Heart Rate Variability to Predict Hypotension Following Spinal Anesthesia in Cesarean Delivery

Study Overview
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Brief Summary
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Based on the patient's heart rate variability, the analgesia nociception index (ANI) measures the activity of the autonomic nervous system and the sympathetic/parasympathetic nervous system and expresses it as a numerical value through a specific algorithm. The investigators will analyze it and see if it has the ability to predict severe hypotension following spinal anesthesia.

Official Title
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Heart Rate Variability Monitoring to Predict Hypotension Following Spinal Anesthesia for Cesarean Delivery: Prospective Observational Study

Conditions
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Cesarean Section

Intervention / Treatment
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* Other: analgesia nociception index (ANI) monitoring


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult pregnant women scheduled for cesarean section under spinal anesthesia Exclusion Criteria: Emergency cesarean section When performing general anesthesia or epidural anesthesia Multiple pregnancies Surgery in which massive hemorrhage and massive blood transfusion are expected due to placenta previa Cardiac arrhythmias, congestive heart failure, ischemic heart disease, congenital heart anomalies Cranial nervous system disease Autonomic nervous system-related underlying diseases not related to pregnancy Fetal malformations Those who have an allergic skin reaction to adhesive substances such as bandages

Ages Eligible for Study
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Minimum Age: 20 Years

Sexes Eligible for Study
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Female

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 |
| --- | --- |
| normal pregnancy<br>Adult pregnant women scheduled for cesarean section under spinal anesthesia | Other: analgesia nociception index (ANI) monitoring<br>* The ANI monitor starts lying on the bed in the waiting area before entering the operating room, and the monitoring period should be at least 15 minutes. After entering the operating room, monitoring begins again and is maintained during the operation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The change of averaged value | The change of averaged value presented in ANI monitor | 15 min, 10 min and 5 min before entering the operating room; every 5 min after entering the operating room | 
| The change of instantaneous value | The change of instantaneous value presented in ANI monitor | 15 min, 10 min and 5 min before entering the operating room; every 5 min after entering the operating room | 
| Total dose of injected phenylephrine |  | During the anesthesia (from initiation of anesthesia until the end of anesthesia) | 
| Total dose of injected glycopyrrolate |  | During the anesthesia (from initiation of anesthesia until the end of anesthesia) | 
| The change of systolic blood pressure |  | Every 1 min after entering the operating room until finishing the operation |