German version of the Chelsea Critical Care Physical Assessment Tool (CPAx-GE): translation, cross-cultural adaptation, validity, and reliability

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 (https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=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.