Neurogenic Shock | Shock (Part 7)

Summary

This educational video, presented by Eddie Watson, delves into neurogenic shock, a type of distributive shock resulting from CNS injury, typically at T6 or higher spinal cord levels. It explains the lack of sympathetic response leading to decreased blood pressure, heart rate, and cardiac output. The video outlines key signs like hypotension, bradycardia, and hypothermia with warm extremities, emphasizing the importance of ruling out other shock causes. Treatment involves protecting the spine, IV fluids, vasopressors, inotropes, and possibly pacing to increase heart rate. It also stresses maintaining a higher mean arterial pressure for spinal cord perfusion and protecting the airway due to potential respiratory failure, offering a comprehensive guide for medical professionals.

Takeaways

• 🧠 Neurogenic shock is a type of distributive shock resulting from CNS injury, typically involving the cervical or high thoracic spinal cord (T6 level or higher).
• 🚫 The injury leads to an impact on sympathetic nerve outflow, causing a lack of sympathetic response while the parasympathetic response remains active.
• 🌡️ In neurogenic shock, there's a decrease in systemic vascular resistance and blood pressure due to the absence of catecholamines that normally cause vasoconstriction.
• 💓 The sympathetic nervous system's absence also affects the heart, leading to decreased cardiac contraction and preload, contributing to reduced cardiac output.
• 🐦 A characteristic sign of neurogenic shock is a low heart rate due to the lack of sympathetic innervation of the SA node.
• 🌡️ Hypothermia can occur in neurogenic shock, but it is central, meaning the patient's core temperature drops due to hypothalamic dysregulation, not peripheral vasoconstriction.
• 📋 Diagnosing neurogenic shock requires ruling out all other possible causes of shock to ensure accuracy.
• 🩺 Key signs of neurogenic shock include decreased blood pressure, bradycardia, decreased cardiac output, and warm, dry extremities despite hypothermia.
• 🛑 Initial treatment involves protecting the spine to prevent further damage, using measures like a flat bed, c-collar, and log rolling.
• 💧 The first line of treatment for neurogenic shock is IV fluids to replace intravascular volume and counteract the effects of decreased vascular tone.
• 💊 If hypotension persists, vasopressors and inotropes may be used to induce vasoconstriction and improve cardiac contractility, respectively.
• 🔁 For significant bradycardia, medications like dopamine and atropine, or pacing, may be considered to increase heart rate and counteract the parasympathetic response.

Q & A

What is the main focus of the seventh lesson in the series?

The seventh lesson focuses on neurogenic shock, a type of distributive shock, and its various aspects including its causes, effects, diagnosis, and treatment.

What does the term 'neurogenic shock' refer to?

Neurogenic shock refers to a state of shock that results from an injury to the central nervous system (CNS), particularly involving the brain and spinal cord.

What is the role of the sympathetic nervous system in neurogenic shock?

In neurogenic shock, there is an impact on the sympathetic nerve outflow, leading to a lack of sympathetic response while the parasympathetic response remains preserved.

How does neurogenic shock affect coronary blood vessels?

In neurogenic shock, the lack of sympathetic response means there is no dilation of the coronary blood flow that normally occurs during the fight-or-flight response.

What is the impact of neurogenic shock on systemic vascular resistance?

Neurogenic shock leads to a decrease in systemic vascular resistance, which contributes to a decrease in blood pressure due to the lack of sympathetic activation.

Why does neurogenic shock result in decreased cardiac contraction?

The sympathetic nervous system normally has a positive inotropic effect on the heart. In neurogenic shock, the absence of this sympathetic activation results in decreased cardiac contraction.

What is the significance of the SA node in neurogenic shock?

The SA node, or the sinoatrial node, is responsible for controlling the heart rate. In neurogenic shock, the lack of sympathetic innervation to the SA node results in a low heart rate.

Why is hypothermia a potential symptom in neurogenic shock?

Hypothermia can occur in neurogenic shock due to dysregulation within the hypothalamus, which is responsible for body temperature regulation. The lack of sympathetic response also prevents the typical vasoconstriction that leads to cool, clammy skin.

What is the primary treatment for neurogenic shock?

The primary treatment for neurogenic shock includes protecting the spine, administering IV fluids to replace intravascular volume, and using vasopressors and inotropes if necessary.

How does treatment for neurogenic shock differ from other types of shock?

Treatment for neurogenic shock focuses on maintaining a higher mean arterial pressure to ensure adequate spinal cord perfusion, protecting the airway, and managing bradycardia, which are specific considerations due to the CNS injury.

What is the importance of ruling out other causes of shock before diagnosing neurogenic shock?

It is crucial to rule out other causes of shock to ensure an accurate diagnosis and appropriate treatment. Neurogenic shock has specific treatments and considerations that differ from other shock states.