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The CONOX (Fresenius Kabi) calculates two indices, the qCON (hypnotic level) and the qNOX (nociception). The CONOX also calculates indices for electromyographic (EMG) activity and EEG burst suppression (BSR). Because all EEG parameters seem to influence each other, our goal was a detailed description of parameter relationships. Methods:  We used qCON, qNOX, EMG, and BSR information from 14 patients receiving propofol anesthesia. We described index relationships with linear models, heat maps, and box plot representations. We also evaluated associations between qCON\/qNOX and propofol\/remifentanil effect site concentrations (ceP\/ceR). Results: qNOX and qCON (<jats:italic>qCON\u2009=\u20090.79*qNOX\u2009+\u20095.<\/jats:italic>8; <jats:italic>p<\/jats:italic>\u2009&lt;\u20090.001; R<jats:sup>2<\/jats:sup>\u2009=\u20090.84) had a strong linear association. We further confirmed the strong relationship between qCON\/qNOX and BSR for qCON\/qNOX\u2009&lt;\u200925: <jats:italic>qCON=-0.19*BSR\u2009+\u200925.6<\/jats:italic> (<jats:italic>p<\/jats:italic>\u2009&lt;\u20090.001; R<jats:sup>2<\/jats:sup>\u2009=\u20090.72); <jats:italic>qNOX=-0.20*BSR\u2009+\u200926.2<\/jats:italic> (<jats:italic>p<\/jats:italic>\u2009&lt;\u20090.001; R<jats:sup>2<\/jats:sup>\u2009=\u20090.72). The relationship between qCON and EMG was strong at higher indices: <jats:italic>qCON\u2009=\u20090.55*EMG\u2009+\u200933.0<\/jats:italic> (<jats:italic>p<\/jats:italic>\u2009&lt;\u20090.001; R<jats:sup>2<\/jats:sup>\u2009=\u20090.68). There was no qCON\u2009&gt;\u200980 without EMG\u2009&gt;\u20090. The relationship between ceP and qCON was <jats:italic>qCON=-3.8*ceP\u2009+\u200970.6<\/jats:italic> (<jats:italic>p<\/jats:italic>\u2009&lt;\u20090.001; R<jats:sup>2<\/jats:sup>\u2009=\u20090.11). The heat maps also suggest that the qCON and qNOX can at least partially separate the hypnotic and analgetic components of anesthesia. Conclusion: We could describe relationships between qCON, qNOX, EMG, BSR, ceP, and ceR, which may help the anaesthesiologist better interpret the information provided. One major finding is the dependence of qCON\u2009&gt;\u200980 on EMG activity. This may limit the possibility of detecting wakefulness in the absence of EMG. Further, qNOX seems generally higher than qCON, but high opioid doses may lead to higher qCON than qNOX indices.<\/jats:p>","DOI":"10.1007\/s10877-024-01214-6","type":"journal-article","created":{"date-parts":[[2024,9,12]],"date-time":"2024-09-12T16:02:45Z","timestamp":1726156965000},"page":"1281-1290","update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":14,"title":["Relationships between the qNOX, qCON, burst suppression ratio, and muscle activity index of the CONOX monitor during total intravenous anesthesia: a pilot study"],"prefix":"10.1007","volume":"38","author":[{"given":"Federico","family":"Linassi","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sergio","family":"Vide","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ana","family":"Ferreira","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gerhard","family":"Schneider","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pedro","family":"Gamb\u00fas","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthias","family":"Kreuzer","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2024,9,12]]},"reference":[{"issue":"8","key":"1214_CR1","doi-asserted-by":"publisher","first-page":"933","DOI":"10.1111\/aas.12359","volume":"58","author":"EW Jensen","year":"2014","unstructured":"Jensen EW, Valencia JF, Lopez A, Anglada T, Agusti M, Ramos Y, et al. 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Gerhard Schneider and Matthias Kreuzer are named as inventors for a patent filed on a novel method for intraoperative EEG monitoring (U.S. Patent Application Serial No. 62\/960,947) and are also named as inventors for a patent dealing with the EEG features during anaesthesia emergence (U.S. Provisional Patent Application No. 63\/459,294). Matthias Kreuzer received funding from Masimo Corporation, Narcotrend-Gruppe, Medtronic GmbH and Fresenius Kabi Deutschland GmbH for conducting EEG-based training for anaesthesiologists and received honoraria for speaking engagements related to the EEG.","order":4,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}},{"value":"FL, SV, AF, GS, and MK declare no conflict of interest; PG was a co-developer of Q-NOX. He has received consulting fees from Quantium Medical.","order":5,"name":"Ethics","group":{"name":"EthicsHeading","label":"Conflict of interest"}}]}}