Age-Dependent Electroencephalogram Features in Infants Under Spinal Anesthesia Appear to Mirror Physiologic Sleep in the Developing Brain: A Prospective Observational Study

Abstract

BACKGROUND: Infants under spinal anesthesia appear to be sedated despite the absence of systemic sedative medications. In this prospective observational study, we investigated the electroencephalogram (EEG) of infants under spinal anesthesia and hypothesized that we would observe EEG features similar to those seen during sleep. METHODS: We computed the EEG power spectra and spectrograms of 34 infants undergoing infraumbilical surgeries under spinal anesthesia (median age 11.5 weeks postmenstrual age, range 38–65 weeks postmenstrual age). Spectrograms were visually scored for episodes of EEG discontinuity or spindle activity. We characterized the relationship between EEG discontinuity or spindles and gestational age, postmenstrual age, or chronological age using logistic regression analyses. RESULTS: The predominant EEG patterns observed in infants under spinal anesthesia were slow oscillations, spindles, and EEG discontinuities. The presence of spindles, observed starting at about 49 weeks postmenstrual age, was best described by postmenstrual age (P=.002) and was more likely with increasing postmenstrual age. The presence of EEG discontinuities, best described by gestational age (P = .015), was more likely with decreasing gestational age. These age-related changes in the presence of spindles and EEG discontinuities in infants under spinal anesthesia generally corresponded to developmental changes in the sleep EEG. CONCLUSIONS: This work illustrates 2 separate key age-dependent transitions in EEG dynamics during infant spinal anesthesia that may reflect the maturation of underlying brain circuits: (1) diminishing discontinuities with increasing gestational age and (2) the appearance of spindles with increasing postmenstrual age. The similarity of these age-dependent transitions under spinal anesthesia with transitions in the developing brain during physiological sleep supports a sleep-related mechanism for the apparent sedation observed during infant spinal anesthesia.

Intraoperative pediatric electroencephalography monitoring: an updated review

“…Age-related changes in sleep spindles during spinal anesthesia generally correspond to developmental changes reported in the sleep EEG literature, supporting a sleep-related mechanism for the apparent sedation observed during infant spinal anesthesia [ 53 ]. Thalamocortical circuitry maturation is thought to be involved in the generation of sleep spindle oscillations, which begin to appear at approximately 46–48 weeks of gestational age [ 52 , 53 ].…”

“…Sleep spindles are a hallmark of Stage 2 non-rapid-eye-movement sleep, suggesting that spinal anesthetics may confer a more physiological sleep state than traditional sedative-hypnotic effects during general anesthesia [49,52]. Age-related changes in sleep spindles during spinal anesthesia generally correspond to developmental changes reported in the sleep EEG literature, supporting a sleep-related mechanism for the apparent sedation observed during infant spinal anesthesia [53].…”

“…Thalamocortical circuitry maturation is thought to be involved in the generation of sleep spindle oscillations, which begin to appear at approximately 46-48 weeks of gestational age [52,53].…”

Awake Combined Spinal Caudal Anesthesia for Longer-Duration Urologic Surgery in Infants: A Case Series

“…The central sedative effects of SA in infants are an ongoing area of study, but recent data suggests that electroencephalogram waveforms are suggestive of natural sleep rather than sedation. 12…”

“…The central sedative effects of SA in infants are an ongoing area of study, but recent data suggests that electroencephalogram waveforms are suggestive of natural sleep rather than sedation. 12 Our CSC technique is limited to practicing within the context of a dedicated infant spinal program with a high spinal success rate with surgical, anesthesia, nursing, and parental support. 13 Further work is needed to study feasibility in larger sample sizes, a comparison between GA and CSC for longer-duration urologic procedures, and application of this technique to other complex infraumbilical surgeries.…”