Objective Dexmedetomidine is a highly selective alpha-2 adrenergic receptor agonist with sedative and analgesic properties but without respiratory depression effect and has been widely used in perioperative anesthesia. Here we performed a systematic review and meta-analysis to evaluate the effect of dexmedetomidine on maintaining perioperative hemodynamic stability in elderly patients. 
Methods PubMed, EMBASE, Ovid, the Cochrane Library, China National Knowledge Infrastructure (CNKI), and Wanfang Data were searched for randomized-controlled trials (RCTs) on the application of dexmedetomidine in maintaining perioperative hemodynamic stability in elderly patients from their inception to September, 2021. The standardized mean differences (SMD) with 95% confidence interval (CI) were employed to analyze the data. The random-effect model was used for the potential clinical inconsistency. 
Results A total of 12 RCTs with 833 elderly patients (dexmedetomidine group, 546 patients; control group, 287 patients) were included. There was no significant increase in perioperative heart rate (HR), mean arterial pressure (MAP) and diastolic blood pressure (DBP) in the dexmedetomidine group before and during the operation. In addition, the variations of hemodynamic indexes including HR, MAP, SBP (systolic blood pressure) and DBP were significantly lower in the dexmedetomidine group compared with the control group (HR: SMD = -0.87, 95% CI: -1.13 to -0.62; MAP: SMD = -1.12, 95% CI: -1.60 to -0.63; SBP: SMD = -1.27, 95% CI: -2.26 to -0.27; DBP: SMD = -0.96, 95% CI: -1.33 to -0.59). Subgroup analysis found that with the prolongation of 1.0 μg/kg dexmedetomidine infusion, the patient's heart rate declined in a time-depended way. 
Conclusion Dexmedetomidine provides a more stable hemodynamics during perioperative period in elderly patients. However, further well-conducted trials are required to assess the effective and safer doses of dexmedetomidine in elderly patients.

Key words: dexmedetomidine, elderly patient, hemodynamics, perioperative period

Funding: Supported by National High Level Hospital Clinical Research Funding (GSP-QN-16) and Yunnan Provincial Cardiovascular Disease Clinical Medical Center Project (FZX2019-06-01).