Cardiogenic Shock
Monday, 24 August 2020
1:21 pm
Definition:
- Occurs when significant amount of left ventricular
myocardium
has been destroyed
- Heart’s ability to contract and pump blood is impaired, and
supply of oxygen is inadequate for heart and tissues
Risk factors:
1. Coronary factors
a. Myocardial infarction
2. Non-coronary factors
a. Cardiomyopathies
b. Valvular damage
c. Cardiac tamponade
- serious medical condition where the blood or fluids fill the
space between the sac that encases the heart and the
heart muscles
- places extreme pressure on the heart and pressure prevents
heart’s ventricles from expanding fully and keeps heart from
functioning fully
d. Dysrhythmias
Pathophysiology
- Decreased cardiac contractility considering all factors
(coronary and non-coronary) leads to restriction causing
decreased stroke volume and cardiac output
- If there is inability of ventricles to expand fully, this can
affect functioning of the myocardial muscles
Effects:
a. Pulmonary congestion
- because of inability of left ventricle to pump blood out of
heart
b. Decreased systemic tissue perfusion
- because blood is now deposited in the left ventricle and not
pumped out properly
d. Decreased coronary artery perfusion
- there will be compromised oxygenation in heart muscles and
major organs of the body
Clinical Manifestations
1. Angina pain
- Caused by a decrease in oxygen supply to the myocardial
muscles
2. Dysrhythmias
- Demonstrated by palpitations and ECG tracing
3. Hemodynamic instability
- Prescence of changes in vital signs
Medical Management
1. Initiation of First-Line Treatment
a. Supplying of supplemental oxygen
- Supplied in the early stages of shock by nasal cannula at
2-6 L/min to achieve an oxygen saturation exceeding 90%
- Monitoring of ABG is important
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- Pulse oximetry values helps indicate whether pt requires a
more aggressive method of oxygen delivery
b. Pain control
- Provide morphine sulfate IV for pain relief
= Dilates blood vessels
= reduces workload of heart by both
= decreasing cardiac filling pressure and reducing pressure
against which the heart has to eject blood (afterload)
= Relieves pt’s anxiety
- Cardiac enzyme (CPK-MB and cTn-I) levels are measured
- Serial 12-lead electrocardiograms is used to assess
myocardial damage
c. Providing selected fluid transport
d. Administering vasoactive medications
e. Controlling heart rate with medications or by implementation
of a transthoracic/IV pacemaker
f. Implementing mechanical cardiac support
g. Hemodynamic Monitoring: initiated to assess pt’s response to
treatments (usually done in ICU)
- Arterial line can be inserted
= enables accurate and continuous monitoring of BP and
provides a port from which we can obtain frequent arterial
blood samples without performing repeated arterial puncture
- Multilumen pulmonary artery catheter is inserted
= Allows measurements of pulmonary artery pressures,
myocardial filling pressures, cardiac output, and pulmonary
and systemic resistance
2. Pharmacologic Therapy
- Involves administration of vasoactive medication which
consists
of multiple pharmacologic strategies to restore and maintain
adequate cardiac output
- To improve cardiac contractility and decrease preload and
afterload and to have a stable heart rate
a. dobutamine (Dobutrex)
- Produces an inotropic effect by stimulating myocardial betareceptors and increasing the strength of myocardial activity
and improving cardiac output
b. Nitroglycerin
- Administered IV in low doses
- Acts as venous vasodilator and reduces preload
- With higher doses, this can cause arterial vasodilation and
therefore reduces afterload as well
c. Dopamine
- Inotropic agent and a sympathomimetic agent that has a
varying vasoactive effect depending on dosage
d. Antiarrhythmic medications
- Part of the medication regimen
e. Other vasoactive medications:
➢ Norepinephrine (Levophed)
➢ Epinephrine (Adrenalin)
➢ Milrinone (Primacor)
➢ Amrinone (Inocor)
➢ Vasopressin (Pitressin)
➢ Phenylephrine (NeoSynephrine)
Note: each of these medications stimulates the different
receptors of the sympathetic nervous system
3. Fluid Therapy
- Administration of fluids must be closely monitored to detect
signs of fluid overload
- A fluid bolus should never be quickly given because it may
result in acute pulmonary edema
Nursing Management
a. Preventing cardiogenic shock
- In some circumstances, it is best to identify pts who are at
risk
- prompting adequate oxygenation of heat muscle
- decreasing cardiac workload
- accomplished by conserving pt’s energy
- promptly relieving angina
- administering supplemental oxygen
b. Monitoring hemodynamic status
- Nurse anticipates medications, IV fluids, and equipment that
may be used and is ready to assist in implementing these
measures
- Changes in hemodynamic in cardiac and pulmonary status are
documented and reported promptly
c. Administering medications and IV fluids
- Nurse has a critical role in safe and accurate administration
of IV fluids and medications
- Fluid overload and pulmonary edema are risks because of
ineffective cardiac function and accumulation of blood and
fluid in pulmonary tissues
- Nurse should document and record medication and treatment
that are administered as well as the pt responds to
treatment
d. Maintaining intra-aortic balloon counterpulsation
e. Enhancing safety and comfort
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