Effects of dexmedetomidine on cerebral blood flow in critically ill patients with or without traumatic brain injury: A prospective controlled trial

Abstract

Study objective: To examine the effect of dexmedetomidine on CBF in critical ill patients with or without TBI.

Research design: Prospective controlled trial (ISRCTN57998533).

Methods: Fifteen patients without TBI and 20 patients with TBI with a Glasgow Coma Scale score of 4–14 were assigned to CON or TBI groups, respectively. All patients received 1 μg kg⁻¹ dexmedetomidine infused over 10 minutes, followed by a 0.4 μg kg⁻¹h⁻¹ continuous infusion for 60 minutes. Blood pressure was maintained at the pre-sedation level with dopamine for all patients. The CBF and cerebral metabolic rate equivalent (CMRe) were measured before sedation and 70 minutes after dexmedetomidine administration.

Results: Dexmedetomidine administration significantly decreased CBF in patients of the CON group (difference = 3.3 ml s⁻¹, 95% confidence interval [CI] = 0.92–5.7 ml s⁻¹, p = 0.008), without altering the CMRe and CMRe/CBF ratio. The dexmedetomidine-induced change of CBF, CMRe and CMRe/CBF was not significant in the TBI group. The percentage of CBF reduction was greater in the CON group than in the TBI group (difference = 13.9%, 95% CI = 5.5–22.2%, p = 0.002).

Conclusions: Dexmedetomidine may be used in patients with TBI without risk of affecting brain oxygenation.

• Cerebral blood flow
• cerebral metabolic rate
• patient
• traumatic brain injury

Acknowledgements

We thank Medjaden Bioscience Limited for language editing of this manuscript.