One hundred and one patients with knee osteoarthritis scheduled for unilateral TKA were randomized to receive intranasal dexmedetomidine 1 μg/kg (n=49) or intranasal saline (n=52) about 45 minutes before spinal anesthesia. The primary outcomes were perioperative changes in mean arterial pressure (MAP) and heart rate (HR). Secondary outcomes included systolic/diastolic blood pressure, SpO₂, intraoperative hypertension/hypotension, bradycardia/tachycardia, vasopressor/antihypertensive use, intraoperative blood loss, and perioperative hemoglobin/platelet changes, with physiologic outcomes measured through 150 minutes and labs to postoperative day 1. Overall, the results of the study revealed lower intraoperative MAP and HR at several timepoints and a lower incidence of intraoperative hypertension with dexmedetomidine, without differences in oxygenation or bleeding. These findings suggest intranasal dexmedetomidine is hemodynamically well tolerated and may stabilize blood pressure during TKA under spinal anesthesia