Assessment of cervical spine movement during laryngoscopy with Macintosh and Truview laryngoscopes

Abstract

Background: Truview laryngoscope provides an indirect view of the glottis and will cause less cervical spine movement since a ventral lifting force will not be required to visualize the glottis compared to Macintosh laryngoscope. Materials and Methods: A randomized crossover study to assess the degree of movement of cervical spine during endotracheal intubation with Truview laryngoscope was conducted in 25 adult ASA-I patients. After a standard anesthetic technique laryngoscopy was performed twice in each patient using in turn both the Macintosh and Truview laryngoscopes. A baseline radiograph with the head and neck in a neutral position was followed by a second radiograph taken during each laryngoscopy. An experienced radiologist analyzed and measured the cervical movement. Results: Significant cervical spine movement occurred at all segments when compared to the baseline with both the Macintosh and Truview laryngoscopes (P < 0.001). However, the movement was significantly less with Truview compared to the Macintosh laryngoscope at C 0 -C 1 (21%; P = 0.005) and C 1 -C 2 levels (32%; P = 0.009). The atlantooccipital distance (AOD) traversed while using Truview laryngoscope was significantly less than with Macintosh blade (26%; P = 0.001). Truview blade produced a better laryngoscopic view (P = 0.005) than Macintosh blade, but had a longer time to laryngoscopy (P = 0.04). Conclusion: Truview laryngoscope produced a better laryngoscopic view of glottis as compared with Macintosh laryngoscopy. It also produced significantly less cervical spine movement at C 0 -C 1 and C 1 -C 2 levels than with Macintosh laryngoscope in patients without cervical spine injury and without manual in-line stabilization (MILS). Further studies are warranted with Truview laryngoscope using MILS.

Keywords

• Airway
• anesthetic techniques
• equipment
• laryngoscopes
• Truview Macintosh
• monitoring
• radiological