title: The responsiveness of the Chelsea Critical Care Physical Assessment tool in measuring functional recovery in the burns critical care population: an observational study.
abstract: BACKGROUND
  Severe burn leads to a state of hypercatabolism, resulting in rapid muscle loss and long-term disability. As survival rates from severe burn are improving, early rehabilitation is essential to facilitate functional recovery. However, there is no way of measuring the degree of disability in the acute stages, and hence, no marker of functional recovery. This hampers both communication and research into interventions to improve functional outcomes. The Chelsea Critical Care Physical Assessment tool (CPAx) is a simple objective measure of function, designed and validated in the general Intensive Care Unit (ICU) cohort. The aim of this study was to test the responsiveness of the CPAx in the burns ICU (BICU) cohort and validate its use.
  
  
  METHODS
  Observational study of 52 BICU patients admitted for over 48h. All patients were assessed on the CPAx retrospectively for pre-admission, and prospectively at ICU admission, ICU discharge (or final ICU assessment for non-survivors) and hospital discharge. Analysis of variance, post hoc between group differences in median CPAx score, and floor and ceiling effect (i.e. the percentage of patients scoring full marks (50), or zero) for the four time points were completed. Minimal clinically important difference (MCID) was estimated as half of the standard deviation of the CPAx score at ICU discharge.
  
  
  RESULTS
  A total of 30 patients were included in the final analysis; mean age was 47.1 years (SD 21.2), 63.3% were male, with a median burn total body surface area (TBSA) of 30% (IQR 11.3-48.8). There was a significant difference in the analysis of variance in median CPAx scores at all four time points (p<.001). In survivors, the differences in CPAx scores post hoc were significant for all time points (p<.05), aside from ICU discharge and hospital discharge. The CPAx MCID for BICU patients was six. Twenty-three (86.7%) patients scored full marks or zero on the CPAx pre-admission. For survivors, no patients scored full marks or zero on the CPAx at ICU and hospital discharge. On ICU admission 66.7% (n=20) scored zero on the CPAx and no patients scored 50.
  
  
  CONCLUSIONS
  The CPAx score appears to be able to detect improvements in physical function as patients recover from acute severe burn. It has a limited floor and ceiling effect in the acute setting and a change in CPAx score of 6 represents clinically important progress. Further work is required in a larger cohort.
authors.affiliation: Chelsea and Westminster NHS Foundation Trust, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH, England, UK; Imperial College London, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH, England, UK. Electronic address: e.corner13@imperial.ac.uk.
authors.forename: Evelyn J
authors.initials: EJ
authors.lastname: Corner
authors.affiliation: Chelsea and Westminster NHS Foundation Trust, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH, England, UK. Electronic address: Louise.Hichens@nbt.nhs.uk.
authors.forename: Louise V
authors.initials: LV
authors.lastname: Hichens
authors.affiliation: Chelsea and Westminster NHS Foundation Trust, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH, England, UK. Electronic address: kate.attrill@chelwest.nhs.uk.
authors.forename: Kate M
authors.initials: KM
authors.lastname: Attrill
authors.affiliation: Imperial College London, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH, England, UK; Chelsea and Westminster NHS Foundation Trust, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH, England, UK. Electronic address: m.vizcaychipi@imperial.ac.uk.
authors.forename: Marcela P
authors.initials: MP
authors.lastname: Vizcaychipi
authors.affiliation: Imperial College London, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH, England, UK; Centre for Perioperative Medicine and Critical Care Research, Imperial College NHS Healthcare Trust, Hammersmith Hospital, Du Cane Road, London W12 0HS, England, UK. Electronic address: stephen.brett@imperial.ac.uk.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Brett
authors.affiliation: Imperial College London, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH, England, UK; Chelsea and Westminster NHS Foundation Trust, Chelsea and Westminster Hospital, 369 Fulham Road, London SW10 9NH, England, UK. Electronic address: j.m.handy@imperial.ac.uk.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Handy
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002056:Burns / Q000534:rehabilitation*; D003422:Critical Care / Q000379:methods / Q000592:standards*; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D007362:Intensive Care Units / Q000592:standards; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010343:Patient Admission / Q000706:statistics & numerical data; D010351:Patient Discharge / Q000706:statistics & numerical data; D020127:Recovery of Function / Q000502:physiology*; D012189:Retrospective Studies; D006113:United Kingdom
keywords: Burns; Critical care; Disability evaluation; Outcome measure; Physiotherapy; Rehabilitation