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Clonidine Conserves Sleep Spindle Properties and Age-Dependent Electroencephalogram Patterns Mirroring Physiologic
Andrew L Chen1, Mingjian He1, Uday Agrawal1
1From the Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
Insights
Clonidine does not alter sleep spindle activity on infant EEGs during spinal anesthesia. Infant EEG patterns under spinal anesthesia show age-related changes similar to quiet sleep, unaffected by clonidine.
Area of Science:
- Anesthesiology
- Neuroscience
- Pediatrics
Background:
- Spinal anesthesia is an alternative to general anesthesia in infants, but has a short block duration.
- Clonidine is often used to extend spinal anesthesia duration in infants, but its mechanism is unclear.
- Infants under spinal anesthesia exhibit a sleep-like state, prompting investigation into EEG sleep spindles.
Purpose of the Study:
- To investigate the effect of clonidine on sleep spindle activity in infants undergoing spinal anesthesia.
- To compare EEG spectral features and spindle characteristics between bupivacaine and bupivacaine with clonidine spinal anesthesia.
- To examine age-related EEG changes in infants under spinal anesthesia.
Main Methods:
- Intraoperative frontal EEG recordings were obtained from 73 infants under spinal anesthesia.
- Nonparametric multitaper spectral analysis compared EEG spectral features.
- Switching state-space modeling was used to extract and compare sleep spindle features.
Main Results:
- No significant difference in power spectra or sleep spindle detection probability was found between bupivacaine and bupivacaine + clonidine groups.
- Age-related EEG changes were observed, mirroring those in physiologic sleep, independent of clonidine.
- Increasing age correlated with decreased low-frequency power and increased higher-frequency power and spindle strength.
Conclusions:
- Low-dose clonidine does not appear to affect sleep spindle properties in infant EEGs during spinal anesthesia.
- Infant EEG patterns under spinal anesthesia exhibit age-related changes similar to quiet physiologic sleep.
- Intrathecal clonidine prolongs anesthetic duration without altering these EEG patterns.
Background:
Spinal anesthesia is an alternative to general anesthesia in infants. A caveat of spinal anesthesia in infants is short block duration. Clonidine is a common adjunct that prolongs spinal anesthesia. The mechanisms by which clonidine prolongs spinal anesthesia are unknown. Infants under spinal anesthesia appear in a sleep-like state. We hypothesized that infants receiving bupivacaine spinal anesthesia with clonidine may exhibit more sleep spindles on the electroencephalogram (EEG).
Methods:
We obtained intraoperative frontal EEG recordings in 73 infants under spinal anesthesia. We compared EEG spectral features of bupivacaine and bupivacaine + clonidine spinal anesthesia using nonparametric multitaper spectral analysis. A recently developed switching state-space modeling approach was then applied to extract and compare spindle features in bupivacaine versus bupivacaine + clonidine spinal anesthesia. We then applied the same model to compare younger versus older infants.
Results:
There was no difference in the power spectra and sleep spindle detection probability between bupivacaine and bupivacaine + clonidine spinal anesthesia ( P = .51). We found age-related EEG changes in both bupivacaine and bupivacaine + clonidine spinal anesthesia independent of clonidine. Increasing age was associated with decreased spectral power from 0 to 0.6 Hz (median difference -2.9 dB, 95% CI [-5.3, -0.5,]) and increased power from 2 to 15 Hz (median difference 3.4 dB, 95% CI [1.5, 5.2]). Increasing age was also associated with increased spindle strength (R 2 = 0.323, F(2,67) = 15.98, P < 0.001). These EEG findings mirror those found in infants under physiologic sleep.
Conclusions:
Our findings suggest that low-dose clonidine does not impact sleep spindle properties in the EEG of infants under spinal anesthesia. The EEG of infants under spinal anesthesia demonstrate age-related changes that mirror quiet physiologic sleep. In addition, the presence of intrathecal clonidine has no effect on the age-related changes in the EEG pattern. Clonidine is an adjunct for spinal anesthesia in infants that appears to prolong anesthetic duration without affecting their EEG patterns of physiologic sleep.
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