Relationship between intensive care unit-acquired weakness, fatigability and fatigue: What role for the central nervous system?

Why does malaise/fatigue occur? Underlying mechanisms and potential relevance to treatments in rheumatoid arthritis

INTRODUCTION

Fatigue and malaise are commonly associated with a wide range of medical conditions, including rheumatoid arthritis (RA). Evidence suggests that fatigue and malaise can be overwhelming for patients, yet these symptoms remain inadequately-managed, largely due to an incomplete elucidation of the underlying causes.

AREAS COVERED

In this assessment of the published literature relating to the pathogenesis of fatigue or malaise in chronic conditions, four key mechanistic themes were identified. Each theme (inflammation, hypothalamic-pituitary-adrenal axis, dysautonomia, and monoamines) is discussed, as well as the complex network of interconnections between themes which suggests a key role for inflammatory cytokines in the development and persistence of fatigue.

EXPERT OPINION

Fatigue is multifaceted, poorly defined, and imperfectly comprehended. Moreover, the cause and severity of fatigue may change over time, as a consequence of the natural disease course or pharmacologic treatment. This detailed synthesis of available evidence permits us to identify avenues for current treatment optimization and future research, to improve the management of fatigue and malaise in RA. Within the development pipeline, several new anti-inflammatory therapies are currently under investigation, and we anticipate that the next five years will herald much-needed progress to reduce the debilitating nature of fatigue in patients with RA.

Impact of COVID-19 critical illness on functional status, fatigue symptoms, and health-related quality of life one-year after hospital discharge: a systematic review and meta-analysis

Purpose: To estimate the prevalence and severity of impairments in functional status, fatigue, and health-related quality of life (HRQoL) among critical COVID-19 survivors one-year after hospital discharge. Methods: A systematic review was conducted following PRISMA statement and registered in PROSPERO (CRD42021258356), with searches in eight databases. Observational studies were selected. The prevalence meta-analysis of abnormalities was performed using random-effects models. Risk of bias was evaluated using the National Heart, Lung, and Blood Institute tool. Results: Twenty studies were included, with data collected between 12 and 13.5 months after hospital discharge and a total of 1828 participants. Of these, 71% were men, and 77.7% were intubated in the intensive care unit (ICU). Impairments and sequelae were identified in varying prevalence and degrees, with greater impact on functional capacity and physical components of fatigue and HRQoL. The prevalence of abnormalities of 32.3% [95% CI 23.9; 41.9] found in the meta-analysis is substantially high. Most studies were classified as having fair and poor quality. Conclusion: Critical COVID-19 survivors experience impairments in functional status, fatigue, and HRQoL to varying degrees one-year after hospital discharge, particularly among patients who stayed in the ICU and on MV for a prolonged period.

Measuring objective fatigability and autonomic dysfunction in clinical populations: How and why?

Fatigue is a major symptom in many diseases, often among the most common and severe ones and may last for an extremely long period. Chronic fatigue impacts quality of life, reduces the capacity to perform activities of daily living, and has socioeconomical consequences such as impairing return to work. Despite the high prevalence and deleterious consequences of fatigue, little is known about its etiology. Numerous causes have been proposed to explain chronic fatigue. They encompass psychosocial and behavioral aspects (e.g., sleep disorders) and biological (e.g., inflammation), hematological (e.g., anemia) as well as physiological origins. Among the potential causes of chronic fatigue is the role of altered acute fatigue resistance, i.e. an increased fatigability for a given exercise, that is related to physical deconditioning. For instance, we and others have recently evidenced that relationships between chronic fatigue and increased objective fatigability, defined as an abnormal deterioration of functional capacity (maximal force or power), provided objective fatigability is appropriately measured. Indeed, in most studies in the field of chronic diseases, objective fatigability is measured during single-joint, isometric exercises. While those studies are valuable from a fundamental science point of view, they do not allow to test the patients in ecological situations when the purpose is to search for a link with chronic fatigue. As a complementary measure to the evaluation of neuromuscular function (i.e., fatigability), studying the dysfunction of the autonomic nervous system (ANS) is also of great interest in the context of fatigue. The challenge of evaluating objective fatigability and ANS dysfunction appropriately (i.e.,. how?) will be discussed in the first part of the present article. New tools recently developed to measure objective fatigability and muscle function will be presented. In the second part of the paper, we will discuss the interest of measuring objective fatigability and ANS (i.e. why?). Despite the beneficial effects of physical activity in attenuating chronic fatigue have been demonstrated, a better evaluation of fatigue etiology will allow to personalize the training intervention. We believe this is key in order to account for the complex, multifactorial nature of chronic fatigue.

Influence of Early Multidisciplinary Collaboration on Prevention of ICU-Acquired Weakness in Critically Ill Patients

Objective. This study focused on elucidating the influence of early multidisciplinary collaboration on preventing intensive care unit- (ICU-) acquired weakness (AW) in critically ill patients (CIPs). Methods. Ninety-five CIPs admitted between December 2018 and December 2021 were selected and assigned to the following two groups according to the intervention pattern: the control group (the Con; $n=40$ ) treated with routine early rehabilitation intervention, and the research group (the Res; $n=55$ ) intervened by early multidisciplinary collaborative intervention. The incidence of complications (ICU-AW, deep vein thrombosis (DVT), and pressure ulcers (PSs)) and recovery indices (days of ventilator use, ICU treatment time, and length of hospital stay (LOS)) were recorded. Besides, patients’ activity function and quality of life (QoL) were evaluated and compared, among which the former was evaluated by the Barthel Index (BI), ICU Mobility Scale (IMS), and Medical Research Council (MRC) Scale, and the latter was assessed by the World Health Organization Quality of Life Assessment (100-item version) (WHOQOL-100). Results. The data identified statistically a lower incidence of complications (ICU-AW, DVT, and PSs) and shorter time of ventilator use, ICU residence, and LOS in the Res compared with the Con. In addition, BI, IMS, MRC, and WHOQOL-100 scores in the Res elevated statistically after treatment and were higher than those of the Con. Conclusions. Early multidisciplinary collaboration can validly prevent ICU-AW in CIPs, reduce the incidence of DVT and PSs, and promote patients’ rehabilitation, mobility, and QoL.

Prevalence of self-reported fatigue in intensive care unit survivors 6 months-5 years after discharge

Prolonged stays in intensive care units (ICU) are responsible for long-lasting consequences, fatigue being one of the more debilitating. Yet, fatigue prevalence for patients that have experienced ICU stays remains poorly investigated. This study aimed to evaluate fatigue prevalence and the level of physical activity in ICU survivors from 6 months to 5 years after ICU discharge using the Functional Assessment of Chronic Illness Therapy Fatigue (FACIT-F) and Godin questionnaires, respectively. Data from 351 ICU survivors (out of 1583 contacted) showed that 199 (57%) and 152 (43%) were considered as fatigued and non-fatigued, respectively. The median FACIT-F scores for fatigued versus non-fatigued ICU survivors were 21 (14–27) and 45 (41–48), respectively (p < 0.001). Time from discharge had no significant effect on fatigue prevalence (p = 0.30) and fatigued ICU survivors are less active (p < 0.001). In multivariate analysis, the only risk factor of being fatigued that was identified was being female. We reported a high prevalence of fatigue among ICU survivors. Sex was the only independent risk factor of being fatigued, with females being more prone to this symptom. Further studies should consider experimental approaches that help us understand the objective causes of fatigue, and to build targeted fatigue management interventions.

Exploring adult critical illness survivors' experiences of fatigue: A qualitative study

AIMS

To explore adult experiences of fatigue after discharge from an intensive care unit and identify potential management strategies.

DESIGN

An exploratory qualitative study.

METHODS

One to one audio-recorded semi-structured interviews with 17 adult survivors of critical illness in the United Kingdom, lasting up to 1 h, between September 2019 and January 2020. Anonymised and verbatim-transcribed interview data underwent a standard process of inductive thematic analysis as described by Braun and Clarke.

FINDINGS

Three themes were identified: fatigue is different for everyone; complex interrelating interactions; and personalised fatigue strategies. Fatigue was described as a distressing symptom, unique to the individual that causes an array of complex, often long-term interrelating impacts on the survivor and their wider family, made worse by a lack of understanding, empathy and support resources. Support from others, alongside interventions such as exercise, good nutrition, information and alternative therapies are used by survivors with variable degrees of success.

CONCLUSIONS

This qualitative study reports peoples' experiences of fatigue after critical illness. Findings highlight the significant impact it has on people's lives and those of their family and friends.