Cushing's Reflex (Define)

• A. Increase heart rate
• B. Decrease cerebral perfusion
• C. Attempt by the body to compensate for a decline in cerebral perfusion by increasing the mean arterial pressure
• D. Dilation of pupils

Answer: (C)

Cushing's reflex is the body's attempt to restore cerebral blood flow when intracranial pressure rises and cerebral perfusion pressure falls. When perfusion to the brain decreases, the body responds by increasing mean arterial pressure to push more blood into the brain. This compensatory rise in MAP helps maintain cerebral perfusion despite the rising ICP. You may also see the accompanying signs of the Cushing triad—hypertension with bradycardia and irregular respirations—meeting the context of impending brain injury. The other options don’t define the reflex: increasing heart rate isn’t the typical response (bradycardia is common), the trigger is decreased cerebral perfusion rather than the reflex itself, and pupil dilation isn’t a defining feature of this reflex.