A new sensor could soon allow hospital patients' blood oxygen levels to be checked via their breath. The technology is claimed to be more reliable and less painful than existing traditional methods.
Blood delivers life-sustaining oxygen to the organs and tissues throughout our body.
Therefore, if there isn't enough oxygen in that blood, serious damage may occur to the brain, heart or other areas – potentially resulting in the death of the patient. It's also possible for blood oxygen levels to be too high, causing damage to the lungs.
With such risks in mind, doctors typically monitor critical patients' blood oxygen levels via devices known as pulse oximeters. These clamp onto the end of one finger, where they use light to determine how much oxygen is currently in the bloodstream.
Because pulse oximeters aren't 100% reliable, doctors will sometimes also draw and analyze blood samples. While this technique is a more accurate indicator of blood oxygen levels, it may also be painful and distressing to the patient. It also doesn't provide real-time or continuous readings.
That's where the new fluorescence-based sensor comes in.
Developed by scientists at Germany's Fraunhofer Institute for Physical Measurement Techniques, the inexpensive 26-mm-wide device can be added to an existing breathing mask or ventilator tube via a T-connector.
Its sensing element consists an aluminum substrate covered with a fluorescent chemical compound known as a pyrene. When exposed to short-wave light from an integrated LED, the pyrene coating glows at a specific intensity. As oxygen molecules from the patient's breath come into contact with the coating, however, that intensity decreases – the greater the number of oxygen molecules, the lower the intensity.
Therefore, by analyzing the intensity at which the pyrene is currently fluorescing, it's possible to continuously and accurately monitor the oxygen content in the patient's breath. And importantly, it's been found that oxygen levels in the breath correspond to those in the bloodstream.
The scientists are now gauging the sensor's reaction to variables such as humidity, temperature, and the presence of other gases like carbon dioxide.
Source: Fraunhofer