A comprehensive evaluation of ICU and post-ICU physical function is crucial to evaluating treatment trajectory and measuring efficacy of therapies (1–3). Critically ill patients are often impaired long after their hospital stay partly due to underlying comorbidities, prolonged immobility, extensive ventilator requirements, and protracted ICU stay (1,3). An understanding of physical function that spans the acute care continuum is necessary.
Although the body of literature on early rehabilitation in the ICU is growing rapidly, there remains a paucity of research in the physical function of patients between the transition from ICU to post-acute setting. There are several scoring systems that are used to evaluate a patient’s physical function in the ICU setting and other tools to measure function in the post-ICU setting. The key issue in assessing patient recovery trajectories is the limitation of available functional assessments across the spectrum of ICU care to post-ICU care. Function assessments created for the ICU such as the Physical Function in ICU Test-scored (PFIT-s) have ceiling effects after discharge and available functional assessments in the post-acute setting, such as the de Morton Mobility Index (DEMMI) have significant floor effects in the ICU (1,4–7). For example, a young patient admitted to the ICU with status epilepticus and recovering from the effects of a midazolam infusion may initially score quite poorly (“flooring”) on the DEMMI scoring system which provides evaluation of higher-level tasks whereas they may score quite well on the ICU specific PFIT-s system. Shortly thereafter and through their recovery, the PFIT-s score may no longer be applicable to the patient, as they “ceiling” and the DEMMI would become more of a pertinent scoring system.
In this issue of Critical Care Medicine, Parry et al (8) propose a single measure of physical function for use across the acute care continuum integrating both the PFIT-s (a 4-item scale) and DEMMI (a 15-item scale) scoring systems. They designed a multicenter prospective cohort study across four international hospital centers between 2015 and 2017. All patients had to be mechanically ventilated for greater than 48 hours and ambulant prior to admission without neurologic injury, trauma, or approaching imminent death. All patients received standard of care physiotherapy in the ICU which included early mobility activities. Physical function assessments were made at ICU awakening, ICU discharge, and hospital discharge and the order of testing for PFIT-s and DEMMI was randomized. They then performed a two-part analysis; the first was an evaluation of both the PFIT-s and DEMMI to determine floor and ceiling effects, as well as validity, and the second was a Rasch analysis to develop the new single measure across the continuum of care.
The primary finding reported was that the PFIT-s and DEMMI had a significant ceiling and floor effect, respectively, and that patients with higher scores in both domains discharged home more readily. Based on the analysis they completed, a new 10-item scale (four items from the PFIT-s and six from the DEMMI) was created and was dubbed the Physical Function in Critical Care (PaciFIC) score. This score showed a significant improvement from awakening to ICU discharge and from ICU discharge to hospital discharge. There was also a significant difference in awakening test scores between participants discharged home versus not home.
Although, in recent years, throughout the critical care community, there has been a new awakening to rehabilitative efforts in the ICU, a physical function assessment across the acute care continuum has been lacking (9,10). Critically ill patients are often misassessed or not assessed for physical function and this leads to delays in care, inaccurate assessments of recovery trajectory and inability to predict individuals at risk for ongoing disability. As physical function outcomes are gaining importance in clinical and research applications of critical care, the development of a single tool to measure physical function across the continuum of injury and recovery is very important.
The tool created by Parry et al (8) appears to be valid and seems to follow the injury and recovery trajectory. Obviously, this scoring system must be validated in a prospective cohort of patients. The patients seen in the study by Parry et al (8) were from mixed general ICUs including medical, surgical, and neurologic ICUs. Further evaluation of this tool is required in future studies across multiple settings to substantiate the responsiveness, validity, and predictive utility. The choice by their group to use the PFIT-s is an interesting one as it covers endurance, strength, and mobility as opposed to mainly the mobility domain. The PFIT-s is also of note used in several research trials, a factor that may lead the newly created PaciFIC to be easily incorporated into future research studies. The time consideration for physical function assessment is also a limiting factor when it comes to patient care. The authors remark in their article that the PaciFIC tool should take less than 15 minutes and provides a comprehensive assessment.
The study by Parry et al (8) creating a new systematic tool to follow the injury and recovery trajectory across the continuum of acute care with limited ceiling and floor effect is valuable to clinicians and therapists who care for the general ICU population. This article has brought to the field a potential tool to assess patients’ functionalities across the continuum of ICU and post-ICU care. Rigorous validation is the next step in applying this functional assessment to the ICU population.
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