A German team unveils an "electronic nose" system that uses metal oxide-based gas sensors to detect heart failure.
Elizabeth Armstrong Moore
Elizabeth Armstrong Moore is based in Portland, Oregon, and has written for Wired, The Christian Science Monitor, and public radio. Her semi-obscure hobbies include climbing, billiards, board games that take up a lot of space, and piano.
A good nose can be a curse. Dogs, for instance, have been shown to be able to sniff out lung cancer in humans, which means the poor creatures have to smell our breath, with a lot of smokers in the mix, one sample at a time.
Good news out of Germany, then, for man's best friend. A team of scientists at the University Hospital Jena is testing an electronic nose system that's able to distinguish between people without heart failure and people with it, and even between two types of heart failure (compensated and decompensated) with almost 90 percent accuracy--higher than what canines were able to achieve in the lung cancer study.
The system includes three thick-film metal oxide-based gas sensors with heater elements. Each is tailored to sense different odorant molecular types. As oxygen reacts to the heated sensor surface, the molecules interact with the sensors and change the free charge carrier concentrations, and thus conductivity, in the metal oxide layer.
Having already collected the relevant parameters for heart failure (BNP, creatinine, clinical history, etc.) in 126 patients in 2010, physicians blinded to those results then used the electronic nose to assign the patients to one of three groups: no heart failure, and then two types of chronic heart failure--compensated (a condition where treatment is able to compensate for the failure) and decompensated (where treatment is not working, and can be caused by arrhythmias, infections, electrolyte disturbances, etc.).
The sensor was simply placed on the arm much like a blood pressure monitor for three minutes at a time and then analyzed for heart failure markers. It was able to distinguish between patients without heart failure (the control group) and patients with heart failure with almost 90 percent accuracy, and then to divide patients with decompensated heart failure from those with compensated heart failure with almost 90 percent accuracy.
The team, which says more research is required to identify the responsible components, presented its findings over the weekend at the ESC Congress 2011 in France. Ultimately, the scientists hope to create a minimally invasive method to help rapidly screen, diagnose, group and monitor compensated heart failure.