Between what range does cerebral autoregulation occur? How does this change in chronically hypertensive patients?

  • Cerebral blood flow is autoregulated between a MAP of 50 – 150 mmHg
    • Outside the autoregulatory range:
      • When MAP >150 mmHg CBF becomes directly proportional to CPP
      • When MAP falls <50 mmHg CBF falls proportionally below the ‘normal’ value of 50 mL/100 g/min, resulting in ischaemia
  • In hypertensive patients autoregulation occurs between a higher range of pressures (60 and 160 mmHg)
Effects of cerebral autoregulation, demonstrating the relationship between cerebral perfusion pressure and cerebral blood flow