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

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.

Inclusion Criteria:

• Ages ranged from 65 to 80
• ASA I~II
• patients undergoing elective general anesthesia
• BMI 18.5-30.0

Exclusion Criteria:

• refusal of patients
• emergency surgery, neurological or mental disorders , Liver and kidney dysfunction
• previous allergy to ephedrine and phenylephrine
• heart disease history, such as pacemaker implantation, unstable angina, congestive heart failure, Heart valve disease
• nerve, digestive, endocrine system diseases, and affect intravascular Fluid volume or balance diseases (such as inflammatory diseases or gastrointestinal obstructive diseases)
• emergency surgery
• malignant tumors
• tachycardia (HR>100)
• bradycardia ( HR<50)
• intraoperative hypotension that is difficult to correct with ephedrine and phenylephrine
• use of other vasoactive drugs.
• surgery time <40 min