A Prospective Comparative Study of Laryngeal Glottic View Using the Vie Scope® versus Standard Macintosh Laryngoscope in Morbidly Obese Patients

Abstract

Background: The visualization of the glottis may be inadequate in morbidly obese patients when a standard Macintosh blade laryngoscope (MCL) is used. The Vie Scope® (VS) is a novel type laryngoscope consisting of a straight, enclosed, illuminated tube that offers intubation via a bougie using the paraglossal technique. In this prospective, nonrandomized comparative study, we tested the research hypothesis that the VS may improve visualization of the glottic larynx in comparison to the MCL. Materials and Methods: After obtaining institutional ethics committee approval, 60 morbidly obese patients (BMI >40 kg/m2) undergoing elective non-head and neck surgery were included in the study. After induction of general anesthesia (GA), the glottic visualization was performed using the two laryngoscopes in succession, first MCL size 3 or 4 followed by the VS and was assessed using the modified Cormack–Lehane scale. Tracheal intubation was performed using the VS The first pass intubation success and the total success rate was recorded only for the VS Intubation time was not measured because of the paired study design. Results and Discussion: Mean demographic data included: age 41.9±8.2 years, height 171.2±10.2 cm, weight 129.9±21.6 kg, BMI 44.95±3.85 kg/m2. Using MCL, Cormack–Lehane grade 1 was observed in 36 (60%) cases; grade 2 in 7/60 (11.6%); grade 3 in 13/60 (21.7%); and grade 4 in 4/60 (6.7%). Poor laryngeal views represented by grades 3 and 4 were observed in 28.4% of patients with the MCL. Grades obtained with the VS were all grade 1 (100%). The first attempt intubation success was in 58/60 (96.7%) with the VS. No complications were observed. Conclusion: The Vie Scope® laryngoscope, using the paraglossal technique of tracheal intubation, significantly improves visualization of the vocal cords in morbidly obese patients compared to the standard Macintosh laryngoscope.