CC13: Emergency care and cardiogenic shock

Question 1

What is cardiogenic shock?

Answer 1

-Primary cardiac disorder characterised by a low cardiac output state of circulatory failure
-Results in end-organ hypoperfusion and tissue hypoxia

Question 2

Causes of cardiogenic shock

Answer 2

-Acute myocardial ischaemia
-Mechanical defect: MR, MS, AS, cardiac tamponade
-Contractility defect: cardiomyopathy, septic shock, myocarditis
-Pulmonary embolus
-Aortic dissection

Question 3

Normal rhythm with no cardiac output?

Answer 3

-Cardiac tamponade

Question 4

Other causes of cardiogenic shock?

Answer 4

-Cardiotoxic drugs (doxorubicin)
-Medication overdose (beta/CCBs)
-Metabolic derangements (acidosis)
-Electrolyte abnormalities (calcium)

Question 5

What factors increase risk of cardiogenic shock after STEMI?

Answer 5

-Age>70 years
-Systolic BP < 120
-Sinus tachycardia/bradycardia
-Long duration of symptoms before treatment

Question 6

Pathophysiology of cardiogenic shock

Answer 6

-Ischaemia to myocardium decreases LV function and contractility
-This causes reduced CO and BP which worsens ischaemia and contractility

Question 7

What are the compensatory processes in cardiogenic shock?

Answer 7

-Activation of sympathetic system
-Causes peripheral vasoconstriction
-Improves coronary perfusion at cost of increased afterload

-Tachycardia increases myocardial oxygen demand
-This worsens myocardial ischaemia

Question 8

Symptoms of cardiogenic shock?

Answer 8

-Hypotension
-Altered mental status
-Oliguria
-Cold, clammy skin

Question 9

Diagnostic evaluation of cardiogenic shock?

Answer 9

-Arterial blood gas
-Cardiac biomarkers
-Electrocardiogram
-2D echo
-Coronary angiography

Question 10

Treatment/management of cardiogenic shock?

Answer 10

-Early restoration of coronary blood is most important
-Medical management to restore CO and prevent end-organ damage
-Mechanical ventilation for oxygenation and airway protection
-Percutaneous coronary intervention and coronary artery bypass

Question 11

Types of mechanical circulatory support (MCS) in cardiogenic shock?

Answer 11

-Intra-aortic balloon pump (severe MR, VSD, when other MCS cannot be placed)
-Extra Corporeal Membrane Oxygenation (ECMO) - patients with poor oxygenation not expected to improve rapidly with other devices
-Left ventricular assist device - bridge to recovery, transplant or destination therapy
-Cardiac transplant not expected to recover after MCS

Question 12

Differential diagnoses for cardiogenic shock

Answer 12

-Septic shock (infection)
-Shock due to haemorrhage (hypovolaemia)
-Neurogenic shock (trauma/toxicity to nervous system)

Question 13

List of cardiac emergencies

Answer 13

-STEMI
-NSTEMI
-Tamponade
-VF
-CHB
-PEA

Question 14

How to treat asystole?

Answer 14

-Pacing
-CPR
-Drugs (adrenaline, atropine)

Question 15

How to treat VF?

Answer 15

-Defib shock

Question 16

How to treat PEA?

Answer 16

-CPR
-Drugs (adrenaline)

Question 17

Reversible causes of cardiac arrest (5Hs)

Answer 17

-Hypovolemia - give fluids
-Hypoxia/hypoxaemia - ventilation
-Hydrogen ion excess (acidosis) - ventilation/sodium bicarbonate
-Hypo/hyperkalemia - ventilation/sodium bicarbonate
-Hypothermia - Active warming measures

Question 18

Reversible causes of cardiac arrest (5Ts)

Answer 18

-Tamponade - Pericardiocentesis
-Toxins - Supportive care
-Tension pneumothorax - needle decompression
-Thrombosis (pulmonary) - embolectomy/anticoagulant
-Thrombosis (coronary) - PCI/bypass

Question 19

What are peri-arrest situations?

Answer 19

-Acute MI
-Profound bradycardia
-VT
-SVT
-Fast AF

Question 20

Investigations for peri-arrest situations

Answer 20

-ECG
-Blood pressure
-Echo
-Coronary angiography
-Arterial blood gas
-Cardiac biomarkers