Use of Accelerometry to Monitor Physical Activity in Critically Ill Subjects: A Systematic Review

Abstract

Medical management of critically ill patients often incorporates prolonged bed rest, which, in combination with the underlying illness, results in global muscle weakness and atrophy. Recent evidence has demonstrated improvements in clinical and functional outcomes when exercise and physical activity are incorporated early in the management of ICU patients. Accurate monitoring of ICU patients’ physical activity is essential for proper prescription and escalation of activity levels. Accelerometry is a technique used to measure physical activity and has been validated in several ambulatory populations. However, its use in critically ill, hospitalized patients with poor functional mobility is limited. In this review, we focus on the few studies assessing the use of accelerometry to measure physical activity in the care of mechanically ventilated adult ICU patients. The selected literature demonstrates that accelerometry correlates well with direct observation in reporting frequency and duration of various types of physical activity (rolling, sitting up, transferring, walking), but cannot differentiate various intensities of activity or whether movements are voluntary or involuntary with respect to effort. Thus, although accelerometry may serve as a useful adjunct in reporting temporality of physical activity in critically ill patients, other objective information may be needed to accurately record frequency, duration, and intensity of activity in this population.

Feasibility of Continuous Actigraphy in Patients in a Medical Intensive Care Unit

“…31,35,36 Given that actigraphy has been used in prior ICU interventional studies to demonstrate improvements in sleep and activity 17,18 and in observational studies to estimate sleep, 19–23 activity, 22,24 sedation, 20,37 and delirium, 38 the use of actigraphy during future sleep and rehabilitation interventional studies seems logical. However, prior ICU-based evaluations of actigraphy were limited in scope and generalizability because of enrollment of convenience samples, 19,37,39 small sample sizes, 17,20,32,40 recording times of 24 hours or less, 19,32,37 and inclusion of only low-or high-acuity patients or exclusively surgical ICU patients.…”

“…16 Additionally, these devices have been used to evaluate sleep and activity in ICU-based studies 17–24 and may be useful in large-scale interventions. However, the feasibility of actigraphy has not been evaluated in a heterogeneous population of critically ill patients.…”

Construct validity of the Functional Status Score for the Intensive Care Unit: a prospective observational study using actigraphy in mechanically-ventilated patients

“…Actigraphy uses accelerometers and has been validated in a wide variety of admitted and out-patient populations [22][23][24]. Its use in ICU patients is simple since it is a small instrument that does not interfere with clinical procedures and has been used in the ICU setting to measure human activity [25,26].…”

Process Monitoring in the Intensive Care Unit: Assessing Patient Mobility Through Activity Analysis with a Non-Invasive Mobility Sensor

“…Accelerometry is one method that has been validated [12], but it has limited use in critically ill inpatient populations [6]. Related to multi-person tracking, methods have been introduced to leverage temporal cues [13,14], however hand-annotated regions are typically required at the onset, limiting automation.…”