The investigators assessed upper airway management at the pre-anaesthetic consultation using the usual clinical criteria. On the day before surgery, diabetic patients were assessed for the palm print sign to predict difficult laryngoscopy. After induction of anesthesia, laryngoscopy was performed with a Macintosh metal laryngoscope blade. At this stage of the study, patients were categorized into two groups: difficult and easy laryngoscopy.

During pre-anesthesia consultation, all participants were assessed for airway conditions using usual clinical tests (Mallampati classification, Thyromental distance, mouth-opening test, upper lip biting test (ULBT), Head extension and Prayer sign). Demographic characteristics, diabetes duration, Blood glucose regulation and diabetes-related complications were also recorded.

On the day before surgery, patients were assessed for the palm print sign during preoperative evaluation rounds. On the day of surgery, after an intravenous line (IV) and complete monitoring, induction of anesthesia was initiated, and a muscle relaxant was used to facilitate intubation. Laryngoscopy was performed with a Macintosh metal laryngoscope blade by an anesthesiologist who had more than 2 years of intubation experience. McGrath® videolaryngoscope, McCoy laryngoscope, LMA Fastrack®, or i-gel® airway were kept ready for emergency situations. At this stage of the study, patients were categorized into two groups: difficult and easy laryngoscopy.

Inclusion Criteria:

• diabetes mellitus
• aged more than 18 years
• undergoing surgery under general anesthesia with endotracheal intubation.

Exclusion Criteria:

• physical or intellectual disabilities preventing cooperation
• Malformations, trauma, tumors, or infections of the maxillofacial region and upper airways,
• a history of burns or cervicofacial irradiation
• neurosurgical conditions causing temporomandibular pseudoankylosis.
• hand joint stiffness (e.g., carpal tunnel syndrome, Dupuytren's disease, scleroderma, rheumatoid arthritis)
• restricted cervical mobility (due to osteoarthritis, ankylosing spondylitis, or cervical trauma),
• a history of difficult intubation
• pregnancy (including up to six weeks postpartum)

Were included adult patients with diabetes mellitus undergoing surgery under general anesthésia with intubation.