Predictive accuracy of intubation scores and parameters for double lumen tube placement in elective thoracic surgery: a prospective study

Background Standard predictors (Mallampati score, Wilson Risk Score, airway measurements) validated for single-lumen tubes might not apply to double-lumen tubes (DLT). The aim of this study is to evaluate whether these predictors can identify challenging DLT intubations. Material and methods In this prospective study, 200 adult patients undergoing elective thoracic surgery and intubated with DLT were enrolled. Preoperative airway assessments included Mallampati score, Wilson Risk Score, Cormack–Lehane Classification Score (CLS), body mass index (BMI), neck circumference (NC), neck and head mobility, Interincisor distance (IID), Sternomental distance (SMD), thyromental distance (TMD), and the ratio of height to TMD (RHTMD), as well as the NC to TMD ratio were performed. Intubation difficulty was measured using the Intubation Difficulty Scale (IDS). Based on IDS, patients were grouped as easy or difficult intubation, and the effectiveness of the criteria mentioned above in predicting intubation difficulty was assessed. Results Intubation difficulties occurred in 36 out of 200 patients (18%). There were no significant demographic differences between the easy and difficult intubation groups. The difficult intubation group showed higher Mallampati, Wilson, and CLS scores. They also had shorter SMD and TMD, smaller IIDs, and a higher height-to-TMD ratio ( p < 0.01). New DLT-specific cut-off values (SMD 15 cm, TMD 8 cm, IID 3.5 cm) ​​were established. Only the Cormack-Lehane grade independently predicted difficulty. Patients with difficult intubation required additional interventions. Other measures differed between groups but lost significance in regression analysis. Conclusion The Cormack–Lehane grade was the only independent predictor of difficulty in intubation with DLT. The new DLT-specific cutoff values suggest that DLT intubation might require its own customized assessment criteria. The proposed new cutoff values could make risk stratification more accurate. Combining scoring and measurements may improve preparation for difficult DLT intubations.