Arterial Carbon Dioxide Monitoring Device

Background

Many medical environments and conditions require the measurement of arterial carbon dioxide (CO2) in non‑invasive ways. Opioids, for example, impair breathing by suppressing the excitability of neurons in the body, which may result in opioid-induced ventilatory impairment (OVI), causing complications and sometimes death. Human observation is the primary method of monitoring patients in these conditions. Most monitoring devices surveil oxygen diffusion and respiration, leading to inaccuracies and patient endangerment. Pulse oximetry is an inexpensive and widely available technology that is also commonly used, however, it is an extremely late indicator of inadequate ventilation. Other methods which monitor CO2 such as capnography and plethysmography are expensive, potentially invasive, and can contain inaccuracies. Most attempts at alleviating the issue associated with monitoring adequate ventilation focus on raising awareness and changing protocols rather than advancing technology. Thus, there is a need to develop a low‑cost device that can accurately measure arterial CO2 non‑invasively without such high risks of inaccuracy or complication.

Technology

Researchers at Stony Brook University (SBU) have developed an arterial CO2 monitoring device comprised of a monitoring module that will measure CO2 and pressure differences in the ear. The housing is made from a comfortable, diffusion resistant material with a hermetic seal containing a CO2 sensor which measures changes in CO2 diffusion from arterial blood vessels. All elements are positioned to minimize dead space and gas volume within the enclosed space, leading to more rapid equilibration between the contained airspace and arterial blood vessels. The sealing allows for equilibration of arterial CO2 while avoiding contamination or dilution by environmental gases, in addition to allowing for accurate changes in pressure which reflect changes in arterial CO2 levels. An adjustable alert system is included in the system to inform others of significant ventilatory changes. Additionally, the device includes an LCD screen for configuration, data display, settings, etc., as well as buttons for easy navigation.

Advantages

Efficient, accurate, and quick detection of ventilatory changes - Shorter read time compared to pulse oximetry - Non‑invasive - Low‑cost - Potential to prevent deaths

Application

Monitoring arterial carbon dioxide levels - Ventilation monitoring - Overdoses - Intubation - Ambulatory care - Nursing homes - Opioid induced ventilatory impairment (OVI)