Physical Activity Monitoring in Children in the 1-Year After 3 or More Days of Invasive Ventilation: Feasibility of Using Accelerometers.

Objectives: To measure physical activity in a cohort of children who survived greater than or equal to 3 days of invasive ventilation.

Design: Prospective cohort study (2018-2021).

Setting: Quaternary children's hospital PICU.

Patients: Children (2-17 yr old) without a preexisting tracheostomy who were ambulatory pre-illness and received greater than or equal to 3 days of invasive ventilation.

Interventions: None.

Measurements and main results: We measured duration and intensity of physical activity using hip- (< 6 yr old) or wrist- (≥ 6 yr old) worn ActiGraph GT3XP-BTLE accelerometers (ActiGraph, Pensacola, FL) for 7 days at three timepoints: hospital discharge, 3 months, and 12 months post-discharge. We measured duration of moderate or vigorous physical activity (MVPA) and nonsedentary activity, both characterized as percent of total awake wear time and total minutes per day. We categorized participants based on when they first attained a "high activity" day defined as greater than or equal to 60 minutes of MVPA or a day with percent of MVPA in the top quartile of all days measured. We evaluated 55 children of whom 43 (78%) had data from greater than or equal to 1 timepoint including 19 (35%) with data from all timepoints. Maximum daily MVPA increased across the three post-discharge timepoints (median, 16.0 min [interquartile range (IQR), 8.0-42.8 min], 48.3 min [27.8-94.3 min], and 68.4 min [34.7-111.0 min], respectively) as did maximum daily percent of awake wear time in MVPA (median, 4.3% [IQR, 2.8-9.0%], 10.1% [5.7-14.4%], and 11.1% [7.1-17.5%], respectively). Of the 43 participants, 27 achieved a high activity day: nine of 43 during the hospital discharge period, 14 of 43 during the 3 months post-discharge period, and four of 43 during the 12 months post-discharge period; 16 of 43 did not demonstrate high activity during the post-discharge year.

Conclusions: In the 1-year after PICU discharge measuring physical activity with accelerometers in children 2-17 years old is feasible. Furthermore, demonstration of variable recovery trajectories in our pilot cohort suggests it has potential to be an outcome measure in clinical trials.