Anesthesia and analgesia
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Anesthesia and analgesia · May 1993
Comparative StudyThe effect of fentanyl, sufentanil, and alfentanil on cerebral arterioles in piglets.
The effect of fentanyl, sufentanil, and alfentanil on cerebral arterioles was determined in 17 halothane-anesthetized newborn piglets. A closed cranial window was inserted over the parietal cortex, and changes in the luminal diameter of pial arterioles were measured by intravital microscopy as increasing concentrations of opioid (10(-9)-10(-5) M) were suffused over the cortical surface. ⋯ Naloxone alone had no effect at concentrations < or = 10(-5) M, suggesting that endogenous opioids contribute little to resting cerebrovascular tone. These results indicate that fentanyl, sufentanil, and alfentanil produce cerebral vasoconstriction by action at an opioid receptor and that their vasoconstrictive potency appears to differ from their analgesic potency.
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Anesthesia and analgesia · May 1993
Fentanyl plasma concentrations maintained by a simple infusion scheme in patients undergoing cardiac surgery.
The ability of a simple infusion scheme for fentanyl to achieve and maintain one of two target concentrations of fentanyl in plasma was studied in 17 patients having cardiac surgery that required the use of moderate hypothermic cardiopulmonary bypass (CPB). All patients received preanesthetic medication including morphine, a benzodiazepine, and/or scopolamine. Anesthesia was induced and maintained by one of two fentanyl infusion regimens: HIGH-FEN (n = 6), a priming infusion of 2.4 micrograms.kg-1 x min-1 for 20 min in combination with a continuous infusion of 0.3 microgram.kg-1.min-1 for the duration of the operation to produce a plasma fentanyl concentration of 20-25 ng/mL; or LOW-FEN (n = 11), priming and maintenance infusions of 2.4 and 0.15 micrograms.kg-1 x min-1 designed to produce a fentanyl concentration of 12-15 ng/mL of plasma. ⋯ The 11 patients receiving LOW-FEN had a plasma fentanyl concentration maintained below 20 ng/mL (range 13-17 ng/mL). Eight patients before and 10 patients after CPB required anesthetic supplementation for adverse hemodynamic or somatic responses. For comparison purposes, another eight patients received a single 75 micrograms/kg dose of fentanyl during 20 min for induction of anesthesia, and 7 of the 8 required supplemental anesthetic agents before and after CPB.(ABSTRACT TRUNCATED AT 250 WORDS)