Optimal bent length of lightwand for intubation in adults: a randomized, prospective, comparative study

To evaluate the effect on intubation success of different bent lengths of a lightwand (a malleable illuminating stylet used for intubation), based on the patient's thyroid prominence-to-mandibular angle distance (TMD), thyroid prominence-to-incisor distance (TID) and gender.

This prospective, randomized, blinded study included patients undergoing elective surgery. In group A, the bent length was determined based on the patient's gender. In groups B and C, the bent length was calculated according to the patient's TMD or TID, respectively. Intubation success rate, time required for intubation, haemodynamics and complications postintubation were documented.

A total of 246 patients were recruited and randomly assigned to one of the study groups. There were no significant differences in number of intubation attempts and success rate among the three groups. The mean time required for intubation was significantly shorter in group A than in the other groups. There were no major complications in any group.

Gender-determined bent length was more suitable for lightwand-guided intubation than TID or TMD. For most patients, the optimal bent length was in the range of 6.0-6.9 cm.