Problem Hospitalization and prolonged immobilization often lead to the functional decline of vulnerable older persons. Bed rest and inactivity accelerate the functional changes that are part of normal aging; the link between inactivity and adverse outcomes is increasingly appreciated by medical professionals, and the mobilization of patients is a critical aspect of patient care. Monitoring and documenting patient activity levels in acute-care settings is generally absent, as is assurance of adequate levels of mobilization. Staff reports from nurses, physical therapists, physicians, and aides, where extant, often lack agreement and documentation consistency. This is particularly true in the context of competing priorities in busy hospital wards and varying levels of staff knowledge and motivation. Patient documentation requirements already place a significant burden on health care professionals, and limit the time spent with patients. Patient self-reports of activity levels have questionable validity and reliability, especially in critical care settings. These factors all manifest a need for automated monitoring of patient mobility and activity levels to provide a safety net and to ensure that prophylactic and therapeutic mobilization of patients is performed. Solution The proposed wireless Patient/Resident Mobility Tracker (PREEMPT) will provide an effective, accurate, noninvasive, and practicable method for automatically documenting patient mobility, providing the desired activity and body posture information that is relevant in both hospital and senior care settings. In particular, the PREEMPT will be used to track and provide hourly/daily summaries of the following: (1) sedentary time (time spent lying or sitting); (2) upright time; (3) walking time; (4) body posture (e.g., supine, prone, left-side, right-side, seated, etc.); (5) step count; (6) step cadence (steps per minute) and gait speed (m/s or mi/hr); and (7) number of lie- or sit-to-stand transitions. Collected data will be transmitted wirelessly to a touch-screen tablet computer located in the patient's room, where the information will be readily accessible by health care professionals for use in patient management. The PREEMPT will not interfere with other patient monitoring or therapeutic treatments, including chest monitors, intravenous lines, Foley catheters, etc. The PREEMPT will require minimal maintenance (e.g., cleaning, etc.); a key objective of this technology is to decrease clinical staff burden. The PREEMPT can also be used to track patient turning in bed to prevent decubitus ulcers, and to provide an alternative to bed/chair alarms for patients at risk for falls to alert nurses when a patient transitions from bed lying to sitting, or from chair sitting to standing. Phase I Results In Phase I, the research team developed and evaluated custom-made PREEMPT prototypes on both healthy participants and hospital patients. The results demonstrated statistically significant equivalence (p<0.05) with ground truth for all outcome measures.
There are currently 770,000 acute-care hospital beds in the United States and 1.7 million nursing-home beds. Tracking and documenting the activity levels of critically ill patients will provide health care professionals and family members with valuable information that can be used to ensure patient mobilization and mitigate iatrogenic outcomes. The proposed system will provide an effective, practicable, and affordable method for meeting the challenges of monitoring the mobility of hospital patients and residents of elder-care facilities, where excessive immobility is commonplace and documentation is generally lacking.
