Pre‐operative dexmedetomidine nasal spray and emergence agitation in adults undergoing ear, nose and throat surgery: a reply

We thank Hsiao et al. [1] and Sun et al. [2] for their interest in our study [3], in which we showed that pre-operative dexmedetomidine nasal spray reduced emergence agitation in adults undergoing ear, nose and throat (ENT) surgery (relative risk 0.53, 95%CI 0.34–0.82, number needed to treat 4.6). Dexmedetomidine nasal spray was also associated with less venipuncture pain, better sleep on the first postoperative night and higher patient satisfaction, without increasing adverse events. Hsiao et al. note that sevoflurane anaesthesia carries a higher baseline risk of emergence agitation than propofol-based total intravenous anaesthesia (TIVA). Sevoflurane is nevertheless used widely in various surgical procedures including ENT surgery, especially where TIVA is unavailable or impractical. In our centre, sevoflurane is our routine choice. We acknowledged in the original report that the effect of dexmedetomidine under TIVA needs further study. The Fragility Index of 5 (Walsh method [4]) indicates modest robustness; our trial was powered a priori for a 22% absolute reduction in emergence agitation incidence, and the observed 22% reduction aligns with this estimate. We encourage confirmatory trials. We agree that preventing serious complications such as postoperative bleeding, particularly in procedures like tonsillectomy, is vital. Although our study was not powered for rare events, one patient in each group experienced postoperative bleeding after tonsillectomy and required re-operation. The potential for intranasal dexmedetomidine to improve the surgical field via local vasoconstriction is interesting, but larger trials are needed to address long-term and clinically important outcomes such as postoperative delirium and surgical morbidity, especially in high-risk populations. Sun et al. requested details on airway management and fresh gas flow. At the end of surgery and before cuff deflation, oropharyngeal suction was performed routinely in every patient. This was done gently to avoid provoking airway reflexes or agitation. Suctioning was repeated only if copious secretions were noted, and the timing and number of suction passes were recorded. Once sevoflurane was discontinued, the fresh gas flow was fixed at 6 l.min-1 (50% oxygen in air) for all patients until tracheal extubation, as pre-specified to ensure rapid washout of sevoflurane. A total of 57 patients developed emergence agitation in the operating theatre (20 allocated to the dexmedetomidine group and 37 allocated to the 0.9% saline group). The patients with agitation were monitored closely, and once agitation had resolved, they were transferred to the post-anaesthesia care unit (PACU). Among them, 56 were calm and co-operative in the PACU; only one patient allocated to the saline group, who had earlier shown dangerous agitation (Riker sedation agitation scale score 7), became agitated again and required verbal reassurance. We observed fewer sleep disturbances on the first postoperative night in patients allocated to the dexmedetomidine group. However, we did not assess baseline sleep quality, and pre-existing sleep disorders could confound this finding. All secondary outcomes were exploratory, and no multiplicity adjustment was applied. Consequently, definitive conclusions cannot be drawn and we did not report p values to avoid over-interpretation. Thus, the observed better sleep in the dexmedetomidine group is hypothesis-generating and warrants further investigation.