Sensors Track Walking to Help Predict Patient Recovery

Published in Insight - Insight July/August 2018

A team of Johns Hopkins researchers is using ceiling sensors in the hospital to measure the mobility of patients who have had heart surgery. One of numerous precision medicine initiatives at Johns Hopkins Medicine, the system will identify patients with poor mobility so clinicians can tailor interventions to improve their recovery time and health.

“Increasing mobility after procedures can reduce the likelihood of complications like pneumonia and delirium and can help maintain muscle strength and sleep-wake cycles,” says cardiac anesthetist Charles Brown.

Despite its importance, measuring patient mobility remains a rudimentary process. After surgery, patients are encouraged to get out of bed and walk three times a day; they are rated on their mobility based on the Johns Hopkins Highest Level of Mobility Scale. Wearable fitness trackers are an option, but they aren’t always effective because some patients walk with abnormal and slow gaits that can distort the number of steps tracked.

The ceiling sensors are part of an existing real-time location system (RTLS) in the hospital that tracks staff members and equipment tagged with infrared signal-transmitting badges. Together, the badges and 3,500 ceiling sensors make it possible to instantly locate staff or apparatus, such as infusion pumps.

To monitor patient mobility, bioengineer Peter Searson and his team mapped the location of the sensors in the cardiovascular progressive care unit so they could calculate how far and fast patients walked. During a pilot study, 200 patients wore badges to monitor their movements, and the team developed an algorithm to convert the sensor data into information on patient mobility.

“From the mobility profile for each patient, we can predict with quite high accuracy those who are at risk for readmission, whether they will need to be discharged to acute rehab and how long they will be on the progressive care unit,” says Searson.

The team will soon publish its proof of concept. Searson says they hope to secure federal funding to further develop the system, then partner with an RTLS manufacturer to produce and market it. They’re also exploring methods to increase patients’ activity and mobility before they present for surgery.