Comparative Evaluation of Performance of McGrath® and GlideScope® Videolaryngoscopes with Conventional Macintosh Laryngoscope for Laryngoscopy and Intubation in Patients with Immobilised Cervical Spine - A Randomised Controlled Trial

Rashmi Salhotra, AK Sethi, Deepti Agarwal, Medha Mohta, Varun Arora

Videolaryngoscopes are nowadays very commonly being used. This study evaluated McGrath®, GlideScope® and Macintosh laryngoscopes for intubation in patients with normal airways but immobilised cervical spine, thereby simulating a difficult airway scenario.This prospective, randomised controlled trial was conducted on60 adult ASA I/II patients of either sex, between 18-60 years of age undergoing elective surgical procedures requiring general anaesthesia with tracheal intubation.Patients were randomly allocated to one of the three groups, depending on the laryngoscope used for intubation; Group MVL, McGrath® videolaryngoscope; Group GVL, GlideScope® and Group ML, Macintosh laryngoscope. Cervical collar was applied after induction of anaesthesia. Success rate of intubation in the first attempt was similar with all three laryngoscopes.Time taken to intubate was longer with McGrath® (41.1±8.6 s) compared to GlideScope®(34.5±7.1 s) and Macintosh (31.8±9.3 s) laryngoscopes. The mean percentage of glottic opening(POGO) score was significantly better with McGrath® (p=0.004) and GlideScope®(p=0.001) than with Macintosh laryngoscope.Cormack Lehane grading with both videolaryngoscopeswas also better thanthat with Macintosh (p=0.042 and p=0.003 vs. McGrath® and GlideScope® respectively). Laryngoscopy difficulty score and intubation difficulty score with GlideScope® werecomparable to McGrath®butlowerthan Macintosh laryngoscope. Both videolaryngoscopes, McGrath® and GlideScope®, provided better glottic view compared to Macintosh laryngoscope in patients with immobilised cervical spine. GlideScope® allowed easier laryngoscopy and intubation with minimum manoeuvres as compared to Macintosh laryngoscope.