Measurement of Hemodynamic Responses to Lower Body Negative Pressure

Study Overview
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Brief Summary
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This study will be collecting data on participants undergoing lower body negative pressure (LBNP) to simulate progressive blood loss. The goal of the study is to collect data to allow for development of an algorithm with machine learning to predict blood pressure responses to hypovolemia by analyzing the arterial waveforms collected during LBNP.

Detailed Description
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Death from exsanguination continues to be a major problem in combat casualty care and the care of civilians subjected to trauma. The ability to detect significant blood loss using traditional vital signs (heart rate, blood pressure) is marginal due to a variety of compensatory mechanisms that maintain blood pressure in the face of marked reductions in circulating blood volume. Along these lines, it is critical to develop monitoring devices and algorithms to non-invasively assess central blood volume in humans for the purposes of facilitating more timely interventions. The standard way to simulate hemorrhage in humans is to use Lower Body Negative Pressure (LBNP). In this technique, the lower body of a supine volunteer is enclosed in an airtight container while suction is applied to cause venous pooling in the legs and reduce central blood volume. This technique generates many physiological adaptations that are similar to that observed during blood loss studies in animals and human volunteers. Thus, the purpose of this study is to obtain data for use in developing monitoring technology to detect hemorrhage and other surrogate markers of central blood volume in humans.

Official Title
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Physiology of the Early Stage of Hemorrhage and Early Identification of Progression Toward Hemodynamic Instability in Humans for Validation of Current Machine Learning Models

Conditions
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Hypotension and Shock

Intervention / Treatment
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* Other: Lower body negative pressure


Participation Criteria
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Eligibility Criteria
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Inclusion criteria: 18-55 year of age Non-smoker No history of hypertension No history of diabetes No history of coronary artery disease No history of neurologic disease Exclusion criteria Prescribed medications other than birth control Inability to lie flat for two hours BMI > 30 kg/m2

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 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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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Healthy volunteers<br>All volunteers will be studied at rest and during experimental condition (lower body negative pressure) | Other: Lower body negative pressure<br>* Simulated hypovolemia by applied suction to lower extremities to cause venous pooling.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Blood pressure | Arterial blood pressure prior to and during lower body negative pressure | One day of study visit | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart rate | Heart rate prior to and during lower body negative pressure | One day of study visit |