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Cardiac Surgery: When the Ceiling Has Eyes

a doctor monitoring a patient's mobility

After cardiac surgery, patients are encouraged to get out of bed and walk three times a day to support their recovery. “Increasing mobility after procedures can reduce the likelihood of complications like pneumonia and delirium and can help maintain muscle strength and sleep-wake cycles,” explains Johns Hopkins cardiac anesthetist Charles Brown.

Despite the importance of measuring patient mobility, the current measurement process—using the Johns Hopkins Highest Level of Mobility Scale to rate patients during their thrice-daily walks—remains rudimentary. 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.

So a Johns Hopkins team has turned to some “eyes in the sky”—or, to be more precise, to sensors in the hospital’s ceiling—for help in identifying patients with poor mobility to tailor interventions to improve their recovery time and health.

The ceiling sensors are part of an existing real-time location system 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, Johns Hopkins 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.