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Shock and Cardiac Emergencies Overview

Jun 10, 2025

Overview

This lecture covers critical alterations in perfusion, focusing on pathophysiology, epidemiology, risk factors, clinical presentations, nursing roles, and management of shock, cardiac events, and related syndromes.

Types and Pathophysiology of Shock

  • Shock is a life-threatening condition from circulatory failure causing tissue hypoxia, cell death, and organ dysfunction.
  • Main types: Distributive (low systemic vascular resistance), Hypovolemic (blood volume loss), Cardiogenic (heart pump failure), Obstructive (physical blockage).
  • Distributive shock subtypes: Septic, Anaphylactic, Neurogenic, Toxic.
  • Hypovolemic shock results from ≥25-30% blood loss; can be hemorrhagic or non-hemorrhagic.
  • Cardiogenic shock is due to cardiac dysfunction, reduced output, and compensatory vasoconstriction.
  • Obstructive shock comes from blood flow blockage (e.g., PE, cardiac tamponade).

Phases, Causes, and Clinical Presentations of Shock

  • Four stages: Initial (subtle symptoms), Compensatory (tachycardia, stable BP), Progressive (altered consciousness, weak pulses), Refractory (organ failure, death).
  • Early sign: increased respiratory rate, especially in sepsis.
  • Causes include trauma, infection, blood loss, MI, arrhythmias, and cardiac tamponade.

Diagnosis and Nursing Management of Shock

  • Lab tests: CBC, electrolytes, cultures, cardiac enzymes, ABGs, lactate.
  • Elevated lactate indicates anaerobic metabolism and tissue hypoxia.
  • Nurses monitor perfusion, educate patients/families, and move patients to ICU as needed.
  • Treatments: IV fluids, antibiotics, vasopressors, blood products, mechanical support.
  • Specific therapies depend on shock type (e.g., epinephrine for anaphylaxis, blood for hemorrhage).

Cardiac Tamponade

  • Fluid accumulation in pericardium compresses the heart, causing decreased output and shock.
  • Presents with hypotension, jugular vein distension, muffled heart sounds (Beck's triad), pulsus paradoxus.
  • Diagnosed by echocardiogram; treated by pericardiocentesis or surgery (pericardial window).

Coronary Artery Bypass Graft (CABG)

  • CABG restores heart blood flow using grafts for severe coronary artery disease.
  • Risks: infection, bleeding, MI, arrhythmias, anxiety, depression.
  • Pre/post-op care: vital signs, lab work, sedation, pain control, chest tube monitoring, infection prevention.
  • Medications: statins, antiplatelets, beta-blockers, insulin, antibiotics.
  • Nutrition: high protein/calorie intake post-op.

Heart Valve Replacement

  • Replaces dysfunctional valves (often aortic/mitral) with tissue or mechanical options.
  • Risk factors: family history, age, endocarditis, MI, rheumatic fever.
  • Complications: stroke, heart failure, clots, death.
  • Nursing role: communication, safety, monitoring, client education.

Cardiac Arrest

  • Loss of heart function; shockable rhythms: VFib, VTach; non-shockable: asystole, PEA.
  • Causes: heart disease, arrhythmias, sepsis, trauma.
  • Outcome worsens with delayed treatment.
  • Role of nurse: initiate CPR, call code, assist with meds, family support.

Abdominal Aortic Aneurysm (AAA)

  • Dilated aorta (>30 mm); rupture is life-threatening (90% mortality).
  • Risk: atherosclerosis, smoking, male, family history, hypertension.
  • Diagnosed by imaging; treated with surgery (EVAR/open repair) if large.

Systemic Inflammatory Response Syndrome (SIRS) & MODS

  • SIRS: widespread inflammation due to infection/injury; can progress to sepsis.
  • Criteria: temp, HR, RR, WBC abnormalities.
  • MODS: failure of ≥2 organs from unbalanced immune response (high mortality).
  • SOFA score assesses organ failure.

Disseminated Intravascular Coagulation (DIC)

  • DIC: simultaneous clotting and bleeding, high mortality.
  • Causes: transfusion reaction, infection, cancer, trauma.
  • Labs: high PT, PTT, D-dimer; low fibrinogen, platelets.
  • Signs: bleeding, hypotension, organ dysfunction.

Key Terms & Definitions

  • Perfusion — The flow of blood to tissues to supply oxygen and nutrients.
  • Systemic Vascular Resistance (SVR) — Force opposing blood flow in vessels.
  • Sepsis — Life-threatening organ dysfunction from infection.
  • Lactate — Blood marker of anaerobic metabolism and hypoxia.
  • Beck's Triad — Hypotension, JVD, muffled heart sounds in cardiac tamponade.
  • CABG — Surgical graft to restore heart blood flow.
  • MODS — Multi-Organ Dysfunction Syndrome; failure of two or more organs.
  • DIC — Widespread clotting and bleeding disorder.

Action Items / Next Steps

  • Review lab values and diagnostic criteria for shock and related conditions.
  • Practice recognizing early signs of shock and cardiac arrest.
  • Complete assigned readings on perfusion disorders.
  • Prepare for case studies/clinical scenarios on shock management and response.

Full transcript