Cerebral blood flow and transcranial doppler sonography measurements of CO2-reactivity in acute traumatic brain injured patients.
BACKGROUND
Cerebral blood flow (CBF) measurements are helpful in managing patients with traumatic brain injury (TBI), and testing the cerebrovascular reactivity to CO(2) provides information about injury severity and outcome. The complexity and potential hazard of performing CBF measurements limits routine clinical use. An alternative approach is to measure the CBF velocity using bedside, non-invasive, and transcranial Doppler (TCD) sonography. This study was performed to investigate if TCD is a useful alternative to CBF in patients with severe TBI.


METHODS
CBF and TCD flow velocity measurements and cerebrovascular reactivity to hypocapnia were simultaneously evaluated in 27 patients with acute TBI. Measurements were performed preoperatively during controlled normocapnia and hypocapnia in patients scheduled for hematoma evacuation under general anesthesia.
Although the lack of statistical correlation between the calculated reactivity indices, there was a significant decrease in TCD-mean flow velocity and a decrease in CBF with hypocapnia. CBF and TCD do not seem to be directly interchangeable in determining CO(2)-reactivity in TBI, despite both methods demonstrating deviation in the same direction during hypocapnia. TCD and CBF measurements both provide useful information on cerebrovascular events which, although not interchangeable, may complement each other in clinical scenarios.
Department of Neuroanesthesia, Lund University Hospital, Lund, Sweden, peter.reinstrup@med.lu.se.
Peter
P
Reinstrup
Erik
E
Ryding
Bogi
B
Asgeirsson
Karin
K
Hesselgard
Johan
J
Unden
Bertil
B
Romner
D000293:Adolescent; D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D001930:Brain Injuries / Q000000981:diagnostic imaging*; D002245:Carbon Dioxide / Q000097:blood*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006801:Humans; D016857:Hypocapnia / Q000000981:diagnostic imaging; D008875:Middle Aged; D017585:Ultrasonography, Doppler, Transcranial / Q000379:methods*; D055815:Young Adult
D002245:Carbon Dioxide