Dexmedetomidine Use and Intraoperative Bradycardia During Radiofrequency Rhizotomy for Trigeminal Neuralgia: A Retrospective Observational Study.

Intraoperative bradycardia occurred significantly more frequently in patients receiving dexmedetomidine compared to those who did not.

• Bradycardia occurred in 59.8% of the Dex group vs 29.0% of the Non-Dex group (p<0.001).
• Bradycardia was defined as heart rate <60 beats per minute or the need for atropine.
• The study included 517 patients, with 331 (64.0%) receiving dexmedetomidine.
• Dexmedetomidine use was independently associated with bradycardia with an odds ratio of 5.16 (95% CI 2.57–10.39; p<0.001) on multivariable logistic regression.

Atropine administration was significantly more frequent in the dexmedetomidine group than in the non-dexmedetomidine group.

• Atropine was administered in 18.1% of the Dex group vs 4.8% of the Non-Dex group (p<0.001).
• Atropine use was included as part of the primary outcome definition and also assessed as a secondary outcome.
• The study was conducted at a single center covering procedures between August 2020 and December 2022.

Dexmedetomidine significantly reduced intraoperative requirements for both midazolam and propofol.

• Median midazolam requirement was 0.038 mg/kg/h in the Dex group vs 0.044 mg/kg/h in the Non-Dex group (p<0.001).
• Median propofol requirement was 0.73 mg/kg/h in the Dex group vs 1.25 mg/kg/h in the Non-Dex group (p<0.001).
• These reductions represent the sedative-sparing effect of dexmedetomidine during monitored anesthesia care.

Younger age and longer anesthesia duration were additional independent predictors of intraoperative bradycardia.

• Younger age was associated with higher bradycardia risk (OR 0.97 per year; 95% CI 0.96–0.99; p<0.001), meaning each additional year of age was associated with a 3% reduction in odds of bradycardia.
• Longer anesthesia duration increased bradycardia risk (OR 1.04 per minute; 95% CI 1.02–1.06; p<0.001).
• These predictors were identified through multivariable logistic regression analysis.

Age-stratified analyses revealed a more pronounced reduction in heart rate among younger patients receiving dexmedetomidine.

• Patients younger than 45 years showed a more pronounced bradycardic response to dexmedetomidine compared to older patients.
• The findings suggest an age-dependent modulation of the bradycardic response to dexmedetomidine.
• This finding was identified through age-stratified subgroup analyses performed as part of the study.

Intraoperative bradycardia during radiofrequency rhizotomy for trigeminal neuralgia is primarily related to the trigeminal-cardiac reflex.

• The trigeminal-cardiac reflex is identified as the primary mechanism for intraoperative bradycardia in this procedure.
• The hemodynamic impact of dexmedetomidine in this specific procedural context had not been well characterized prior to this study.
• All procedures were performed under monitored anesthesia care.