Observation of Blood Flow in Major Neck Vessels Modulated 1 by Physiological Maneuvers

TL;DR

This study investigates how various physiological maneuvers affect blood flow in major neck vessels using optical PPG, introducing new maneuvers that show significant modulation, aiming to improve non-invasive hemodynamic monitoring in realistic clinical settings.

Contribution

The paper introduces new physiological maneuvers, such as Valsalva and IJV occlusions, demonstrating their effectiveness in modulating blood flow in neck vessels, extending prior research beyond healthy, controlled conditions.

Findings

New maneuvers significantly modulate blood flow.

Blood flow modulation is more pronounced with Valsalva and IJV occlusions.

Optical PPG effectively detects blood flow changes during maneuvers.

Abstract

Large neck vessels (carotid artery and internal jugular vein, IJV) offer a unique opportunity to monitor hemodynamics non-invasively by optical means. The primary shortcoming of past work has been the focus on healthy volunteers in normal physiological conditions and well-controlled environments. To drive the technology closer to the bedside, testing is required under more re-alistic conditions, including in pathologies and real-world environments (e.g., similar toICU or emergency care settings). The primary goal of the current work was to extend the range of physiological maneuvers for blood flow modulation by introducing new maneuvers and ob-serving PPG response to them. The data from the necks of two healthy volunteers in a supine position were collected by clinical PPG and in-house built PPG sensors, accompanied by ECG signal collection. Seven maneuvers (abdominojugular test, breath holding, Valsalva, proximal occlusion of right IJV, distal occlusion of right IJV, proximal occlusion of left IJV, distal occlusion of left IJV) were performed in sequence with 1 min allocated for each maneuver. The 1 min was split into three segments: baseline (15 s), experiment (15 s), and recovery (30 s). Thus, the overall du-ration of the experiment was 7 min. AC amplitude from clinical PPG, DC amplitudes from in-house built PPG, and ECG signal were compared during all seven physiological maneuvers. Newly proposed maneuvers (Valsalva and IJV occlusions) demonstrated modulation of blood flow, which was more significant than previously reported maneuvers (abdominojugular test and breath holding). The proposed physiological maneuvers demonstrate high potential as instruments for modulating blood flow in major neck vessels.