A Clinical Comparison of the Flexiblade™ and Macintosh Laryngoscopes for Laryngeal Exposure in Anesthetized Adults

Comparison of glottic visualisation and ease of intubation with different laryngoscope blades

CONTEXT

Literature suggests glottic view is better with straight blades while tracheal intubation is easier with curved blades.

AIMS

To compare glottic view and ease of intubation with Macintosh, Miller, McCoy blades and the Trueview(®) laryngoscope.

SETTINGS AND DESIGN

This prospective randomised study was undertaken in operation theatres of a 550 bedded tertiary referral cancer centre after approval from the Institutional Review Board.

METHODS

We compared the Macintosh, Miller, McCoy blades and the Trueview(®) laryngoscope for glottic visualisation and ease of tracheal intubation; in 120 patients undergoing elective cancer surgery; randomly divided into four groups. After induction of anaesthesia laryngoscopy was performed and trachea intubated. We recorded: Visualisation of glottis (Cormack Lehane grade), ease of intubation, number of attempts; need to change the blade and need for external laryngeal manipulation.

STATISTICAL ANALYSIS

Demographic data, Mallampati classification were compared using the Chi-square test. A P<0.05 was considered significant.

RESULTS

Grade 1 view was obtained most often (87% patients) with Trueview(®) laryngoscope. Intubation was easier (Grade 1) with Trueview(®) and McCoy blades (93% each). Seven patients needed two attempts; one patient in Miller group needed three attempts. No patient in McCoy and Trueview(®) Groups required external laryngeal manipulation.

CONCLUSIONS

We found that in patients with normal airway glottis was best visualised with Miller blade and Trueview(®) laryngoscope however, the trachea was more easily intubated with McCoy and Macintosh blades and Trueview(®) laryngoscope.

Comparison of Flexiblade and Macintosh laryngoscopes: cervical extension angles during orotracheal intubation

SUMMARY

The Flexiblade(TM) is a new laryngoscope with a flexible blade, a handle and a lever, allowing gradual flexion over the distal half of the blade. In this study, we aimed to compare cervical vertebral movements during tracheal intubation with the Flexiblade and Macintosh laryngoscope in 32 patients undergoing elective surgery requiring general anaesthesia (n = 16 per group). Fluoroscopic images of cervical movement were captured before, during and after intubation and evaluated by a radiologist. C1-C2 cervical vertebral movement was significantly reduced during the intubation in the Flexiblade group (p < 0.0001). C2-C3 cervical movement was similar in both groups (p = 0.81). No significant differences were noted in success rates for intubation, oxygen saturation levels, haemodynamic variables or intubation-related injury. The decreased extension angle between C1-C2 during Flexiblade laryngoscopy compared with Macintosh laryngoscopy may be an advantage where neurological damage with cervical movement is a concern.