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

Study Overview
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Brief Summary
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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 assessed the effect of FTc combined with perioperative fluid therapy on preventing hypotension after general anesthesia induction in elderly patients.

Official Title
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Effect of Carotid Corrected Flow Time Combined With Perioperative Fluid Therapy on Preventing Hypotension After General Anesthesia Induction in Elderly Patients

Conditions
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General Anesthesia Induction for Elective Surgery

Intervention / Treatment
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* Procedure: ultrasonographic measurement of carotid artery corrected flow time (FTc)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients who received elective surgery under general anesthesia, aged 65-85 years old, gender unlimited, ASAI-II Exclusion Criteria: uncontrolled hypertension unstable angina pectoris history of myocardial infarction after heart stent implantation severe arrhythmia：Atrial fibrillation、Ventricular premature beat, frequent atrial premature beat, other non-sinus rhythm pacemaker implants cardiomyopathy a left ventricular ejection fraction of < 40% history of neck trauma and surgery BMI>30

Ages Eligible for Study
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Minimum Age: 65 Years
Maximum Age: 85 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Hypotension after anesthetic induction group<br>Patients with hypotension after anesthetic induction | Procedure: ultrasonographic measurement of carotid artery corrected flow time (FTc)<br>* Ultrasonic measurement of carotid corrected blood flow time: 1. Patient's head turned to the left 30°. Firstly, the 6.0   13.0MHz linear probe was placed longitudinally on the maternal neck, and the probe marker was oriented towards the maternal head. Real-time B-ultrasound images of the long axis of the right common carotid artery were obtained from the lower margin of the thyroid cartilage. Then, the probe was placed in the center of the carotid lumen, about 2cm from the bifurcation of the carotid artery, to obtain the arterial pulse Doppler flow spectrum and store the carotid flow waveform. 2. Using the caliper function of the ultrasonic instrument, carotid flow time (FT) was obtained by measuring the interval between the systolic ascending stage and the restroke notch. Wodey (W) formula to calculate FTc. FTc= FT+[1.29× (HR-60)<br>|
| Non-hypotension after anesthetic induction group<br>Patients without hypotension after anesthetic induction | Procedure: ultrasonographic measurement of carotid artery corrected flow time (FTc)<br>* Ultrasonic measurement of carotid corrected blood flow time: 1. Patient's head turned to the left 30°. Firstly, the 6.0   13.0MHz linear probe was placed longitudinally on the maternal neck, and the probe marker was oriented towards the maternal head. Real-time B-ultrasound images of the long axis of the right common carotid artery were obtained from the lower margin of the thyroid cartilage. Then, the probe was placed in the center of the carotid lumen, about 2cm from the bifurcation of the carotid artery, to obtain the arterial pulse Doppler flow spectrum and store the carotid flow waveform. 2. Using the caliper function of the ultrasonic instrument, carotid flow time (FT) was obtained by measuring the interval between the systolic ascending stage and the restroke notch. Wodey (W) formula to calculate FTc. FTc= FT+[1.29× (HR-60)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Carotid artery corrected flow time (FTc) | the area under the receiver operating characteristics curve of corrected flow time in carotid artery measured by ultrasonography to predict hypotension after anesthetic induction | 5 minutes before induction of general anesthesia |