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NCT Number: NCT06419699

CPAx: Responsiveness and Minimal Clinically Important Difference

Intensive care unit (ICU) acquired weakness is a common complication associated with long-term physical impairments in survivors of a critical illness. The Chelsea Critical Care Physical Assessment tool (CPAx) is a valid and reliable instrument for physical function and activity in critically ill patients at risk for muscle weakness. However, its ability to measure change over time (responsiveness) and the minimal clinically important difference (MCID) have not yet been rigorously investigated. This multi-centre, mixed-methods, longitudinal cohort study therefore aims to establish responsiveness and the MCID of the CPAx in the target population from ICU baseline to ICU and hospital discharge. The study uses routine data from standard physiotherapy sessions like mobility, function and activity with no additional burden for critically ill adults. The investigators expect the CPAx to be responsive allowing its use as a primary outcome in future effectiveness trials for the treatment of ICU-acquired weakness using the newly established MCID for sample size calculation. A high quality, rigorously tested measurement tool for physical function and activity in the ICU should benefit researchers, clinicians and patients.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Muscle Weakness Behavior Critical Illness Critical Illness Myopathy Critical Illness Polyneuromyopathy Critical Illness Polyneuropathy Disease Attributes Motor Activity Muscular Diseases Musculoskeletal Diseases Nervous System Diseases Neurologic Manifestations Neuromuscular Diseases Neuromuscular Manifestations Pathologic Processes Pathological Conditions, Signs and Symptoms Peripheral Nervous System Diseases Physical Inactivity Polyneuropathies Sedentary Behavior Signs and Symptoms

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Monash Health, Clayton, Australia

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About this study

The use of invasive life support in critically ill patients clearly saves lives but carries substantial risks, including intensive care unit (ICU) acquired weakness and long-term disability. The investigators urgently need a valid, reliable, and responsive measurement tool for this population to use in clinical practice and trials. The Chelsea Critical Care Physical Assessment tool (CPAx) is a promising measurement instrument to measure change in critically ill patients' physical function and activity. After several studies have confirmed its validity and excellent reliability, it is time to confirm responsiveness and to establish the MCID in a large, international sample of the target population. This multi-centre, mixed-methods, longitudinal cohort study will include critically ill, mechanically ventilated (>72h) adults at risk for muscle weakness and collect their mobility, physical function and activity with the CPAx and other relevant measures at ICU baseline, to ICU and hospital discharge. Responsiveness will be determined by the ability of the CPAx to identify change according to a prespecified anchor (criterion validity) and by testing prospective hypotheses about the expected magnitude of change between the CPAx and other relevant measures (construct validity). The MCID will be established with anchor- and distribution-based methods, whereby a seven-point global rating of change scale obtained from treating ICU physiotherapists will serve as anchor to distinguish improved from unchanged patients.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age ≥ 18 years
  • Mechanical ventilation ≥ 72 hours
  • Expected to remain for ≥ 48 hours in the ICU
  • Physiotherapy referral

Exclusion criteria

  • Not expected to survive to hospital discharge (imminent to death)
  • Second or subsequent ICU admission for this hospital stay
  • Transfer from external ICU (with an ICU stay of >72 hours)
  • Primary neurological admission diagnosis (i.e., of the central nervous system including stroke, intracerebral haemorrhage, traumatic brain injury)
  • Known pregnancy
  • Living in a care facility pre-admission (severe pre-existing mental or physical disability)
  • Local regulations (i.e. Switzerland: refusal of general consent)

Treatment and study plan

Primary outcomes

  1. Chelsea Critical Care Physical Assessment tool (CPAx) change score

    Time frame: Assessed at ICU discharge (within 24 hours before or after ICU discharge)

    CPAx change score for ICU period (ICU baseline to ICU discharge); CPAx ranges from 0 (worst score) to 50 (best score)

Secondary outcomes

  1. CPAx change score

    Time frame: Assessed at hospital discharge (last value before discharge)

    CPAx change score for hospital period (ICU to hospital discharge); CPAx ranges from 0 (worst score) to 50 (best score)

  2. Global rating of change scale

    Time frame: ICU and hospital discharge (change for ICU and hospital period)

    Seven-point global rating of change scale (GRC): (1) very much improved; (2) much improved; (3) little improved; (4) no change; (5) little deterioration; (6) much deterioration; (7) very much deterioration for 'physical function and activity' (rated by treating physiotherapist)

  3. ICU Mobility Scale

    Time frame: ICU baseline (within 72-144h after ICU admission), ICU and hospital discharge

    To evaluate mobility level, the score ranges from 0 (worst) to 10 (best)

  4. Medical Research Council Sum Score

    Time frame: ICU baseline (within 72-144h after ICU admission), ICU and hospital discharge

    To assess muscle strength, the minimal score is 0 (worst), the maximal score 60 (best), ICUAW is defined as <48 points

  5. Richmond Agitation-Sedation Scale

    Time frame: ICU baseline (within 72-144h after ICU admission), ICU and hospital discharge

    To assess the level of sedation and/or cooperation, score ranges from -5 (unarousable) to +4 (combative)

  6. Modified Iowa Level of Assistance Scale

    Time frame: ICU baseline (within 72-144h after ICU admission), ICU and hospital discharge

    To determine assistance in functional tasks, the score ranges from 0 (worst) to 36 (best)

  7. ICU and discharge destinations

    Time frame: ICU and hospital discharge

    Categorical variable (death, external/internal hospital ward, external ICU/hospital, rehabilitation, home, other) to assess the predictive validity of the CPAx score

Sponsors and collaborators

Lead sponsor

Insel Gruppe AG, University Hospital Bern

Other

Collaborators

  • Monash University

Registry information

Official study title

Responsiveness and the Minimal Clinically Important Difference of the Chelsea Critical Care Physical Assessment Tool (CPAx) in Critically Ill, Mechanically Ventilated Adults

Important dates

Study start
2024
Primary completion
2026
Study completion
2026
First posted
May 17, 2024
Registry last updated
May 27, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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