Serial measurement of static and dynamic cerebrovascular autoregulation after brain injury.
BACKGROUND
In patients with neuronal injury, the knowledge of the status of cerebrovascular autoregulation can help to optimize the management of the cerebral perfusion pressure. This study characterizes dynamic and static cerebrovascular autoregulation during the first 7 days after severe traumatic brain injury or intracranial hemorrhage.


METHODS
After approval from the IRB, 16 patients were studied. Cerebral blood flow velocity (CBFV) was measured daily for the assessment of dynamic (10 patients) and static (16 patients) cerebrovascular autoregulation in both the middle cerebral arteries using the transcranial Doppler sonography. Dynamic cerebrovascular autoregulation (dAR) was measured using the cuff-deflation method and was expressed by the index of the dAR. The index of the static cerebrovascular autoregulation (sAR) was calculated from changes in the CBFV in relation to drug-induced alterations of the arterial blood pressure. For statistical analyses, t test and mixed effect model were used.


RESULTS
Both dAR and sAR after brain injury were impaired in most of the patients. The chronologic sequence of the dAR at the ipsilateral injured hemisphere showed a significant decrease until day 4 followed by an incomplete recovery (P < 0.002). Changes in sAR were similar, however, they did not gain statistical significance. CBFV was lower at day 1-2 after injury in comparison with day 4 to 7 (P < 0.02).


CONCLUSIONS
Daily measured dAR and sAR were impaired after brain injury with a nadir on day 4 and consecutive incomplete recovery over time.
Department of Anesthesiology, University Medical Center of the Johannes Gutenberg-University Mainz, Mainz, Germany. schrammp@uni-mainz.de
Patrick
P
Schramm
Klaus Ulrich
KU
Klein
Monika
M
Pape
Manfred
M
Berres
Christian
C
Werner
Eberhard
E
Kochs
Kristin
K
Engelhard
D000328:Adult; D000368:Aged; D000465:Algorithms; D001794:Blood Pressure / Q000502:physiology; D001930:Brain Injuries / Q000000981:diagnostic imaging / Q000503:physiopathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D005260:Female; D006706:Homeostasis / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017585:Ultrasonography, Doppler, Transcranial; D055815:Young Adult