The Change of Tissue Oxygen Saturation Following Volatile Anesthesia

Study Overview
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Brief Summary
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General anesthesia can affect tissue oxygen saturation and microcirculatory reactivity. However, the differences in microcirculation caused by anesthetic methods have not been well studied. Near-infrared spectroscopy (NIRS) measures peripheral tissue oxygen saturation noninvasively and can be used in conjunction with vascular occlusion (VOT) experiments. The purpose of this study was to examine the changes in NIRS derived tissue oxygen saturation (StO2) and microcirculatory reactivity by VOT after inhalation anesthesia in healthy population. This prospective, observational study will be performed on 60 healthy patients who had undergone elective surgery under volatile general anesthesia. The investigators measure StO2 and microvascular reactivity using NIRS combined with vascular occlusion test (VOT). The parameters were performed twice per patient, before and after the induction of anesthesia. Occlusion slope and recovery slope during VOT will be compared before and after anesthesia. Moreover, the changes depend on the age will be analyzed.

Detailed Description
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This prospective observational study was performed on 60 patients without comorbidities who underwent elective surgery under general anesthesia. Before and after the induction of anesthesia, StO2 monitoring and VOT were performed to investigate the effect of anesthesia on microcirculation. To investigate the effect of age on microcirculation, the patients were divided into two different groups, young (< 65 yrs) and old (> 65 yrs) groups, and the VOT-derived parameters and hemodynamics between two groups were compared.

Official Title
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The Change of Tissue Oxygen Saturation Measured by Dynamic Near Infrared Spectroscopy Following Volatile Anesthesia in Healthy Population

Conditions
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Healthy, Aging

Intervention / Treatment
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* Drug: Desflurane
* Device: Near-infrared spectroscopy monitor


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Adult Over 18 years of age undergoing general surgery under general anesthesia. Exclusion Criteria: ASA category III or IV, Diabetes, Chronic Kidney Disease, Vascular Disease

Ages Eligible for Study
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Minimum Age: 18 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

| Intervention/Treatment |
| --- |
|Drug: Desflurane|general anesthesia using desflurane.|
|Device: Near-infrared spectroscopy monitor|tissue oxygen saturation monitoring combined with vessel occlusion test|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Changes in Tissue Oxygen Saturation after General Anesthesia | Vascular occlusion test (VOT) will be performed twice for each patient, before (T0) and 30 min after the induction of general anesthesia (T1). Before induction, a NIRS sensor will be placed on the thenar eminence and an automated tourniquet will be placed around the ipsilateral upper arm. After the baseline StO2 stabilization, the automatic tourniquet will be inflated to 50 mmHg over the patient's baseline systolic blood pressure and maintain for 5 min. After the 5-min ischemic period, the tourniquet will be rapidly deflated to 0 mmHg. StO2 data will be continuously recorded during the VOT procedure. Baseline StO2, minimum StO2 during the 5-min inflation of the tourniquet, maximum StO2 during deflation of the tourniquet, time to minimum StO2, and time to maximum StO2 will be obtained. The occlusion slope and recovery slope will be calculated based on the measured StO2 data. | before and 30 minutes after anesthetic induction | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Age-related changes in microcirculation | Patients will be divided into three groups by age (younger group: < 65 years old and older group: ≥ 65 years old) to perform age-based analysis. The acquired StO2 data by the VOT test among the groups will be analyzed and compared. | before and 30 minutes after anesthetic induction |