Effect of intratracheal dexmedetomidine combined with ropivacaine at various times prior to tracheal intubation in patients undergoing thyroidectomy: a randomized clinical trial.

BACKGROUND: Optimizing the clinical workflow, this study evaluated the impact of varying the time interval between topical airway anesthesia with a dexmedetomidine-ropivacaine combination and tracheal intubation in patients undergoing thyroidectomy. METHODS: Patients were given surface anesthesia at various times prior to tracheal intubation according to their group randomized to E group (Topicalization via an epidural catheter method, followed by immediate intubation), S-I group (topicalization via a traditional atomizer, followed by immediate intubation), or S-II group (Topicalization via a traditional atomizer, followed by intubation after a 2-min delay). The following timepoints were recorded: the mean arterial pressure (MAP) and heart rate (HR) before induction, before the endotracheal tube (ETT) was inserted, 1 min after the ETT was inserted (T2), after the ETT was removed (T3), and 1 min after the ETT was removed (T4). The MAP at T2 was recognized as the primary outcome in this study. The secondary outcomes were the occurrence of sore throat and hoarseness at 2 and 24 h postoperatively. Additional assessments included the level of cough at T3 and the pain score of the incision at 2 and 24 h postoperatively. RESULTS: At the T2 timepoint, the S-II cohort demonstrated a statistically significant reduction in both mean arterial pressure (MAP) and heart rate (HR) compared to the S-I and E groups (P < 0.001). Pairwise comparisons revealed substantial differences between S-II group and both intervention groups: E versus S-II (median difference 16.8 (95% confidence interval [CI] 13.5-20.0), P < 0.001) and S-I versus S-II (median difference 15.2 (95% CI 12.1-18.4), P < 0.001). However, comparisons between the S-I and E groups revealed no statistically significant differences, with a median difference of 1.7 (95% CI-1.9-5.2), P > 0.999). In addition, the occurrence of sore throat and hoarseness were not affected during the first 24 h after surgery. CONCLUSIONS: Immediate endotracheal intubation following topical airway anesthesia, as a convenient approach, induces transient hemodynamic instability during the procedure but does not increase the incidence of sore throat and hoarseness 24 h postoperatively. TRIAL REGISTRATION: This research was approved by the research ethics committee of the present institution (No. 2024-091-01, approval on June 7, 2024) and was registered at the Chinese Clinical Trial Registry (ChiCTR2400085572, https://www.chictr.org.cn/showproj.html?proj=233656 ; date of registration: June 12, 2024) before patient enrollment.