale -> cyanotic
numbness
diminished peripheral pulses
pain and increased sensitivity
19
Q

Chillbains

A

Non-freezing injury - 0-15 degrees; short exposure (1-5hr

Superficial cold injury
Red, itchy, swollen papules on dorsum of fingers, ears and face
Painful, swollen, tender
Upon rewarming remain hot to touch, inflamed with burning and pain sensation lasting

20
Q

Frostbite

A

<0 degrees
wet skin more likely
common in exposed skin sites (nose, ears, hands, feet)

pain
numbness
wooden sensation
upon re-warming significant pain

21
Q

Cardiac Arrhythmias

A

Potentially fatal

ECG
Sinus bradycardia, J wave (repolarisation abnorm after QRS), prolonged PR interval

22
Q

Composition of the atmosphere

A

Troposphere
Stratosphere
Mesosphere

23
Q

Partial Pressure of O2

A

P of a gas is proportional to the concentration of the gas and barometric pressure
PO2 = PB x FiO2
Sea level PO2 = 101.3 kPA x 0.2095 = 21.1 kPA
Top of mount everest PO2 = 7.6 kPA

As you elevate abose sea level the atmospheric pressure decreases exponentially

24
Q

Acute Mountain Sickness

A
Recent gain in altitude >2500m
Secondary to hypoxia
Headache + at least one of:
- nausea, anorexia, vomiting
- dizziness 
- fatigue or weakness
- difficulty sleeping

No physical signs
onset within 6-12 hrs

Rx

  • stop and rest; do not ascend until sx resolve (1-2d)
  • analgesia +/- anti-emetics
  • if sx worsen
    • descend!!
    • acetazolamide 250mg BD
    • dexamethasone 4mg QDS
    • O2
25
Q

High Altitude Cerebral Edema

A

Vasogenic oedema due to hypoxia - leaky cerebral vessels

Disorientation, lethargy, nausea, confusion, LOC, ataxia, severe headaches

Rx
Descend
High flow oxygen
acetazolamide and dexamethasone

Not treatment = coma and death

26
Q

High Altitude Pulmonary Edema

A

Non cardiogenic pulmonary oedema secondary to hypoxia

Defined by the Lake Louise Consensus

  • At least two symptoms of
    • dyspnoea
    • cough
    • weakness or decreased exercises performance
    • chest tightness or congestion
  • At least 2 signs of
    • Tachypnoea
    • Tachycardia
    • Wheezing or crackles in at least one lung field
    • Central cyanosis

Rx

  • descend and O2
  • Dexamethasone
  • Nifedipine (given at lower altitudes)
27
Q

At what heigh should altitude training occur?

A

> 1500-2500m above sea level

28
Q

Why do altitude training?

A

VO2 max is reduced at 700m

Reduced PO2 causes physiological adaptations over days to weeks; consider individual varioations

29
Q

What is desirable effect and the physiological adaptations?

A

Sustained hypoxia causes increased EPO production and thus oxygen capacity of blood

  • Carotid bodies: sensitive to PaO2, PaCO2 and pH
    • Increase ventilation
    • Increase HR and CO
  • Hypoxia causes EPO production
    • Increased RBC production
30
Q

Methods of altitude training

A
Natural altitude: to see effect needs to stay in chamber for at least 16h/d
 - hypobaric hypoxia
 - normobaric hypoxia
 - normobaric hyperoxia
Live high, train high
Live high, train low
Live low, train high