To the Editor:

In a randomized clinical trial comparing single-handed chin lift and two-handed jaw thrust techniques for lightwand-guided intubation in anesthetized patients, Yang et al. [1] showed that two-handed jaw thrust facilitated intubation and reduced the incidence and severity of postoperative sore throat (POST) compared to single-handed chin lift. However, in the Methods, the authors did not specify whether the two intubators were experienced in the lightwand-guided intubation, and whether they practiced the two techniques equally or preferred to use one of the techniques before this study. In fact, experience and competence with any intubation technique is critical for its successful use in any clinical setting [2]. For the results of a comparative study to be valid, the investigators must be equally proficient with each studied technique to avoid bias. We are concerned that different proficiency levels of the investigators with the two techniques would have contributed to their findings.

Furthermore, the incidence and severity of POST were used as the final end-points of performance. However, postoperative analgesia was not standardized in this study. The authors did not provide the type and dose of postoperative analgesics and the timing of their administration in relation to assessment of POST. In the absence of comparing postoperative analgesic medications, we argue that the secondary findings and subsequent conclusions should be interpreted with caution, as they may have been determined by incomplete methodology.

Finally, it should be emphasized that a shortcoming of the two-handed jaw thrust technique is the need for an additional assistant.