Cardiogenic shock resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Ahmed Zaghw, M.D. [2]

Overview

Cardiogenic shock is characterized by end organ failure due to systemic hypoperfusion resulting from cardiac failure. Cardiogenic shock is defined by the following hemodymanic parameters:
1- Persistent hypotension:

• Systolic blood pressure <80 to 90 mm Hg, or
  
• Mean arterial pressure 30 mm Hg lower than baseline
  

AND

2- Severe decrease in the cardiac index (CI):

• CI <1.8 L/min/m² without support, or
  
• CI <2.0 to 2.2 L/min/m² with support
  

AND

3- Adequate or elevated filling pressure:

• Left ventricular end-diastolic pressure >18 mm Hg, or
  
• Right ventricular end-diastolic pressure >10 to 15 mm Hg

Causes

Life Threatening Causes

Life-threatening causes include conditions which may result in death or permanent disability within 24 hours if left untreated. Cardiogenic shock is a life-threatening condition and must be treated as such irrespective of the causes.

Common Causes

• Pump failure secondary to MI
• Mechanical complications of MI
  • Ventricular septal rupture
  • Free wall rupture
  • Papillary muscle rupture
• Arrythmia
• Acute heart failure
  • Myocarditis
  • Stress induced cardiomyopathy
  • Hypertrophic cardiomyopathy
• Acute valve regurgitation
• Aortic dissection

Management

Shock

ABCD ❑ Secure airway ❑ O2 ❑ 2 wide bore IV access ❑ 12-lead ECG ❑ CXR ❑ Arterial line & Swan ganz catheter

Hemodynamic optimization ❑ Fluid therapy(guided by PCWP,SaO2,CO) ❑ Contributing factors(-ve inotropes,diuretics) ❑ Vasopressors (norepinephrine,dopamine) ❑ Correct Acidosis (affect vasopressors) ❑ Correct Hypoxemia (affect vasopressors) ❑ Medications (aspirin,heparin,GP IIb/IIIa)

ECG evidence of STEMI †

ECG inconclusive No ST/Limited ST/delayed CS

ECG: - ve Clinical history of HF

STEMI

Focused cardiac ultrasound rule out Acute valvular lesions

Heart failure

Focused cardiac ultrasound to associated valvular causes ††

*Pump failure RV/LV *High risk NSTEMI‡

Acute severe MR VSR Critical AS,MS

Aortic dissection Tamponade

Treatment of heart failure ❑ Oxygen ❑ Diuretics ❑ Morphine ❑ Vasodilators

PCI capable center

IABP

PCI Non-capable center

Urgent PCI

Surgical correction Valve surgery ± CABG

If 1-2 vessels do PTCA

If severe lesion & 3 vessels do CABG

Transfer to PCI center¶ < 90 min

Transfer to PCI center > 90 min

Urgent Transfer to PCI

Thrombolytics

Get stable

Still Non stable * Hypotension * ECG evidence

Transfer to PCI center within 3-24 hrs after Thrombolytics

IABP+ Urgent Transfer to PCI center

Still Cardiogenic shock

Ventricular Assist Device VAD

† New ST elevation at the J point in at least 2 contiguous leads of 2 mm in men or 1.5 mm in women in leads V2-V3 and/or of 1 mm in other contiguous chest leads or the limb leads.

†† Early focused cardiac ultrasound should be done before PCI as long as the patient is not crashing, as it may change the treatment course.

‡ High risk NSTEMI is when Non ST-elevation MI is associated with

• Hemodynamic instability or cardiogenic shock
• Severe left ventricular dysfunction or heart failure
• Sustained ventricular arrhythmias
• Recurrent or persistent rest angina despite intensive medical therapy
• New or deteriorating mitral regurgitation
• New ventricular septal defect

¶ Door To Baloon, D2B

Do's

• 250 mL of isotonic saline should be given empirically as an intravenous volume challenge before the right heart catheterization in patients with suspected CS as long as no clinical evidence of respiratory distress or radiological evidence of pulmonary congestion.
• Correct metabolic acidosis caused by global tissue hypoperfusion, as acidosis can significantly reduce the responsiveness of the vasopressors.
• Monitor the hypovolemic state and hemodynamic status as cardiogenic shock occurs in 5-8% of hospitalized STEMI patient.
• Using smaller combined doses of vasopressors and inotropes is preferable over a single agent used at higher doses to avoid dose-related adverse effects.
• Perform PCI within 90 minutes of initial hospital presentation.
• Focused cardiac ultrasound (emergency echocardiography) is helpful to rule out mechanical problems when the initial ECG findings are not conclusive or when the cardiogenic shock occurs with the first non anterior MI.
• Echocardiography should be performed early before PCI unless the diagnosis is extensive anterior MI and the patient is undergoing prompt percutaneous coronary intervention (PCI).
• Transfer the STEMI patients with cardiogenic shock to PCI irrespective to time delay from time of presentation.
• Clopidogrel should be stopped till after angiography.
• Use IABP when there is rapid deterioration of hemodynamic paramaters, while the on vasopressors and inotropic support.
• Use IABP with rapid initiation of Thrombolytics < 30 min prior transfer, when there is anticipated very long delay in transfer, low risk of fibrinolysis and MI symptoms > 3 hours.
• Use the fibrinolytic agents combined with vigorous vasopressor and IABP.

Don'ts

• Donot give negative inotropic medications (Ca channel blocker-β Blockers)
• Do not routinely use an intraaortic balloon pump (IABP)in all MI patients complicated with cardiogenic shock (CS), especially when there is no mechanical complications (VSD,MVR) and when the patient is scheduled for revascularization intervention.
• Avoid fibrinolytics in NSTEMI as it is non beneficial.
• Lidocaine should not be used in ventricular arrythmia, and if used must be with the lowest dose.