Predictability of Preoperative Carotid Artery Corrected Flow Time for Hypotension After Spinal Anesthesia in Patients Undergoing Cesarean Section

Study Overview
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Brief Summary
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The purpose of this study was to investigate the incidence of hypotension after spinal anesthesia in patients undergoing cesarean section as predicted by preoperative carotid artery corrected flow time measured by Doppler ultrasound. Before entering the operation room, Two inspectors perform two measurements of carotid artery corrected blood flow time respectively, and an average of the four measurements is calculated and analyzed. At this time, the patient's posture is supine, and the head is turned about 30 degrees to the left. Corrected blood flow time (FTc) is measured using carotid ultrasound as previously described by Blehar and colleagues. Corrected blood flow time is calculated by Bazett's formular and Wodey's formular by evaluating a single cycle after several successive cycles have reached a stable and acceptable quality level. The occurrence of hypotension is recorded from the spinal anesthetic injection until the fetus is delivered. The definition of hypotension after spinal anesthesia is that the systolic blood pressure drops to 80 mmHg, less than 75% of the baseline value, or even if it does not meet the former criteria, symptoms that are consistent with hypotension (dizziness, dizziness, dyspnea, nausea or vomiting).

Official Title
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Predictability of Preoperative Carotid Artery Corrected Flow Time for Hypotension After Spinal Anesthesia in Patients Undergoing Cesarean Section

Conditions
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Cesarean Section

Intervention / Treatment
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* Diagnostic Test: Doppler sonographic measurement


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Uncomplicated singleton full-term parturients undergoing cesarean delivery age 20 40 ASA class 1 3 Exclusion Criteria: Emergency surgery Placenta previa Preeclampsia or Preeclampsia Cardiovascular or cerebrovascular disease Morbid obesity with a body mass index (BMI) of 40 kg / m2 or higher Gestational age <36 or ≥ 41 weeks Contraindications to spinal anesthesia Carotid stenosis> 50% (angiography, CT angiography, MR angiography, or duplex ultrasonography) Basal systolic blood pressure> 160 mmHg The preoperative examination revealed that the electrocardiogram was not normal sinus rhythm Chronic kidney disease (eGFR <60 mL / min / 1.73 m2) If the subject includes a person who can not read the written consent (eg, illiterate, foreigner, etc.)

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 40 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Uncomplicated cesarean delivery<br>Uncomplicated singleton full-term parturients undergoing cesarean delivery | Diagnostic Test: Doppler sonographic measurement<br>* First, place a 4.5-12.0 MHz linear array transducer vertically on the neck with the probe marker facing the patient's head. A long axis B-mode image of the right common carotid artery is obtained at the lower border of the thyroid cartilage. The sample volume is then placed in the center of the lumen located approximately 2 cm proximal to the carotid bifurcation. Next, pulsed wave Doppler tracing is performed in the arterial blood flow. The cycle time using the calliper function in an ultrasonic machine is obtained by measuring the interval between heartbeats at the beginning of the Doppler blood flow upstroke and the Flow time is measured as the time from the beginning of the systolic upstroke to the dicrotic notch.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Occurrence of Hypotension | The definition of hypotension after spinal anesthesia is that the systolic blood pressure drops to 80 mmHg, less than 75% of the baseline value , or even if it does not meet the former criteria, symptoms that are consistent with hypotension (dizziness, dizziness, dyspnea, nausea or vomiting) . | from the spinal anesthetic injection until the fetus is delivered. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The systolic blood pressure difference | The most significant difference in systolic blood pressure dropped | from the spinal anesthetic injection until the fetus is delivered. |