Results within a minute: UvA student obtains PhD on fake nose that recognizes lung diseases
The SpiroNose, a kind of technological fake nose, can detect within a minute whether a patient is suffering from a lung disease and whether it is asthma or COPD, for example. UvA's Rianne de Vries is pursuing a PhD on how the nose works and hopes that hospitals can start using it within a few years.
Worldwide, hundreds of million people suffer from lung disease. Rapid diagnosis makes it possible to treat them more quickly and correctly. PhD candidate Rianne de Vries therefore conducted research at Amsterdam UMC (AMC campus) on determining and improving the accuracy of the digital nose, a so-called eNose, for diagnosing lung diseases.
Sniffing it out
To use the eNose, patients breathe in and out through a device containing multiple sensors. Exhaled air consists mainly of nitrogen, oxygen and CO2, but also about one percent of volatile organic compounds (VOCs). "For the analysis, we are interested in precisely those VOCs," says de Vries. "The mixture of different substances is picked up by the eNose sensors and sent to an analysis platform. This information is stored by the platform in a unique breath profile."
The online platform contains a large database of breathing profiles of diagnosed patients. The eNose then compares the new patient's breath profile to the database. "The eNose is trained on breath profiles of patients with a proven diagnosis. When the odor of a new profile resembles a previous profile, it allows a diagnosis to be made very quickly."
It is not that the eNose can identify particular molecules or substances. De Vries explains that it is about pattern recognition: "The eNose recognizes patterns in the complete mixture of substances in the breath. It is very similar to our human nose. If you sit in front of a cup of coffee, you recognize the smell of coffee, but you can't tell exactly which substances determine the smell of coffee.”
Learning to smell
Much of the doctoral research was devoted to collecting breath profiles and teaching the eNose how different diseases smell. The analysis platform can be thought of as the brain and the measuring device is the nose that transmits signals. "People have to learn as children what smell goes with what. In the same way, we trained the eNose with lots of breath profiles and corresponding diagnoses."
"To find out exactly which substances are responsible for the breathing profile of asthma, for example, you need other, more expensive technologies. Those other methods are mainly useful to better understand diseases, while the eNose is really aimed at an easy and quick diagnosis."
Improved treatment
The eNose can also offer improvement for the patient experience. It can diagnose COPD, asthma and lung cancer. A measurement with the eNose consists of a series of normal and deep inhalations and exhalations lasting 45 seconds. The results are there in seconds. "It is very nice for a patient to know quickly where they stand. There is usually no need to wait long for a result or to make an extra appointment. That saves the doctor a lot of administrative work."
Patients with COPD and asthma are sometimes difficult to distinguish based on symptoms. During her research, however, De Vries found that the eNose does an excellent job of differentiating patients and can even classify them based on subtypes. "With the eNose, we can divide patients into different clusters."
De Vries says that in this study she mainly investigated whether groups of asthma and COPD patients can be distinguished by which treatment they require. "The added value is mainly that you can then better offer individual treatments. With just the diagnosis of asthma or COPD, you don't know how to treat the patient. Hopefully, the eNose will be able to do that."
The study also took its first steps toward predicting whether lung cancer patients will respond well to immunotherapy. For the prediction, researchers apply fairly strict requirements, so as not to exclude patients on whom it might work. De Vries says that eventually almost a quarter could be excluded. "Every therapy has side effects, so if we can predict that a particular therapy won’t work, an alternative treatment can be pursued.”
Follow-up
The eNose has a lot of potential, according to de Vries. Research is also being done to diagnose other diseases with this technology such as epilepsy or various forms of cancer. Efforts are currently under way to obtain CE certification for various applications of the eNose. This is required to be allowed to use the eNose in daily practice and will initially be focused on hospitals. In addition, convincing the field of this whole new medical technology is an important step that the researchers are not losing sight of. "We are not there yet, but certainly not 10 years away from clinical application, either.”
Rianne de Vries hopes to receive her doctorate on September 30th with her thesis, "The eNose analysis of exhaled breath for diagnosing and phenotyping respiratory diseases.” The promotion ceremony will take place at 10:00 a.m. in the Agnietenkapel.
