Hypothermia

Question 1

What temperature is defined as hypothermia?

1 - <38
2 - <37
3 - <36
4 - <35

Answer 1

4 - <35

Question 2

Hypothermia can be subdivided into primary and secondary hypothermia. Which of these is due to environmental exposures and no underlying medical conditions?

Answer 2

• Primary

Secondary hypothermia is due to a medical illness where the body is losing heat faster than it can generate it

Question 3

Is primary hypothermia always accidental?

Answer 3

• No

Can be deliberate, such as perioperative

Question 4

Which of the following are approaches where primary hypothermia is therapeutic or used as part of a patients management?

1 - hypoxic perinatal brain injury
2 - post-resuscitation period following traumatic brain injury with high ICP
3 - perioperative surgery
4 - all of the above

Answer 4

4 - all of the above

Question 5

All of the following are secondary causes of hypothermia due to a reduction in heat production, EXCEPT which one?

1 - hypopituitarism
2 - hypoadrenalism
3 - hyperthyroidism
4 - severe malnutrition
5 - hypoglycaemia
6 - neuromuscular disorders

Answer 5

3 - hyperthyroidism

Hypothyroidism can cause hypothermia

Question 6

All of the following are secondary causes of hypothermia due to a increased heat loss, EXCEPT which one?

1 - vasoconstriction
2 - erythrodermas
3 - burns
4 - psoriasis
5 - iatrogenic
6 - cold infusions
7 - emergency deliveries.

Answer 6

1 - vasoconstriction

Vasodilatation can cause hypothermia

Question 7

All of the following are secondary causes of hypothermia due to impaired thermoregulation, EXCEPT which one?

1 - trauma affecting CNS
2 - stroke and increased ICP
3 - hypoglycaemia
4 - toxicologic and metabolic derangements 5 5 - Parkinson’s disease,

Answer 7

3 - hypoglycaemia

Essentially, anything that may cause damage to the CNS can lead to secondary hypothermia, specially damage to the thermoreceptors in the anterior hypothalamus

Question 8

Which of the following drugs is NOT known to cause secondary hypothermia?

1 - beta-blockers
2 - clonidine
3 - ibuprofen
4 - meperidine
5 - neuroleptics
6 - general anaesthetic agents
7 - ethanol
8 - phenothiazines, and sedative-hypnotics

Answer 8

3 - ibuprofen

Question 9

Hypothermia can be categorised based on the drop in temperature. Which of the following severities of hypothermia would we anticipate to see lethargy, confusion, shivering and loss of fine motor coordination?

1 - Moderate hypothermia (28-32°C)
2 - Mild hypothermia (32-35°C)
3 - Severe hypothermia (below 28°C)

Answer 9

2 - Mild hypothermia (32-35°C)

Moderate = delirium and hyporeflexia

Severe hypothermia = very cold skin, unresponsive, coma, difficulty breathing, and abnormal heart rhythms

Question 10

Which of the following are risk factors for patients developing hypothermia?

1 - very elderly or the very young
2 - chronically illness (cardio especially)
3 - malnourished and exhausted
4 - intoxicated with alcohol or drugs
5 - cognitive impairment - eg, in Alzheimer’s disease.
6 - underlying medical conditions - eg hypothyroidism, stroke, severe arthritis, Parkinson’s disease, trauma, spinal cord injuries, and burns
7 - all of the above

Answer 10

7 - all of the above

Essentially anything that can affect:

• head production
• increase heat loss
• dysfunctional thermoregulation
• iatrogenic (drugs, ethanol etc.)

Question 11

Is hypothermia a gradual or rapid presentation?

Answer 11

• Typically gradual

Question 12

Which of the following is NOT a typical presentation of hypothermia?

1 - low body temperature
2 - shivering and slurred speech
3 - tachycardia and bradypnea
4 - pale and grey skin with cyanosis
5 - reduced consciousness

Answer 12

3 - tachycardia and bradypnea
Causes bradycardia

Often the most common presenting symptom = reduced consciousness

For low body temperatures, oesophageal thermometers are required

Question 13

Which of the following is NOT routinely performed in a patient with suspected hypothermia?

1 - FBC
2 - U&Es
3 - blood gas
4 - head CT
5 - ECG
6 - chest X-ray

Answer 13

4 - head CT

All the others are trying to identify the cause of the hypothermia, but no real indication for X-ray

Question 14

Which of the following is NOT common on an ECG in a patient with hypothermia?

1 - prolonged PR interval
2 - reduced QRS
3 - prolonged QT interval
4 - Osborne (J waves)

Answer 14

2 - reduced QRS

Reduces all intervals as conduction of electrical activity through the heart is slower

Height of J wave is typically proportional to the patients level of hypothermia

Question 15

When managing a patient with hypothermia, which of the following should be implemented?

1 - warmed IV 0.9% sodium chloride
2 - warmed sweetened fluids if no dysphagia
3 - warmed humidified oxygen
4 - heat lamps and blankets
5 - airway, respiratory and cardiac monitoring
6 - all of the above

Answer 15

6 - all of the above

Useful approach in mild/moderate hypothermia, but in severe hypothermia, core body temperature changes are required.

Should always be transferred to ICU and treatment should not delay transfer unless life saving

Question 15

At what temperature does cardiac irritability, i.e. increased risk of arrhythmias (i.e. VF) typically occur?

1 - <37
2 - <33
3 - <30
4 - <28

Answer 15

2 - <33

VF can occur around 28
Aystole (absence of ventricular contractions) can occur around 25

Question 16

Are cardiac drugs and defibrillation always effective in patients with hypothermia?

Answer 16

• No

Typically useful >28 degrees

Question 17

Which of the following complications can occur in hypothermia?

1 - cardiac arrhythmias and cardiac failure
2 - hypotension
3 - intravascular thrombosis and DIC
4 - pneumonia and pulmonary oedema.
5 - acute abdominal
6 - metabolic acidosis and hyperkalaemia
7 - Gangrene
8 - all of the above

Answer 17

8 - all of the above