Noninvasive Monitor of Vascular Volume Fluid Shifts

Summary

Blood volume measurements are a critical step in the emergency care of trauma patients. The typical approach to this is to rely on historical information, physical examination and metrics such as heart rate. There is currently no good real-time measure to track blood volume. This study investigates the use of phonocardiography (listening to the sounds made by the heart) to track changes in central blood volume.

Conditions

• Blood Loss

Interventions

DIAGNOSTIC_TEST

phonocardiographic measurement: InnoVital Systems

The instrument consists of one or more low-profile microphones in plastic housings with nitrile or silicon diaphragms. These sensors convert heart sounds into analog signals that will be acquired by the BIOPAC data acquisition system.

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phonocardiographic measurement: ThinkLabs StethOne

This device senses heart sounds and may be listened to using headphones and converted to an analog signal and saved using the BIOPAC data acquisition system.

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physiological measurements: BIOPAC

Non-invasive blood pressure, electrocardiogram, heart rate, respiratory rate, and leg circumference - This is a commercially available device used regularly in health care settings to monitor continual blood pressure and heart rate.

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physiological measurements: Masimo Radical-7

A commercially available device for pulse oximetry and continuous non-invasive hematocrit measurement.

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physiological measurements: CoVa Monitoring System 2

This device will be used for thoracic bioimpedance and other physiological measures. This is a commercially available device. It also measures ECG, heart rate, heart rate variability, estimated stroke volume, and estimated cardiac output. The study team may measure either while body bioimpedance or thoracic bioimpedance.

DIAGNOSTIC_TEST

Thoracic impedance

Thoracic impedance is measured using the Starling device (https://usstarling.baxter.com/starling-system). Baxter uses a series of proprietary algorithms to infer stroke volume and cardiac output from thoracis impedance. Calculated values will be recorded, but the main variable that will be recorded is simply the temporal profile of thoracic impedance during the manipulations in each group (changing lower body negative pressure or therapeutic phlebotomy).

Sponsors & Collaborators

• Dartmouth-Hitchcock Medical Center

  lead OTHER

Principal Investigators

• James C Leiter, M.D. · Dartmouth-Hitchcock Medical Center

Study Design

Allocation

NA

Purpose

BASIC_SCIENCE

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

18 Years

Max Age

49 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2021-12-15

Primary Completion

2022-12-01

Completion

2022-12-01

Countries

• United States

Study Locations