Difficult Airways Scores Validation Difficult Laryngoscopy and Mask Ventilation: Prospective and Evaluative Study

Clinical screening tests were included to define a difficult laryngoscopy such as history of difficult or impossible intubation, NC, MMS, retrognathia, protrusion of the upper incisors, TMD, mouth opening, dentition, macroglossia, presence of a beard, UBLT, spine mobility and palm print test for diabetes.

Ultrasound airway assessment was performed: Clinical screening tests were included to define a difficult laryngoscopy such as history of difficult or impossible intubation, NC, MMS, retrognathia, protrusion of the upper incisors, TMD, mouth opening, dentition, macroglossia, presence of a beard, UBLT, spine mobility and palm print test for diabetes.

Ultrasound airway assessment was performed Three parameters were measured to calculate the scores: Tongue thickness (TT) in coronal plane, Distance from the skin to hyoid bone (SHB), Distance from the skin to the thyrohyoid membrane (STM). Two scores were developed from a study conducted in 2019. The first score, to predict a difficult laryngoscopy, uses two parameters: the modified MALLAMPATI class (MMS) and the STM. A score strictly greater than 2 is predictive of a difficult laryngoscopy. The second score, to predict difficult ventilation, uses four parameters: BMI, NC, TT in coronal plane, and SHB. A score strictly greater than 20 is predictive of difficult ventilation. A well-experienced anesthesiologist performed a direct laryngoscopy and graded it as Cormack-Lehane's grading.

Difficulty in intubation and/or mask ventilation was managed according to the 2017 SFAR guidelines.