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Muscle WeaknessNCT06419699

CPAx: Responsiveness and Minimal Clinically Important Difference

An observational study of Muscle Weakness and Critical Illness Myopathy, run by Insel Gruppe AG, University Hospital Bern at 3 sites in 2 countries.

Active, not recruiting

Under way, not looking for participants. Everyone needed has enrolled. The study is still running.

Official record
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Trial summary

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… Read more about this study

Who is it for?
Ages 18 years and older
How many people
120 participants
Where
3 sitesin 2 countries
Study dates
23 May 2024to Oct 2026
Phase
Observational
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Study population: The target population are critically ill adults who are mechanically ventilated for a prolonged period (≥ 72 hours) and who have an increased risk for ICUAW and long-term impairment.

Who may be able to join

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

Who cannot join

  • 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)

Trial locations and contacts

3 sites in 2 countries.

3 sites in 2 countries

Australia2 sites

  • Monash Health

    Clayton

  • Alfred Health

    Melbourne

Other trials in Australia

Switzerland1 site

  • Inselspital

    Bern

Other trials in Switzerland

About this study

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

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.

Read the detailed description

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.

Keywords
Physiotherapy, Physical function and activity, Early rehabilitation, Measurement instrument, Critical illness, Critical care outcomes
Medical subject headings
Muscle Weakness, Polyneuropathies, Sedentary Behavior, Motor Activity, Critical Illness

What is being measured

The primary outcome is the main question the study is designed to answer.

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

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

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

Secondary outcomes (7)

  1. CPAx change score

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

    Measured: Assessed at hospital discharge (last value before discharge)

  2. Global rating of change scale

    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)

    Measured: ICU and hospital discharge (change for ICU and hospital period)

  3. ICU Mobility Scale

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

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

  4. Medical Research Council Sum Score

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

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

  5. Richmond Agitation-Sedation Scale

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

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

  6. Modified Iowa Level of Assistance Scale

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

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

  7. ICU and discharge destinations

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

    Measured: ICU and hospital discharge

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted17 May 2024
  2. Study start23 May 2024
  3. Primary completionOct 2026 (estimated)
  4. Study completionOct 2026 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Observational
Observational model
Cohort
Time perspective
Prospective
Enrolment
120 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT06419699
Sponsor's protocol ID
5678
Status last verified
May 2026
First submitted
13 May 2024
Last updated
27 May 2026
Results posted
No
Data monitoring committee
No
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
No: Solely anonymised main outcome data

Publications

  • Corner EJ, Wood H, Englebretsen C, Thomas A, Grant RL, Nikoletou D, Soni N. The Chelsea critical care physical assessment tool (CPAx): validation of an innovative new tool to measure physical morbidity in the general adult critical care population; an observational proof-of-concept pilot study. Physiotherapy. 2013 Mar;99(1):33-41. doi: 10.1016/j.physio.2012.01.003. Epub 2012 Mar 30.

    PubMed 23219649

  • Eggmann S, Verra ML, Stefanicki V, Kindler A, Seyler D, Hilfiker R, Schefold JC, Bastiaenen CHG, Zante B. German version of the Chelsea Critical Care Physical Assessment Tool (CPAx-GE): translation, cross-cultural adaptation, validity, and reliability. Disabil Rehabil. 2022 Aug;44(16):4509-4518. doi: 10.1080/09638288.2021.1909152. Epub 2021 Apr 19.

    PubMed 33874842

  • Eggmann S, Verra ML, Stefanicki V, Kindler A, Schefold JC, Zante B, Bastiaenen CHG. Predictive validity of the Chelsea Critical Care Physical Assessment tool (CPAx) in critically ill, mechanically ventilated adults: a prospective clinimetric study. Disabil Rehabil. 2023 Jan;45(1):111-116. doi: 10.1080/09638288.2021.2022785. Epub 2022 Jan 7.

    PubMed 34994664

  • Eggmann S, Paton M, Villinger C, Bradley S, Hellings T, Hills A, Venetz P, Broadley T, Charles-Nelson A, Hodgson C. Responsiveness and the minimal clinically important difference of the Chelsea Critical Care Physical Assessment tool (CPAx) in critically ill, mechanically ventilated adults: a study protocol for a prospective, multicentre, cohort study. BMJ Open. 2025 Sep 18;15(9):e102374. doi: 10.1136/bmjopen-2025-102374.

    PubMed 40973373

Questions about this trial

What is this clinical trial studying?

An observational study of Muscle Weakness and Critical Illness Myopathy, run by Insel Gruppe AG, University Hospital Bern at 3 sites in 2 countries.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 4 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: under way, not looking for participants, as of the sponsor's last update on 27 May 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 3 sites in Australia, Switzerland. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Chelsea Critical Care Physical Assessment tool (CPAx) change score (time frame: Assessed at ICU discharge (within 24 hours before or after ICU discharge)). It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT06419699, which also lists 4 linked publications.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 27 May 2026.

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