Unique Sensing Technology


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Unique Sensing Technology

CO2 sensor

CO2 sensor kit TG-920P CO2 sensor kit TG-920P
The CO2 sensor, which measures the concentration of carbon dioxide in the exhaled breath, is one product that incorporates advanced engineering and production technology.

End tidal CO2 (EtCO2) is an important parameter which indicates the condition of gas exchange in the lungs. EtCO2 is an effective way to ensure medical safety during respiratory management, such as making sure there are no abnormalities in the breathing circuit when using a ventilator or confirming correct insertion of the breathing tube during intubation.

CO2 sensors make use of the fact that carbon dioxide absorbs specific wavelengths of infrared light. However, stable measurement is sometimes impossible when a ventilator and humidifier are used together because water droplets condense inside the respiratory circuit and make it very difficult to measure.
CO2 sensor kit TG-970P CO2 sensor kit TG-970P
To overcome this challenge, Nihon Kohden developed a unique patented single-wavelength spectrometric method, an anti-fogging membrane, and a new concept airway adapter. The result is a revolutionary CO2 sensor that provides long-term stable CO2 measurement even when used with a humidifier.

The sensor also overcomes other limitations of conventional CO2 sensors that are large, easy-to-break, and take a long time for calibration.

Nihon Kohden’s TG-970P CO2 sensor is the world’s smallest and lightest mainstream CO2 sensor. Going against conventional expectations, it is also more durable. Another Nihon Kohden sensor, TG-920P, incorporates a new algorithm which does not require zero calibration. Using a patented technology, TG-920P is the only CO2 sensor in the world which can measure expired CO2 at the mouth. It is very lightweight which reduces the patient burden.

The Viewpoint of the Engineer

Masayuki Inoue, Engineer
Masayuki Inoue, Engineer

We developed the TG-920P CO2 sensor kit based on a new concept which did not exist anywhere in the world — a sensor that can be placed at the mouth to detect the supressed breathing of spontaneous respiration patients in the ICU or post-surgery who are just coming out of pain-killing sedation.

"Smallest in the world," a "new measuring method to measure respiration at the mouth," "durable" — each one of those was a new challenge. The key to success was team power, from sensor design to electrical engineering, mechanical design and manufacturing. For example, to improve the durability of each individual part against impact, we did repeated drop testing and the design team kept making improvements. Also, to embed extremely tiny components such as printed circuits inside tiny sensor parts was a level of difficulty that required a high level of production skill. To achieve this, the manufacturing team was involved from the design stage and working from trial and error. I think Nihon Kohden’s great strength is combining its power, from development to manufacturing, into one team so our technological power can overcome even the highest wall.

The sensor directly touches a person’s skin. So when I’m developing a sensor, I always try to imagine how it would be if this sensor were attached to a member of my own family. Before the products are used in hospitals, by thinking of a person close to us, we can make products from the patient’s point of view.