Evaluation of the Alaris Auditory Evoked Potential Index as an indicator of anesthetic depth in preschool children during induction of anesthesia with sevoflurane and remifentanil.
BACKGROUND
Autoregressive modeling with exogenous input of middle latency auditory evoked potentials (A-Line autoregressive index [AAI]) has been proposed for monitoring depth of anesthesia in adults. The aim of this study was to evaluate the performance of the AAI during induction of anesthesia with sevoflurane and remifentanil in pediatric patients.


METHODS
Twenty preschool children were anesthetized with sevoflurane and remifentanil. AAI, heart rate, and mean arterial pressure were compared for their ability to distinguish between different hypnotic states before inhalation induction and during sevoflurane anesthesia with and without remifentanil infusion. The prediction probability was calculated for discrimination between the predefined case milestones Awake, Spontaneous Eye Closure, and insertion of a laryngeal mask airway during general anesthesia (Laryngeal Mask Insertion).


RESULTS
The AAI (mean +/- SD) in Awake children was 79 +/- 10, declining to 59 +/- 22 at Spontaneous Eye Closure and 34 +/- 13 when anesthetized. AAI values significantly overlapped between anesthetic states. For the AAI, the prediction probabilities regarding the ability to discriminate the hypnotic state at the case milestones Awake versus Spontaneous Eye Closure and Awake versus Laryngeal Mask Insertion were 0.77 and 0.99, respectively. In terms of prediction probability values, heart rate and mean arterial pressure were not indicative for anesthetic states. Remifentanil did not influence the AAI.


CONCLUSIONS
During induction of pediatric patients with sevoflurane, the AAI is of higher value in predicting anesthetic states than hemodynamic variables and reliably differentiates between the awake and anesthetized states. However, individual AAI values demonstrate significant variability and overlap between different clinical conditions.
Department of Anesthesiology, University Hospital Regensburg, Regensburg, Germany. frank.weber@klinik.uni-regensburg.de
Frank
F
Weber
Thomas
T
Bein
Jonny
J
Hobbhahn
Kai
K
Taeger
D000768:Anesthesia, General; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D001794:Blood Pressure / Q000187:drug effects; D002675:Child, Preschool; D004562:Electrocardiography; D005072:Evoked Potentials, Auditory / Q000187:drug effects*; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D017214:Laryngeal Masks; D008297:Male; D008738:Methyl Ethers; D016343:Monitoring, Intraoperative / Q000379:methods*; D013508:Ophthalmologic Surgical Procedures; D010880:Piperidines; D000077208:Remifentanil; D000077149:Sevoflurane
D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D008738:Methyl Ethers; D010880:Piperidines; D000077149:Sevoflurane; D000077208:Remifentanil