Comparative effects of dexmedetomidine, propofol, sevoflurane, and S-ketamine on regional cerebral glucose metabolism in humans [Elektronisk resurs] a positron emission tomography study

• Introduction: The highly selective α 2 -agonist dexmedetomidine has become a popular sedative for neurointensive care patients. However, earlier studies have raised concern that dexmedetomidine might reduce cerebral blood flow without a concomitant decrease in metabolism. Here, we compared the effects of dexmedetomidine on the regional cerebral metabolic rate of glucose (CMR glu ) with three commonly used anaesthetic drugs at equi-sedative doses. Methods: One hundred and sixty healthy male subjects were randomised to EC 50 for verbal command of dexmedetomidine (1.5 ng ml -1 ; n =40), propofol (1.7 μg ml -1 ; n =40), sevoflurane (0.9% end-tidal; n =40) or S-ketamine (0.75 μg ml −1 ; n =20) or placebo ( n =20). Anaesthetics were administered using target-controlled infusion or vapouriser with end-tidal monitoring. 18 F-labelled fluorodeoxyglucose was administered 20 min after commencement of anaesthetic administration, and high-resolution positron emission tomography with arterial blood activity samples was used to quantify absolute CMR glu for whole brain and 15 brain regions. Results: At the time of [F 18 ]fluorodeoxyglucose injection, 55% of dexmedetomidine, 45% of propofol, 85% of sevoflurane, 45% of S-ketamine, and 0% of placebo subjects were unresponsive. Whole brain CMR glu was 63%, 71%, 71%, and 96% of placebo in the dexmedetomidine, propofol, sevoflurane, and S-ketamine groups, respectively ( P <0.001 between the groups). The lowest CMR glu was observed in nearly all brain regions with dexmedetomidine ( P <0.05 compared with all other groups). With S-ketamine, CMR glu did not differ from placebo. Conclusions: At equi-sedative doses in humans, potency in reducing CMR glu was dexmedetomidine>propofol>ketamine=placebo. These findings alleviate concerns for dexmedetomidine-induced vasoconstriction and cerebral ischaemia. 

Ämnesord

Medical and Health Sciences  (hsv)

Clinical Medicine  (hsv)

Anesthesiology and Intensive Care  (hsv)

Medicin och hälsovetenskap  (hsv)

Klinisk medicin  (hsv)

Anestesi och intensivvård  (hsv)

Medical and Health Sciences  (hsv)

Other Medical Sciences  (hsv)

Other Medical Sciences not elsewhere specified  (hsv)

Medicin och hälsovetenskap  (hsv)

Annan medicin och hälsovetenskap  (hsv)

Övrig annan medicin och hälsovetenskap  (hsv)

Indexterm och SAB-rubrik

cerebral blood flow

cerebral metabolism

positron emission tomography

sedation

target-controlled infusion