Results
hoarseness, postoperative hoarseness, postoperative sore throatThe, pain, cord injuries, tracheal injury, postoperative sore throat
The study recruited 137 patients who were treated between December 2022 and April 2023, and 17 patients were excluded (Fig. 
Flow diagram of the study designBoth groups showed no significant differences in patient characteristics (Table 
Comparison of general characteristics of the two groups (Double-lumen tube size(32/35/37/39-Fr)BMI: body mass index, ASA physical status: American Society of AnesthesiologistsDLTs passed the trachea more smoothly with lower resistance in the thermal softening group than in the control group (
Intubation conditions and hemodynamic responses of the patients to intubation with double-lumen tubesValues are expressed as number of patients or mean (SD). SD: standard deviationThe incidence of POST was significantly lower in the thermal softening group than in the control group at 1, 6, and 24 h after the surgery (
Incidence and pain score of POST and incidences of postoperative hoarseness and oral dryness (Values are expressed as median [interquartile range] or number of patients (%). CI: confidence interval
Proportion of patients with POST over time. POST: postoperative sore throat
Proportion of patients with severe POST (grade ≥ 2) and hoarseness of voice throughout 24 h after the surgery. POST: postoperative sore throatThe thermal softening group had a lower total incidence of tracheal injury than the control group(P < 0.05)(Table 
Incidence of tracheal and vocal cord injuries (Values are expressed as number of patients (%)