Biphasic Effects of Different Doses Ephedrine on Hemodynamics in Elderly Patients Under General Anesthesia

Ephedrine is commonly clinically vasoactive drugs, which can constrict blood vessels and increase blood pressure. Ephedrine can not only stimulate α receptors, but also β receptors, that\'s to say, it can increase heart rate, stroke volume, and cardiac output, but it also can decrease the level of systemic vascular resistance. This research aims to observe the short-term vasodilator effect of diffierent doses of ephedrine used in elderly patients under general anesthesia in clinical practice, and analyze the main reasons for this phenomenon and take preventive actions to minimize the possibility of further lowering of blood pressure to provide references for clinical rational use of drugs.