Carotid Artery Corrected Flow Time as a Predictor of Hypotension After Induction of General Anesthesia in Elderly Patients

The number of elderly patients undergoing elective surgery has been growing in recent years. Elderly patients often have a variety of underlying diseases, including hypertension, coronary heart disease, diabetes, arteriosclerosis, etc., which increase the risk. When the elderly receive general anesthesia, hypotension often occurs after anesthesia induction. Once hypotension occurs, it may lead to myocardial ischemia, myocardial infarction, stroke and other serious complications. Therefore, in clinical anesthesia, a simple, quick and accurate prediction method is needed to evaluate and predict the risk of hypotension in elderly patients after induction, so that appropriate intervention measures can be taken in advance to reduce the incidence of hypotension in elderly patients after induction, thus reducing the occurrence of related complications and ensuring the safety of anesthesia and surgery.Carotid Artery Corrected Flow Time（FTc） is a recently developed volumetric predictor, which refers to the time between the the onset of systolic flow until the closure of the aortic valve. It is related to cardiac preload and can reflect cardiac output to a certain extent. It is considered as a reliable indicator for evaluating volume status and volumetric reactivity. Therefore, this study will investigate the predictive value of carotid corrected blood flow time in the elderly after general anaesthesia induced hypotension.

Inclusion Criteria:patients who received elective surgery under general anesthesia, aged 65-85 years old, gender unlimited, ASAI-IIExclusion Criteria:uncontrolled hypertensionunstable angina pectorishistory of myocardial infarctionafter heart stent implantationsevere arrhythmia：Atrial fibrillation、Ventricular premature beat, frequent atrial premature beat, other non-sinus rhythmpacemaker implantscardiomyopathya left ventricular ejection fraction of < 40%history of neck trauma and surgeryBMI>30