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October 16, 2018
10/16/2018 10:30:00 AM - 10/16/2018 12:30:00 PM
Room North, Hall D, Area E
NOL Index Response after Laryngoscopy Performed with Macintosh Blade versus GlidescopeTm Videolaryngoscope
Virginie Sbeghen, M.D., Jason McDevitt, M.D., M.S., Olivier Verdonck, M.D., M.S., Valerie Zaphiratos, M.D., M.S., Veronique Brulotte, M.D., M.S., Christian Loubert, M.D., Pierre A. Drolet, M.D., Louis-Philippe Fortier, M.D., M.S., Marie-Claude Guertin, Ph.D., Philippe G. Richebe, M.D.,Ph.D.
University of Montreal, Department of Anesthesia, Montreal, Quebec, Canada
Disclosures: V. Sbeghen: None. J. McDevitt: None. O. Verdonck: None. V. Zaphiratos: None. V. Brulotte: None. C. Loubert: None. P.A. Drolet: None. L. Fortier: None. M. Guertin: None. P.G. Richebe: Honoraria; Self; member of the advisory board for Medasense LTD, the manufacturer of the PMD200, since 2015.
Background: Studies have reported several advantages of the use of videolaryngoscopes, as the GlideScopeTM (GVL), over the MacIntosh blade (MAC), such as a higher rate of successful intubations, exertion of less force on tissues, etc. However, comparison between direct laryngoscopy versus videolaryngoscopy over their nociceptive stimulation has not been quantitatively studied. A newly available monitoring device, the PMD200TM, generates the NOL index, which has been shown to be more sensitive and specific to detect noxious stimuli than classical hemodynamic parameters. Using this NOL index, our objective is to compare GVL versus MAC blade over their nociceptive response during laryngoscopy and laryngoscopy + intubation. Methods: In this prospective, randomized clinical trial, patients having surgery under general anesthesia underwent 2 laryngoscopies at 4-minute intervals (L1 and L2), one with the GlideScopeTM Titanium Spectrum Single-Use blade, the other with a Macintosh blade (order determined by randomization). This 1:1 allocation in two parallel groups constituted a crossover design to control for any effects related to the order of laryngoscopy techniques. A third laryngoscopy (L3) followed by tracheal intubation was performed 4 minutes after L2 (blade chosen with a second randomization). Nociception was quantitatively assessed by NOL. Standard hemodynamic parameters were also examined. Patients with anticipated difficult airway management and having recognized risk factors for (or contraindications to) difficult ventilation were not included. Statistic analysis was performed using two factors ANOVA for repeated measures. Results: 50 patients were randomized in the study. 49 were included in the analysis, one was excluded because of loss of NOL signal after L1. 78% were female. 61% of patients had an ASA Class II, 39% had an ASA Class I. 24/49 were 50 years and under and 8/49 were 70 years and older. All of them had a BMI <35. NOL basal values were not statistically different between groups before L1 (p=0,8806, MAC versus GVL) and between subsequent laryngoscopies (p=0.6260 for comparison of NOL basal values before L1 and L2). Comparison of post-stimulus delta-NOL (mean maximum NOL over 30 seconds post-laryngoscopy minus mean basis NOL over 30 seconds before laryngoscopy) showed a significant reduction in the nociceptive response after GVL for L2 (ΔNOL GVL 14,29±11,16 vs MAC 16,55±10,96, p=0,0193) and an almost significant reduction for L1 (ΔNOL GVL 11,05±14,72 vs MAC 14,41±11,37, p=0,0887). Delta-NOL values after L3+intubation were significantly higher than delta-NOL values after L1 and L2 (ΔNOL L3 45,75±16,68 vs L1+L2 14,08±12,10, p<0,0001), GVL and MAC groups combined. Discussion: NOL values reflecting nociceptive response after laryngoscopy increased less with the GlideScopeTM Titanium Spectrum Single-Use blade than with the MacIntosh blade. However, tracheal intubation significantly produced a nociceptive response greater than the laryngoscopy itself, no matter which blade was used.
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