Background Different opioids have different delays (hysteresis) between their concentrations
in blood and their cerebral effects. Possible mechanisms include differences in their rate of …

Background The pharmacodynamic differences in time to onset and dissipation of effect of
sufentanil, fentanyl, and alfentanil probably result from different rates of blood-brain …

Background Thiopental and propofol are highly lipid-soluble, and their entry into the brain
often is assumed to be limited by cerebral blood flow rather than by a diffusion barrier …

BACKGROUND: There are two recognized methods of estimating the brain concentrations
of IV anesthetic drugs:(i) use of pharmacokinetic/pharmacodynamic (PK/PD) modeling of …

Two groups of surgical patients each comprising six individuals received an intrathecal
injection of morphine 0.3 mg or meperidine 10 mg. Cerebrospinal fluid (CSF) and plasma …

Background The pharmacokinetics of epidurally administered drugs has been the subject of
many studies, yet drug concentration in the epidural space has never been measured. This …

Little information exists about which spinal meninx is the principal permeability barrier
between the epidural space and the spinal cord or about what physicochemical properties of …

Background The ability of epinephrine to improve the efficacy of epidurally administered
drugs is assumed to result from local vasoconstriction and a consequent decrease in drug …

Background The current study investigated dose-dependent effects of the mu-selective
agonist remifentanil on regional cerebral blood flow (rCBF) in volunteers using positron …

Investigations on the effects of opioids on cerebrovascular dynamics have repeatedly
demonstrated mild to moderate increases in cerebral blood flow velocity in the middle …