Emergency Medical Technician (EMT) Basic Certification Practice Exam

Increased levels of carbon dioxide in the blood cause what effect on intracranial pressure?

1. Cerebral vessels constrict

2. Decrease in blood flow

3. Cerebral vessels dilate

4. Increase in neurological function

The correct answer is: Cerebral vessels dilate

Increased levels of carbon dioxide in the blood lead to a physiological response known as hypercapnia. When carbon dioxide levels rise, it causes cerebral vasodilation. This dilation of the cerebral blood vessels occurs because carbon dioxide acts as a potent vasodilator, meaning it relaxes the smooth muscle within the vessel walls, thereby increasing their diameter. As the cerebral vessels dilate, blood flow to the brain increases. This increased blood flow can lead to a rise in intracranial pressure, as the volume of blood within the confined space of the skull grows. This is significant in clinical settings, particularly in patients experiencing respiratory failure or other conditions leading to elevated carbon dioxide levels, as management of intracranial pressure is critical. Understanding this response is essential for EMTs and healthcare professionals, as it emphasizes the importance of monitoring and managing patients' respiratory status and carbon dioxide levels to prevent secondary complications such as increased intracranial pressure.