A comparative study to evaluate the cervical spine movements during laryngoscopy using Macintosh and Airtraq laryngoscopes.

Background and aim: Intubation with Macintosh requires flexing the lower cervical spine and extending the atlanto-occipital joint to create a "line of sight." Primary aim of study was to compare the extent of cervical spine movement during laryngoscopy using conventional Macintosh laryngoscope and Airtraq.

Material and methods: A total of 25 patients of either sex between the age group of 18 and 60 years, having American Society of Anesthesiologists (ASA) physical status of Grade-I and Grade-II, scheduled for elective surgery under image control requiring general anesthesia and intubation were enrolled. A baseline image of the lateral cervical spine including the first four cervical vertebrae was taken by an image intensifier. After administration of general anesthesia, laryngoscopy was first performed using a Macintosh laryngoscope and a second X-ray image of the lateral cervical spine was taken. The second laryngoscopy using a Airtraq laryngoscope was done and the third image of the lateral cervical spine was taken. Angles between occiput and C_1; C₁ and C_2; C₂ and C_3; C₃ and C_4; and occiput and C₄ were calculated. Atlanto-occipital distance (AOD) was calculated as the distance between occiput and C₁.

Results: Macintosh showed greater cervical movement as compared with Airtraq but a significant difference in the movement was observed at C₂-C₃ and C₀-C₄. Baseline mean AOD was 2.21 ± 1.25 mm, after Macintosh and Airtraq laryngoscopy was found to be 1.13 ± 0.60 and 1.6 ± 0.78 mm, respectively, and was found to be significant (P < 0.05).

Conclusion: We conclude that Airtraq allows intubation with less movement of the upper cervical spine makes Airtraq preferred equipment for intubation in patients with a potential cervical spine injury.