Dexmedetomidine and postoperative pain: An anesthesiologists’ perspective

Dear Editor, The recently published article by Liu et al.[1] has been read with interest and we as practicing anesthesiologists would wish to present our sincere reflections on the index randomized controlled trial (RCT). The RCT investigated the efficacy-safety of dexmedetomidine in postoperative pain management. In this regard, the authors narrate having administered dexmedetomidine 1 μg/kg intravenously 15 min post-endotracheal intubation in the intervention group.[1] Herein, the corresponding rate of drug administration can be particularly important in relation to safety and ought to have been presented. Meanwhile, the hemodynamic consequences of a fast-loading dose (typically less than 10 min), like transient hypertension followed by profound bradycardia, can be concerning, Liu et al.[1] mention having maintained dexmedetomidine at 0.2–0.6 mg/kg·h, wherein it is only safe to assume that they meant the same to be 0.2–0.6 μg/kg·h.[2] It also remains to be clarified whether/or not the authors employed any formal depth of anesthesia monitoring in their research setting, allowing for a safer titration across the dosages specified.[1] Of note, the authors studied an assorted set of patient outcomes where postoperative pain appeared to feature as the major outcome under evaluation.[1] Having said that, the role of a dynamic inter-group comparison based on the respective pain scores at the chosen time stamps in the study would have significantly enhanced the lucidity of the findings. For instance, talking of significance in specific, despite achieving statistical significance (P < 0.001), the comparable mean values of the pain scores at pretty much all the time stamps in the RCT except T2 (6h postoperatively) are intriguing enough to captivate attention, as far as the clinical significance of the present research findings is concerned.[1,3,4] Further, duly acknowledging the well-chalked-out roles and responsibilities with regard to data compilation in the study, Liu et al.[1] should have simultaneously shed light on the intraoperative role assignment of the investigators, in special reference to the utmost relevant facet of blinding in an RCT focusing on perioperative analgesia.[4] The former becomes important when the researchers declare having given no treatment to the control group. A simulated control setting with normal saline preparation in the control group, akin to the drug preparation in the intervention group, would have allowed for a more robust comparison, in our opinion.[1,4] Finally, a prospective cohort study by Gu et al.[5] involving a laparoscopic gynecologic surgical setting (much alike Liu et al.[1]); brings to light the role of other additional and often overlooked factors, such as preoperative patient anxiety in affecting the associated severity of the postoperative pain experienced. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.