Wave VI of Auditory Evoked Potentials as an Objective Indicator of Sedation Depth in Neonates Undergoing Chloral Hydrate Sedation: A Double-Blind

Zong Zheng¹Shanpu Yang¹Hongyan Liu¹Zhimin Sheng^2*

• ¹People's Hospital of Yuhuan City, Taizhou, China
• ²Wenling Maternal and Child Health Care Hospital, Wenling, China

Background: Neonatal sedation depth monitoring is critical yet depends on the subjective Ramsay Scale when used and lacks objective biomarkers. Although auditory evoked potential (AEP) wave VI disappearance is linked to reduced consciousness, its use for neonatal sedation monitoring remains underexplored. We aimed to determine whether the wave VI could function as an objective indicator for sedation levels in neonates. Methods: This prospective, double-blind, randomized trial enrolled 100 neonates requiring hearing screening. Participants were randomly assigned in a 4:1 ratio to either a treatment group (n=80; 50 mg/kg oral chloral hydrate) or a control group (n=20; 0.9% saline placebo). The treatment group was further divided into three subgroups according to Ramsay sedation scores: level 4 (n=22), level 5 (n=23), and level 6 (n=35), while the control group was divided into levels 3 (n=5), level 4 (n=12), and level 5 (n=3). All neonates received a standardized AEP test performed by an experienced audiologist. Sedation depth was evaluated with the Ramsay scale, and the latency and disappearance rate of wave VI were recorded and correlated with sedation levels. The Receiver Operating Characteristic (ROC) curve was used to evaluate the predictive ability of wave VI latency in deep sedation, analyzing sensitivity, specificity, and predictive values. Results: In the treatment group, wave VI disappearance rates increased in a sedation-dependent manner across the Ramsay Sedation Scale: 0% at level 4, 26% at level 5, and 68.6% at level 6 (p < 0.05). No wave VI disappearance was observed in the control group. ROC analysis demonstrated that wave VI latency predicted deep sedation (Ramsay ≥ 5) with an area under the curve (AUC) of 0.861 (95% confidence interval [CI]: 0.746–0.975). The optimal latency cutoff was 8.465 ms (72.7% sensitivity, 86.2% specificity). Conclusion: AEP wave VI latency and disappearance are objective, sensitive, and specific indicators of sedation depth in neonates. With further validation, wave VI has the potential to become a reliable neurophysiological tool for precise sedation monitoring in neonates.