Respiratory muscle dysfunction in long-COVID patients

Insomnia, cardiorespiratory function and quality of life in individuals with post-COVID-19 fatigue

Objective

This study aimed to compare the prevalence of insomnia, lung function, inspiratory muscle function, functional capacity, and quality of life in individuals with and without post-COVID-19 fatigue.

Methods

Thirty-four post-COVID-19 individuals participated in the study, 20 with fatigue (32 ± 12 years old, 15% male) and 14 without fatigue (31 ± 12 years old, 42.9% male). The Chalder Fatigue Scale (CFS) was employed to categorize the volunteers into two groups: those with fatigue (score ≥4) and those without fatigue (score <4). The Insomnia Severity Index (ISI) and the Epworth Sleepiness Scale (ESS) were used to assess insomnia and excessive daytime sleepiness, respectively. Pulmonary function was evaluated by spirometry, inspiratory muscle strength was assessed by the maximum inspiratory pressure (MIP), and inspiratory endurance was evaluated by maintaining an inspiratory load of 60% of MIP until fatigue. The 6-min walk test (6MWT) was used to evaluated functional capacity, while the WHOQOL-BREF questionnaire assessed quality of life.

Results

Individuals with post-COVID-19 fatigue demonstrated a higher prevalence of insomnia (80% vs. 49%) and excessive daytime sleepiness (45% vs. 7%), as well as lower MIP, shorter distance covered in the 6MWT, and lower FEV1/FVC (forced expired volume in the first second divided by forced vital capacity), and FEV1/FVC% of predicted. Additionally, they exhibited poorer quality of life in the physical and environmental domains. CFS demonstrated a direct correlation with ISI (r=0.436, p=0.01) and ESS (r=0.593, p=0.001), as well as an inverse correlation with the distance covered in the 6MWT (r=-0.398, p=0.022) and FEV1 (r=-0.412, p=0.01). ISI was an independent predictor of CFS, with 62% of CFS variance explained by ISI variance.

Conclusion

Individuals with symptoms of post-COVID-19 fatigue may have a higher prevalence of insomnia, reduced inspiratory muscle strength, functional capacity, and Tiffeneau index, along with impaired quality of life. ISI is an independent predictor of post-COVID-19 fatigue.

A multidisciplinary review of long COVID to address the challenges in diagnosis and updated management guidelines

Long COVID has emerged as a significant challenge since the COVID-19 pandemic, which was declared as an outbreak in March 2020, marked by diverse symptoms and prolonged duration of disease. Defined by the WHO as symptoms persisting or emerging for at least two months post-SARS-CoV-2 infection without an alternative cause, its prevalence varies globally, with estimates of 10-20% in Europe, 7.3% in the USA, and 3.0% in the UK. The condition's etiology remains unclear, involving factors, such as renin-angiotensin system overactivation, persistent viral reservoirs, immune dysregulation, and autoantibodies. Reactivated viruses, like EBV and HSV-6, alongside epigenetic alterations, exacerbate mitochondrial dysfunction and energy imbalance. Emerging evidence links SARS-CoV-2 to chromatin and gut microbiome changes, further influencing long-term health impacts. Diagnosis of long COVID requires detailed systemic evaluation through medical history and physical examination. Management is highly individualized, focusing mainly on the patient's symptoms and affected systems. A multidisciplinary approach is essential, integrating diverse perspectives to address systemic manifestations, underlying mechanisms, and therapeutic strategies. Enhanced understanding of long COVID's pathophysiology and clinical features is critical to improving patient outcomes and quality of life. With a growing number of cases expected globally, advancing research and disseminating knowledge on long COVID remain vital for developing effective diagnostic and management frameworks, ultimately supporting better care for affected individuals.

Midterm Effects of SARS-CoV-2 on Respiratory Function in Judokas With and Without Exercise-Induced Bronchoconstriction: A Retrospective Study

OBJECTIVES

The clinical consequences of coronavirus infection in elite judokas with exercise-induced bronchoconstriction (EIB) are unclear. We aimed to determine potential respiratory function abnormalities and recovery in athletes with and without EIB after severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection.

DESIGN

Retrospective cohort study.

SETTING

Türkiye Olympic Preparation Centre.

PARTICIPANTS

This retrospective study analyzed data collected from 25 consecutive elite judokas diagnosed with and without EIB and SARS-CoV-2 infection, routinely followed at an Olympic Sports Center between September 2020 and 2021.

INDEPENDENT VARIABLES

Respiratory muscle strength and pulmonary function data were collected before and up to 90 days after SARS-CoV-2 infection.

MAIN OUTCOME MEASURES

Measurements included maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), forced expiratory volume in 1 second (FEV 1 ), forced vital capacity (FVC), FEV 1 /FVC ratio, and peak expiratory flow (PEF).

RESULTS

Infected athletes with EIB had more markedly reduced respiratory muscle strength and pulmonary function than those without EIB. Maximal inspiratory pressure was decreased by 14% and MEP by 8% from baseline in infected athletes with EIB during follow-up. Likewise, FEV 1 and FVC decreased by 4%. Maximal inspiratory pressure, MEP, FEV 1 , and FVC remained abnormal after 90 days of SARS-CoV-2 infection in EIB athletes but normalized rapidly in non-EIB athletes. Peak expiratory flow seemed unaffected during follow-up. Exercise-induced bronchoconstriction severity was moderately correlated with the maximum fall in MEP during follow-up.

CONCLUSIONS

Severe acute respiratory syndrome coronavirus-2 infection notably decreases respiratory muscle strength and pulmonary function in judokas, especially those with pre-existing EIB, thereby prolonging spontaneous recovery time.

Respiratory Muscle Dysfunction and Associated Risk Factors Following COVID-19-Related Hospitalisation

BACKGROUND

Studies have highlighted long-term respiratory muscle dysfunction in COVID-19 survivors, although the underlying risk factors remain unclear. This single-centre study assessed respiratory muscle function and individual associated factors at follow-up in patients hospitalised with COVID-19 and related acute respiratory failure.

METHODS

Data were collected for consecutive patients, aged ≥ 18 years, at the post-COVID outpatient service of Hospital Policlinico in Modena (Italy) in the time frame of 3 to 6 months after discharge. Data were analysed using single and multiple logistic regression models. Correlations among MIP/MEP, hand-grip values, and lung function were further explored.

RESULTS

Out of 223 patients (mean age 67 years, 69% male) 121 (54.3%) exhibited MIP or MEP dysfunction, which was found to be associated with the use of non-invasive ventilation (aOR = 1.91 [1.07-3.49], p = 0.04) and female gender (aOR = 1.76 [1.09-4.16], p = 0.03) as independent risk factors. A positive correlation was observed between MIP dysfunction and hand-grip strength (p = 0.03 and 0.01), whereas both MIP and MEP were significantly associated with FEV1, FVC, TLC, and DLCO.

CONCLUSIONS

Respiratory muscle dysfunction is consistently prevalent and parallels peripheral muscle weakness and the lung function level in patients at follow-up after severe COVID-19. The need for non-invasive ventilation during the acute phase and female gender might represent risk factors. MIP/MEP assessment should be recommended to observe respiratory muscle dysfunction in severe post-COVID survivors.

Self-Reported Dyspnea Is Associated with Reduced Health-Related Quality of Life in Quaternary Hospital Workers 1 Year Post Mild COVID-19 Infection

BACKGROUND/OBJECTIVES

The COVID-19 pandemic had significant implications for healthcare workers (HWs), especially those that work in hospitals. This study evaluated health related quality of life (HRQOL) and its relationship with dyspnea approximately one year after COVID-19 infection in HWs.

METHODS

HWs with previous COVID-19 infections were interviewed, and the EuroQol five-dimensional three-level questionnaire (EQ-5D-3L) with a visual analog scale (VAS) was used to evaluate HRQOL. Self-reported clinical and sociodemographic data were also obtained. Data were stratified by the presence of self-reported dyspnea in the moment of the study interview. The association between self-reported dyspnea and HRQOL was evaluated by regression models, either unadjusted or adjusted for potential confounders (for age and sex, marital status, work category, number of comorbidities, and number of days between diagnosis and evaluation).

RESULTS

A total of 109 HWs were interviewed; the median number of days post COVID-19 diagnosis for this group was 400 (IIQ 25-75% 321-428). The majority were women (67.9%); the median age was 44 (IIQ 25-75% 38-52) years. Overall, the median EQ-5D-3L score was 0.79 (IIQ 25-75% 0.74-0.85), and the median VAS score was 80 (IIQ 25-75% 70-90). Self-reported dyspnea was indicated by 22 individuals (20.2%). Self-reported dyspnea was associated with lower EQ-5D-3L and VAS scores, both in adjusted and non-adjusted models. In addition, self-reported dyspnea was associated with more problems in carrying out usual activities in both the non-adjusted and adjusted models (p < 0.01).

CONCLUSIONS

Our results underscore the long-term implications of COVID-19, based on persistent perceptions of self-reported dyspnea and its relationship with HRQOL in HWs. Future studies, with extended follow-up and the employment of cardiopulmonary and mental health testing, may help to elucidate the nature and extent of COVID-19 sequelae.

Impact of COVID-19 on Diaphragmatic Function: Understanding Multiorgan Involvement and Long-Term Consequences

The COVID-19 pandemic has brought significant attention to the respiratory system, with much focus on lung-related disorders. However, the diaphragm, a crucial component of respiratory physiology, has not been adequately studied, especially in the context of long COVID. This review explores the multipotential role of the diaphragm in both respiratory health and disease, emphasizing its involvement in long-term complications following SARS-CoV-2 infection. The diaphragm's fundamental role in respiratory physiology and its impact on balance and posture control, breathing patterns, and autonomic nervous system regulation are discussed. This review examines complications arising from COVID-19, highlighting the diaphragm's involvement in neurological, musculoskeletal, and inflammatory responses. Particular attention is given to the neuroinvasive impact of SARS-CoV-2, the inflammatory response, and the direct viral effects on the diaphragm. The diaphragm's role in long COVID is explored, with a focus on specific symptoms such as voice disorders, pelvic floor dysfunction, and sleep disturbances. Diagnostic challenges, current methods for assessing diaphragmatic dysfunction, and the complexities of differentiating it from other conditions are also explored. This article is the first to comprehensively address diaphragmatic dysfunction resulting from COVID-19 and long COVID across various physiological and pathological aspects, offering a new perspective on its diagnosis and treatment within a multisystem context.

Musculoskeletal, Pulmonary, and Cardiovascular COVID-19 Sequelae in the Context of Firefighter Occupational Health: A Narrative Review

For most individuals infected with SARS-CoV-2, the acute illness resolves completely. However, for millions of people, symptoms or sequelae from COVID-19 recur or persist for months to years after infection. Post-COVID-19 sequelae are wide-ranging, often affecting the musculoskeletal, pulmonary, and cardiovascular systems. All who experience post-COVID-19 sequelae face significant challenges navigating home and work life. Occupations such as firefighting, however, are of particular concern given the strenuous nature of a job that relies on a healthy musculoskeletal, pulmonary, and cardiovascular system. Research has documented significant musculoskeletal impairment (including muscle weakness, pain, and fatigue), respiratory dysfunction (including reduced lung function, interstitial disease, and diffusion abnormalities), cardiovascular conditions (including cardiac events, ischemic disease, dysrhythmias, and infectious diseases), and diminished cardiorespiratory fitness that continues for months to years in some individuals. These persistent post-COVID-19 conditions may affect a firefighter's ability to return to work, function at full capacity while at work, and potentially compromise firefighter health and public safety. This review, therefore, explores musculoskeletal, pulmonary, and cardiovascular sequelae post-COVID-19 and the impact of these sequelae on firefighter health and occupational readiness.

Cut-off values of one-minute sit-to-stand test for determining physical performance in mild-post-COVID-19 individuals

Background

This study aims to establish cutoff values for the one-minute sit-to-stand test (1STST) to predict physical performance in mild-post- coronavirus disease 2019 (COVID-19) individuals and to compare the 1STST with the 6-minute walk test (6MWT) in assessing hemodynamic response and to explore the correlation between 1STST, 6MWT, and muscle strength, including leg and respiratory muscle strength.

Methods

A cross-sectional study of 93 participants with mild post-COVID-19 symptoms was conducted. Sociodemographic and anthropometric data were collected, and pulmonary function, as well as respiratory and quadriceps muscle strength, were evaluated. Functional capacity was assessed using the 6MWT and 1STST. Additionally, hemodynamic responses, fatigue, and dyspnea were measured before and after each test.

Results

The cutoff for the 1STST in mild post-COVID-19 individuals was ≥29 repetitions, with an AUC of 0.84, sensitivity of 80.52%, and specificity of 75.00%. The 1STST resulted in higher heart rate, systolic blood pressure, and dyspnea compared to the 6MWT, and showed a significant moderate correlation with the 6MWT (r = 0.532, p < 0.0001) and weak correlations with leg strength and respiratory muscle strength.

Conclusion

A cutoff of less than 29 repetitions on the 1STST indicates functional impairment in mild post-COVID-19 cases, as it induces greater physiological stress than the 6MWT and correlates with muscle strength, making it crucial for rehabilitation assessment.

Sex-specific differences of cardiopulmonary fitness and pulmonary function in exercise-based rehabilitation of patients with long-term post-COVID-19 syndrome

BACKGROUND

Post-COVID-19 Syndrome (PCS) entails a spectrum of symptoms, including fatigue, reduced physical performance, dyspnea, cognitive impairment, and psychological distress. Given the effectiveness of exercise-based rehabilitation for PCS, this study examined the efficacy of rehabilitation for PCS patients, focusing on sex-specific differences.

METHODS

Prospective cohort study during inpatient rehabilitation. Cardiopulmonary exercise testing and spirometry were performed at admission and discharge. Questionnaires were used to assess fatigue, health-related quality of life, wellbeing, and workability for up to 6 months.

RESULTS

145 patients (36% female, 47.1 ± 12.7 years; 64% male, 52.0 ± 9.1 years; p = 0.018) were referred to rehabilitation 262.0 ± 128.8 days after infection (female, 285.5 ± 140.6 days; male, 248.8 ± 112.0 days; p = 0.110). Lead symptoms included fatigue/exercise intolerance (81.4%), shortness of breath (74.5%), and cognitive dysfunction (52.4%). Women presented with higher relative baseline exercise capacity (82.0 ± 14.3%) than males (68.8 ± 13.3%, p < 0.001), but showed greater improvement in submaximal workload (p = 0.026). Men exhibited higher values for FEV1, FEV1/VC, PEF, and MEF and lower VC at baseline (p ≤ 0.038), while FEV1/VC improvement more in women (p = 0.027). Higher baseline fatigue and lower wellbeing was detected in women and correlated with impaired pulmonary function (p < 0.05). Disease perception including fatigue, health-related quality of life, wellbeing and workability improved with rehabilitation for up to six-month.

CONCLUSIONS

Rehabilitation improves cardiopulmonary fitness, pulmonary function and disease burden in women and men with long-term PCS. Women with PCS may benefit from intensified respiratory muscle training. Clinical assessment should include cardiopulmonary exercise testing and pulmonary function tests and fatigue assessments for all PCS patients to document limitations and tailor therapeutical strategies.

Association of physical symptoms with accelerometer-measured movement behaviors and functional capacity in individuals with Long COVID

Long COVID has been linked to a decline in physical activity and functional capacity. However, it remains unclear which physical symptoms are associated with specific aspects of movement behaviors and functional capacity. We aimed to investigate the associations of fatigue, dyspnea, post-exertional malaise, myalgia, and the co-occurrence of symptoms with movement behaviors and functional capacity in individuals with Long COVID. A cross-sectional multicenter study was conducted. Questionnaires were used to assess fatigue, dyspnea, post-exertional malaise, and myalgia. Accelerometry was employed to assess sedentary time, steps per day, light physical activity, and moderate-to-vigorous physical activity. The six-minute walk test, 30-s chair stand test, and timed up and go were used to assess functional capacity. One hundred and two community-dwelling individuals who had been living with Long COVID for 15 ± 10 months participated in the study. Fatigue, post-exertional malaise, and the co-occurrence of physical symptoms showed a negative association with step count, while post-exertional malaise was also negatively associated with moderate-to-vigorous physical activity. Dyspnea showed a negative association with the functional score, including all tests. Our findings suggest that fatigue, post-exertional malaise, and the co-occurrence of physical symptoms are negatively associated with physical activity, while dyspnea is negatively associated with functional capacity in individuals with Long COVID.

Use of Locally Produced Novel Low-Cost 3D Printed Respiratory Muscle Strength Trainer Device (RMSTD) for Long COVID-Rehabilitation: An Innovative Case Report

Introduction. This article details the development and use of a low-cost, custom RMST device for a patient with long COVID who had received positive airway flow support during ICU treatment. By sharing our successful management of respiratory muscle weakness in a severe COVID-19 patient, we aim to contribute to the broader conversation around effective long COVID management. Case Description. A patient with respiratory muscle weakness used a hospital-made RMST device. The training involved ten short forced exhalations per cycle for five cycles, followed by five long forced exhalations held for five seconds. Additionally, the patient learned lower abdominal and box breathing techniques. The patient showed significant improvement, using the RMST device without supplemental oxygen within 24 hours and completely weaned off by day 5. By discharge, the patient could complete the RMST exercise regime and achieved 290 meters in the 6MWT. After six weeks of outpatient therapy, the patient used the RMST device at 80 cm H2O and increased their 6MWT distance to 390 meters. Device Description. The RMST device was designed for in-house production with a 3D-printed PETG cap, base, and plunger, and a standard pen spring. Its design mimicked a standard PEEP valve with a different geometry. The spring closed the valve until a pressure threshold was reached, allowing airflow. The adjustable pressure threshold ranged from -40 to +40 cm H2O, calibrated in 10 cm H2O increments by measuring displaced water column height. Discussion and Limitation. COVID-19 can cause long-term respiratory issues needing proper management and rehabilitation. Inspiratory muscle training benefits those recovering from severe COVID-19 who were weaned from mechanical ventilation. However, the device's design and production method are unsuitable for large-scale and commercial production. Rehabilitation centers should prepare for postintensive care syndrome in post-COVID-19 individuals, with interprofessional teams addressing various recovery aspects. Early medical attention and therapy can improve patients' quality of life.

A new phenotype of patients with post-COVID-19 condition is characterised by a pattern of complex ventilatory dysfunction, neuromuscular disturbance and fatigue symptoms

Background

Patients with post-COVID-19 condition frequently suffer from chronic dyspnoea. The causes and mechanism for dyspnoea in these patients without evidence of structural lung disease are unclear.

Methods

Patients treated for COVID-19 at Charité University Hospital in Berlin received pulmonary function testing including respiratory muscle strength tests and completed health-related quality-of-life questionnaires during follow-up. Patients with post-COVID-19 condition during outpatient follow-up with fatigue and exertional intolerance (PCF) were compared to patients with post-COVID-19 condition with evidence of chronic pulmonary sequelae (post-COVID-19 restriction (PCR)) as well as to patients without post-COVID-19 condition (NCF).

Results

A total of 170 patients presented for follow-up. 36 participants met criteria for PCF, 28 for PCR and 24 for NCF. PCF patients reported dyspnoea in 63.8%. % predicted value of respiratory muscle strength (median (IQR)) was reduced in PCF (55.8 (41.5-75.9)) compared to NCF and PCR (70.6 (66.3-88.9) and 76.8 (63.6-102.2), respectively; p=0.011). A pattern of reduced forced vital capacity (FVC), but normal total lung capacity (TLC), termed complex ventilatory dysfunction defined as TLC - FVC >10% predicted was observed and occurred more frequently in PCF (88.9%) compared to NCF and PCR (29.1% and 25.0%, respectively; p<0.001).

Conclusion

Dyspnoea in PCF is characterised by reduced respiratory muscle strength and complex ventilatory dysfunction indicating neuromuscular disturbance as a distinct phenotype among patients with post-COVID-19 condition. These observations could be a starting point for developing personalised rehabilitation concepts.

Normative Values and Calculation Formulas of Respiratory Muscle Strength of Adults in Turkish Society: A Population-based Study

This study aimed to establish normative values for maximum inspiratory pressure and maximal expiratory pressure in the Turkish population while creating specific equations to calculate these values. The study involved 219 healthy adults, with a minimum of 50 individuals in specific age ranges: 20-29, 30-39, 40-49, and 50-60 years. Each age group comprised at least 25 males and 25 females. Participants were required to be free from health conditions influencing respiratory muscle strength and non-smokers. Measurements of maximum inspiratory pressure and maximal expiratory pressure were recorded for all participants. As a result of the regression analysis performed for the maximum inspiratory pressure values, the model P value was < .001, and the R2 value was found to be 0.261. The equation obtained as a result of the model was: 82.583 - 3.218 × gender - 0.093 × age+9.534 × height+0.343 × weight. As a result of the regression analysis performed for maximal expiratory pressure values, the model P value was <.001, and the R2 value was found to be 0.285. The equation obtained as a result of the model was: 157.165 - 35.522 × gender - 0.271 × age-42.036 × height+0.787 × weight. The newly developed equations offer valuable tools for evaluating respiratory muscle strength in the Turkish population. These results confirm the importance of using maximum inspiratory pressure and maximal expiratory pressure to monitor changes in each patient, while also emphasizing the necessity of reliable reference equations.

Pulmonary function trajectories in COVID-19 survivors with and without pre-existing respiratory disease

A significant proportion of COVID-19 survivors still experience a reduced diffusion capacity three and twelve months after discharge. We aimed to compare pulmonary function trajectories between hospitalized COVID-19 patients with pre-existing respiratory disease (PRD) and patients without pre-existing respiratory disease (Non-PRD) at three and twelve months after hospital discharge. This single-centre retrospective cohort study included COVID-19 patients admitted to the VieCuri Medical Centre (Venlo, the Netherlands) between February and December 2020 that were invited to the outpatient clinic at three and twelve months after discharge. During this visit, pulmonary function tests were performed and impairments were based on lower limit of normal. Data of 239 patients were analysed (65% male, 66 ± 10 years, and 26% with a history of respiratory disease). Three months after discharge, 49% and 64% of the Non-PRD patients (n = 177) and PRD patients (n = 62) had a low diffusion capacity, respectively. This improved over time in Non-PRD patients (p = 0.003), but not in PRD patients (p = 0.250). A low diffusion capacity was still observed in 34% and 57% of the Non-PRD and PRD group, respectively, twelve months after discharge. Pulmonary function impairments, mainly a reduced diffusion capacity, are observed among hospitalized COVID-19 patients with PRD and Non-PRD, at three and twelve months follow-up. Although diffusion capacity impairments restore over time in Non-PRD patients, poor recovery was observed among PRD patients.

Clinical and Physiological Variables in Patients with Post-COVID-19 Condition and Persistent Fatigue

Background/Objectives: Post-COVID-19 condition can manifest through various symptoms such as dyspnea, cognitive disturbances, and fatigue, with mechanisms related to these symptoms, particularly those related to fatigue, still requiring further clarification. Therefore, our aim was to assess the clinical and physiological variables in patients with post-COVID-19 condition and persistent fatigue. Methods: After one year post-COVID-19 infection, the patients underwent a comprehensive evaluation, including a complete blood count, a metabolic panel, complete spirometry, and assessments of dyspnea, quality of life, anxiety and depression, physical capacity, body composition, muscle strength, comorbidities, and medications. The participants were categorized into two groups: G1-fatigue and G2-non-fatigue. Results: Seventy-seven patients (53% female; 55 ± 11.8 years) were included, 37 in G1 and 40 in G2. As for clinical markers and symptoms of illness, in those with persistent fatigue symptoms, a greater sensation of dyspnea [BDI score: 7.5 (6-9) vs. 12 (9-12), p < 0.001; mMRC score: 1 (1-2) vs. 0 (0-1), p = 0.002], worse quality of life [SGRQ total score: 1404 (1007-1897) vs. 497 (274-985); p < 0.001], higher levels of anxiety [HADS-A score: 8 (5-9) vs. 3 (0.5-4); p < 0.001], and a reduction in peripheral and inspiratory muscle strength [handgrip strength: 34 (28-40) vs. 40 (30-46.5) kgf, p = 0.044; MIP: -81 ± 31 vs. -111 ± 33 mmHg, p < 0.001)] were observed. Conclusions: Those with persistent fatigue exhibited a greater sensation of dyspnea, higher levels of anxiety, reduced peripheral and inspiratory muscle strength, and a greater impairment of quality of life. The severity of fatigue was influenced by the worsening quality of life, heightened anxiety levels, and decreased peripheral muscle strength. Additionally, the worse quality of life was associated with a higher sensation of dyspnea, lower muscle strength, and reduced physical capacity.

Effectiveness of pulmonary rehabilitation programmes and/or respiratory muscle training in patients with post-COVID conditions: a systematic review

BACKGROUND

The term "post-COVID-19 condition" refers to the symptomatology that appears between four to twelve weeks after Covid-19 infection. These symptoms can persist for weeks or even months, significantly diminishing the quality of life for affected individuals. The primary objective of this study was to assess the effectiveness of pulmonary rehabilitation programs and/or respiratory muscle training on respiratory sequelae in patients with post-COVID condition.

METHODS

The literature search was conducted in the following databases: PubMed, PEDro, Embase, Cochrane, Scopus, and Web of Science. Randomized clinical trials were included in which participants were aged 18 years or older. Articles were excluded if at least one of the therapies did not involve pulmonary rehabilitation or respiratory muscle training, if the participants were COVID positive, if studies lacked results, and finally, if interventions were conducted without supervision or at home. This review only encompasses supervised non-virtual interventions. This study adheres to the PRISMA statement and has been registered in the PROSPERO database (CRD42023433843).

RESULTS

The outcomes obtained in the included studies are assessed across the following variables: Exercise capacity using the 6-minute walk test, Dyspnea, fatigue, Pulmonary function, Maximum inspiratory pressure, and Quality of life.

CONCLUSION

Despite the absence of a specific treatment at present, it was evident from this review that a well-structured pulmonary rehabilitation program that incorporates both aerobic and muscular strength exercises along with techniques and inspiratory muscle exercises was the most effective form of treatment.

Diaphragmatic morphological post-mortem findings in critically ill COVID-19 patients: an observational study

Our study investigates the post-mortem findings of the diaphragm's muscular structural changes in mechanically ventilated COVID-19 patients. Diaphragm samples of the right side from 42 COVID-19 critically ill patients were analyzed and correlated with the type and length of mechanical ventilation (MV), ventilatory parameters, prone positioning, and use of sedative drugs. The mean number of fibers was 550±626. The cross-sectional area was 4120±3280 μm2, while the muscular fraction was 0.607±0.126. The overall population was clustered into two distinct populations (clusters 1 and 2). Cluster 1 showed a lower percentage of slow myosin fiber and higher fast fiber content than cluster 2, 68% versus 82%, p<0.00001, and 29.8% versus 18.8%, p=0.00045 respectively. The median duration of MV was 180 (41-346) hours. In cluster 1, a relationship between assisted ventilation and fast myosin fiber percentage (R2=-0.355, p=0.014) was found. In cluster 2, fast fiber content increased with increasing the length of the controlled MV (R2=0.446, p=0.006). A high grade of fibrosis was reported. Cluster 1 was characterized by fibers' atrophy and cluster 2 by hypertrophy, supposing different effects of ventilation on the diaphragm but without excluding a possible direct viral effect on diaphragmatic fibers.

Blood T cell phenotypes correlate with fatigue severity in post-acute sequelae of COVID-19

PURPOSE

Post-acute sequelae of COVID-19 (PASC) affect approximately 10% of convalescent patients. The spectrum of symptoms is broad and heterogeneous with fatigue being the most often reported sequela. Easily accessible blood biomarkers to determine PASC severity are lacking. Thus, our study aimed to correlate immune phenotypes with PASC across the severity spectrum of COVID-19.

METHODS

A total of 176 originally immunonaïve, convalescent COVID-19 patients from a prospective cohort during the first pandemic phase were stratified by initial disease severity and underwent clinical, psychosocial, and immune phenotyping around 10 weeks after first COVID-19 symptoms. COVID-19-associated fatigue dynamics were assessed and related to clinical and immune phenotypes.

RESULTS

Fatigue and severe fatigue were commonly reported irrespective of initial COVID-19 severity or organ-specific PASC. A clinically relevant increase in fatigue severity after COVID-19 was detected in all groups. Neutralizing antibody titers were higher in patients with severe acute disease, but no association was found between antibody titers and PASC. While absolute peripheral blood immune cell counts in originally immunonaïve PASC patients did not differ from unexposed controls, peripheral CD3+CD4+ T cell counts were independently correlated with fatigue severity across all strata in multivariable analysis.

CONCLUSIONS

Patients were at similar risk of self-reported PASC irrespective of initial disease severity. The independent correlation between fatigue severity and blood T cell phenotypes indicates a possible role of CD4+ T cells in the pathogenesis of post-COVID-19 fatigue, which might serve as a blood biomarker.

Minimal Clinically Important Differences in EQ-5D-5L Index and VAS after a Respiratory Muscle Training Program in Individuals Experiencing Long-Term Post-COVID-19 Symptoms

The primary aim of this study was to determine the minimal clinically important difference (MCID) for the EuroQol-5D questionnaire (EQ-5D-5L) index and visual analogic scale (VAS) in individuals experiencing long-term post-COVID-19 symptoms. In addition, it was pretended to determine which variable discriminates better and to compare changes between individuals classified by the MCID.

DESIGN

Secondary analysis of a randomized controlled trial involving 42 individuals who underwent an 8-week intervention in a respiratory muscle training program.

RESULTS

A change of at least 0.262 and 7.5 for the EQ-5D-5L index and VAS represented the MCID, respectively. Only the EQ-5D-5L VAS showed acceptable discrimination between individuals who were classified as "improved" and those classified as "stable/not improved" (area under the curve = 0.78), although with a low Youden index (Youden index, 0.39; sensitivity, 46.2%; specificity, 93.1%). Those individuals who exceeded the established MCID for EQ-5D-5L VAS had significantly greater improvements in inspiratory muscle function, exercise tolerance, and peripheral muscle strength compared to participants classified as "stable/not improved".

CONCLUSIONS

Only the EQ-5D-5L VAS, especially when MCID was exceeded, showed an acceptable discriminative ability to evaluate the efficacy of an intervention in individuals with long-term post-COVID-19 symptoms.

Dyspnea in Post-Acute COVID-19: A Multi-Parametric Cardiopulmonary Evaluation

Post-acute COVID-19 is characterized by the persistence of dyspnea, but the pathophysiology is unclear. We evaluated the prevalence of dyspnea during follow-up and factors at admission and follow-up associated with dyspnea persistence. After five months from discharge, 225 consecutive patients hospitalized for moderate to severe COVID-19 pneumonia were assessed clinically and by laboratory tests, echocardiography, six-minute walking test (6MWT), and pulmonary function tests. Fifty-one patients reported persistent dyspnea. C-reactive protein (p = 0.025, OR 1.01 (95% CI 1.00-1.02)) at admission, longer duration of hospitalization (p = 0.005, OR 1.05 (95% CI 1.01-1.10)) and higher body mass index (p = 0.001, OR 1.15 (95% CI 1.06-1.28)) were independent predictors of dyspnea. Absolute drop in SpO₂ at 6MWT (p = 0.001, OR 1.37 (95% CI 1.13-1.69)), right ventricular (RV) global longitudinal strain (p = 0.016, OR 1.12 (95% CI 1.02-1.25)) and RV global longitudinal strain/systolic pulmonary artery pressure ratio (p = 0.034, OR 0.14 (95% CI 0.02-0.86)) were independently associated with post-acute COVID-19 dyspnea. In conclusion, dyspnea is present in many patients during follow-up after hospitalization for COVID-19 pneumonia. While higher body mass index, C-reactive protein at admission, and duration of hospitalization are predictors of persistent dyspnea, desaturation at 6MWT, and echocardiographic RV dysfunction are associated with this symptom during the follow-up period.

Minimal Clinically Important Differences in Inspiratory Muscle Function Variables after a Respiratory Muscle Training Programme in Individuals with Long-Term Post-COVID-19 Symptoms

OBJECTIVE

To establish the minimal clinically important difference (MCID) for inspiratory muscle strength (MIP) and endurance (IME) in individuals with long-term post-COVID-19 symptoms, as well as to ascertain which of the variables has a greater discriminatory capacity and to compare changes between individuals classified by the MCID.

DESIGN

Secondary analysis of randomised controlled trial of data from 42 individuals who performed an 8-week intervention of respiratory muscle training programme.

RESULTS

A change of at least 18 cmH₂O and 22.1% of that predicted for MIP and 328.5s for IME represented the MCID. All variables showed acceptable discrimination between individuals who classified as "improved" and those classified as "stable/not improved" (area under the curve ≥0.73). MIP was the variable with the best discriminative ability when expressed as a percentage of prediction (Youden index, 0.67; sensitivity, 76.9%; specificity, 89.7%). Participants classified as "improved" had significantly greater improvements in quality of life and lung function compared with the participants classified as "stable/not improved".

CONCLUSION

In individuals with long-term post-COVID-19 symptoms, the inspiratory muscle function variables had an acceptable discriminative ability to assess the efficacy of a respiratory muscle training programme. MIP was the variable with the best discriminative ability, showing better overall performance when expressed as a percentage of prediction.

Post-intensive Care Unit COVID-19 Survivors: Functional Status and Respiratory Function Three Months After an Inpatient Rehabilitation Program

Introduction and objectives Long-term coronavirus disease 2019 (COVID-19) sequelae have become an increasing concern, with persistent dyspnoea and fatigue being the most common and long-lasting symptoms reported. The aim of this study was to evaluate the functional status and respiratory function three months after discharge from an inpatient rehabilitation program. Materials and methods This was a prospective study including post-ICU COVID-19 survivors consecutively admitted to an inpatient and multimodal rehabilitation program in a rehabilitation center. Evaluation of functional status (brief balance evaluation systems test (brief-BESTEST), timed up and go (TUG) test, 1 min sit to stand test (1STST), 6 min walking test (6MWT)); respiratory muscle strength (maximum expiratory pressure (MEP), maximum inspiratory pressure (MIP)); cough effectiveness (peak cough flow (PCF)); and fatigue (fatigue assessment scale (FAS)) were assessed at admission (T0), discharge (T1), and three months after discharge (T2). Results A total of 36 patients were included. Between T1 and T2, there was a significant improvement in MEP (84.47±20.89 vs 97.23±24.63 cmH₂O, p<0.001), PCF (367.83±117.24 vs 441.33±132.90 L/min, p=0.003), functional capacity (1STST (19.90±6.37 vs 23.13±6.07, p=0.004), and 6MWT (459.25±153.70 vs 500.00±163.74 meters, p=0.003)). No differences were seen in MIP, brief-BESTEST, or TUG. Patients presented a higher median final FAS score at T2 compared to T1: 21.50±5 vs 18.60±2.65, p=0.002. Conclusions Post-ICU COVID-19 survivors admitted to an inpatient rehabilitation program maintained a good functional recovery at the three-month follow-up. Despite overall improvement, we found higher scores of FAS, suggesting worse fatigue levels.

The Challenge of Long COVID-19 Management: From Disease Molecular Hallmarks to the Proposal of Exercise as Therapy

Long coronavirus disease 19 (COVID-19) is the designation given to a novel syndrome that develops within a few months after infection by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) and that is presenting with increasing incidence because of the numerous cases of infection. Long COVID-19 is characterized by a sequela of clinical symptoms that concern different organs and tissues, from nervous, respiratory, gastrointestinal, and renal systems to skeletal muscle and cardiovascular apparatus. The main common molecular cause for all long COVID-19 facets appears to be related to immune dysregulations, the persistence of inflammatory status, epigenetic modifications, and alterations of neurotrophin release. The prevention and management of long COVID-19 are still inappropriate because many aspects need further clarification. Exercise is known to exert a deep action on molecular dysfunctions elicited by long COVID-19 depending on training intensity, duration, and continuity. Evidence suggests that it could improve the quality of life of long COVID-19 patients. This review explores the main clinical features and the known molecular mechanisms underlying long COVID-19 in the perspective of considering exercise as a co-medication in long COVID-19 management.