Influence of Obesity on Microvascular Reactivity During General Anesthesia

Study Overview
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Brief Summary
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The purpose of this study was to investigate the effect of obesity on changes in microvascular reactivity and tissue oxygen saturation (StO2) during general anesthesia using near-infrared spectroscopy in conjunction with vascular occlusion tests (VOT). For this prospective observation investigation, a total of 128 patients who underwent elective surgery under general anesthesia at Pusan National University Hospital between June 2018 and February 2021 were participated in this study. Baseline StO2 on thenar eminence, hemodynamics, and laboratory profile were monitored before (Tpre) and 30 min after general anesthesia (Tpost). During vascular occlusion tests (VOT), the occlusion slope representing oxygen consumption of muscle and recovery slope representing microvascular reactivity were also collected at Tpre and Tpost. For analysis, the patients were divided into two groups: overweight (body mass index [BMI] ≥ 25 kg/m2) and normal weight (BMI < 25).

Detailed Description
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Preoperative laboratory findings were obtained. Mean blood pressure (MBP), pulse oxygen saturation (SpO2), heart rate (HR), skin temperature, and VOT-derived measurements, including baseline tissue oxygen saturation (StO2), occlusion slope, minimum StO2, time to minimum StO2, recovery slope, maximum StO2, and time to baseline StO2 were recorded before (Tpre) and 30 min after general anesthesia (Tpost).

Official Title
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Influence of Obesity on Microvascular Reactivity During General Anesthesia

Conditions
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Microcirculation, Obesity, Anesthesia

Intervention / Treatment
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* Device: Near-infrared spectroscopy monitor


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Subjects who underwent elective surgery under general anesthesia. Exclusion Criteria: Society of Anesthesiologists (ASA) physical status > II patients with a neuraxial block uncontrolled hypertension patients with major cardiovascular disease diabetes pregnant individuals peripheral vascular disease chronic venous insufficiency smoking: Pack-years > 10 chronic obstructive and restrictive pulmonary 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

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| overweight group<br>Subjects with a body mass index (BMI) ≥ 25 | Device: Near-infrared spectroscopy monitor<br>* tissue oxygen saturation monitoring combined with vascular occlusion test<br>|
| normal weight group<br>Subjects with BMI < 25 | Device: Near-infrared spectroscopy monitor<br>* tissue oxygen saturation monitoring combined with vascular occlusion test<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Recovery slope after general aneshtesia (Tpost) | Representing microvascular reactivity (Tpost: 30 minutes after general anesthesia); recovery slope was calculated from deflation of the tourniquet until the recovery of StO2 to the baseline value. | 10 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Recovery slope before general aneshtesia (Tpre) | Representing microvascular reactivity (Tpre: before general anesthesia); recovery slope was calculated from deflation of the tourniquet until the recovery of StO2 to the baseline value. | 10 minutes | 
| Occlusion slope before general anesthesia (Tpre) | representing oxygen consumption of muscle (Tpre: before general anesthesia); occlusion slope was defined as the slope of StO2 descent to the lowest value. | 10 minutes | 
| Occlusion slope before general anesthesia (Tpost) | representing oxygen consumption of muscle (Tpost: 30 minutes after general anesthesia); occlusion slope was defined as the slope of StO2 descent to the lowest value. | 10 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Obesity, Body mass index, Anesthesia, general, Microcirculation