Cardiogenic Shock
Cardiogenic shock is one of the most dangerous cardiac emergencies you will encounter on medical on-call.
Although less common than pulmonary oedema or fast AF, it carries very high mortality, and early recognition is critical.
Your role is not to “fix” cardiogenic shock alone — your role is to:
👉 recognise it early
👉 avoid harmful treatments
👉 stabilise safely
👉 escalate immediately
This is a senior-led emergency.
What is cardiogenic shock?
Cardiogenic shock occurs when the heart fails to pump enough blood to maintain organ perfusion.
In simple terms:
👉 Pump failure → low cardiac output → organ hypoperfusion
Despite adequate or increased fluid volume.
Common NHS causes
Most commonly:
- Acute myocardial infarction (biggest cause)
- Severe acute heart failure
- End-stage cardiomyopathy
- Severe arrhythmias (VT, complete heart block)
- Mechanical complications post-MI:
- Papillary muscle rupture
- Ventricular septal rupture
- Severe valvular disease
Always think: Why has the pump failed?
How patients present
Patients often look critically unwell.
Symptoms
- Severe breathlessness
- Chest pain
- Extreme fatigue
- Confusion
- Reduced urine output
Signs (classic pattern)
- Hypotension (SBP <90)
- Tachycardia (sometimes bradycardia)
- Cold, clammy peripheries
- Poor capillary refill
- Altered mental state
- Oliguria
- Often pulmonary oedema
Key feature:
👉 Cold + hypotensive + congested
First step = A–E assessment
Immediately assess:
- Airway
- Oxygenation
- Perfusion
- Conscious level
- Urine output
Attach monitoring early.
🚨 Red flags suggesting cardiogenic shock
- Persistent hypotension
- Signs of pulmonary oedema + low BP
- Rising lactate
- Reduced consciousness
- Minimal urine output
- Failure to respond to fluids
If suspected → escalate immediately.
Immediate actions (what you should do first)
1️⃣ Call for senior help early
Registrar + ICU/outreach + cardiology.
Do not wait.
2️⃣ Oxygen
Give oxygen if hypoxic.
Consider NIV if pulmonary oedema present (with senior support).
3️⃣ Cardiac monitoring + IV access
- Continuous monitoring
- Large-bore IV access
- Urinary catheter (monitor output)
4️⃣ ECG immediately
Look for:
- STEMI
- arrhythmia
- heart block
Many patients need urgent reperfusion.
5️⃣ Bloods
- FBC
- U&E
- Troponin
- Lactate
- ABG/VBG
- Coagulation
Lactate helps assess severity.
⚠️ Fluids — major pitfall
Unlike septic shock:
👉 Fluids can worsen cardiogenic shock
If pulmonary oedema present:
❌ avoid routine fluid boluses.
Small cautious bolus only if clearly hypovolaemic and senior agrees.
Definitive management (senior-led)
Often includes:
- Urgent PCI (if MI)
- Inotropes (e.g. dobutamine)
- Vasopressors (e.g. noradrenaline)
- Mechanical support (IABP, Impella, ECMO in specialist centres)
- ICU admission
These are not ward-level decisions.
When to escalate immediately
Always escalate if:
- SBP <90 persistently
- Suspected cardiogenic shock
- Severe pulmonary oedema + hypotension
- Rising lactate
- Reduced consciousness
- Need for inotropes
Early escalation saves lives.
Common on-call mistakes
- Giving large fluid boluses reflexively
- Treating as sepsis without reassessment
- Delayed senior involvement
- Missing MI on ECG
- Waiting for blood results before escalation
- Managing alone too long
Cardiogenic shock deteriorates quickly.
Practical bedside mindset
When you see:
Hypotension + breathlessness + crackles
Think immediately:
👉 cardiogenic shock until proven otherwise.
Ask:
- Is the pump failing?
- Could this be MI?
- Do they need ICU now?
Take-home concept
Cardiogenic shock is not a ward problem — it is a recognition and escalation problem.
Your job:
- recognise early
- avoid harmful fluids
- stabilise basics
- call for help fast
Early escalation changes outcomes.