A Comparison of the D Blade and Mac Blade C-MAC Video Laryngoscope for Double-Lumen Endotracheal Intubation in Patients With Predicted Normal Airways

The double-lumen tracheal tube (DLT) is the standard device for achieving one-lung ventilation in thoracic surgery. Compared to a single-lumen endotracheal tube, the DLT is longer, stiffer, and has a larger external diameter, making its insertion more challenging. Recently, videolaryngoscopes have been increasingly used in thoracic surgery, particularly in patients with difficult airways, as they enhance visualization of laryngeal structures and facilitate lung separation.However, the role of the videolaryngoscope in DLT intubation remains unclear due to the larger size of the DLT and the discrepancy between the curves of the DLT and the videolaryngoscope blade, which can affect vocal cord visualization and, consequently, intubation success.

Videolaryngoscopes can be classified as standard or hyperangulated based on blade angulation. The results of clinical studies on hyperangulated videolaryngoscopes for DLT placement have been inconsistent, particularly regarding intubation time. While some hyperangulated videolaryngoscopes have demonstrated superiority over the macintosh (Mac) blade laryngoscope in normal airway patients, others have not. These discrepancies may stem from the use of manikins in some studies, variations in clinician experience with videolaryngoscopes, or differences in intubation techniques.

In patients without predicted difficult airways undergoing thoracic surgery, direct laryngoscopy with a Mac blade remains the recommended technique for DLT placement. The C-MAC videolaryngoscope is designed based on the Mac blade and has been associated with improved laryngeal visualization and reduced need for additional maneuvers to facilitate intubation. The D-blade and Mac blade are adapted for use with the C-MAC system. The C-MAC Mac and D-blade may be a viable alternative to direct laryngoscopy with the Mac blade in routine practice.

This randomized controlled study aimed to compare the C-MAC D-Blade and the C-MAC Mac blade with the conventional direct laryngoscopy Mac blade in patients with predicted normal airways undergoing thoracic surgery requiring DLT placement. The primary outcome measure was intubation time. Additional parameters assessed included exposure time, the ease of intubation, number of laryngoscopy attempts, and maneuvers.