Introduction
bradycardia, hypotension
Spinal anesthesia causes iatrogenic central sympatholysis by blocking the pre-ganglionic sympathetic fibers and cardiac sympathetic innervation. This iatrogenic sympathetic blockage causes hypotension and bradycardia, which occasionally require clinical intervention [In clinical practice, spinal anesthesia is usually combined with sedation, mainly using propofol or dexmedetomidine. In addition to spinal anesthesia, propofol and dexmedetomidine induce hemodynamic changes and alter the autonomic nervous system. Previous studies have reported that propofol induces bradycardia and hypotension [Spinal anesthesia is known to reduce sympathetic activity, and sometimes requires clinical intervention. Since dexmedetomidine and propofol have been shown to induce different hemodynamic changes, we hypothesized that they would also cause different changes in the autonomic nervous system additional to the effect of spinal anesthesia. Such information could be valuable in selecting a sedative for use in spinal anesthesia. The present preliminary study aimed to compare the differences in HRV dynamic during sedation with propofol or dexmedetomidine in patients who underwent spinal anesthesia.