Methods
 This randomized, double-blind prospective clinical trial was conducted on 120 patients aged 20‒60 years with ASA (American Society of Anesthesiologists) classes I and II. Patients who were candidates for percutaneous nephrolithotomy with spinal anesthesia were divided into intervention (received 1 cc = 5 mg ephedrine) and control groups (received 1 cc normal saline). All vital parameters, including HR (heart rate) and NIBP (noninvasive blood pressure), were recorded perioperatively T0–T25) and finally at the end of surgery time (Tf). The results were analyzed by SPSS software version 23, and a 