Fig. 3
From: Regulation of the cerebral circulation: bedside assessment and clinical implications
Long-term invasive CBF and CPP monitoring. Example of the ‘Lassen curve’ depicting the relationship between CPP and CBF. It is derived from a long-term plot of thermal-dilution CBF and CPP monitored in a patient after severe brain injury. The curve shows lower (LLA) and upper (ULA) limits of autoregulation, outside which CBF is pressure passive. Notably, within the autoregulation range, CBF is not ideally stable but shows an increase in CBF around the LLA, which is commonly observed in patients under mild hyperventilation (in this case PaCO2 was on average 32 mmHg). CBF cerebral blood flow, CPP cerebral perfusion pressure, ICP intracranial pressure