Monitoring Depth of Hypnosis: Mid-Latency Auditory Evoked Potentials Derived aepEX in Children Receiving Desflurane-Remifentanil Anesthesia

Cheung, Yuen Man; Scoones, Gail P.; Stolker, Robert Jan; Weber, Frank

doi:10.1213/ane.0000000000003546

Cited by 6 publications

(16 citation statements)

References 27 publications

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“…22 The studies by Ironfield et al and Cheung et al investigated a commercially available MLAEP monitor and its performance (prediction probability and area under the ROC) between age groups of <1 year versus ≥1 year 18 and <3 years versus 3-6 years versus ≥6 years. 30,31 No differences between the age groups were observed, however, in these studies. Table 4 summarizes studies concerning the effect of age on MLAEP.…”

Section: Agecontrasting

confidence: 57%

“…30 Seven studies using a commercially available MLAEP monitor reported the average index values observed during different depths of hypnosis. 20,23,27,28,[30][31][32] These values are illustrated in Figure 2.…”

Section: F I G U R Ementioning

confidence: 99%

“…28 The studies by Cheung et al were conducted with the aepEX PLUS monitor (Medical Device Management Ltd., Braintree, Essex, UK). [30][31][32] Instead of an autoregressive model, it applied the more conventional "moving time averaging" technique to extract the MLAEP and to compute the aepEX index. This technique requires 256 repeated measurement to extract an entirely new MLAEP waveform, which takes about 37 s. Instead of computing an entirely new MLAEP waveform every 37 s, the MLAEP and aepEX index is updated every 0.3 s by discarding the first (oldest) measurement and adding the last (newest) measurement.…”

Section: F I G U R Ementioning

confidence: 99%

“…The primary objective of these seven studies was to evaluate the performance of a MLAEP monitor to detect different levels of depth of hypnosis in children (Table 2). 20,23,27,28,[30][31][32] Six studies investigated the MLAEP during different amounts of anesthetics or during certain anesthetic procedures, such as intubation and extubation [17][18][19]21,22,29 and 3 studies investigated the effect of MLAEP monitoring on efficiency of the anesthetic regime, such as recovery time from anesthesia and total anesthetics used (Table 3). 16,19,24 Two studies investigated the effect of age on the MLAEP as the primary objective 17,18 and four manuscripts investigated age as their secondary objective.…”

Section: F I G U R Ementioning

confidence: 99%

“…16,19,24 Two studies investigated the effect of age on the MLAEP as the primary objective 17,18 and four manuscripts investigated age as their secondary objective. 22,[30][31][32] A brief summary of these studies can be found in Table 4.…”

Section: F I G U R Ementioning

confidence: 99%

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Midlatency auditory evoked potentials during anesthesia in children: A narrative review

Cheung

Heer

Stolker

et al. 2021

Pediatric Anesthesia

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The relationship between anesthesia and the electrical activity of the brain has been described as early as in the 1940's. 1 Development in this field has been extended to the investigation of the relationship between the brain activity and depth of anesthesia. 2 Research of the brain activity as a surrogate to monitor the depth of hypnosis during anesthesia has mostly focused on the spontaneous electroencephalogram (EEG). However, the spontaneous EEG does not mature before adult age, which could influence its reliability in children. 3 Although Mid-Latency auditory evoked potentials (MLAEP) are electrical brain activity, they are fundamentally different from the spontaneous EEG. These potentials are electric responses of the brain to an auditive stimulus.They occur at about 8-50 ms after the stimulus, which is after the auditory brainstem response (0-8 ms) and before the late cortical response (>50 ms). Needless to say, an impaired auditory pathway and/or inadequate delivery of the acoustic stimulus (poor fit of the earbuds in children) will make the recording of a MLAEP unreliable or even impossible.A typical MLAEP waveform consists of 3 troughs (labelled with N for negative polarity) and 2 peaks (labelled with P for positive polarity) of a few microvolts (Figure 1). To put in perspective, the EEG is about ten times stronger and the ECG is about 100 times stronger. The weak signal of the MLAEP makes it susceptible to noise and diminishes its signal quality. The peaks and troughs are commonly labeled as N 0 , P 0 , Na, Pa and Nb and occur, in the awake adult, at about 9 ms, 12 ms, 16 ms, 25 ms and 36 ms, respectively, after the application of an auditive stimulus. 4 The MLAEP is believed to be generated from the medial geniculate body and primary auditory cortex. 5 In anesthetized adult patients, the peaks and troughs decrease in amplitude and the interval when they occur, which are called latencies, increases. [5][6][7][8][9] Myelination of the brain in de developing child strongly influences evoked potentials, this makes it difficult to elicit these in infants having an age of less than 1 year and very difficult in infants less than 6 months of age.MLAEP mature after the first decade of life, around 10-12 years. [10][11][12][13] Mid-Latency auditory evoked potentials could be a parameter to measure the depth of hypnosis in anesthetized children. This narrative review summarizes the current literature concerning the use of MLAEP and its implications in anesthetized children. | ME THODSThis study adheres to the Preferred Reporting Items for Systematic Reviews and MetaAnalysis (PRISMA) guidelines, since it was initiated

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