Relationship Between Airway Examination with LEMON Criteria and Difficulty of Tracheal Intubation with IDS Criteria

Tracheal intubation is a common technique used to secure a patient's airway, which is crucial in anesthesia. Successful tracheal intubation depends on various factors, including the assessment of the patient's airway before the procedure. In recent years, scoring systems, such as LEMON (an acronym for the assessment of the airway's appearance, identification of any dental issues, evaluation of Mallampati classification, assessment of airway obstruction, and examination of neck mobility) and intubation difficulty scale (IDS) have gained attention. This study aimed to investigate the relationship between the LEMON criteria and IDS in tracheal intubation. The goal was to provide valuable insights that can assist medical professionals in optimizing their approach to airway management by analyzing clinical data, assessing patient outcomes, and evaluating the consistency between these scoring systems.

This study was based on a descriptive-analytical study involving a group of patients requiring intubation. This study examined 105 patients scheduled for elective surgeries, aged between 19 and 60 years, without specific underlying diseases, such as laryngeal cancer, temporomandibular joint stiffness, or significant tongue enlargement, and with a body mass index (BMI) below 40 kg/m². Initially, expert anesthesiologists assessed the patients using the LEMON criteria, and then the degree of intubation difficulty was measured using the IDS scoring system. Finally, these two criteria were compared.

In this study, there was a significant correlation between the LEMON score and the IDS score (P < 0.001). The difficult intubation group (IDS score higher than 0) had higher LEMON scores (with the highest score equal to 4) than the non-difficult intubation group (IDS score of 0) (P = 0.017). The average LEMON and IDS scores were 3.11 and 1.35, respectively. Among the participants, 96.2% had an intubation difficulty score of ≤ 5; nevertheless, 3.8% had a score of > 5. Additionally, limited neck mobility emerged as the sole independent predictor of intubation difficulty (P = 0.002, odds ratio = 6.152).

The LEMON score is associated with difficult intubation in adult patients requiring intubation.