Supplementary Material for: Factors Associated with Tremor Changes during Sedation with Dexmedetomidine in Parkinson's Disease Surgery

<b><i>Introduction:</i></b> Dexmedetomidine is an α<sub>2</sub>-agonist recently proposed as a potentially ideal drug for sedation during the surgical treatment of Parkinsonʼs disease (PD). This report documents the incidence of changes in motor symptoms (especially tremor) in PD patients sedated with dexmedetomidine for deep brain stimulation or ablation procedures. <b><i>Methods:</i></b> We reviewed a retrospective cohort of 22 patients who underwent surgery for PD with dexmedetomidine sedation at a single institution from 2010 to 2014. A logistic regression analysis was performed to analyze possible confounding factors. <b><i>Results:</i></b> 14 cases of tremor reduction or suppression were recorded (cumulative incidence: 63.6%; 95% CI: 40.7-82.8). No association could be identified between loading dose, β-blocker use and preoperative total Unified Parkinson's Disease Rating Scale III, with tremor changes. The maintenance dose of dexmedetomidine was higher in patients who did not experience changes [median and range for patients with and without tremor alteration 0.75 (0.2-1.0) and 1.0 µg × kg<sup>-1</sup> × h<sup>-1</sup> (0.7-1.4), respectively; p = 0.021]. <b><i>Conclusion:</i></b> Dexmedetomidine provides adequate sedation during surgery for PD, but it might affect motor signs making intraoperative testing difficult or even impossible. Dosage appears not to be the determining factor in motor changes, whose cause remains unclear.