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Fig. 3 | Critical Care

Fig. 3

From: Clinical pathophysiology of hypoxic ischemic brain injury after cardiac arrest: a “two-hit” model

Fig. 3

The zone of preserved autoregulation after hypoxic ischemic brain injury appears to be narrowed and right-shifted after cardiac arrest. Within the zone of autoregulation, regional saturation of oxygen (rSO2) is stable owing to the innate vasoconstriction and vasodilation of the cerebral vasculature to maintain stable cerebral blood flow. Outside the zone of autoregulation, a linear relationship exists between rSO2 and mean arterial pressure (MAP). By continually integrating the fluctuations of MAP and rSO2 with one another, a correlation coefficient (COx) can be generated. The COx approaches negative values or near-zero within the preserved zone of autoregulation, resulting in a U-shaped curve. The nadir of the U-shaped curve represents the optimal MAP (MAPOPT) for each individual patient

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