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ClearRounds Health · Cardiology · Quick Reference
Cardiogenic Shock
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ICU, Shock & EmergenciesAdvancedIn progressOne-page PDF
SCAI stages, shock recognition, lactate/end-organ markers, hemodynamics, CPO/PAPI/CVP concepts, initial stabilization, escalation.
Last reviewed
June 12, 2026
Sources / guidelines to verify
- SCAI SHOCK Stage Classification (2022 update)
- SCAI Door to Lactate Clearance Initiative (2025)
- National Cardiogenic Shock Initiative (NCSI) protocol
- 2022 AHA/ACC/HFSA HF Guideline (PA catheter in shock); 2025 ACS Guideline (MCS / microaxial flow pump)
- AHA Scientific Statement on Cardiogenic Shock
Disclaimer: Educational reference only. Not a substitute for clinician judgment, local protocols, or current guideline review.
One-page reference
Clinically reviewed by the site owner. Still verify against the sources above and local protocol before clinical use.
1
What it is / why it matters
- Primary cardiac dysfunction → inadequate cardiac output → end-organ hypoperfusion.
- High mortality — recognize early and stage with SCAI. Acute MI is the most common cause.
2
Key diagnostic clues
- Hypotension (SBP <90 or vasopressor requirement) PLUS hypoperfusion: cool/clammy or mottled skin, altered mentation, oliguria, rising lactate.
- Common settings: large MI, decompensated HF, sustained arrhythmia, mechanical complication.
SCAI shock stages
- A — at risk
- B — beginning (hypotension/tachycardia, no hypoperfusion)
- C — classic (hypoperfusion, needs intervention)
- D — deteriorating
- E — extremis (refractory / arrest)
3
Initial workup
- Lactate, ECG (ischemia), troponin, CMP (metabolic panel incl. LFTs), arterial blood gas.
- Natriuretic peptide (BNP/NT-proBNP): not required for the shock diagnosis; use if HF is a suspected contributor or for prognosis/trending.
- Echo: EF, RV function, mechanical complication, tamponade.
- Invasive hemodynamics: a PA (Swan-Ganz) catheter can be useful to guide management in cardiogenic shock — Class 2a in selected patients per the 2022 HF guideline (not for routine HF use, per ESCAPE). Define filling pressures/CVP, cardiac power output (CPO <0.6 W = poor), and PAPI (RV failure).
4
Management framework
- Treat the cause: emergent revascularization (culprit-vessel PCI) for ACS-related shock; correct arrhythmia; surgery for mechanical complications.
- Support perfusion: cautious fluids only if not congested; norepinephrine is first-line vasopressor ± inotrope (dobutamine/milrinone).
- Mechanical circulatory support per shock team: microaxial flow pump (Impella) has randomized support in selected AMI shock (DanGer Shock; 2025 ACS guideline conditional upgrade); VA-ECMO for refractory or biventricular shock.
- Routine IABP is no longer recommended in AMI cardiogenic shock (Class III, IABP-SHOCK II); reserve IABP for mechanical complications (acute MR/VSD).
- Protect the RV (avoid hypoxia and acidosis); avoid over-diuresis if preload-dependent.
5
Recognize early & escalate on a clock
Recognize before the pressure falls
- Don’t wait for frank hypotension. Any of these → assess for shock and assign a SCAI stage now: lactate >2 mmol/L, cool/mottled extremities, urine output <0.5 mL/kg/h, altered mentation, narrowing pulse pressure, or any new/rising vasopressor requirement.
| When | Objective check | If not improving → act |
|---|---|---|
| At diagnosis | Lactate; assign SCAI stage (A–E); CPO/PAPI if a PA catheter is in place | Treat the cause; involve the shock team early (by stage C) — not after stage D/E |
| Every 2–3 h | Repeat lactate (SCAI “Door to Lactate Clearance”) | Lactate flat or rising = current therapy is failing → escalate now, don’t observe another shift |
| By 24 h | Goal: lactate cleared to <2 mmol/L | Not cleared → reassess the cause, escalate support / MCS, or transfer |
| While unstable | Re-stage SCAI ~q1–2h | A B→C→D trajectory is the warning — escalate proactively, don’t wait for arrest |
“Current therapy is failing” → escalate / shock team / MCS / transfer
- Lactate flat or rising on serial draws (failure of lactate clearance).
- Escalating vasopressor dose or need for ≥2 vasoactive agents.
- CPO <0.6 W, rising filling pressures, or low PAPI (RV failure).
- Worsening urine output, mentation, or other end-organ function.
- SCAI stage D or E — activate the shock team / transfer immediately.
- Mindset: treat shock with door-to-balloon urgency. Programs that protocolize early invasive hemodynamics, early shock-team activation, and early MCS (National Cardiogenic Shock Initiative) reported markedly higher survival than historical care.
- Consensus/QI-informed framework — verify against your local shock protocol.
6
Red flags / escalate now
- Rising lactate despite therapy, escalating vasopressor needs, or SCAI stage D/E.
- Refractory arrhythmia or need for mechanical support → activate the shock team / transfer immediately.
7
Follow-up / monitoring
- Serial lactate and perfusion markers, hemodynamics, and end-organ recovery.
- Wean support as tolerated.
8
Clinic pearls
- Lactate, mottling, and mentation tell you more than blood pressure alone.
- Norepinephrine is the first-line pressor.
- Call the shock team EARLY — support buys time, but identifying and treating the cause is the cure.
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