Macintosh Videolaryngoscope for Intubation in the Operating Room

BACKGROUND:

“Macintosh”-videolaryngoscopes (VLs) are VLs that allow both direct and indirect laryngoscopy for intubation. We describe the decision-making and implementation-processes that our hospital used regarding the choice of device. We compared the performances of 4 Macintosh-VLs both in direct and indirect laryngoscopy.

METHODS:

A quality-improvement-project for airway management aiming at implementing Macintosh-VL for all intubation procedures performed in the operating room, involving 4 Macintosh-VLs (McGrath-Mac, C-MAC-S, C-MAC-S-Pocket-Monitor [PM], and APA). Three consecutive steps were described: (1) direct laryngoscopy with Macintosh-VL, (2) indirect laryngoscopy with Macintosh-VL (intubation attempt with Macintosh-style blade in case of Cormack I or II), (3) intubation attempt with hyperangulated blade in case of Cormack III/IV or failure of Macintosh-style blade. The main end point was the need to move to step III and use a hyperangulated blade. A mixed-effects multivariable logistic regression analysis was performed to compare devices on the main end point while considering site as a random effect. Comparison of means was performed using analysis of variance and Tukey’s test for multiple comparisons (number of laryngoscopy attempts, numeric rate scale [NRS] difficulty of intubation and NRS user-friendliness). Comparison of percentages was performed using a χ² test for the need to move to step III and a Kruskal-Wallis test for the quality of image (bad, passable, good, very good, excellent). A P value ≤.008 was considered statistically significant.

RESULTS:

From May to September 2017, 589 patients were included. Using the McGrath-Mac (22/180 [12%]) was associated with less use of hyperangulated blade than using the C-MAC-S (39/132 [30%], odds ratio [OR] [99.2% confidence interval {CI}] 0.34 [0.16–0.77], P = .0005), the APA (35/138 [25%], OR [99.2% CI] 0.42 [0.19–0.93]; P = .004), but not the C-MAC-S-PM (29/139 [21%], OR [99.2% CI] 0.53 [0.23–1.2]; P = .04).

Overall, the number of intubation attempts was significantly lower using the McGrath Mac than the C-MAC-S or the C-MAC-S-PMVLs. Subjective appreciation of intubation difficulty and user-friendliness of the devices showed respectively lower and higher NRS scores for the McGrath-Mac compared to the other devices, whereas subjective assessment of image quality showed higher quality for the C-MAC-S and C-MAC-S-PM compared to the APA or McGrath-Mac.

CONCLUSIONS:

Among 4 single-use Macintosh-VLs, glottic visualization in direct and indirect laryngoscopy with the Macintosh-style blade was significantly improved with the McGrath-Mac compared to other Macintosh-VLs, leading to a less frequent need to resort to the hyperangulated blade and reduced overall number of intubation attempts.