Auditory evoked potentials

Auditory evoked potentials Plourde

Tag layer of the DHSS Meta-Tagging Project. The article text is reproduced from the staged copy named in sourceDesc and is not altered; the tags are held separately in standOff so that overlapping and nested spans are preserved.

Auditory evoked potentials 2006 Best Practice & Research Clinical Anaesthesiology 10.1016/j.bpa.2005.07.012 Plourde2006-auditory-evoked-potentials Plourde2006-auditory-evoked-potentials.txt, the project's staged copy c291945aa4e191d33df52a7017db68333a406664 not-redistributable anaesthesiology

the paper's own words

the tag layer; a sentence written by the tagger about the paper, always anchored to a quotation but not itself a quotation

0 spans located by searching the stored text for the quote's exact words, allowing any whitespace between them method Quotation withheld because this record is not cleared for redistribution. auditory evoked potentials as a measure of anaesthetic depth Quotation withheld because this record is not cleared for redistribution. review review Quotation withheld because this record is not cleared for redistribution. mechanisms at ~40 stimuli per second each new stimulus arrives during wave Pa of the preceding response, so successive middle-latency responses overlap and progressively build up into the steady-state response Quotation withheld because this record is not cleared for redistribution. mechanisms the 40 Hz ASSR is generated partly by anesthetic-sensitive synchronization of naturally occurring neuronal rhythms, and/or anesthetics disrupt the superimposition process by non-uniformly changing the refractory periods of AMLR components Quotation withheld because this record is not cleared for redistribution. mechanisms general anesthetics abolish consciousness by interfering with thalamocortical 40 Hz rhythms, which is why the 40 Hz response and consciousness disappear together Quotation withheld because this record is not cleared for redistribution. Scope restricted to human studies for reasons of space what this limits: the scope of the review: BECAUSE OF SPACE CONSTRAINTS, THIS REVIEW WILL BE LIMITED TO HUMAN STUDIES Quotation withheld because this record is not cleared for redistribution. The association between ASSR attenuation and loss of consciousness is correlational, not demonstrated to be functional what this limits: any use of the 40 Hz ASSR as a consciousness monitor: THESE OBSERVATIONS SUGGEST BUT DO NOT PROVE THAT THERE IS FUNCTIONAL RELATIONSHIP BETWEEN THE ATTENUATION OF THE 40 HZ ASSR AND LOSS OF CONSCIOUSNESS Quotation withheld because this record is not cleared for redistribution. Applicability to real-world multi-drug anaesthetic regimens is untested what this limits: clinical application specifically: APPLICABILITY [to the] MULTI-DRUG REGIMEN COMMONLY SEEN IN CLINICAL PRACTICE REMAINS TO BE ASSESSED Quotation withheld because this record is not cleared for redistribution. Whether ASSR parameters other than amplitude could support titration has not been examined what this limits: the amplitude measure only: whether ASSR parameters other than amplitude could support titration has not been examined Quotation withheld because this record is not cleared for redistribution. The monitor and the patient's state may both be effects of the drug rather than related to each other, and the review says so of its own subject. what this limits: a 40 Hz ASSR or AMLR reading used to infer that a patient is unconscious: the review states both the response and the loss of consciousness could be effects of the anaesthetic that are otherwise functionally independent Quotation withheld because this record is not cleared for redistribution. The supporting evidence is explicitly said to fall short of proof. what this limits: the claim that attenuation of the 40 Hz ASSR indicates loss of consciousness: the review states the observations suggest but do not prove a functional relationship Quotation withheld because this record is not cleared for redistribution. Whole components of the response are excluded from clinical use for being TOO sensitive, so the monitored signal is selected for stability rather than for sensitivity. what this limits: the auditory evoked potentials used in anaesthetic monitoring: slow and late responses are excluded as too sensitive to anaesthetic effect for routine clinical monitoring Quotation withheld because this record is not cleared for redistribution. 40 Hz ASSR 40 Hz ASSR Quotation withheld because this record is not cleared for redistribution. level of consciousness level of consciousness Quotation withheld because this record is not cleared for redistribution. auditory middle latency response auditory middle latency response Quotation withheld because this record is not cleared for redistribution. 40 Hz ASSR as an index of consciousness - AS CORRELATION: a fairly reliable measure of the level of consciousness, on evidence the review calls suggestive but not probative Quotation withheld because this record is not cleared for redistribution. 40 Hz ASSR as an index of consciousness - AS TESTED BY DISSOCIATION: consciousness was restored with the anaesthetic concentration held constant, and the response returned to awake baseline Quotation withheld because this record is not cleared for redistribution. contradicts → Pockett et al.3 Quotation withheld because this record is not cleared for redistribution. contradicts → Galambos et al.42 (the 40 Hz ASSR as superimposition of the AMLR) Quotation withheld because this record is not cleared for redistribution. level of consciousness —operationalised-as→ 40 Hz ASSR level of consciousness 40 Hz ASSR strength of the relation: 1 Quotation withheld because this record is not cleared for redistribution. statistical significance test statistical significance test Quotation withheld because this record is not cleared for redistribution. mean (signal averaging across trials) mean (signal averaging across trials) Quotation withheld because this record is not cleared for redistribution. Most volatile and intravenous general anesthetics lengthen the latency and reduce the amplitude of the auditory middle latency response, and do so in proportion to concentration. Quotation withheld because this record is not cleared for redistribution. Nitrous oxide and ketamine leave the main AMLR components unchanged even at concentrations that produce unconsciousness. Quotation withheld because this record is not cleared for redistribution. Unlike other anesthetics, ketamine increased the amplitude of the 40 Hz steady-state response. Quotation withheld because this record is not cleared for redistribution. Reversing anesthetic hypnosis with physostigmine raises the 40 Hz ASSR in proportion to the behavioural reversal, so ASSR attenuation seems to reflect impaired consciousness. Quotation withheld because this record is not cleared for redistribution. Under enflurane/N2O the 40 Hz ASSR was attenuated far more than the accompanying AMLR changes predicted. Quotation withheld because this record is not cleared for redistribution. The 40 Hz ASSR amplitude does not appear useful for titrating anesthetic dose, because it is already markedly reduced at loss of consciousness. Quotation withheld because this record is not cleared for redistribution. The AMLR is suggested to reflect the balance between anesthetic suppression and brain activation caused by noxious stimulation. Quotation withheld because this record is not cleared for redistribution. auditory evoked potential auditory evoked potential Quotation withheld because this record is not cleared for redistribution. transient AEP transient AEP Quotation withheld because this record is not cleared for redistribution. steady-state AEP steady-state AEP Quotation withheld because this record is not cleared for redistribution. 40 Hz auditory steady-state response (40 Hz ASSR) 40 Hz auditory steady-state response (40 Hz ASSR) Quotation withheld because this record is not cleared for redistribution. auditory middle latency response (AMLR) auditory middle latency response (AMLR) Quotation withheld because this record is not cleared for redistribution. coherent frequency (CF) coherent frequency (CF) Quotation withheld because this record is not cleared for redistribution. unintentional awareness unintentional awareness Quotation withheld because this record is not cleared for redistribution. AAI AAI Quotation withheld because this record is not cleared for redistribution. concentration of the anesthetic concentration of the anesthetic Quotation withheld because this record is not cleared for redistribution. 40 Hz ASSR amplitude 40 Hz ASSR amplitude Quotation withheld because this record is not cleared for redistribution. level of consciousness level of consciousness Quotation withheld because this record is not cleared for redistribution. 2.1 ng/ml — sufentanil concentration producing half-maximal suppression of the 40 Hz ASSR Quotation withheld because this record is not cleared for redistribution. more than 70% — reduction in 40 Hz ASSR amplitude when sevoflurane was titrated to unconsciousness (mean 0.85% end-tidal) Quotation withheld because this record is not cleared for redistribution. about 33 Hz / 15 Hz — coherent frequency of the steady-state response when awake versus when unconscious Quotation withheld because this record is not cleared for redistribution. z20% — reduction of the A-Line ARX index caused by the neuromuscular blocker vecuronium during steady-state anesthesia (i.e. muscle-artefact contribution to the index) Quotation withheld because this record is not cleared for redistribution. 10 of 11 — propofol-anesthetized volunteers in whom physostigmine restored consciousness Quotation withheld because this record is not cleared for redistribution. two of eight — sevoflurane-anesthetized subjects who regained consciousness after physostigmine (three more regained wakefulness only) Quotation withheld because this record is not cleared for redistribution.

The full text of this article is not redistributable, so it is not included here. The evidence sentences are withheld with it; the tag layer and its grounding status remain. The article itself is at https://doi.org/10.1016/j.bpa.2005.07.012.