Cardiovascular System and Neurogenic Shock

Cardiovascular System Overview

• Heart: Central organ of the system.
• Arteries: Deliver oxygenated blood from the heart to the organs.
• Veins: Return deoxygenated blood from the organs to the heart.

Neurogenic Shock

• Definition: A type of shock where the nervous system stops functioning properly.
• Causes:
  • Trauma (e.g., spinal cord injury).
  • Epidural issues causing nerve damage.
• Mechanism:
  • Loss of sympathetic tone.
  • Leads to pooling of peripheral blood.

Vascular Tone and Blood Flow

• Sympathetic Tone: Maintains vascular tightness and is critical for blood pressure.
  • Similar to muscle flexing for tightness.
• Trampoline Analogy: Taut trampolines allow better bouncing akin to vascular tone maintaining blood flow.
• Loss of Tone:
  • Blood vessels become floppy (arteries and veins).
  • Reduced blood flow to organs.
  • Blood pooling in venous system.

Impact on Cardiovascular Function

• Decreased Systemic Vascular Resistance:
  • Lower blood pressure and tissue perfusion.
• Cardiac Output:
  • Dependent on stroke volume and heart rate.
  • Decreased blood return reduces stroke volume.
  • Reduced cardiac output decreases blood pressure further.
• Heart Rate:
  • Controlled by the sympathetic nervous system.
  • Loss of input causes bradycardia.

Symptoms of Neurogenic Shock

• General Symptoms:
  • Altered mental status.
  • Decreased urine output.
  • Overall organ dysfunction.
• Specific to Neurogenic Shock:
  • Bradycardia (unique among shock types).
  • Warm skin due to vessel dilation affecting blood distribution.

Treatment of Neurogenic Shock

• Pressers:
  • Medications to restore vascular tone by clamping blood vessels.
• IV Fluids:
  • Increase vascular fluid volume to maintain blood flow.
• Atropine:
  • Blocks parasympathetic action, enhances "fight or flight".
  • Increases heart rate and cardiac output.