Middle cerebral artery flow, the critical closing pressure, and the optimal mean arterial pressure in comatose cardiac arrest survivors—An observational study

Abstract

CrCP is high after cardiac arrest with high cerebrovascular resistance and low MFV. This suggests that cerebral perfusion pressure should be maintained at a sufficient high level to avoid secondary brain injury. Failure to normalize the cerebrovascular profile may be a parameter of poor outcome.

Cerebral Perfusion and Cerebral Autoregulation after Cardiac Arrest

“…Finally, CBF returns to normal, remains low, or increases [ 24 , 25 ]. In more recent literature, only a return to normal or an increase in CBF is described [ 2 , 26 ]. Bisschops et al described a low mean flow velocity in the middle cerebral artery (MFV MCA ) on admission, which remained relatively stable during the first day and increased to normal levels at 48 hours [ 2 ].…”

“…The MFV MCA was shown to be similar in survivors and nonsurvivors upon ICU admission [ 26 ]. However, in survivors of cardiac arrest, the MFV MCA increases towards normal values in the following 72 hours, whereas a much more pronounced increase in MFV MCA , resulting in an overshoot of CBF, was observed in nonsurvivors [ 26 ]. This overshoot is most likely the result of a loss in vascular tone resulting in a decrease in cerebrovascular resistance in these nonsurvivors [ 26 ].…”

“…The critical closing pressure (CrCP) is a reliable method to quantify characteristics of the cerebrovascular bed and is defined as the lower limit of arterial blood pressure below which vessels collapse and flow ceases [ 43 , 44 ]. Immediately following cardiac arrest, CrCP was shown to be high, accompanied by increased cerebrovascular resistance [ 26 ]. The CrCP decreased in the first 48 hours after admission towards normal values [ 26 ].…”

“…Immediately following cardiac arrest, CrCP was shown to be high, accompanied by increased cerebrovascular resistance [ 26 ]. The CrCP decreased in the first 48 hours after admission towards normal values [ 26 ]. The CrCP was significantly higher in patients who survived compared to those who deceased [ 26 ].…”

“…The CrCP decreased in the first 48 hours after admission towards normal values [ 26 ]. The CrCP was significantly higher in patients who survived compared to those who deceased [ 26 ]. Apparently, vasoactive tone was lost in patients with unfavourable outcome, resulting in reduced cerebrovascular resistance and a subsequent-increased CBF.…”