PCT - Bleeding and Shock (Chapter 21)

Introduction to Bleeding and Hemorrhage Control

• Recognition of bleeding as a primary concern in emergency medicine.

• Shift from airway being the top priority to understanding the time-sensitive nature of bleeding control.

• Courses like "Stop the Bleed" teach skill levels from laypeople to EMS practitioners on bleeding control.

Key Concepts

Time-Sensitivity of Bleeding

• All types of bleeding can potentially be life-threatening.

• Example: An epistaxis (nosebleed) in elderly patients or those on anticoagulants can lead to shock.

Function of the Cardiovascular System

• Primary purpose: to maintain blood flow to organs, delivering oxygen through the lungs and peripheral tissues.

• Inadequate blood flow can trigger anaerobic metabolism, producing toxic waste.

• Three Components of the Cardiovascular System:

  • Heart

  • Blood

  • Blood vessels

• All components must maintain effective interaction to sustain life.

Anatomy of the Heart

• Structure and Location:

  • Muscular, cone-shaped organ behind the sternum, mainly on the left side.

• Size: Roughly the size of a closed fist; weighs around 280-350g in men and 255-280g in women.

• Chambers of the Heart:

  • Four chambers: two atria and two ventricles.

  • Atria receive blood; ventricles pump blood to the body.

• Valves:

  • Atrioventricular valves prevent backflow; semilunar valves allow blood flow from ventricles to systemic circulation.

Blood Flow Process

• Deoxygenated blood returns from the body via superior/inferior vena cavae to the right atrium.

• Blood flows through the tricuspid valve to the right ventricle, then into the pulmonary artery and lungs for oxygenation.

• Oxygenated blood returns to the left atrium via pulmonary veins, flowing through the mitral valve to the left ventricle.

• Oxygenated blood pumped into the aorta for distribution throughout the body.

Cardiac Cycle

• A repetitive process that begins with contraction and ends just before the next contraction.

• Terminology to Know:

  • Afterload

  • Stroke volume

  • Myocardial contraction

  • Ejection fraction.

• Cardiac output: amount of blood pumped in one minute (calculation: pulse rate x stroke volume).

• Factors affecting cardiac output include pulse rate and stroke volume, influencing oxygen delivery to tissues.

Components of Blood

Plasma

• Clear, straw-colored fluid majority of blood composition (92% water, 8% dissolved substances).

• Water enters plasma from digestive tract, between cells, or as metabolic by-product.

Red Blood Cells (RBCs)

• Most numerous formed elements in blood, lacking movement ability, rely on plasma.

• Contain hemoglobin; each molecule can bind to four oxygen molecules, accounts for blood color.

White Blood Cells (Leukocytes)

• Primary function: fighting infection; various types exist.

Platelets

• Key for clot formation; small cell fragments essential in controlling bleeding.

• Lifespan of 7-10 days; count ranges from 50,000 to 400,000 per microliter of blood.

Blood Vessels

Types of Blood Vessels

• Arteries: High-pressure, oxygenated blood.

• Veins: Often low-pressure, deoxygenated blood.

• Capillaries: Sites for perfusion and diffusion between blood and tissues.

Perfusion

• Definition: circulation of blood within organ/tissue to meet oxygen and nutrient needs.

• Adequate circulation depends on speed to maintain flow while allowing for exchange processes.

• Critical organs require constant perfusion; lack of can result in damage within specific time frames.

• Special conditions like cooling and permissive hypothermia may influence responses.

Assessment of Bleeding

Types of Bleeding

• External Bleeding: Visible, often classified by vessel type.

• Internal Bleeding: Not directly visible; use signs and symptoms for diagnosis.

• Severity of bleeding correlates to type of injury and vessel affected.

Indicators of Serious Bleeding

• Significant mechanism of injury, poor patient appearance, signs of shock, and ongoing blood loss indicate serious conditions.

Managing Bleeding

Initial Assessment

• Search for life-threatening bleeding; address as necessary.

• Use direct pressure to manage most external bleeding.

Treatment Options

• Direct Pressure: First line for managing external bleeding.

• Tourniquets: Last resort for severe arterial bleeding; avoid joints, apply tightly, never loosen after application.

• Wound Packing: Highly effective for specific injuries; use hemostatic dressings if available.

Internal Hemorrhage Management

• Stabilization via maintaining airway and circulation; high-flow oxygen.

• Administer IV fluids as needed but transport without delay.

Conclusion

• Understanding bleeding mechanisms, management tactics, and rapid assessment can significantly improve patient outcomes in emergency situations.

• Continuous updates on clinical practices and techniques, such as the importance of tourniquets and wound packing, are crucial for paramedics.