Comparing Macintosh, Miller and Truview Laryngoscopes for Evaluation of Intubation Difficulty in Patients with Immobilized Cervical Spine

Abstract

Context: To evaluate intubation difficulty comparing Macintosh, Miller and Truview blades in patients with immobilized cervical spine. Aims: 1. To compare the difficulty during orotracheal intubation between Macintosh, Miller or Truview laryngoscopes utilizing the Intubation Difficulty Scale (IDS). 2. To compare the time taken for intubation. 3. Success rate of intubation in the three groups. Settings and Designs: Prospective randomized cross sectional study. Methods and Materials: This study was conducted in healthy Patients to evaluate the difficulty during intubation using the mentioned laryngoscopes, with the neck immobilized using Manual In-line Axial Stabilization (MIAS). Evaluation was done using intubation difficulty score (having seven parameters), success rate and duration of intubation. Intubation failure was defined as duration exceeding 120 seconds for which MIAS was relaxed and intubation was done conventionally. Statistics: One Way Analysis of Variance with Duncan’s mean test. Results: All patients in the Macintosh group , 18 (90%) in Miller group and 16 (80%) in Truview group were intubated successfully. The duration of intubation was significantly longer and IDS score, least in Truviewgroup. Truview provided better glottic view and required less optimizing maneuvers. Conclusions: The Intubation Difficulty Scale (IDS) score in parients with cervical spine immobilization (MIAS) is significantly least with TruView laryngoscope compared to conventional laryngoscopy using Macintosh or Miller laryngoscope. The time taken for intubation was shortest with Macintosh laryngoscope. Success rate of intubation is highest with Macintosh laryngoscope while it is least with TruView laryngoscope under the stipulated time limit (120 seconds) for laryngoscopy.