autoregulaation

Autoregulation is the intrinsic ability of an organ or tissue to maintain a relatively constant blood flow despite changes in perfusion pressure. This local control helps stabilize tissue oxygen delivery and metabolic waste removal across a range of mean arterial pressures, ensuring stable function under varying systemic conditions.

Mechanisms include the myogenic response, where vascular smooth muscle constricts in response to increased transmural pressure to limit blood flow, and metabolic regulation, where local accumulation of CO2, adenosine, hydrogen ions, and potassium promotes vasodilation to match metabolic demand. Endothelial factors such as nitric oxide and endothelin modulate vascular tone, and organ-specific feedback systems, such as tubuloglomerular feedback in the kidney, contribute to local control of flow and filtration.

Different organs rely on autoregulation to varying degrees. The brain and heart exhibit robust autoregulation to protect tissue from hypo- or hyperperfusion, typically maintaining stable flow over a defined pressure range (roughly around 60 to 150–160 mmHg of mean arterial pressure in many contexts). The kidney uses tubuloglomerular feedback to stabilize the glomerular filtration rate, while pulmonary circulation has its own distinctive autoregulatory patterns. In disease, autoregulation can be impaired or shifted, as in chronic hypertension, aging, or acute injury, altering the range or effectiveness of the response.

Clinical relevance is prominent in anesthesia, critical care, neurology, and nephrology, where understanding autoregulation informs blood pressure targets and the interpretation of perfusion status. Measurement and assessment of autoregulation employ physiological monitoring and imaging techniques to gauge how well tissue perfusion remains stable under changing conditions.