Validity of an Actigraph Accelerometer Following Critical Illness

Ward based patients recovering from critical illness who satisfy the inclusion criteria will have an Actigraph GT3X accelerometer positioned on the thigh and ankle of the non dominant leg. These will be used as an objective method of identifying adoption of lying, sitting and standing postures and quantification of step count. Both placement sites will be investigated in isolation. A further analysis will be undertaken to determine whether combining data from both placement sites (ankle and thigh) is superior in identification of lying, sitting and standing postures compared to an isolated single site. Accelerometer data will be compared against direct observation as the criterion measure.

Patients will undertake a semi-structured movement protocol consisting of typical activities undertaken by this population. These include lying in bed, transferring over the side of the bed, sit to stand postural transfers (and the reverse), sitting in a chair and walking. Observation periods will not exceed 3 hours. During this time all aspects of the movement protocol will be completed.

The data from this study will be analysed to determine the validity of the Actigraph GT3X in identification of body position and quantification of step count using the placement sites described above.

Inclusion criteria

1 18 years of age or above.

• Ventilated in excess of 48 hours during admission in the Intensive Care Unit (ICU).

• Currently resident on a hospital ward (secondary care) following step down from ICU

• Able to undertake all postural transfers independently or with minimal assistance (one person only).

• Able to mobilise short distances, either independently or with assistance from a walking aid or one person.

• Willing to permit application of two Actigraph GT3X accelerometers Each device weighs 27g with dimensions of 3.8cm x 3.7cm x 1.8cm.

• Willing to consent to a period of direct observation for a length of time not exceeding three hours.

Exclusion criteria

• Unable to provide informed written consent themselves
• Unwilling to consent to a period of observation not exceeding three hours.
• Unable to make an informed decision about participation or demonstrating an inability to interpret information or follow study instructions
• Significant neurological or coordination impairment
• Unable to speak or understand English.
• Clostridium Difficile/ similar infection or unmanaged urinary incontinence.
• Evidence/ diagnosis of peripheral vascular disease.
• Lower limb amputation
• Polytrauma which prevents the adoption or normal lying, sitting or standing postures, or placement of the accelerometers