Non-invasive Characterization of Systemic Microvascular Reactivity by Near-infrared Diffuse Optical Spectroscopy in COVID-19 Patients

Study Overview
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Brief Summary
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The purpose of this study is to characterize microvascular reactivity on the forearm muscle using non-invasive near-infrared spectroscopy in critically ill COVID-19 patients, and to correlate its alterations with 28-day mortality in ICU COVID-19 patients.

Detailed Description
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After giving consent to participate in the study, the subjects included in the study will undergo a 15-minute measurement of tissue oxygen saturation (StO2) measured non-invasively on the forearm by means of near-infrared spectroscopy (NIRS). Once a baseline stable StO2 value is obtained, a provocative test, consisting of a transient vascular occlusion, will be performed. The test will allow the obtention of a local metabolic rate, and a StO2 recovery rate after the ischemic stimulus. This StO2 recovery rate will be considered as a reflection of the endothelial health of the patient. Patients will be studied as soon as possible after admission to the ICU, and followed-up until ICU discharge or death.

Official Title
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Non-invasive Characterization of Systemic Microvascular Reactivity by Near-infrared Diffuse Optical Spectroscopy in COVID-19 Patients

Conditions
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COVID-19, Endothelial Function

Intervention / Treatment
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* Device: Vascular occlusion test


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Recent diagnosis of SARS-CoV2 infection Arterial hypoxemia and bilateral alveolar infiltrates, not explained by cardiac dysfunction or fluid overload. Exclusion Criteria: Severe peripheral vasculopathy Raynaud's syndrome Skin lesions or trauma in upper limbs interfering the placement of NIRS probe and/or the occlusion tourniquet Deep venous thrombosis in the upper limbs

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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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 |
| --- | --- |
| COVID-19<br>Hospitalized patients diagnosed with COVID-19, presenting with arterial hypoxemia. | Device: Vascular occlusion test<br>* The ischemic challenge will consist in a standardized Vascular Occlusion Test (VOT), as previously described in the literature. Briefly, a blood pressure cuff will be placed proximal to the forearm, and rapidly inflated at 40 mmHg above systolic pressure, and kept inflated during three minutes. Then the cuff will be rapidly deflated. The resulting deoxygenation (DeO2) and reoxygenation (ReO2) slopes will be reported as change in O2 saturation over time.<br>|
| Control<br>Healthy subjects | Device: Vascular occlusion test<br>* The ischemic challenge will consist in a standardized Vascular Occlusion Test (VOT), as previously described in the literature. Briefly, a blood pressure cuff will be placed proximal to the forearm, and rapidly inflated at 40 mmHg above systolic pressure, and kept inflated during three minutes. Then the cuff will be rapidly deflated. The resulting deoxygenation (DeO2) and reoxygenation (ReO2) slopes will be reported as change in O2 saturation over time.<br>|
| Non-COVID critically ill patients<br>Non-COVID critically ill patients admitted to the ICU. | Device: Vascular occlusion test<br>* The ischemic challenge will consist in a standardized Vascular Occlusion Test (VOT), as previously described in the literature. Briefly, a blood pressure cuff will be placed proximal to the forearm, and rapidly inflated at 40 mmHg above systolic pressure, and kept inflated during three minutes. Then the cuff will be rapidly deflated. The resulting deoxygenation (DeO2) and reoxygenation (ReO2) slopes will be reported as change in O2 saturation over time.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 28-day mortality | Mortality at 28 days of patients admitted to the ICU as results of respiratory failure secondary to COVID-19 | 28 days | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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COVID-19