Hypothermia Flashcards

1
Q

Define hypothermia

A

Temp less than 35

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2
Q

What are the risk factors for hypothermia

A

Elderly, homeless, alcohol, immersion, trauma

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3
Q

Define mild moderate and severe hypothermia and describe how a patient would present

A

Mild 32-35 (normal mental state and shivering)
Moderate 28-32 (altered mental state and not shivering)
Severe 24-28 (unconscious with vital signs) or 13.7-24 (no vital signs)
Dead <13.7

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4
Q

How does the ALS algorithm change for hypothermic patients?

A

CENTRAL pulse check for 1 minute (low pressure, low volume state means its harder to find)
Can also use ECG and Echo to determine signs of life
Harder compressions
Maximum 3 shocks until rewarmed to 30
No drugs below 30
Double interval between doses from 30-35

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5
Q

How can you rewarm a hypothermic patient

A
Remove wet clothes
Dry
Cover in wool blankets or aluminium foil
Put in a warm environment
Warm IV fluids
Warm inspired air
Bladder lavage
VA ECMO
Exercise if possible
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6
Q

When should ECMO for hypothermic patients be used?

A

Patient below 32 with potassium <8mmol/L

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7
Q

Why is prognosis for a frozen patient good?

A

Decreased metabolic rate conserves ATP and oxygen so cells last longer before hypoxic damage

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8
Q

At what temperature can a cold patient be pronounced dead?

A

32 is generally the cut off

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9
Q

How do humans generate and lose heat?

A

Generated by cellular metabolism primarily in the liver

Lost by convection (currents of air), conduction (adjacent surface), radiation and evaporation (of sweat)

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10
Q

What does the hypothalamus stimulate when low temperature is detected?

A

Shivering
Increased sympathetic drive
Stimulates thyroid
Peripheral vasoconstriction

Ultimately leads to increased metabolism, CO and ventilation

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11
Q

At what temperature does metabolism drop and shivering stop?

A

32

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12
Q

What are the physiological effects of hypothermia?

A
Bradycardia 
Hypotension 
Low minute volume (tidal volume x RR)
Arrhythmia (AF progress to VF to CA)
J waves on ECG
Peripheral vasoconstriction 
Hypoglycaemia progressing to hyperglycaemia
Cold diuresis (reduced ADH)
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13
Q

Why do you get arrhythmias in hypothermia?

A

Difference in temperature across the myocardium leads to variability in electrical conduction

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14
Q

Why are hypothermic patients hypotensive?

A

Bradycardic
Low volume
Reduced myocardial contractility

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15
Q

What happens to glucose levels in hypothermic patients?

A

Initially hypo because shivering uses it up

Progress to hyper because insulin used up + there is insulin resistance

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16
Q

How is hypothermia diagnoses

A

Oesophageal probe placed in lower 1/3 of oesophageal

Rectal probe often more practical and available

17
Q

What changes to CPR should be made in a patient <28 degrees

A

Intermittent CPR can be carried out

5 minutes of CPR followed by <5 minutes no CPR

18
Q

Why does a hypothermic patient being rewarmed need fluids

A

As they rewarm they will vasodilate

19
Q

Is rectal temperature (hypothermia) recommend or not and why

A

No - it lags behind core temperature

20
Q

Will tympanic temperature readings be higher or lower than core

A

Depends on environment and things in the EAM eg snow

21
Q

Primary goal prehospitally for hypothermic patients is…

A

Get them out of the environment - shouldn’t prolong transport with any treatments or investigations as most patients will continue to drop their temperatures and you need to get them out of there

22
Q

What is the effect of cold diuresis on electrolytes?

A

Hypophosphataemia, hypokalaemia, hypomagnasaemia, hypocalcaemia