Validation of the CPAx Tool for Physical Functionality in ICU Patients at the Chilean Air Force Cinical Hospital: Preliminary Report.

Margarita Ibañez, Oscar Urrejola, Daniel Cid
Purpose:

The purpose of the study is to validate the CPAx in critical ICU patients in Chile, measuring its reliability and validity as a standardized tool in the functional evaluation by physiotherapists.



Methods:

Study Design: Cross-sectional and prospective observational study.
Participants: adults patients admitted to the ICU of the Clinical Hospital of the Chilean Air Force. 
Instrument: The culturally adapted Chilean version of the CPAx consists of 10 items, with a functional difficulty scale ranging from complete difficulty (0) to independence without difficulty.
Evaluators: The team of physiotherapists was trained to perform standardized evaluations, ensuring high inter- and intra-evaluator consistency.
Analysis:

  • Cronbach’s Alpha: To measure internal consstency
  • Pearson Correlation: To assess inter- and intra-observer reliability.
  • Exploratory Factor Analysis (EFA): To validate the factorial structure of the instrument. 
Results:

The internal consistency was excellent (0.9593). In the intra-item analysis, hand strength had the lowest item-rest correlation (0.6997); however, its exclusion did not affect the final Cronbach’s Alpha result, so it remains an adequate and consistent item. All results are comparable to the original CPAx. Inter- and intra-observer reliability at 48 hours of ICU admission was greater than 0.8 (0.9167 and 0.9590, respectively), indicating high reproducibility. Regarding content validity, the EFA supports adequate factorial validity with one main factor in a 10-item model. It also presented high internal reliability with Cronbach’s Alpha > 0.7. In the item analysis, the elbow rule in the screeplot resulted in one significantly superior factor. The results support the reliability and factorial validity of the CPAx scale for evaluating functionality in ICU patients. 

Conclusion(s):

The study validates that the CPAx is a reliable and valid tool for evaluating functionality in critical ICU patients in Chile. As a standardized tool, it allows physiotherapists to perform reproducible evaluations, facilitating personalized rehabilitation and clinical intervention planning, optimizing patient outcomes, and clinical management. 

Implications:
  • Management: Standardizing functional assessments with CPAx in ICUs improves clinical decision-making and resource planning in rehabilitation.
  • Education: Training physiotherapists in using this tool ensures uniform, evidence-based evaluation.
  • Clinical: Continuous functionality assessment enables detailed patient monitoring and adjusts therapeutic interventions to maximize recovery. 
Funding acknowledgements:
This work did not receive funding.
Keywords:
validation
functionality
ICU
Primary topic:
Critical care
Did this work require ethics approval?:
Yes
Name the institution and ethics committee that approved your work:
Scientific ethics committee of the Clinical Hospital of the Chilean Air Force
Provide the ethics approval number:
161008
Has any of this material been/due to be published or presented at another national or international conference prior to the World Physiotherapy Congress 2025?:
No

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