Cardiac Arrest (CVS) Flashcards
(C)
Define cardiac arrest
It is the sudden loss of effective heart systolic function resulting in immediate cessation of blood flow to vital organs.
It can happen due to either no heart beat or ineffective chaotic beating. It is an electrical problem.
What causes cardiac arrest (the diff rhythms)
4 types of arrhythmias can lead to cardiac arrest. Pulseless ventricular tachycardia and ventricular fib are the two shockable rhythms while pulseless electrical activity and asystole are non-shockable.
Describe ventricular tachycardia (type of arrhythmia) and how it can lead to cardiac arrest
Regular broad complex tachycardia that when becomes severe can become pulseless. Pulseless VT is what can cause cardiac arrest as the ventricles cannot fill with blood.
Describe ventricular fib and how it can lead to cardiac arrest
This is an irregular broad complex tachycardia and is always pulseless. Because the ventricles quiver/fibrillate instead of strong contractions they cannot effectively pump tf cessation of effective heart function and blood flow.
Describe PEA and how it can lead to cardiac arrest
Pulseless electrical activity is a cardiac rhythm where there is organised or semi organised electrical activity (not incl VF/VT) but no pulse. Sudden weak or no contractions so leads to cardiac arrest
Describe asystole and how it can lead to cardiac arrest
Asystole refers to the cessation of electrical activity in the heart a.k.a flatline. This tf results in complete cessation of the heart beat and so cardiac arrest
What does it mean if a cardiac rhythm or arrhythmia is shockable?
Defibrillation (electrical shock) can be used to treat the arrhythmia during cardiac arrest to restore sinus rhythm
What is the most common rhythm of cardiac arrest?
Ventricular fibrillation caused cardiac arrest
What are the risk factors of cardiac arrest?
IHD, left vent dysfunction, age, hypertrophic cardiomyopathy (HCM), long QT syndrome
List the possible causes of cardiac arrests (aetiology)
MI (e.g. due to IHD), PE, trauma, tension pneumothorax, cardiomyopathies, resp arrest, electrolyte imbalance
What are the reversible causes of cardiac arrest?
4 Hs - hypoxia, hypovolemia, hyper/hypokalaemia, hypothermia
4 Ts - thrombosis, tension pneumothorax, tamponade, toxins
Pathophysiology of cardiac arrest?
Abnormal electrical activity (cardiac arrest rhythms) -> ineffective heart pumping -> cessation of circulatory blood flow so ischemia in organs -> o2 deprivation in brain leads to loss of consciousness -> ischemia/ loss of o2 in heart results in anaerobic metabolism so lactic acid so metabolic acidosis -> so the ischemia ultimately results in multi organ failure
What are the clinical features of cardiac arrest?
Sudden and acute, pt is unresponsive or loss of consciousness, absent or abnormal breathing (e.g. agonal respiration), chest pain, palpitations, extreme dizzyness, absent pulse at carotid
Investigations for cardiac arrest?
Check the carotid pulse. Do continuous cardiac monitoring i.e. continuous ECG to see if rhythm is shockable. FBC blood test to see if haemorrhage and tf hypovolemia. Serum electrolytes to see if abnormalities. ABG to see if acidosis. Cardiac biomakers to see if elevated (can suggest MI, but arrest can also cause it to elevate itself). Point of care US (POCUS) - helps identify tamponade, PE, haemorrhage etc
What is the first priority management for cardiac arrest? Explain procedure
CPR. Compressions only CPR should be done if untrained, compressions and rescue breaths/ventilation if trained. 30 compressions (at least 5cm depth) at 100-120 rate per minute with 2 rescue breaths for 5 cycles.
