autoregulation
The brain's ability to maintain constant cerebral blood flow despite changes in systemic blood pressure.
Full Definition
Autoregulation is a critical physiological mechanism whereby cerebral blood vessels automatically adjust their diameter to maintain consistent blood flow to brain tissue across a range of systemic blood pressures, typically between 50-150 mmHg mean arterial pressure. This process is often impaired in neurocritical care patients following brain injury, stroke, or other neurological insults. Loss of autoregulation makes patients vulnerable to both ischemia during hypotension and hemorrhage during hypertension. Monitoring and assessment of autoregulatory capacity is essential for optimizing blood pressure targets in critically ill neurological patients.
Usage
Usage note: Often used in context of pressure reactivity monitoring and targeted therapy.
In Context
- "The patient's impaired autoregulation necessitated tight blood pressure control to prevent secondary injury." — Neurocritical care progress note
- "Autoregulation testing revealed a lower limit of 70 mmHg, requiring adjustment of MAP targets." — Monitoring report