Tracking Patients' Every Move Predicts Risk After Heart Surgery

Patient mobility after cardiac surgery, scrutinized with the same infrared technology used for tracking hospital equipment, was tied to better outcomes, one center found.

Researchers used an infrared real-time location system to track 100 progressive care unit (PCU) patients after cardiac surgery. Nineteen metrics from step count and gait speed to frequency of ambulation and changes in parameters between ambulations were incorporated into each person's patient ambulation profile.

These ambulation profiles turned out to be predictive of:

• 30-day readmission: sensitivity 86.7%, specificity 88.2%, C-statistic 0.925
• Discharge to acute rehabilitation: sensitivity 84.6%, specificity 86.4%, C-statistic 0.930
• Length of stay: correlation coefficient 0.927

"The findings of this study suggest that a real-time location system, already installed in the hospital for tracking the locations of staff and equipment, can be used to monitor voluntary out-of-room ambulations in a cardiac surgery PCU," concluded Peter Searson, PhD, of Johns Hopkins University in Baltimore, and colleagues in their paper, published online in JAMA Network Open.

Whenever patients left their rooms for a walk, the infrared badges attached to their gowns transmitted real-time information about their location to ceiling sensors.

Such location monitoring presents several advantages over strategies such as questionnaires, timed-walk tests, and wearable sensors, the investigators said, citing the objective measurement of multiple parameters that could refine assessment of patient mobility and improve prediction models.

The 100 people in the study included 81 men and averaged 63.1 years of age. As a group, they walked a total of 79.4 miles over a median PCU length of stay of 5.9 days.

Outcomes tended to be better when patients walked at least once a day, walked more than 3,550 feet in total around the PCU, slightly sped up their ambulation over time (at least 0.018 m/s improvement per ambulation), and had a length of stay of less than 6 days, according to study authors.

They only counted voluntary out-of-room ambulations while in the PCU, however, and could not distinguish between ambulation and transport by wheelchair, Searson's team acknowledged. Another limitation of the study was its small sample.

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