NCLEX Cardiogenic Shock

NCLEX Cardiogenic Shock 

Cardiogenic Shock Overview

Cardiogenic shock is a life threatening medical condition resulting from an inadequate circulation of blood due to primary failure of the ventricles of the heart to function effectively.  Cardiogenic shock is a type of circulatory shock, where there is insufficient perfusion of tissue to meet the demands for oxygen and nutrients.  Cardiogenic shock is a largely irreversible condition and as such is more often fatal than not.  The condition involves increasingly more pervasive cell death from oxygen starvation (hypoxia) and nutrient starvation (low blood sugar).  Because of this, it may lead to cardiac arrest, which is an abrupt stopping of cardiac pump function.

Cardiogenic shock is defined by sustained low blood pressure with tissue hypoperfusion despite left ventricular filling pressure.  Signs of tissue hypoperfusion include low urine production (<30 mL/hr), cool extremities, and altered level of consciousness.

Signs and Symptoms

• Anxiety, restlessness, altered mental state due to decreased blood flow to the brain and subsequent hypoxia
• Low blood pressure due to decrease in cardiac output
• A rapid, weak, thready pulse due to decreased circulation combined with tachycardia
• Cool, clammy, and mottled skin due to vasoconstriction and subsequent hypoperfusion of the skin
• Distended jugular veins due to increased jugular venous pressure
• Oliguria due to inadequate blood flow to the kidneys if the condition persists
• Rapid and deeper respirations due to sympathetic nervous system stimulation and acidosis
• Fatigue due to hyperventilation and hypoxia
• Absent pulse in fast and abnormal heart rhythms
• Pulmonary edema, involving fluid back up in the lungs due to insufficient pumping of the heart

Causes

Cardiogenic shock is caused by the failure of the heart to pump effectively.  It can be due to any of the following

• Myocardial infarction
• Abnormal heart rhythms
• Cardiomyopathy, Cardiac valve problems
• Aortic valve stenosis, aortic dissection
• Cardiac tamponade
• Constrictive pericarditis
• Systolic anterior motion
• Hypertrophic cardiomyopathy
• Sudden decompressurization (aircraft)

Risk Factors

• Old age
• History of heart failure or heart attack
• Coronary artery disease
• Diabetes and/or HTN

Diagnosis

Electrocardiogram – helps establishing the exact diagnosis and guides treatment, it may reveal:

• Abnormal heart rhythm
• Myocardial infarction
• Signs of cardiomyopathy

Ultrasound – may show poor ventricular function, rupture of the interventricular septum, an obstructed outflow tract or cardiomyopathy.

Swan-Ganz Catheter – or PA catheter may assist in the diagnosis by providing information on the hemodynamics.

Biopsy – when cardiomyopathy is suspected as the cause of cardiogenic shock, a biopsy of heart muscle may be needed to make a definite diagnosis.

Treatment

• Aspirin
• Thrombolytics
• Blood thinners
• Inotropic agents
• Angioplasty and stenting
• Balloon pump
• Coronary artery bypass surgery
• Ventricular assist devices
• Heart transplant