Cardiogenic Shock
at the bedside
Think cardiogenic shock when hypotension, systolic blood pressure (SBP) <90 mmHg or mean arterial pressure (MAP) <65 mmHg, comes with signs of pump failure, not volume loss.
Look for cold, clammy extremities, narrow pulse pressure, elevated jugular venous pressure (JVP), an S3, or crackles; not a flat neck and warm periphery.
- 12-lead ECG immediately →, to identify ST-elevation myocardial infarction (STEMI) or an arrhythmia driving the shock.
- bedside POCUS: left ventricular (LV) function, inferior vena cava (IVC), pericardial effusion, B-lines.
- oxygen → only if SpO2 <90%, target 90–94% (2); IV access, and call cardiology early if an acute coronary syndrome (ACS) appears likely.
- no reflex fluid bolus →: a congested left ventricle will not tolerate one; small, reassessed boluses only if POCUS clearly shows hypovolemia.
early warning signs
- mottling extending to the knees, or lactate rising rather than clearing
- urine output <0.5 mL/kg/hr
- a new murmur after a recent myocardial infarction (MI), this suggests a mechanical complication
escalate now if
- SCAI stage D or E, or deterioration despite first-line therapy → mechanical support
- cardiac power output <0.6 W or lactate that keeps rising → mechanical support
- refractory hypotension on two vasoactive agents, see vasopressors & inotropes
- a suspected mechanical complication of MI: new murmur, VSD, papillary muscle rupture, tamponade → echo now
- biventricular failure with concomitant respiratory failure, a VA-ECMO candidate → mechanical support
- any patient needing revascularization, MCS evaluation, or transfer to a center capable of temporary MCS → revascularization
define & classify
Acute MI (ST-elevation more than non-ST-elevation) is the leading cause. Cardiogenic shock is dynamic → reassess stage and trajectory repeatedly, not just the admission snapshot (1).
| SCAI stage | picture | typical action |
|---|---|---|
| A, at risk | no hypoperfusion, eg large MI, decompensating chronic HF | close monitoring |
| B, beginning | intact perfusion, hypotension or compensatory tachycardia | volume optimization, consider early vasoactive |
| C, classic | hypoperfusion needing pharmacologic or mechanical support | vasoactive + inotrope, start mechanical circulatory support (MCS) evaluation |
| D, deteriorating | rising lactate or escalating support despite initial therapy | urgent MCS evaluation, cardiac ICU (CICU) or ICU |
| E, extremis | cardiovascular collapse, ongoing CPR | crash MCS, resuscitation |
- MI-related → think mechanical complication (ventricular septal defect (VSD), papillary muscle rupture, free wall rupture) if shock is out of proportion to the infarct.
- non-MI → decompensated chronic heart failure, myocarditis, a tachy- or bradyarrhythmia, acute valve failure, Takotsubo, or right ventricular (RV) failure, eg massive pulmonary embolism (PE) or RV infarct.
initial management
confirm the diagnosis, involve cardiology
Cardiogenic shock from acute MI needs immediate cath lab activation and urgent revascularization, do not delay for ward stabilization (2).
- activate the STEMI pathway for immediate percutaneous coronary intervention (PCI) if the ECG shows infarction; with cardiogenic shock, primary PCI is recommended regardless of time since symptom onset
- door-to-balloon targets (first medical contact to device ≤90 min) still apply; do not extend them for pre-cath stabilization (2)
- dual antiplatelet therapy and anticoagulation per cardiology, don’t delay them for the shock physiology alone.
volume
- small, reassessed bolus (250 mL crystalloid) only if POCUS shows a flat IVC or another clear hypovolemic contributor; reassess after every bolus.
- avoid an empiric 30 mL/kg fluid bolus, a congested ventricle will not tolerate it.
- most are volume overloaded, not underfilled: once MAP and perfusion are adequate, IV loop diuretics, titrated against urine output and volume status.
first-line vasoactive
- norepinephrine 0.01–0.5 mcg/kg/min, titrate to MAP ≥65 mmHg; preferred over dopamine (SOAP-II cardiogenic-shock subgroup: more arrhythmia and a mortality signal with dopamine (3)).
inotrope if low cardiac output despite an adequate MAP
- dobutamine 2.5–10 mcg/kg/min, titrate up to 20 mcg/kg/min. quick onset, short half-life, less effective on chronic beta-blockade.
- milrinone 0.375–0.75 mcg/kg/min as an alternative: omit the loading dose (hypotension); renally cleared, reduce or avoid in acute kidney injury (AKI) or chronic kidney disease (CKD); no head-to-head outcome difference between them (DOREMI) (4); renal function is the practical tiebreaker.
oxygen and ventilation
- high-flow nasal cannula (HFNC) or low-dose continuous positive airway pressure (CPAP) for hypoxemia; treat as preload-sensitive and watch for a blood pressure (BP) drop with positive pressure.
- don’t delay intubation if the patient is fatiguing or failing to improve on noninvasive ventilation (NIV).
RV failure driving the picture
- RV preload is not one-directional: an underfilled RV needs cautious volume, a congested RV needs decongestion; let POCUS guide it, not a fixed rule.
- minimize positive intrathoracic pressure: tidal volume 6–8 mL/kg, avoid excess positive end-expiratory pressure (PEEP); both raise RV afterload.
- if pulmonary hypertension is driving it, a pulmonary vasodilator (inhaled nitric oxide or epoprostenol) can offload the RV, involve cardiology.
- milrinone lowers pulmonary vascular resistance and may be favored over dobutamine here, but weigh its own systemic vasodilating effect on blood pressure.
reassess
- every 30–60 min while titrating: MAP, urine output, lactate trend, and mixed or central venous oxygen saturation as a perfusion trend (no single universal target); a low or falling value alongside the others supports inadequate perfusion and escalation.
- repeat POCUS for LV function, IVC, and a new effusion if the picture isn’t improving as expected.
- recheck rhythm, a new arrhythmia can be the whole problem.
advanced management
- invasive arterial line for continuous MAP, consider a central line for vasoactive titration.
- track cardiac power output, calculated as MAP × cardiac output (CO) / 451, a value <0.6 W predicts the need for mechanical support (7).
- evaluate every SCAI stage C patient or worse for MCS candidacy by an expert team, don’t wait for stage E (5).
- intra-aortic balloon pump (IABP) is no longer routine: IABP-SHOCK II showed no mortality benefit; select cases per cardiology (6).
- microaxial flow pump (Impella) for STEMI-related severe or refractory shock, selected patients: mortality benefit in DanGer Shock (8), class 2a in the 2025 ACC/AHA ACS guideline (2).
- VA-ECMO is not routine: no benefit in ECLS-SHOCK (9); reserve for biventricular failure, concomitant respiratory failure, or as a bridge; Impella + VA-ECMO (ECPELLA) offloads the LV when ECMO alone raises afterload.
- discuss with, or transfer early to, a center capable of temporary MCS where indicated; do not wait for instability to move.
troubleshooting
- reconfirm rhythm and ECG, treat any correctable arrhythmia first.
- reassess volume status with POCUS (IVC, B-lines), don’t keep dosing fluid on reflex.
- look for a mechanical complication, new murmur, VSD, papillary muscle rupture, tamponade, with echo if the patient isn’t improving as expected.
- escalate vasoactive or inotrope support to match the phenotype, vasoplegic versus low-output.
- reassess SCAI stage and MCS candidacy, call cardiology or the CICU early rather than after several escalations.
evidence
| source | type |
|---|---|
| 1. SCAI SHOCK Stage Classification, 2022 expert consensus update | guideline |
| 2. 2025 ACC/AHA/ACEP/NAEMSP/SCAI guideline for the management of acute coronary syndromes | guideline |
| 3. SOAP-II trial, N Engl J Med 2010 | RCT |
| 4. DOREMI trial, N Engl J Med 2021 | RCT |
| 5. AHA scientific statement 2022, escalating / de-escalating temporary MCS in cardiogenic shock | statement |
| 6. IABP-SHOCK II trial, N Engl J Med 2012 | RCT |
| 7. Fincke et al., cardiac power as the strongest hemodynamic correlate of mortality, SHOCK trial registry, JACC 2004 | cohort |
| ESC 2023 focused update, acute & chronic heart failure guidelines | guideline |
| AHA scientific statement, contemporary management of cardiogenic shock | statement |
| Oxford Handbook of Critical Care Medicine, 4th ed | textbook |
| 8. DanGer Shock trial, N Engl J Med 2024 | RCT |
| 9. ECLS-SHOCK trial, N Engl J Med 2023 | RCT |
| 10. 2025 ACC expert consensus, evaluation and management of cardiogenic shock | statement |
Verify indication, dose, allergies, interactions, renal/hepatic function and local protocols before prescribing.
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Last updated · October 2026