Shock for NP
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Shock for the Nurse Practitioner Licensing Exam
Shock is a critical condition of inadequate tissue perfusion that can result in organ dysfunction. It is categorized into four main types: hypovolemic, distributive, cardiogenic, and obstructive.
Types of Shock
Hypovolemic Shock
- Etiology: Caused by significant fluid loss, commonly due to hemorrhage (e.g., trauma, gastrointestinal bleeding) or dehydration (e.g., severe vomiting, diarrhea, burns).
- Pathophysiology: Reduced blood volume decreases cardiac output and tissue perfusion.
- Clinical Features: Tachycardia, hypotension, cool and clammy skin, and delayed capillary refill.
- Management: Rapid administration of crystalloids (e.g., normal saline) and blood transfusions if hemorrhagic.
Distributive Shock
Distributive shock is characterized by systemic vasodilation, leading to a relative decrease in intravascular volume.
Septic Shock
- Etiology: Caused by a severe infection leading to systemic inflammation.
- Pathophysiology: Widespread vasodilation and capillary leakage decrease systemic vascular resistance.
- Clinical Features: Fever, tachycardia, hypotension, warm skin (early stage).
- Management: Broad-spectrum antibiotics, IV fluids, and norepinephrine if hypotension persists.
Anaphylactic Shock
- Etiology: Severe allergic reaction to allergens (e.g., foods, medications, insect stings).
- Pathophysiology: IgE-mediated release of histamine causes vasodilation and bronchoconstriction.
- Management: First-line treatment is epinephrine; also give IV fluids, antihistamines, and corticosteroids.
Cardiogenic Shock
- Etiology: Most often due to acute myocardial infarction, but can also be from severe heart failure or arrhythmias.
- Pathophysiology: Cardiac pump failure reduces cardiac output.
- Clinical Features: Hypotension, cool extremities, jugular venous distention, pulmonary crackles.
- Management: Inotropes (e.g., dobutamine) and vasopressors; revascularization if due to myocardial infarction.
Obstructive Shock
Obstructive shock is due to mechanical blockage of blood flow.
- Etiology: Common causes include pulmonary embolism (PE), tension pneumothorax, and cardiac tamponade.
- Management:
- PE: Anticoagulation or thrombolytics.
- Tension Pneumothorax: Immediate needle decompression.
- Cardiac Tamponade: Urgent pericardiocentesis.
Key Points
- Types of Shock:
- Hypovolemic: Caused by fluid loss; treated with IV fluids and blood products if needed.
- Distributive: Septic and anaphylactic shock involve vasodilation; managed with fluids and vasopressors.
- Cardiogenic: Due to pump failure; treated with inotropes, vasopressors, and revascularization if needed.
- Obstructive: Mechanical blockages; managed by removing the obstruction.
- Hemodynamic Profiles:
- SVR: Decreased in distributive shock; increased in hypovolemic and cardiogenic shock.
- CVP: Low in hypovolemic shock; elevated in cardiogenic and obstructive shock.
- Management Principles:
- Fluid Resuscitation: Primary treatment for hypovolemic and distributive shock.
- Vasopressors: Norepinephrine is first-line in septic shock if fluids are insufficient.
- Inotropes: Used in cardiogenic shock to improve cardiac output.