On-line analysis of middle latency auditory evoked potentials (MLAEP) for monitoring depth of anaesthesia in laboratory rats

Abstract

A study was conducted to determine whether the auditory evoked potential (AEP) could serve as an indicator of the depth of anesthesia in rats. The AEP was elicited with a click stimulus and monitored in an 80 ms window synchronized to the stimulus. The AEP was extracted applying an Auto Regressive Model with Exogenous Input from which a depth of anesthesia index (DAI) was calculated. A simple dosing regimen based on weight was unable to give the same depth of anesthesia in individual rats. The decrease in DAI correlated well with the loss of stimulus response.