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Chapter 17: Cardiovascular Emergencies

Jun 28, 2024

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Chapter 17: Cardiovascular Emergencies

Key Learning Objectives

By the end of this chapter, you should understand:

  • Anatomy and physiology of the cardiovascular system
  • Pathophysiology of respiration and perfusion
  • Signs and symptoms of common cardiac conditions
  • Indications, contraindications, and use of Automated External Defibrillators (AED)
  • General care for patients experiencing a cardiac emergency

Overview of Cardiovascular Emergencies

  • Cardiovascular disease has been the leading cause of death in the U.S. since the 1900s.
  • EMS can help reduce deaths by promoting a healthy lifestyle, early medical care access, CPR training, advanced technology usage, and public defibrillation device availability.

Anatomy and Physiology of the Cardiovascular System

Structure of the Heart

  • Heart's function: Pumps blood to supply oxygenated red blood cells to tissues.
  • Divisions: Left and right sides, each with an atrium (upper chamber) and a ventricle (lower chamber).
  • One-way valves: Ensure proper blood flow direction.
  • Aorta: Main artery that receives blood from the left ventricle and delivers it to other arteries.

Blood Circulation

  • Right side: Receives deoxygenated blood from the venous circulation.
  • Left side: Receives oxygenated blood via pulmonary arteries.
  • Electrical System: Sinus node generates electrical impulses, allowing the heart to contract rhythmically.
  • Autonomic Nervous System: Controls involuntary activities—sympathetic vs. parasympathetic systems.
  • Myocardial demand: Increased blood flow to the myocardium through coronary arteries during heightened activity.

Arteries and Blood Vessels

  • Coronary arteries: Supply blood to the heart muscle.
  • Major Arteries: Include carotid (head, brain), subclavian (upper extremities), brachial (arms), radial and ulnar (hands and lower arms), iliac (groin, pelvis), femoral (legs), and tibial (lower legs, feet).
  • Blood Components: Red blood cells (O2 transport), white blood cells (infection fighting), platelets (clotting), plasma (fluid matrix).
  • Blood Pressure: Systolic (during heart contraction), Diastolic (during heart relaxation).
  • Pulses: Peripheral (extremities) vs. central (trunk).

Pathophysiology

  • Ischemia: Decreased blood flow leading to tissue death if untreated.
  • Atherosclerosis: Build-up of calcium and cholesterol causing artery blockage.
  • Thromboembolism: Mobile blood clot causing tissue hypoxia if lodged.
  • Acute Myocardial Infarction (AMI): Death of heart muscle cells due to impaired blood flow, leading to heart's diminished pumping ability.

Types of Dysrhythmias

  • Premature Ventricular Contractions (PVCs): Harmless extra beats.
  • Tachycardia: ≥100 BPM.
  • Bradycardia: ≤60 BPM.
  • Ventricular Tachycardia: 150-200 BPM, risks turning into ventricular fibrillation (quivering ventricles, no blood pumping).

Cardiac Conditions

  • Cardiogenic Shock: Insufficient oxygen to tissues due to heart's inability to pump blood.
  • Congestive Heart Failure (CHF): Heart fails to pump effectively, leading to pulmonary edema.
  • Hypertensive Emergencies: Systolic BP >180 mm Hg, causing potential strokes or aortic aneurysms.
  • Aortic Aneurysm: Weakened aorta walls, potentially leading to rupture.

Emergency Care and Assessment

Patient Assessment Steps

  1. Scene Size-Up: Ensure safety, identify nature of illness.
  2. Primary Assessment: General impression, airway, and breathing checks. Immediate CPR and AED if unresponsive.
  3. Secondary Assessment: Focus on cardiac/respiratory systems, measure vitals, and perform a 12-lead ECG.
  4. History Taking: Use SAMPLE and OPQRST methods for getting patient history and assessing symptoms.
  5. Reassessment: Monitor patient condition, reassess vital signs, ensure AED availability.

Treatment and Procedures

  • Administer aspirin and assist with nitroglycerin if indicated.
  • AED usage: Proper application, checking for contraindications (e.g. pacemaker).
  • Carry out effective CPR and transport decisions based on patient stability.

Cardiac Surgeries and Devices

  • CABG and Angioplasty: Emergency interventions for coronary artery blockages.
  • Pacemakers and Defibrillators: Manage chronic heart conditions, ensure proper AED pad placement.
  • LVADs: For severe heart failure patients, ensure continuous monitoring and support.

Using an AED

  • Follow protocol for patient safety and proper AED operation.
  • Understand different scenarios: in-field cardiac arrest, during transport, using AED if advanced support is delayed.
  • Post-Resuscitation Care: Monitor respiration, maintain oxygen supply, ascertain blood pressure.

Additional Takeaways

  • Importance of Quality Improvement: Regular AED checks, operator training, incident reviews.
  • Advanced Life Support: Coordination with paramedic units, efficient transition from CPR to defibrillation.

Conclusion

By learning these key concepts, EMS providers can effectively manage cardiovascular emergencies, ensuring rapid intervention and increased survival rates. Stay current with continuous education and practical training.

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