The Sensing Endotracheal Tube.

Area of Science:

• Biomedical Engineering
• Medical Devices
• Anesthesiology

Background:

• Current pulse oximetry sensors fail in anesthetized patients with reduced peripheral circulation.
• There is a critical need for reliable internal monitoring of vital signs during anesthesia.

Purpose of the Study:

• To develop and evaluate a novel photoplethysmography (PPG) endotracheal (ET) sensor for internal monitoring of pulse rate and oxygen saturation (SpO2).
• To address the limitations of external pulse oximetry in compromised circulatory conditions during anesthesia.

Main Methods:

• Flexible printed circuit board (PCB) technology and miniature optoelectronic components were integrated into an ET tube sensor.
• A custom instrumentation system and 3D-modeled silicon encapsulation were utilized for sensor integration and protection.
• The sensor was designed to conform to standard ET tube sizes (7 and 8 French) above the cuff.

Main Results:

• The developed ET sensor demonstrated successful acquisition of high-quality red and infra-red PPG signals in a pilot study.
• Preliminary analysis confirmed accurate heart rate measurement via PPG.
• Oxygen saturation (SpO2) readings closely agreed with commercial monitors, averaging 97.9% (STD 0.2%) and 98.6% (STD 0.8%).

Conclusions:

• The novel internal PPG ET sensor shows promise for accurate and reliable monitoring of SpO2 and pulse rate in anesthetized patients.
• This technology overcomes the functional limitations of external pulse oximetry in patients with reduced peripheral circulation.
• Further clinical validation is warranted to establish its efficacy in diverse anesthetic scenarios.