Digital stethoscope wins Imagine Cup

A team of medical and computer science students from the University of Melbourne has won the Australian finals of Microsoft's Imagine Cup with the StethoCloud device, a digital stethoscope attached to a smartphone which listens to and digitalises a patient’s breathing sounds and patterns.

The patterns are then compared against a medical database to deliver an automated diagnosis and treatment plan via an app on the smartphone. The digital stethoscope is aimed at assisting in the early diagnosis of childhood pneumonia in developing countries.

The team, consisting of Hon Weng Chong, Andrew Lin, Kim Ramchen and Masha Salehi, will now represent Australia at the worldwide finals of the 2012 Imagine Cup, being held in Sydney in July.

Mr Chong, a final-medical student, said he got the idea during his paediatric rotation, when he came across several children with respiratory disorders, mainly asthma but also pneumonia. He was also inspired by his international child health lectures, which taught him the disturbing fact that pneumonia kills more children worldwide than measles, HIV and malaria combined.

“The thing about pneumonia is it is an easily treated disease if you catch it early enough – the treatment is antibiotics and they are not expensive. It's just penicillin,” he said. “The problem is that diagnosis of pneumonia is hard and in developing countries you may have to walk several kilometres to the nearest clinic. Sometimes you might wait, and if you wait too long it might be too late to treat.”

Mr Chong discussed the issue with his mentor, Jim Black, a professor at the Nossal Institute of Global Health. “We thought, why don't we find a way to make diagnosing pneumonia easier so any healthcare worker can do it simply by building a stethoscope attachment and an application to do the diagnosis.”

So they did. The team has designed a stethoscope that looks like a traditional device from one end, but instead of the other end being inserted into the clinician's ears, there is a common 3.5mm stereo jack, the same as used for iPhones and smartphones.

“We utilised the ubiquity of these connections and we have an inline microphone to capture the sounds signals that we get from the stethoscope and simply put them as digital signals into the application, which we then transmit back to our back end for processing,” he said.

Computer science students Kim Ramchen and Masha Salehi then designed an algorithm for the digital signal. “We have been responsible for designing the algorithm that does the acoustic digital signal and from that we are able to extract a whole variety of features, which are useful for diagnosing childhood pneumonia and potentially other respiratory disorders,” Mr Ramchen said.

Mr Chong was responsible for the design and development of the phone application on Windows phones and also the cloud infrastructure back-end. “The way it works is that first we do the recording, the recording gets uploaded to our cloud storage on Windows Azure, we store that temporarily and we notify a process to go look at those sound samples along with some questions that we ask,” he said.

“For instance, does the child have convulsions, is the child unconscious? We put that through and the part that then comes into play is, as Kim mentioned, the algorithm – it looks at the sound samples and tries to figure out what the respiratory rate is. Respiratory rate is the most sensitive measure of respiratory illness and is certainly a hallmark of pneumonia.

“We put together the respiratory rate with the data that we have collected and we crunch it through our diagnostic model and come back with a result.”

The team has used the Integrated Management of Childhood Diseases (IMCI) guidelines devised by the World Health Organisation and UNICEF as the basis of the clinical decision making.

“The diagnosis you get is turned into three colours – red for severe pneumonia, yellow for pneumonia and green for no pneumonia,” Mr Chong said. “We send back the colour and the treatment that should be given with a rationale – if it is in the red zone, the treatment is 'send immediately to hospital' and 'give the antibiotic right now'. If you are in the green zone, it is more soothe the throat, reassure the parent and tell them to come back if it doesn't get better in five days.”

Mr Lin said while the group doesn't not have a firm marketing plan yet, there is a definite business model. “Basically we can make the stethoscope as it is now for about $15 retail,” Mr Lin said. “We reckon that if we mass produce it we can make it for maybe less than $10.”

The team will now represent Australia at the world finals of the Imagine Cup, being held in Sydney from July 6 to 15. Australia has won the title before, in 2008, and previous winners have gone on to great things. A device made by a Czech team was used to track people during the earthquake recovery in Haiti.

There are also other applications closer to home. Mr Chong said that as the stethoscope can be used to listen to the heart as well as the lungs, there is a far wider application. One area of obvious application is in earlier diagnosis of rheumatic heart disease as well as pneumonia in indigenous children living in remote areas.

“When I was doing my paediatric rotation, and we had finished our prototype I wanted to test it out on a patient, so I went up to the cardiac ward at the Children's Hospital and found a three-year-old girl called Maddie who had a congenital heart disease,” he said.

“I brought out the attachment and plugged it into my phone and her mother asked, where did you buy that from, and I went, I made it! They live way out in the bush, about three or four hours by plane, and the diagnosis of what Maddie had was delayed by several months because the local GP and the cardiologist weren't trained in paediatric cardiology and weren't sure what the murmur was.

“They said with this attachment it would have been easier to take a recording and to send it to the specialist at the Children's Hospital and they would have had a diagnosis much earlier.”

Posted in Australian eHealth

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