Project title: Influence of Vasopressors on Brain Oxygenation and Microcirculation in
Anesthetized Patients with Cerebral Tumors
Sponsor-investigator: Klaus Ulrik Koch M.D.
Sponsor: Department of Anesthesia Aarhus University Hospital, Nørrebrogade 44, 8000 Aarhus C,
Denmark
Objective:
To investigate whether phenylephrine and ephedrine causes different alterations in
microcirculation and oxygenation, as measured with MRI and PET, in anesthetized patients with
brain tumors. Using MRI and PET, the study will assess whether there is a difference in
deoxyhemoglobin concentration (Bold signal), CTTH, cerebral blood flow (CBF) and cerebral
metabolic rate of oxygen (CMRO2) between ephedrine and phenylephrine
Method:
Double blinded controlled randomized clinical trial. Either phenylephrine or ephedrine are
infused intravenously under general anesthesia. MRI is performed in 20 patients before and
after infusion. PET/CT is performed in 20 patients before and after infusion. BIS and NIRS
monitoring will be used in either scanner. After scanning patients are transported to the
operating theatre and the craniotomy is performed. After removal of the bone flap subdural
ICP is measured and recorded.
MRI to analyze CBF, CTH, max.CMRO2, maxOEF, CBV and grey-scale ADC before and after ephedrine
and phenylephrine. PET/CT to analyze CBF and CMRO2 before and after ephedrine and
phenylephrine and calculation of OEF. During each PET/CT scan session oxygen saturation and
hemoglobin concentration is measured.
Data from the proposed studies will add substantial new knowledge to the investigators
current understanding of the effects of vasopressors on cerebral circulation. This
information will aid the neuroanesthesiologist, neurointensivist and the neurosurgeon in the
choice of the optimal method to manage cerebral perfusion pressure during craniotomy for
brain tumor.