Feasibility of measuring memory response to increasing dexmedetomidine sedation in children

Abstract

Background: The memory effect of dexmedetomidine has not been prospectively evaluated in children. We evaluated the feasibility of measuring memory and sedation responses in children during dexmedetomidine sedation for non-painful radiological imaging studies. Secondarily, we quantified changes in memory in relation to the onset of sedation.

Methods: A 10 min bolus of dexmedetomidine (2 mcg kg-1) was given to children as they named simple line drawings every five s. The absence of sedation was identified as any verbal response, regardless of correctness. After recovery, recognition memory was tested with correct Yes/No recognitions (50% novel pictures) and was matched to sedation responses during the bolus period (subsequent memory paradigm).

Results: Of 64 accruals, 30 children (mean [SD]6.1 (1.2) yr, eight male) received dexmedetomidine and completed all study tasks. Individual responses were able to be modelled successfully in the 30 children completing all the study tasks, demonstrating feasibility of this approach. Children had 50% probability of verbal response at five min 40 s after infusion start, whereas 50% probability of subsequent recognition memory occurred sooner at four min five s.

Conclusions: Quantifying memory and sedation effects during dexmedetomidine infusion in verbal children was possible and demonstrated that memory function was present until shortly before verbal unresponsiveness occurred. This is the first study to investigate the effect of dexmedetomidine on memory in children.

Clinical trial registration: NCT 02354378.

Trial registration: ClinicalTrials.gov NCT02354378.

Keywords: child; conscious sedation; dexmedetomidine; memory.

© The Author 2017. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Figures

Fig 1.

Individual probabilities (faint plots) of verbal responses (sedation) and subsequent recognition memory with time (s) as the predictor variable during the induction of dexmedetomidine sedation. Group average plots are indicated in bold. Probability of recognition memory consistently decayed before onset of sedation, and the distribution of time intervals between 50% probabilities are shown in part (B). Positive values indicate that 50% recognition memory occurred sooner than 50% sedation.

Fig 2.

Individual probabilities (faint plots) of verbal responses (sedation) and subsequent recognition memory with predicted serum dexmedetomidine concentration (ng ml-1) as the predictor variable during the induction of dexmedetomidine sedation. Group average plots are indicated in bold. Probability of recognition memory consistently decayed at lower predicted concentrations than onset of sedation, and the distribution of concentrations differences between 50% probabilities are shown in part (B). Positive values indicate that 50% recognition memory occurred at a lower concentration than 50% sedation.