In Silico Optimization of a Non-Invasive Optical Sensor for Hemoconcentration Monitoring in Dengue Fever Management.

Area of Science:

• Biomedical Optics
• Medical Devices
• Dengue Fever Research

Background:

• Severe Dengue fever can lead to Dengue Hemorrhagic Fever (DHF), a critical condition marked by plasma leakage and hemoconcentration.
• A hematocrit (Hct) increase of ≥20% signals the need for medical intervention, but current monitoring methods are invasive and intermittent.

Purpose of the Study:

• To determine optimal design parameters for a non-invasive optical sensor for continuous hemoconcentration monitoring.
• To enable early detection and management of hemoconcentration in Dengue Hemorrhagic Fever.

Main Methods:

• Developed a high-fidelity Monte Carlo model for light transport in multi-layered skin.
• Simulated diffuse reflectance at four wavelengths (577 nm, 660 nm, 800 nm, 940 nm) across various source-detector separations (0.5-8.0 mm).
• Quantified sensor sensitivity based on a +25% relative Hct rise and its dependence on baseline dermal blood volume fraction (BVF).

Main Results:

• Optimal sensor sensitivity (6.41%) achieved at 800 nm wavelength and 8.0 mm source-detector separation with a 5% BVF.
• High sensitivity (5.71%) maintained even under low-perfusion shock conditions (1% BVF) at 8.0 mm separation.
• 800 nm wavelength showed superior reliability; visible wavelengths had high sensitivity, while 940 nm was affected by water absorption.

Conclusions:

• A non-invasive optical sensor operating at 800 nm with ≥6.0 mm source-detector separation is optimal for hemoconcentration monitoring.
• This design balances tissue penetration, sensitivity to Hct changes, and minimizes superficial interference for stable signal acquisition.
• Enables continuous monitoring of hemoconcentration trends, crucial for managing plasma leakage progression in Dengue Hemorrhagic Fever.