Effects of sufentanil on cerebral circulation and metabolism in dogs.

The cerebral and peripheral vascular effects of sufentanil (10-200 micrograms/kg) were examined in dogs. The cerebral blood flow (CBF) was measured continuously by an electromagnetic flow probe on the outflow of the posterior sagittal sinus. Sufentanil at all doses significantly increased CBF that lasted for approximately 20 min. The CBF then gradually decreased so that it was significantly below baseline levels by the end of the 60-min study period. The transient increase in CBF was accompanied by an equally transient statistically significant decrease in cerebrovascular resistance. Intracranial pressure did not change. Sufentanil produced an electroencephalographic pattern of deep anesthesia accompanied by a decrease in cerebral oxygen consumption significantly below baseline levels. At the end of the study tissue concentrations of metabolites taken from the cerebral hemispheres were within normal limits, indicative of a normal cerebral energy state. Sufentanil had little effect on systemic hemodynamics. The observation that sufentanil significantly increases CBF in the absence of seizure activity makes it unique among the narcotics. It is hypothesized that in the presence of decreased intracranial compliance, this sudden increase in CBF, although transient, may be detrimental if it is accompanied by an acute increase in intracranial pressure which could produce cerebral ischemia.