Comparative effectiveness of laryngoscopes for successful intubation in difficult adult airways: A systematic review

Background: Endotracheal intubation (ETI) is a commonly performed emergency procedure used to secure the airways in critically ill patients. Despite its importance, ETI presents significant risks to patients with difficult airways. The availability of different types of laryngoscopes, most notably video laryngoscopes and direct laryngoscopes (DLs), has contributed to improved intubation success rates and reduced complications. While numerous studies have compared video laryngoscopes and DLs, there remains a limited synthesis of evidence evaluating the full range of all laryngoscopes across different patient population and clinical settings. Methods: A narrative synthesis approach was employed in this review. Relevant articles were obtained from multiple databases, including PubMed (MEDLINE), CINAHL, and PsycINFO. Articles published up to June 23, 2025, were considered for inclusion. The methodological rigor and reporting quality of each article were appraised. The screening and exclusion process were documented using the PRISMA flow diagram. Titles, abstracts, full texts, and reference lists of all retrieved articles were thoroughly reviewed to identify potentially relevant publications. Results: Video laryngoscopes, particularly the McGrath, GlideScope, and C-MAC D-Blade, demonstrated superior performance compared to laryngoscopes. There was better first-pass success, better view of the larynx, less need for external adjusting maneuvers, and shorter time to intubation. Other devices such as Airtraq and Bonfils fiberscope have good results in some clinical settings, but are useful only where there is high operator dependence and have a more difficult learning curve. Conclusion: Video laryngoscopes have proven to be better than DLs in managing adult patients with difficult airways due to the advantages of the success rate, visualization of the glottis, and efficiency of the procedure. However, methodological heterogeneity and an absence of consistently high quality in clinical trial data lead to inadequate evidence for recommending one specific laryngoscope as being better for all difficult airway scenarios. Further well-designed high-quality clinical studies are required to determine the most effective laryngoscope for intubating adults with difficult airways across diverse clinical settings.