The NARCOguide index – a novel parameter for monitoring depth of hypnosis during anaesthesia/sedation with propofol

Abstract

The NARCOguide algorithm calculates an EEG-derived index to monitor the hypnotic component of anaesthesia. This study evaluates the accuracy of the index calculated by NARCOguide against the Narcotrend index as a reference. Secondly, the automatic detection of burst-suppression patterns as represented by the burst suppression ratio was compared. Comparative study to assess the agreement between two medical devices. At two study centres, patient data were collected from a total of 40 adults receiving general anaesthesia or sedation with propofol. Patients underwent either general anaesthesia for oral surgery with propofol/remifentanil/rocuronium (study centre 1) or light general anaesthesia/deep sedation with propofol alone for laryngoscopic upper airway exploration (study centre 2). In a posthoc analysis, the NARCOguide index was compared with the Narcotrend index. Comparison was made after averaging over 1 min at defined clinical markers using classic linear least squares regression and Bland–Altman plots. Precision and recall for the detection of burst suppression were determined using human scoring as a reference. Data analysis showed good agreement [Bland–Altman mean difference (MD) = −2.3; limits of agreement = −27.1, to +22.4; n = 1209] and high correlation (r 2 = 0.76) between the depth of anaesthesia index calculated by NARCOguide and Narcotrend. The precision and recall of NARCOguide and Narcotrend for the detection of burst suppression were in a similar range. Over the entire dataset, the NARCOguide algorithm showed higher precision and recall than the Narcotrend algorithm (56% vs. 36% and 68% vs. 58%, respectively). The NARCOguide index can be used to monitor the hypnotic component of anaesthesia in patients undergoing general anaesthesia or sedation with propofol, with a performance similar to that of the Narcotrend index. Trial registration number: 18020, regulatory authority: Ethikkommission der bayerischen Landesärztekammer, chairman: Dr med. Gerald Quitterer, applicant: Dr Gert Küchler, date of approval: 12. Jun 2018, completion of data collection: 12 December 2018, study completion: 31 March 2022.