ITLS Hemorrhage control and shock

Chapter 4: Hemorrhage Control and Shock

Understanding Shock

• Definition and Causes:

  • Shock is a life-threatening condition marked by inadequate oxygen delivery to cells, leading to cellular dysfunction and hypoxia.

  • Transition to anaerobic metabolism occurs, resulting in increased lactate levels.

Components of Perfusion

• Fundamental Relationship:

  • Perfusion equation: Blood Pressure = Cardiac Output × PVR

    • Cardiac Output = Heart Rate × Stroke Volume

• Vascular System Components:

  • normal and adequate perfusion consists of

    • functioning pump

    • adequate air exchange

    • working vascular system

    • fluid volume

  • YOU NEED THE HEART TO PUMP OXYGENATED BLOOD AND THAT BLOOD NEEDS TO FLOW THROUGH YOUR BLOOD VESSELS TO GET PROPER TISSUE PERFUSION AND PREVENT CELL DEATH… duh

• Sequence of Events:

  • Inadequate blood volume leads to reduced oxygen delivery, hypoxia worsens, triggering anaerobic processes, which result in increased catecholamines and ultimately cell death.

Classic Shock Pattern

• Compensated Shock (15-25% blood volume loss):

  • Symptoms include weakness, pallor, tachycardia, thirst, and delayed capillary refill.

• Decompensated Shock (30-45% blood volume loss):

  • Identified by hypotension (first late sign), weak or absent peripheral pulse, and prolonged capillary refill.

Types of Shock

1. Hypovolemic Shock

• Related to low blood volume.

2. Distributive Shock (High Space Shock)

• Problems with vascular resistance.

3. Obstructive Shock

• Due to obstructions in circulatory flow.

4. Cardiogenic Shock

• Issues with heart function.

• Multiple types can occur simultaneously.

Hypovolemic Shock

• Early Signs:

  • Weakness, tachycardia, diaphoresis, low urinary output.

• Late Signs:

  • Hypotension, altered level of consciousness, potential cardiac arrest.

Tachycardia and Shock Indicators

• Critical Vital Sign:

  • Sustained pulse rate >100 bpm suggests hemorrhage; >120 bpm is a red flag.

  • Must rule out other causes, considering anxiety's temporary effects.

Low-Volume Shock

• Absolute Hypovolemia:

  • Manifested as tachycardia and paleness; characterized by thready pulse due to catecholamines prompting vasoconstriction.

High-Space Shock

• Relative Hypovolemia:

  • Disruption of sympathetic vasoconstriction patterns leading to vascular space dilation.

• Neurogenic Shock Characteristics:

  • Symptoms include hypotension, normal or slow heart rate, and warm, dry skin.

Mechanical Shock

• Blood Flow Obstruction:

  • Clinical signs include distended neck veins and cyanosis.

• Impacts Cardiac Output:

  • Results from impaired venous return.

Cardiogenic Shock

• Heart’s Pumping Issue:

  • Causes reduced cardiac output and low blood pressure.

  • Common causes include myocardial infarction or cardiac contusion.

Hemorrhage Management

• Controllable Hemorrhage Protocols:

  • Utilize direct pressure, anti-shock positioning, high-flow oxygen, rapid transportation, and large-bore IV access for fluid bolus administration.

• Uncontrollable Hemorrhage Strategies:

  • Prioritize rapid transport and high-flow oxygen, maintain peripheral pulses via IV access, and implement cardiac monitoring.

Special Situations

• Managing Shock in Specific Cases:

  • For severe head injury leading to hypovolemic shock: fluid administration to maintain specific blood pressure and cerebral perfusion pressure (CPP).

Principles of Shock Management

• Basic Guidelines:

  • C: Control bleeding

  • A: Maintain airway

  • B: Ensure ventilation and oxygenation

  • C: Support circulation with adequate heart rate and intravascular volume.

Tranexamic Acid (TXA)

• TXA Use in Traumas:

  • Stabilizes fibrin clots; should be administered early in bleeding trauma cases to maximize effectiveness.

Emerging Trends in Shock Management

• Blood Product Utilization:

  • Early administration of whole blood is optimized with a balanced ratio of PRBC, platelets, and plasma.

  • Monitoring lactate levels for shock evaluation in field settings.

  • Introduction of REBOA (Resuscitative Endovascular Balloon Occlusion of Aorta) technique for maintaining perfusion.

Summary

• A comprehensive understanding of shock's pathophysiology is vital as it can lead to fatal consequences if not rapidly assessed and managed.