Assessment of Ultrasonographic Carotid Artery Corrected Flow Time and Internal Jugular Vein Collapsibility Index in Prediction of Hypotension During Induction of General Anesthesia
Conditions: Anesthesia
Sponsor: Ain Shams University

  
 
NCT06078228 
Date of Document  
26.9.2023 
 
 
 
 
 
 
 
 
Title of the Protocol: Assessment of Ultrasonographic Carotid Artery 
Corrected Flow Time and Internal Jugular Vein Collapsibility Index 
in Prediction of Hypotension during Induction of General Anesthesia  
 
 

  
 
NCT06078228 
Date of Document  
26.9.2023 
PROTOCOL OF A THESIS FOR PARTIAL FULLFILMENT  
OF M.D. DEGREE IN ANESTHESIA  
  
  
Title of the Protocol: Assessment of Ultrasonographic Carotid Artery 
Corrected Flow Time and Internal Jugular Vein Collapsibility Index 
in Prediction of Hypotension during Induction of General Anesthesia  
  
Postgraduate Student: Marina Adel George 
Degree: M.B.B.CH., M.Sc. Ain Shams University.  
  
  DIRECTOR: Prof. Dr. Amir Ibrahim Salah 
Academic Position: Professor.  
Department: Department of Anesthesia, Intensive Care and Pain Management, 
Faculty of Medicine, Ain Shams University.  
  
Co-DIRECTOR: Prof. Dr. Sherif Sayed Ali Sultan 
Academic Position: Professor.  
Department: Department of Anesthesia, Intensive Care and Pain Management, 
Faculty of Medicine, Ain Shams University.  
  
Co-DIRECTOR:  Dr. Aya Hisham Moussa Ahmad  
Academic Position: Lecturer.  
Department: Department of Anesthesia, Intensive Care and Pain Management, 
Faculty of Medicine, Ain Shams University.  
  
Co-DIRECTOR: Dr. Ahmed Taha Saeed Abdelwahab 
Academic Position: Lecturer.  
Department: Department of Anesthesia, Intensive Care and Pain Management, 
Faculty of Medicine, Ain Shams University.  
 
 
Faculty of Medicine 
Ain Shams University 
2023 

  
 
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Date of Document  
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What is already known on this subject? 
Post induction hypotension is closely related to postoperative complications. 
Patients are at high risk of hypotension due to preexisting hypovolemia and the 
vasodilatory effects of induction agents. Ultrasonographic measurement of the 
Carotid artery corrected flow time and internal jugular vein collapsibility index may 
predict post induction hypotension. 
 
1. INTRODUCTION: 
Hypotension during induction of general anesthesia, is quite common in 
clinical practice. If hypotension is severe or prolonged, it may cause organ 
hypoperfusion and ischemia. It may also increase the incidence of postoperative 
adverse outcomes such as myocardial injury, ischemic stroke, acute kidney injury, 
and even increases 1-year mortality (Wang et al., 2020; Chen et al., 2022). 
The preoperative identification of patients at risk of developing hypotension 
during induction could guide anesthetists to preoperative adjustment of the anesthetic 
management. This may include decreasing the doses of the induction agents, 
increasing the amount of pre-anesthetic fluid loading, and early administration of 
prophylactic vasopressors (Juri et al., 2017). 
Previously, central venous catheterization was a considered the gold standard 
for predicting intravascular volume status. However, its invasiveness and possible 
serious complications limited its wide use in routine anesthetic practice. Recently, 
ultrasonography for assessing volume status or predicting fluid responsiveness as 
well as post-induction hypotension has been widely applied in different clinical 
scenarios (Okamura et al., 2019; Maitra et al., 2020). 
Ultrasonographic-guided corrected flow time (FTc) refers to the left ventricular 
ejection time corrected by heart rate. It is known to be proportional to left ventricular 
preload and cardiac inotropy and inversely proportional to systemic vascular 
resistance (Kim et al., 2018; Deepak et al., 2020). Accordingly, it may have a role in 
prediction of occurrence of hypotension during induction of anesthesia.  
Furthermore, ultrasonographic evaluation of the internal jugular vein (IJV) has 
been shown to be effective in the prediction of intravascular volume. The 
collapsibility index, is defined as the change in IJV diameter associated with the 
respiratory cycle. Previously, inferior vena cava collapsibility index was valid in 
prediction of hypotension during induction of anesthesia (Szabo et al., 2019). 
 
2. OBJECTIVES: 
The aim of this study is to investigate the reliability of preanesthetic ultrasound 

  
 
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measurements of the carotid artery FTc and the internal jugular vein collapsibility 
index in predicting hypotension during the induction of general anesthesia. 
 
3. METHODOLOGY:   
Patients and Methods: 
 Type of Study: Observational Prospective Cohort Design. 
 Study Setting and ethical consideration: The approval of the Scientific Research 
Ethics Committee of the Faculty of Medicine, Ain Shams University will be 
obtained before starting work on the study. This study will be conducted in 
operating theatres of Ain Shams University Hospitals. Informed written consents 
to participate will be obtained from the patients. 
 Study Period: One year (October 2023-October 2024) 
 Study Population: Adult patient undergoing elective surgeries. 
 Selection criteria for cases: 
 Inclusion Criteria:  
1- Patients of American Society of Anesthesiologists (ASA) physical status I to II of 
both genders.  
2- Aged 18-65 years. 
3- Elective surgeries under general anesthesia.   
4- BMI less than 40. 
Exclusion criteria: 
Patients with 
1- Renal diseases. 
2- Hepatic diseases. 
3- ASA scores of 3-4. 
4- The presence of a left ventricular ejection fraction less than 50%. 
5- Age under 18 years old. 
6- Patient refusal. 
7- Coronary heart disease. 
8- Cardiac disease including cardiomyopathy and mild to severe valve disease. 
9- Pulmonary hypertension. 

  
 
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10-Peripheral arterial disease. 
11-Preoperative cervical vascular ultrasound abnormalities including plaque, 
stenosis and anatomical variation. 
12- Any previous neck surgery or trauma. 
 Sample Size: Total patients (70 patients) 
Using PASS 11 program for sample size calculation; setting power at 80%, α error 
at 5%, regarding the results of previous relevant study which revealed that the 
incidence of postinduction hypotension after general anesthesia was 63.6% and 
setting sensitivity and specificity of carotid FTc for predicting postinduction 
hypotension after general anesthesia at 72.2% and 93.7% respectively (Wang et 
al., 2022), the estimated sample size is 63 patients undergoing general anesthesia. 
Assuming that the dropout is of 10%, a sample size at least 70 patients 
undergoing general anesthesia will be needed. 
Study interventions: 
In all patients, the fasting times will be set as at least six hours for light meals, 
eight hours for heavy meals and two hours for clear fluids before surgery. No 
premedication will be advised to the patient before reaching the induction room. The 
patient in the induction room will be attached to a standard monitoring. A saline 
infusion (10 ml/kg/h) will be started. The data will be recorded before induction of 
anesthesia. These data will include: 
1- Heart rate  
2- The baseline systolic (SBP), diastolic (DBP) and mean arterial blood 
(MAP) pressures  
3- Respiratory rate (RR)  
4- Carotid artery FTc  
5- IJV collapsibility index. 
HR and BP will be recorded for 3 mins at 1-min intervals, and the mean values of 
HR and MAP will be recorded as the baseline value. The ultrasonographic examination 
will be performed by the most experienced member of the research team, under 
complete aseptic technique using a 4–12 MHz linear transducer and ultrasound device 
(Sonosite M-Turbo c Ultra sound device HFL-38 X) to measure the carotid artery FTc 
and IJV collapsibility index. 
Finally, anesthesia induction will take place as follows: 0.04 mg/kg midazolam will 
be injected IV then after about 1 minute fentanyl 1 microgram/kg IV will be given. One 
minute later, Propofol 10 mg/ml will be administered, titrated at a speed of 20 - 40 mg 
propofol every 10 seconds, until unconsciousness occurs. Then, Atracurium 0.5 mg/kg 
will take place. Anesthesia will be maintained with 50:50 oxygen mixed with air, 

  
 
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isoflurane 1-1.5% and Atracurium maintenance 0.1 mg/kg. Then blood pressure and heart 
rate will be collected after induction but before surgical incision. The blood pressure and 
HR values will be measured for 3 mins at 1-min intervals, and the mean values of HR and 
MAP will be taken during this period. A MAP less than 55 mmHg or more than a 20% 
decrease compared to the baseline level will be defined as hypotension during anesthesia 
induction. The patients will be then classified into the hypotension or non-hypotension 
group, according to this definition. Ephedrine (5 mg increments) will be administered to 
the patient when the MAP dropped below 55 mmHg, and atropine (0.5 mg) will be given 
when the HR dropped below 50 per minute. Patient will be under the responsibility and 
monitoring of the anesthesiologist who is attending the surgery. 
▪ Data recording:   
Sonographic examinations: 
o Carotid artery ultrasonography: 
Ultrasound measurements will be performed under a vascular setting with a 4–
12 MHz linear transducer and ultrasound device (Sonosite M-Turbo c Ultra sound 
device HFL-38 X) Carotid artery FTc measurements will be performed by one trained 
examiner. The ultrasonic data extraction will be conducted by the researcher. The 
right common carotid artery FTc will be measured in patients with their heads tilted 
30° to the left. 
Pulse wave Doppler will be selected, and the sampling frame will be placed in 
the area where the carotid artery has its best color flow, with an angle of less than 
60°, to obtain the blood flow spectrum. After that, using the caliper function of the 
machine, cycle time (CT) will be measured from the beginning of the systole to the 
beginning of the following systole, and systolic flow time (ST) will be measured from 
the beginning of the systolic upstroke to the dicrotic notch. 
o IJV ultrasonography: 
A clear transverse view of the right IJV will be recorded for fifteen seconds, with 
a linear ultrasound probe placed horizontally to the right of the middle level of the 
thyroid cartilage with minimal pressure. Variations in the IJV diameter with respiration 
will be assessed using M-mode imaging. The following three values will be recorded:  
1. Maximum (max) and minimum (min) IJV diameter values (at the end of the 
expiration and inspiration, respectively);  
2. Collapsibility index (%) = [(max IJV diameter - min IJV diameter)/max IJV 
diameter] × 100;  
3. Max IJV area. 
The primary outcome: the predictive value of the carotid Ftc for prediction of 
hypotension. 

  
 
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The secondary outcome: the predictive value of internal jugular vein 
collapsibility index for prediction of hypotension and predictive value of pre-
anesthesia heart rate, respiratory rate and mean blood pressure. 
Data collection:  vital data of the patients including heart rate, respiratory rate 
and mean blood pressure before induction. Carotid artery Ftc, IJV collapsibility index 
and mean blood pressure during induction will be recorded till the start of the surgical 
incision, then it will be collected by the use of a reliable software program. 
• Statistical package and Analysis:   
The collected data will be revised, coded and introduced to a PC using statistical 
package for social science (SPSS 15.0.1. for windows; SPSS Inc, Chicago, IL, 2001).  
Data will be presented as mean and standard deviation (+- SD) for quantitative 
prometric data. Suitable analysis will be done according to the type of data obtained. 
P< 0.05 will be considered significant. Then by using the receiver operating 
characteristic (ROC) curve will show the cut of values of prediction for both the 
carotid FTC and the internal jugular vein collapsibility index. 
 
4. REFERENCES:  
Chen Y, Liu Z, Fang J, et al. Correlation of carotid corrected flow time and 
respirophasic variation in blood flow peak velocity with stroke volume variation 
in elderly patients under general anaesthesia BMC Anesthesiol. 2022; 22(1):246. 
Deepak S, Bhavna G, Varshney P, et al. Role of carotid corrected flow time and 
peak velocity variation in predicting fluid responsiveness: a systematic review 
and meta-analysis. Korean J Anesthesiol 2023; 76(3):183-193. 
Juri T, Suehiro K, Kuwata S, et al. Hydroxyethyl starch 130/0.4 versus crystalloid 
co-loading during general anesthesia induction: a randomized controlled trial. 
KJ Anesth 2017; 31: 878-884.   
Kim DH, Shin S, Kim N, et al. Carotid ultrasound measurements for assessing fluid 
responsiveness in spontaneously breathing patients: corrected flow time and 
respirophasic variation in blood flow peak velocity. Br J Anaesth 2018; 
121:541–549. 
Maitra S, Baidya DK, Anand RK, et al. Carotid artery corrected flow time and 
respiratory variations of peak blood flow velocity for prediction of hypotension 
after induction of general anesthesia in adult patients undergoing elective surgery: 
a prospective observational study. J Ultrasound Med. 2020; 39(4): 721–30. 
Okamura K, Nomura T, Mizuno Y, et al. Pre-anesthetic ultrasonographic 
assessment of the internal jugular vein for prediction of hypotension during the 

  
 
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induction of general anesthesia. J Anesth 2019; 33: 612-619. 
Szabó M, Bozó A, Darvas K, et al. Role of inferior vena cava collapsibility index in 
the prediction of hypotension associated with general anesthesia: an 
observational study. BMC Anesthesiol. 2019; 19(1):139.  
Wang J, Li Y, Su H, et al. Carotid artery corrected flow time and respiratory variations 
of peak blood flow velocity for prediction of hypotension after induction of 
general anesthesia in elderly patients. BMC geriatrics. 2022; 22(1):1-9.