Clinical and radiologic evaluations for predicting difficult tracheal intubation; [Valutazioni cliniche e radiologiche per prevedere l'intubazione tracheale difficile]

Topcu I.; Ovali G.Y.; Yentur E.A.; Kefi A.; Tuncyurek O.; Pabuscu Y.

Clinical and radiologic evaluations for predicting difficult tracheal intubation; [Valutazioni cliniche e radiologiche per prevedere l'intubazione tracheale difficile]

Date

2006

Authors

Abstract

Objective: The aim of this study is to predict difficult endotracheal intubations preoperatively with clinical and radiographical parameters (lateral x-ray) and to assess their reliability. Design: 208 adult patients (68 male, 140 female) submitted for elective surgery under general anaesthesia were included into this study. Age, height, weight, inter-incisor gap, neck circumference, sternomental and thyromental distance, modified Mallampati classification and protruding upper teeth were measured during preoperative evaluation. Lateral cervical spine radiographs were evaluated to predict the skeletal structure associated with difficult intubation. Laryngeal view was graded according to Cormack-Lehane laryngoscopic classification. The number and duration of attempts at each tracheal intubation were recorded. Results: We obtained the percentage of difficult intubations to be 5.7%. There was no significant association between difficult intubation and age, weight, thyromental and sternomental distances, mandibular protrusion, Wilson risk scores, inter-incisor gap and neck circumference (p > 0.05). Difficult intubations were associated with male sex, Cormack-Lehane grade 3 or 4 and two and more increased Mallampati grade (p < 0.05). After taking the measurements on the radiographs, we observed a significant association between temporomandibular joint (TMJ) to tip of upper incisors (V1), length of the perpendicular from the hard palate to the tip of the upper incisors (V2), TMJ to tip of lower incisors (V5), the distance from the upper incisors to the corniculate cartilages (V17), the anteroposterior thickness of the tongue (V19) for difficult intubation with stepwise multivariate logistic regression model (p < 0.05). According to Cormack-Lehane classification we calculated the highest sensitivity as (83.3%), specificity as (95.9%), positive predictive value as (55.6%) and negative predictive value as (98.9%). Conclusion: We conclude that these clinical and radiographic measurements are of little value in predicting difficult intubation in adults when used alone. For elective cases, we advocate taking additional radiological examinations, if clinical findings predict or indicate the probability of a difficult airway.