EMS Care EMT Chapter 24-MCIT-F3-2106 | Understanding Pathophysiology – Ventilation, Perfusion & Shock    starts with an introduction to the topic and this course is about understanding the Pathophysiology of the human body with respect to Ventilation, Perfusion and Shock. Getting to know the cell structure of the human body, its functioning, the respiratory system and blood circulation will go a long when dealing with emergencies of the same.

The lessons covered are

• Lesson 1: Ventilation, Perfusion, and Shock
• Lesson 2: Ventilation in Depth
• Lesson 3: Perfusion Explored
• Lesson 4: Understanding Shock
• Lesson 5: Interplay of Ventilation, Perfusion and Shock
• Lesson 6: Special considerations and Review

Excerpt from EMS Care EMT Chapter 24-MCIT-F3-2106 | Understanding Pathophysiology – Ventilation, Perfusion & Shock

Several factors affect perfusion. Blood volume is crucial – significant blood loss can severely impair perfusion. A loss of just 15% of blood volume can begin to cause symptoms of hypovolemic shock. Heart function, including rate and strength of contractions, directly impacts cardiac output.

Vascular tone affects blood distribution – vasodilation or vasoconstriction can dramatically change perfusion to different body areas. For example, in septic shock, widespread vasodilation leads to hypotension and poor tissue perfusion.

Blood viscosity can affect flow, especially in small vessels. Conditions like severe dehydration or polycythemia can increase blood viscosity, impairing microcirculation. And don’t forget gravity – it’s why we elevate legs in shock or sit patients upright for respiratory distress.

The effects of gravity on perfusion are particularly important to consider in trauma situations.