Construct validity of the Chelsea critical care physical assessment tool: an observational study of recovery from critical illness

Abstract

IntroductionIntensive care unit-acquired weakness (ICU-AW) is common in survivors of critical illness, resulting in global weakness and functional deficit. Although ICU-AW is well described subjectively in the literature, the value of objective measures has yet to be established. This project aimed to evaluate the construct validity of the Chelsea Critical Care Physical Assessment tool (CPAx) by analyzing the association between CPAx scores and hospital-discharge location, as a measure of functional outcome.MethodsThe CPAx was integrated into practice as a service-improvement initiative in an 11-bed intensive care unit (ICU). For patients admitted for more than 48 hours, between 10 May 2010 and 13 November 2013, the last CPAx score within 24 hours of step down from the ICU or death was recorded (n = 499). At hospital discharge, patients were separated into seven categories, based on continued rehabilitation and care needs. Descriptive statistics were used to explore the association between ICU discharge CPAx score and hospital-discharge location.ResultsOf the 499 patients, 171 (34.3%) returned home with no ongoing rehabilitation or care input; 131 (26.2%) required community support; 28 (5.6%) went to inpatient rehabilitation for <6 weeks; and 25 (5.0%) went to inpatient rehabilitation for >6 weeks; 27 (5.4%) required nursing home level of care; 80 (16.0%) died in the ICU, and 37 (7.4%) died in hospital. A significant difference was found in the median CPAx score between groups (P < 0.0001). Four patients (0.8%) scored full marks (50) on the CPAx, all of whom went home with no ongoing needs; 16 patients (3.2%) scored 0 on the CPAx, all of whom died within 24 hours. A 0.8% ceiling effect and a 3.2% floor effect of the CPAx is found in the ICU. Compliance with completion of the CPAx stabilized at 78% of all ICU admissions.ConclusionThe CPAx score at ICU discharge has displayed construct validity by crudely discriminating between groups with different functional needs at hospital discharge. The CPAx has a limited floor and ceiling effect in survivors of critical illness. A significant proportion of patients had a requirement for postdischarge care and rehabilitation.

Physiotherapy practice in South African intensive care units

“…Recently, emphasis has been placed on the use of validated outcome measurement tools such as the Chelsea Critical Care Physical Assessment (CPAx) tool [21] and Physical Function in ICU test (PFIT) [8] to assess patient function in ICUs. The use of electrical muscle stimulation to prevent disuse muscle atrophy in critically ill patients is gaining popularity among clinicians and researchers.…”

Validez y confiabilidad de las escalas de evaluación funcional en pacientes críticamente enfermos. Revisión sistemática

“…Entre los métodos diagnósticos utilizados para el establecimiento de la DAUCI se encuentra la electromiografía y la biopsia muscular, sin embargo, su alto costo y carácter invasivo han promovido el desarrollo de métodos diagnósticos simplificados como el Medical Research Council Sum Score (MRC-SS) cuyo puntaje se obtiene a partir de la cuantificación de la fuerza ejercida contra la resistencia manual aplicada por el evaluador, lo cual requiere la participación activa del paciente, por lo tanto debe ser aplicada posterior a la suspensión de la sedación 15,16 . Esto retarda significativamente el proceso diagnóstico dificultando el reconocimiento precoz de este síndrome durante la etapa de sedación del paciente.…”

Inspiratory muscle training to enhance recovery from invasive mechanical ventilation

“…Furthermore, to our knowledge the CPax has not been used to describe recovery trajectories beyond intensive care stay. While the authors of the CPax suggest that there will never be a single tool to capture physical function across hospital admission (Corner et al, 2014), our preliminary work suggests that the ACIF tool may achieve this (Latham et al, 2013) and deserves further investigation.…”

“…Like the ACIF, the CPax is completed by physiotherapists within 1 to 2 minutes following a standard assessment, and has robust inter-rater reliability and construct validity (Corner et al, 2014). In contrast to the P-FIT, the CPax does not have substantial floor (3.2%) or ceiling (0.8%) effects.…”

“…In the last 3 years, tools have been designed to specifically measure physical function in intensive care patients such as the Physical Function in ICU Tool (P-FIT) , the Chelsea Critical Care Physical Assessment tool (CPax) (Corner et al, 2014) and the ICU Mobility Scale (IMS) (Hodgson et al, 2014). All these tools have demonstrated inter-rater reliability.…”