Cardiogenic Shock
Cardiogenic shock is defined as:
“Decreased cardiac output and evidence of tissue hypoxia in the presence of adequate intravascular volume”
It is a clinical condition with a very high mortality, as essentially the heart can no longer meet the metabolic demands of the body.
This failure results in significant metabolic disturbance at a chemical level.
The haemodynamic criteria are:
“Decreased cardiac output and evidence of tissue hypoxia in the presence of adequate intravascular volume”
It is a clinical condition with a very high mortality, as essentially the heart can no longer meet the metabolic demands of the body.
This failure results in significant metabolic disturbance at a chemical level.
The haemodynamic criteria are:
- Systolic hypotension (< 90mmHg)
- Reduced cardiac index (< 2.2L/min/m^2)
Aetiology
Cardiogenic shock is commonly related to acute coronary disease.
It may occur following such an event:
Other cause of cardiogenic shock include:
Particular features of an MI that are associated with cardiogenic shock include:
As such, it is commonly associated with vasculopathic disease:
It may occur following such an event:
- STEMI - in 7%
- NSTEMI - in 3%
Other cause of cardiogenic shock include:
- Decompensated ischaemic cardiomyopathy
- Cardiac contusion (post trauma)
- Cardiac dysfunction post cardiac surgery
Particular features of an MI that are associated with cardiogenic shock include:
- Loss of greater than 40% LV wall function
- Papillary muscle rupture, leading to acute mitral regurgitation
- Ventricular septal defect
- Tamponade
As such, it is commonly associated with vasculopathic disease:
- Ischaemic heart disease - 66%
- Hypertension - 50%
- Previous MI - 33%
- Diabetes - 25%
Presentation
The presentation can be of a mixture of cardiac failure.
These can be broken down into:
Impaired LV pump function - impaired perfusion
LV back pressure - increased lung hydrostatic pressure
RV back pressure - increased peripheral hydrostatic pressure
These can be broken down into:
- Impaired LV pump function
- LV back pressure
- RV back pressure
Impaired LV pump function - impaired perfusion
- Cold peripheries
- Cyanosis/hypoxia
- Fatigue
- Altered mental state
- Metabolic disturbance (acid-base, electrolyte)
- Oligouria
- Myocardial ischaemia
LV back pressure - increased lung hydrostatic pressure
- Pulmonary oedema
RV back pressure - increased peripheral hydrostatic pressure
- Peripheral oedema
- Hepatic congestion
- Splanchnic ischaemia
- Raised ICP
Assessment
Assessment will be based on a thorough, systematic approach, e.g. A to E.
Routine investigations will be essential
Routine investigations will be essential
- ECG
- CXR
- Bloods - U&E, LFTs, Troponins
- Blood gases
- Echocardiography
- Angiography
Management
Resuscitation
This will run in parallel to a focused assessment
A/B:
Apply high flow oxygen if hypoxia present.
A loop diuretic, usually furosemide is usually first line for pulmonary oedema. Part of this effect is probably from some vasodilation rather than the diuretic effect.
Consideration should be given to ventilatory support. This can reduce the work of breathing and improve gas exchange in pulmonary oedema.
Early NIV can be helpful to avoid intubation and has been shown to improve morbidity and mortality in these patients.
Positive pressure ventilation also has beneficial effects on cardiac function, offloading the left ventricle.
C:
A cautious fluid challenge may be indicated early in the assessment process, if the volume status/aetiology is unclear.
Nitrates (e.g. via a GTN infusion) can be used in patients with a preserved blood pressure (quoted as a SBP over 110 mmHg). The vasodilatory effects act to reduce preload.
Rhythm disturbances (e.g. fast AF) should be treated if present as they may add a significant degree of impairment to cardiac function.
Consideration should be given to inotropic support, as detailed below.
D:
Opioids may be indicated for the severe dyspnoea and distress that may be present. The vasodilatory effects can also be beneficial.
E:
Appropriate monitoring should be instigated.
A high level care area is required.
Invasive blood pressure monitoring is almost certainly indicated.
Central venous cannulation may be indicated for drug infusion and may aid cardiovascular assessment.
Revascularization
This should be considered in those who meet the appropriate criteria i.e those with STEMI features.
The benefit appears to be notable at 6 and 12 months rather than early on.
Surgical intervention
This should be considered for those with an acute surgical pathology:
Cardiovascular support
These can include pharmacological and mechanical options.
The pharmacological effects can be through effects on inotropy or as vasopressors.
Inotropes increase cardiac contractility but at the cost of increased cardiac metabolic demands.
Pharmacological:
Mechanical
This will run in parallel to a focused assessment
A/B:
Apply high flow oxygen if hypoxia present.
A loop diuretic, usually furosemide is usually first line for pulmonary oedema. Part of this effect is probably from some vasodilation rather than the diuretic effect.
Consideration should be given to ventilatory support. This can reduce the work of breathing and improve gas exchange in pulmonary oedema.
Early NIV can be helpful to avoid intubation and has been shown to improve morbidity and mortality in these patients.
Positive pressure ventilation also has beneficial effects on cardiac function, offloading the left ventricle.
C:
A cautious fluid challenge may be indicated early in the assessment process, if the volume status/aetiology is unclear.
Nitrates (e.g. via a GTN infusion) can be used in patients with a preserved blood pressure (quoted as a SBP over 110 mmHg). The vasodilatory effects act to reduce preload.
Rhythm disturbances (e.g. fast AF) should be treated if present as they may add a significant degree of impairment to cardiac function.
Consideration should be given to inotropic support, as detailed below.
D:
Opioids may be indicated for the severe dyspnoea and distress that may be present. The vasodilatory effects can also be beneficial.
E:
Appropriate monitoring should be instigated.
A high level care area is required.
Invasive blood pressure monitoring is almost certainly indicated.
Central venous cannulation may be indicated for drug infusion and may aid cardiovascular assessment.
Revascularization
This should be considered in those who meet the appropriate criteria i.e those with STEMI features.
The benefit appears to be notable at 6 and 12 months rather than early on.
Surgical intervention
This should be considered for those with an acute surgical pathology:
- Acute MR from papillary muscle rupture
- Tamponade
- Ischaemic ventricular septum rupture
Cardiovascular support
These can include pharmacological and mechanical options.
The pharmacological effects can be through effects on inotropy or as vasopressors.
Inotropes increase cardiac contractility but at the cost of increased cardiac metabolic demands.
Pharmacological:
- Beta-adrenergic effects e.g. adrenaline, dopamine, dobutamine
- Alpha-adrenergic effects e.g. noradrenaline
- Phosphodiesterase inhibitors e.g milrinone, enoximone
- Calcium sensitiser e.g. levosimendan
Mechanical
- Aortic balloon pump
- Ventricular assist devices
Links & References
- Bennett, M. Management of cardiogenic shock. e-LFH. 2016
- Harris, P. Kuppurao, L. Ventricular assist devices. CEACCP. 2012. 12(3). 145-151
Updated 16th June 2017
