Hypothermia + Syncope Flashcards
1
Q
What are the ECG changes with hypothermia?
A
- Bradycardia (<60bpm) and not tachycardia
- J waves (small hump at the end of the QRS complex)
- Prolonged PR, QT and QRS intervals
- Shivering artefacts
- First degree heart block
- VT, VF or asystole
2
Q
When do you get asystole?
A
Asystole dominates once the core body temperature drops to below 16ºC
3
Q
What is syncope?
A
- Transient loss of consciousness
- Global cerebral hypoperfusion
- Rapid onset
- Short duration
- Spontaneous complete recovery
- Definition excludes other causes of collapse such as epilepsy
4
Q
What are the three main classifications of syncope?
A
- Reflex syncope (neurally mediated):
* most common in all age groups - Orthostatic syncope
- Cardiac syncope
5
Q
What is reflex syncope?
A
- vasovagal: triggered by emotion, pain or stress. Often referred to as ‘fainting’
- situational: cough, micturition, gastrointestinal
- carotid sinus syncope
6
Q
What is orthostatic syncope?
A
- primary autonomic failure: Parkinson’s disease, Lewy body dementia
- secondary autonomic failure: e.g. Diabetic neuropathy, amyloidosis, uraemia
- drug-induced: diuretics, alcohol, vasodilators
- volume depletion: haemorrhage, diarrhoea
7
Q
What is cardiac syncope?
A
arrhythmias: bradycardias (sinus node dysfunction, AV conduction disorders) or tachycardias (supraventricular, ventricular)
structural: valvular, myocardial infarction, hypertrophic obstructive cardiomyopathy
others: pulmonary embolism
8
Q
How do you investigate syncope?
A
- cardiovascular examination
- postural blood pressure readings: a symptomatic fall in systolic BP > 20 mmHg or diastolic BP > 10 mmHg or decrease in systolic BP < 90 mmHg is considered diagnostic
- ECG
- carotid sinus massage
- tilt table test
- 24 hour ECG
9
Q
What is carotid sinus massage?
A
It involves gently massaging the carotid artery for 5 seconds on one side of neck whilst monitoring your heart rhythm and blood pressure.
