Validation of Chelsea Physical Assessment Tool (CPAx) in COVID-19 Patients for Assessing Functional Status After Intensive Care Unit Discharge

The present assessment tools for assessing physical function after intensive care unit (ICU) can be categorized as (1) functional tests (2) walk tests (3) strength test (4) Health-related quality of life (HRQOL). Strength tests such as Medical Research Council Scale and HRQOL (e.g. SF-36) tests may require awakening and appropriate mental health. However, mental impairments were seen in a considerable number of patients (2). Walk tests such as Six-Minute Walk Test (6MWT) or Timed Up&Go (TUG) can be impractical, some patients could not be able to perform these due to severe impairment. These tests require space to perform and may require management of several drips, drains, and oxygen delivery systems while the patient is walking and turning which render the test difficult to carry out. Among functional tests, the Physical Function in Intensive Care Test (PFIT) Functional Status Score for the ICU and the Chelsea Critical Care Physical Assessment Tool (CPAx) are specifically designed to assess function after ICU while Barthel and Katz are nonspecific to this population. According to a systematic review of 26 different outcome measures, the CPAx and the Physical Function in Intensive Care Test demonstrated the strongest psychometric properties, however, the Physical Function in Intensive Care Test has a significant floor effect. The PFIT and CPAx may be more suitable for the assessment of patients who may never reach the ability to perform submaximal exercise tests.

Among these three specific tools, CPAx seems to be the assessment tool that can be considered easy to use in the clinical setting due to the short time required for assessment and relatively minimal use of equipment (hand dynamometer for grip strength measurement).

Patients over 18 years of age who suffered COVID-19 pneumonia and stayed in ICU and discharged will be included in the study. Patients who are able to follow at least 2 of the commands from De Jonghe and colleagues' awakening criteria will be evaluated within 48 hours discharge. Patients will be assessed by using Chelsea Critical Care Physical Assessment Tool, Barthel Index, Katz Index, 5 times Sit-To-Stand test, 30 seconds Sit-To-Stand test, Glasgow coma scale, handheld dynamometers, Medical Research Council sum score (MRC-SS) and modified Medical Research Council dyspnea scale. The number (%) of the patients who will be able to complete the tests will be recorded. Another physiatrist will also complete Chelsea Critical Care Physical Assessment Tool at the same time without discussion and will be blinded to score of the other rater. Patients' demographic characteristics such as age, gender, comorbidities will be recorded. Length of stay in ICU, duration of mechanical ventilation, history of Extra Corporeal Membrane Oxygenation (ECMO), presence of tracheostomy, intubation status, the sequential organ failure assessment score (SOFA score) at the day of ICU admission and acute physiology and chronic health evaluation (APACHE II) on ICU admission will be recorded.

For construct validation, the correlation between CPAx and Barthel, Katz, Medical Research Council sum score and grip strength will be calculated. Kappa and weighed Kappa analysis will be conducted for inter-rater reliability. Descriptive analysis (Number (%) of the patients who will be able to complete the tests) will be performed to assess feasibility.

This study aims to investigate validation of the Chelsea Critical Care Physical Assessment Tool in the assessment of the functional status of COVID patients discharged from ICU and investigate the feasibility of commonly used assessment tools for assessing physical function after ICU in COVID patients discharged from ICU.