Cushing reflex
Physiological response to elevated intracranial pressure characterized by hypertension, bradycardia, and irregular respiration.
Full Definition
The Cushing reflex, also known as Cushing's triad, is a late and ominous sign of severely elevated intracranial pressure representing the body's attempt to maintain cerebral perfusion pressure. The reflex consists of three components: systemic hypertension (often with widened pulse pressure), bradycardia, and irregular or abnormal respiratory patterns (such as Cheyne-Stokes breathing). This physiological response occurs when intracranial pressure approaches mean arterial pressure, threatening cerebral blood flow. The hypertension represents an attempt to overcome elevated ICP, while bradycardia results from baroreceptor response to the elevated blood pressure. When present, Cushing reflex indicates impending brain herniation and requires immediate intervention to reduce intracranial pressure. It is considered a pre-terminal sign with grave prognostic implications.
Usage
Usage note: Capitalize Cushing when referring to the eponymous reflex; critical finding requiring immediate action.
In Context
- "The patient developed Cushing reflex with blood pressure 220/100 and heart rate 45." — Emergency assessment
- "Cushing reflex was noted prior to emergent decompressive surgery." — Pre-operative note