Depth of sedation with dexmedetomidine increases transcranial magnetic stimulation-evoked potential amplitude non-linearly
Authors' conclusion
Transcranial magnetic stimulation-evoked potential amplitude changes non-linearly as a function of depth of sedation by dexmedetomidine, with a region-specific paradoxical increase.
Study context
- Population
- Healthy subjects undergoing dexmedetomidine sedation; TMS-EEG in frontal and parietal cortex
- Participants
- 20 subjects
- Comparison
- Light sedation, deep sedation and recovery vs baseline (dexmedetomidine); frontal vs parietal cortex
- Outcome
- Cortical excitability: amplitude of first component (0-30 ms) of transcranial magnetic stimulation (TMS)-evoked potential (TEP), plus slope and peak latencies
Methodological detailswithin-subject, four conditions, generalised linear mixed models
- Within-subject, four conditions
- Generalised linear mixed models
Main finding
As reported in the abstract
Frontal TEP amplitude
Increase
6.52 μV
P < 0.001
Light sedation
Increase
4.55 μV
P = 0.003
Deep sedation
Increase
5.03 μV
P < 0.001
Recovery
Further findings
| Outcome | Estimate | P value |
|---|---|---|
| Frontal vs parietal cortex (region)Frontal vs Parietal | higher amplitude 5.73 μV | P < 0.001 |
| Frontal vs parietal cortex (region)Frontal vs Parietal | higher slope 0.63 μV ms-1 | P < 0.001 |
| Frontal vs parietal cortex (region)Frontal vs Parietal | shorter negative peak latency 2.2 ms | P = 0.001 |
TMS-evoked potential (TEP) slope
- Slope increased vs baseline in all conditions in frontal but not parietal cortex
- P < 0.02
Dexmedetomidine × region interaction
- Interaction effect on amplitude
- P = 0.004
- Interaction effect on slope
- P = 0.009
- Both higher in light sedation, deep sedation and recovery vs baseline
Original publication
Depth of sedation with dexmedetomidine increases transcranial magnetic stimulation-evoked potential amplitude non-linearly. Br J Anaesth. Published 16 August 2023. doi:10.
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