Professor Schatz and colleagues at the college of medicine at Urbana-Champaign, Illinois have developed a smartphone app called ‘MoveSense’ which can monitor a patient’s oxygen saturation level by analysing the way they walk.
Patients suffering from cardiopulmonary disease could use this app to help them accurately monitor their condition and warn doctors early at first signs of trouble simply by carrying their phone around with them.
Unlike other methods of measuring oxygen saturation levels, which detect sharp drops causing desaturation, this app continuously monitors saturation, making the resulting patterns and trends possible to model accurately and visually.
“The ability to accurately measure oxygen saturation without the use of a pulse oximeter is something that has never been achieved, until now. The oximeter, a non-invasive medical device usually placed on the patient’s finger, measures the proportion of oxygen in the blood, combining status of the two major circulatory systems, the heart and the lung. The saturation level is an overall measure of the patient’s cardiopulmonary fitness,” said Schatz.
In a previous discovery Schatz realised that phone sensors can accurately measure people’s walking patterns or gait. Doctor’s often use a 6 Min walk test for patients with heart failure or COPD to provide information regarding a patient’s functional capacity and response to therapy.
It was tested out on patients who used both a pulse oximeter and the phone app at the same time so that results could be compared and that a gait model could be computed to predict transitions in oxygen saturation.
The researcher’s discovered that oxygen saturation readings clustered patients into three pulmonary function categories: one with high saturation, with low saturation and one with variable unstable saturation. In addition they discovered that analysis of the saturation combined with gait data could predict saturation category with 100% accuracy.
The ability to predict the saturation category of the patient internally from the motion of the patient externally is remarkable. This new capability will allow medical professionals to monitor patients’ vital signs, predict their clinical stability, and act quickly should their condition decline. Patients just need to carry their personal phones during daily living, as testing has shown that periodic samples are sufficient and that even inexpensive smartphones are powerful enough to record these.
“A discovery like this will impact general medicine, many medical specialities, and the lives of millions of people suffering from chronic cardiopulmonary diseases.”