Table 4 Sub-themes, categories and example(s) of verbatim extracts of each theme in included studies

Practice variation

Timing of commencement

• Beginning within 24 h of ICU admission [42];

• Within 72 h of mechanical ventilation [45];

• Where the patients could assist with the activity using their own muscle strength and control [48].

Activities

• Involved axial loading of the spine and/or long bones [35, 52];

• Any activity beyond range of motion [43].

Team diversity

• A program of physiotherapist-directed [37];

• Performed by a care provider (nursing, physical or occupational therapy) [43].

Expectation of outcome

Preventative measures of ICU complications

• To prevent joint contractures [46];

Maintaining patient’s mobility

• To maximize physical activity at the highest functional level the patient could achieve [37].

Improving impairment

• To induce acute physiological responses (enhancing ventilation, central and peripheral circulation, muscle metabolism, and alertness) [42]

Mechanical ventilation utilisation

Intubation types

• MV was provided to 51% of patients, including 14% with tracheostomy [42];

• MV was defined as any ventilation via an endotracheal tube (ETT), tracheostomy tube, or non-invasive positive pressure ventilation [77].

Mechanical ventilation duration

• To initiate the early mobilization program within 72 hours of MV [87];

• Occurred while the patient was receiving invasive ventilation [48].

ICU context

ICU stay

• Continuing through the ICU stay [24].

Activity space

• Mobilizing patients out of bed in the ICU can be seen as an earlier rehabilitation[64];

• Both leg and arm exercise with the patient in bed [75].

Protocol vs order

• The early mobilization group (EMG) patients received a systematic early mobilization protocol, twice a day, every day of the week[46];

• Activity orders for critically ill patients required a physician orders with all activity performed by either the bedside nurse and/or a physical occupational therapist [43].

Negotiated process

Stakeholder decisions

Clinical staff judgement

• The decision to mobilise patients out of bed only after tracheostomy formation is based on the decision that a tracheostomy presents as a stable airway [51].

Informed consent

• The physical therapy intervention started when the informed consent was obtained [72];

• Acquire informed consent (e.g., waiting until evening family visits or allowing family members time to think about the decision to enrol) [49].

Goal setting

Progressive mobility

• The types of functional activities performed during treatment sessions were recorded, including (1) rolling, (2) sitting at the edge of the bed, (3) transferring from sitting to standing, (4) ambulation [86].

Improving impairment

• The 30-minute PT sessions, including abdominal breathing training, respiratory muscle weight training, passive and active joints exercises, upper and lower limb exercises[79].

Regaining independence

• Sitting balance activities were followed by participation in activities of daily living (ADLs) and exercises that encouraged increased independence with functional tasks [25].

Patient participation

Active

• Only in 24% of the sessions was more active functional mobilization performed (SOOB, standing, and walking)[68].

Passive

• A combination of passive exercise including positioning, joint range of movement, and hoist transfer to chair [85].

Level of assistance

Independence

• Patients were first allowed to attempt each activity independently [26].

Staff assistance

• With the assistance of a physical therapist, respiratory therapist and an ICU nurse [103].