Monitoring Early Postoperative Mobility at Scale

Background: Early mobilization is considered an important component of postoperative recovery in the hospital; however, a large portion of patients fail to ambulate during their hospitalization, even with mobility programs and dedicated mobility aides. Large-scale patient mobility monitoring could evaluate the effectiveness of mobility programs and screen for patients at higher risk for postoperative complications due to low mobility.  The current study aimed to evaluate posture as an objective measure of postoperative mobility.  

Hypothesis: We hypothesized that existing continuous vital sign patient monitoring (VISI Mobile®) technology can objectively characterize the postural behavior of patients in the early postoperative period and identify patients at risk for adverse postoperative outcomes, like readmission.

Methods: In this IRB-approved cohort study, we examined retrospective accelerometer data from 562 postoperative patients between January and November 2019. We included patients who had undergone major cancer surgery and were monitored for at least 24 hours and had a length of stay longer than 24 hours. To evaluate VISI Mobile’s accuracy in detecting upright position, we performed a validation study in which five patients were monitored at fixed intervals over five hours comparing observed posture to VISI monitor real-time posture data. VISI monitor posture position was also recorded for 11 patient ambulatory events. 

Results: Retrospective accelerometer data allowed us to calculate average time spent upright per day (x̄=206.2 min) and percent of observation spent upright (x̄=14.32%). We did not find a significant difference in the upright behavior between patients who were readmitted and those who were not. In our validation study, we found that VISI detected upright position with a sensitivity and specificity of 1.0 while a patient was in their room. During walking events, VISI correctly detected a patient’s upright position 84% of the time. 

Conclusions: Real-time posture data from continuous vital sign patient monitoring (VISI Mobile®) technology was shown to be valuable for monitoring patients’ mobility after surgery on a large scale.

Source of mentor’s funding or other support that funded this research: none