Efficacy of Dexmedetomidine as an Adjuvant to Ropivacaine for Intercostal Nerve Block in Elderly Patients Undergoing Video-Assisted Thoracoscopic Esophagectomy: A Randomized Double-Blinded Trial [Response to Letter]

We thank Yingying Xu et al for their thoughtful and constructive comments on our study.We really appreciate the interesting highlights they have summarized.In a letter to the editor, they suggest rigorously matching injection volume with drug concentration should be used in the study.We agree that a larger injection volume may improve drug diffusion.Thank you very much for pointing out our inaccurate description of drug preparation.Both the total volumes of the two groups were 25 mL, and 5 mL was injected in each rib space.This research was a clinical study mainly focused on phenomena observation.That is to say, the mechanism or reason was not the main focus.In addition, there have been many studies associated with dexmedetomidine as an adjuvant in peripheral nerve blocking in recent years. 1-3However, large scale research is still needed to establish the various effects of dexmedetomidine and the mechanism of action.Activity-related pain is a kind of short-term episode and triggered by certain actions, such as coughing or movement.Therefore, VAS of activity-related pain is difficult to observe and record.Based on this reason, previous studies did not involve it. 4,5We acknowledged that we did not monitor inflammatory response.However, the purpose of the study was to clearly define its safety profile and analgesic effect.Of course, more research is necessary to explore the mechanism of dexmedetomidine action.For the same reason, differences of sensory and motor block in this study were useless to prove the safety profile and analgesic effect.You pointed out the importance of long-term indicators and we certainly agree on this.Most of the patients would be followed up for 1-3 years.We hope this will clarify the issue and take the opportunity to thank the authors of the letter once again for their particular interest in our work.