Evaluation of the Changes of Pleth Variability Index During Preoxygenation for Predicting Hypotension

Study Overview
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Brief Summary
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The aim of this study is to investigate whether the change in pleth variation index (PVI) according to preoxygenation can predict hypotension during anesthesia induction.

Detailed Description
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In patients with hypovolemia or dehydration, pulse pressure variation can be increased by spontaneous forced inspiratory breathing. PVI is a noninvasive method of indicator of fluid responsiveness like purse pressure variation. We expected that the amount of change in PVI between at the time of entering operating room and after preoxygenation with forced inspiration method could be different depending on the patient's volume status. After entering operating room, monitoring devices, anesthesia depth sensor, and Radical-7® Pulse CO-Oximeter® are attached. Patients rest for 5 minutes, and then baseline systolic blood pressure, diastolic blood pressure, mean blood pressure, and heart rate are collected every 1-minute. Pleth variability index (PVI), perfusion index (PI) are also measured continuously. For pre-oxygenation of anesthesia, take 8 deep breaths at flow 10 l/min of 100% oxygen for 1 minute with maximally forced inspiration. After that, for 2 minutes, patients breathe as usual while maintaining oxygen supply. until tracheal intubation or laryngeal mask insertion. Anesthesia is induced with target concentration infusion of 4.0 ng/ml of remifentanil and 4.0 ug/ml of propofol. When the patient loses consciousness, rocuronium 1.0 mg/kg is administrated and endotracheal tube or laryngeal mask is inserted 2 minutes after. PVI, PI, blood pressure, and heart rate are measured until tracheal intubation or laryngeal mask insertion. Anesthesia induction-related hypotension is defined as a decrease in mean arterial pressure below 60 mmHg at any timepoint from baseline parameter collection to until airway device insertion. The parameters are analyzed by comparing between groups with and without anesthesia induction-related hypotension.

Official Title
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Evaluation of the Changes of Pleth Variability Index During Preoxygenation for Predicting Hypotension During Induction of Anesthesia in Surgical Patients; Prospective Observational Study

Conditions
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Hypotension on Induction

Intervention / Treatment
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* Procedure: Preoxygenation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult patients undergoing elective surgery under general anesthesia Exclusion Criteria: (1) American Society of Anesthesiologists (ASA) physical status classification III or higher (2) Patients with cognitive impairment who are unable to follow instructions (3) Patients with pulmonary dysfunction (4) Other patients who are judged inappropriate to the experiment by the researcher

Ages Eligible for Study
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Minimum Age: 19 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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Design Details

Primary Purpose: Screening
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: preoxygenation<br>Taking 8 deep breaths at 10 l/min of 100% oxygen for 1 minute with forced inspiration for pre-oxygenation | Procedure: Preoxygenation<br>* Taking 8 deep breaths at 10 l/min of 100% oxygen for 1 minute with forced inspiration for pre-oxygenation<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Hypotension during anesthesia induction | When mean blood pressure decreases to less than 60 mmHg at least once from the administration of anesthetic agent to just before intubation | from start of anesthesia induction to just before intubation | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Systolic blood pressure | systolic blood pressure with non-invasive blood pressure at 1-minute intervals. | from entering operating room to just before intubation | 
| Diastolic blood pressure | diastolic blood pressure with non-invasive blood pressure at 1-minute intervals. | from entering operating room to just before intubation | 
| Heart rate | heart rate which was measured continuously. | from entering operating room to just before intubation | 
| Perfusion index | Perfusion index from Radical-7® Pulse CO-Oximeter® which was measured continously. | from entering operating room to just before intubation | 
| Pulse oximetry plethysmographic waveform; ΔPOP | Respiratory variations in the pulse oximetry plethysmographic waveform amplitude | from the administration of anesthetic agent to just before intubation | 
| Pleth Variability Index (PVi®) | the relative variability of the pleth waveform (perfusion index) detected from a Radical-7® Pulse CO-Oximeter® | from entering operating room to just before intubation | 
| Saturation of percutaneous oxygen | from a Radical-7® Pulse CO-Oximeter® | from entering operating room to just before intubation | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Hypovolemia, Pulse Wave Analysis, Hypotension, Anesthesia, General