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.


Purpose: To translate and cross-culturally adapt the Chelsea Critical Care Physical Assessment tool from English to German (CPAx-GE) and to examine its validity and reliability.

Materials and methods: Following a forward-backward translation including an expert round table discussion, the measurement properties of the CPAx-GE were explored in critically ill, mechanically ventilated adults. We investigated construct, cross-sectional, and cross-cultural validity of the CPAx-GE with other measurement instruments at pre-specified timepoints, analysed relative reliability with intraclass correlation coefficients (ICCs) and determined absolute agreement with the Bland-Altman plots.

Results: Consensus for the translated CPAx-GE was reached. Validity was excellent with >80% of the pre-specified hypotheses accepted at baseline, critical care, and hospital discharge. Interrater reliability was high (ICCs > 0.8) across all visits. Limit of agreement ranged from -2 to 2 points. Error of measurement was small, floor, and ceiling effects limited.

Conclusions: The CPAx-GE demonstrated excellent construct, cross-sectional, and cross-cultural validity as well as high interrater reliability in critically ill adults with prolonged mechanical ventilation at baseline, critical care, and hospital discharge. Consequently, the CPAx-GE can be assumed equal to the original and recommended in the German-speaking area to assess physical function and activity of critically ill adults across the critical care and hospital stay. Trial registration: German Clinical Trials Register (DRKS) identification number: DRKS00012983 (, registered on 20 September 2017, first patient enrolled on 21 November 2017.Implications for rehabilitationEarly rehabilitation of critically ill patients is recommended to prevent and treat the subsequent functional disability, but a suitable measurement instrument for the German-speaking area is lacking.The translated, cross-culturally adapted German CPAx demonstrated excellent validity and reliability in assessing physical function and activity in critically ill adults.Cross-sectional validity of the CPAx has been newly established and allows the use of this tool at clinically relevant time-points in the course of a critical illness.The CPAx-GE can therefore be used in clinical practice by German-speaking therapists to assess physical function and activity during early rehabilitation in the ICU and hospital.

Keywords: Physiotherapy; activity; critical illness; early rehabilitation; measurement instrument; physical function.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Critical Care
  • Critical Illness*
  • Cross-Cultural Comparison*
  • Cross-Sectional Studies
  • Humans
  • Physical Therapy Modalities
  • Psychometrics
  • Rehabilitation
  • Reproducibility of Results
  • Surveys and Questionnaires