Introduction and objective:
The oropharyngeal airway, also known as the Guedel airway, is a crucial medical device used for over a century as a basic way to maintain a patient’s airway open and secure. Although it is easy to use, this can be misleading as incorrect sizing can lead to injuries, bleeding, laryngospasm, and potentially fatal complications. This study aims to compare three techniques for selecting the appropriate oropharyngeal airway size using craniofacial anatomical landmarks.

Material and methods:
Three facial distances were measured, each one according to the techniques described in the scientific sources. For greater reliability of the test, measurements were made sequentially with two different methods.

Results:
The study included over 500 participants. Depending on the measurement technique used, different results of average lengths and thus approximate sizes of oropharyngeal airway were obtained. This indicated that depending on which technique is used for measuring purposes, differences in the size of the oropharyngeal airway can be up to 2–3 cm, with a high degree of statistical significance.

Conclusions:
Using different craniofacial anatomical landmarks to select the size of the oropharyngeal airway can yield significantly varied results for the same adult patient, thus posing a potentially fatal threat. To ensure effective and safe airway management, proper ventilation and oxygenation, it is recommended to follow the ISA (Initial Size Approximation) approach when choosing the oropharyngeal airway size in medical education, training, and clinical settings. Further research is needed to explore this matter, also in different populations