The Influence of Lung Function and Respiratory Muscle Strength on Quadriceps Muscle Fatigability in COPD Patients Under Long-term Oxygen Therapy.

BACKGROUND: This research investigates quadriceps muscle fatigability (MF) in chronic obstructive pulmonary disease (COPD) patients with chronic respiratory failure (CRF) at different levels of lung obstruction [severe obstruction (SO)=FEV1 <50% and >30% versus very severe obstruction (VSO)=FEV1 ≤30%]. It explores the relationships between quadriceps MF and lung function, respiratory muscles, and oxygenation status. METHODS: A post hoc cross-over analysis in 45 COPD patients (20 SO and 25 VSO) undergoing long-term oxygen therapy was performed. Delta change in quadriceps maximum voluntary contraction (MVC) (absolute value and percentage) before and after a constant workload was calculated. Associations between quadriceps MF and lung function, respiratory muscles, and gas exchange were examined using Pearson's correlation and multivariate linear regression analysis. RESULTS: SO patients experience a more substantial reduction in MVC compared to VSO (-15.15±9.13% vs -9.29±8.90%, p=0.0357), despite comparable resting MVC. Dyspnea is more pronounced in VSO at the beginning and end of the exercise. Correlations were found between MF and maximal inspiratory pressure (MIP) (r=-0.4412, p=0.0056), maximal expiratory pressure (MEP) (r=-0.3561, p=0.0282), and a tendency for FEV1% (r=-0.2931, p=0.0507). The regression model (R2=0.4719) indicates that lower MIP and FEV1 and high total lung capacity are significant factors in reducing quadriceps muscle fatigability after a fatiguing task. CONCLUSION: COPD patients with more severe pulmonary obstruction and hyperinflation and lower respiratory muscle strength have lower quadriceps MF but higher dyspnea both at rest and during exercise.

Upper-limb interval versus constant-load exercise in patients with COPD: a physiological crossover study.

Objective: Upper-limb exercise is recommended for patients with COPD, albeit there are limited data concerning the optimal modality to implement. We compared interval (INT-EX) to continuous (CONT-EX) upper-limb exercise in terms of exercise tolerance, ventilatory and metabolic responses when both conditions were sustained at an equivalent work rate. Methods: 26 stable COPD patients undertook three upper-limb exercise sessions to initially establish peak work rate (PWR) via an incremental exercise test and subsequently two equivalent work rate tests to the limit tolerance in balanced order: 1) INT-EX consisting of 30-s work at 100% PWR interspersed with 30-s work at 40% of PWR; and 2) CONT-EX at 70% PWR. Results: 20 patients (76.9%) had longer tolerance during INT-EX, while six out of 26 (23.1%) exhibited longer tolerance during CONT-EX. The average endurance time was 434.1±184.7 and 315.7±128.7 s for INT-EX and CONT-EX, respectively. During INT-EX at isotime (i.e. when work completed was the same between INT-EX and CONT-EX), the majority of patients manifested lower oxygen uptake, minute ventilation, pulmonary hyperinflation, heart rate, symptoms and higher CO2 blood concentration. Patients with longer INT-EX had a lower comorbidity score (Cumulative Illness Rating Scale: 1.58±0.30 versus 1.88±0.29, p=0.0395) and better-preserved lung function (forced vital capacity 84.7±15.31% versus 67.67±20.56%, p=0.0367; forced expiratory volume in 1 s 57.15±14.59 versus 44.67±12.99% predicted, p=0.0725) compared to patients with longer CONT-EX. Conclusion: INT-EX is more sustainable than CONT-EX for the majority of COPD patients with moderate obstruction, leading to lower dynamic hyperinflation and symptoms at isotime. Further studies need to define the benefits of its application during pulmonary rehabilitation.

Recovering of oxygenation, physical function and disability in patients with Covid-19.

The present case report describes middle-time course of respiratory and physical variables in eight Covid-19 patients who were transferred from ICU of Covid Hub in our subacute Covid-19 unit. Secondly they were admitted in a pulmonary rehabilitation unit and, at discharge, a tele-rehabilitation program was provided as a continuum of care at home. Time course of oxygenation, physical function and disability were recorded. As expected, the acute event produced in these patients a dramatic worsening in oxygenation and physical activities, with a substantial improvement in oxygenation and mild disability after the sub-acute stay. After rehabilitation program, the patients showed additional improvement in particular in physical function. Anyway, this recover was not complete for all patients. The majority of Covid-19 survivors experienced ARF recovered oxygenation, physical function and disability within a median time of 137 days. A minority needs further follow up and rehabilitation maintenance due to incomplete recovery.

Predictors of Low Physical Function in Patients With COVID-19 With Acute Respiratory Failure Admitted to a Subacute Unit.

OBJECTIVE: To document the level of physical function in patients with coronavirus disease 2019 (COVID-19) recovering from acute respiratory failure and investigate which patient clinical characteristics could predict physical function assessed by the Short Physical Performance Battery (SPPB) test. DESIGN: Cross-sectional study. SETTING: Subacute unit of a Rehabilitation Institute. PARTICIPANTS: Patients with COVID-19 (N=184; aged 18 years or older) who were admitted to a subacute unit to stabilize their condition and recover from acute respiratory failure due to COVID-19. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: At admission patients underwent the SPPB test, represented by the sum of 3 functional tests, standing balance, 4-meter gait speed, and 5-repetition sit-to-stand motion. Comparisons between 2 SPPB score groups were performed by an unpaired t test; multivariate stepwise linear regression analysis was employed to detect predictors of the SPPB score considering several clinical parameters. RESULTS: Participants were 74±12 years old, 52% were men and with more than 2 comorbidities in 43% of cases. SPPB score was 3.02±3.87 denoting patients' profound physical dysfunction. Normal physical function was detected in only 12% of patients, whereas low, intermediate, and severe impairment was found in 65%, 13%, and 10%, respectively. Age, both invasive and noninvasive ventilation use, and the presence of previous disability were significant predictors of SPPB. Patients without any comorbidities (8%) also exhibited low function (SPPB: 5.67±1.12). CONCLUSIONS: The majority of survivors after COVID-19 experienced acute respiratory failure due to pneumonia and exhibited substantial physical dysfunction influenced by age, mechanical ventilation need, and previous disability. Further studies are needed to evaluate the role of rehabilitation to promote recovery and community reintegration in this population.

Muscle Strength and Physical Performance in Patients Without Previous Disabilities Recovering From COVID-19 Pneumonia.

ABSTRACT: In this cross-sectional study, we evaluated skeletal muscle strength and physical performance (1-min sit-to-stand and short physical performance battery tests), dyspnea, fatigue, and single-breath counting at discharge from a postacute COVID department, in patients recovering from COVID-19 pneumonia who had no locomotor disability before the infection.Quadriceps and biceps were weak in 86% and 73% of the patients, respectively. Maximal voluntary contraction for quadriceps was 18.9 (6.8) kg and for biceps 15.0 (5.5) kg (i.e., 54% and 69% of the predicted normal value, respectively). The number of chair rises in the 1-min sit-to-stand test was 22.1 (7.3 corresponding to 63% of the predicted normal value), whereas the short physical performance battery score was 7.9 (3.3 corresponding to 74% of the predicted normal value). At the end of the 1-min sit-to-stand test, 24% of the patients showed exercise-induced desaturation. The single-breath counting count was 35.4 (12.3) corresponding to 72% that of healthy controls. Mild-to-moderate dyspnea and fatigue were found during activities of daily living (Borg scale score, median value = 0.5 [0-2] and 1 [0-2]) and after the 1-min sit-to-stand (Borg scale score, median value = 3 [2-5] and 1 [0-3]). Significant correlations were observed between muscle strength and physical performance indices (R = 0.31-0.69).The high prevalence of impairment in skeletal muscle strength and physical performance in hospitalized patients recovering from COVID-19 pneumonia without previous locomotor disabilities suggests the need for rehabilitation programs after discharge.

The impact of exercise training on fatigue in patients with chronic obstructive pulmonary disease: a systematic review and meta-analysis.

INTRODUCTION AND OBJECTIVE: Fatigue can be divided in perceived fatigue, the feeling of exhaustion or lack of energy, and performance fatigue, the reduction in muscle force/activation during a given task. This meta-analysis evaluates the impact of exercise training on fatigue, compared with normal care in patients with COPD. MATERIAL AND METHODS: We searched randomised controlled trials on MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials and CINAHL databases from their inception to December, 31st 2019 using the terms COPD, Fatigue, Fatigability, Muscle activation, Muscle endurance, Muscle Performance, Voluntary Activation, Motoneuron excitability, Force Development, Exercise, AND Rehabilitation. RESULTS: We evaluated 494 potential articles. Sixteen, all evaluating perceived fatigability, satisfied the inclusion criteria and were included. Twelve studies (463 patients) assessed fatigue by the Chronic Respiratory Questionnaire showing that intervention improved significantly more than the control group [SMD 0.708; 95% CI 0.510, 0.907; p < 0.001; I²â€¯= 34.3%; p = 0.116]. Two studies (68 patients) using the Fatigue Impact Scale, did not find any significant differences between groups [SMD -0.922; 95%CI -2.258, 0.413; p = 0.176; I²â€¯= 83.9%; p = 0.013]. Two studies (82 patients) assessed perceived fatigue by the Fatigue Severity Scale: the intervention improved significantly more than the control group [SMD -2.282; 95%CI -2.870, -1.699; p < 0.001; I²â€¯= 64.6%, p = 0.093]. No study evaluating performance fatigue was found. CONCLUSIONS: This study provided low-quality evidence of a positive impact of different exercise training programs on perceived fatigue in patients with COPD. Further studies are needed to assess the effects of exercise training on fatigue and to test tailored programs.

Physical Activity in Patients with Chronic Obstructive Pulmonary Disease on Long-Term Oxygen Therapy: A Cross-Sectional Study.

Background and aim: There are few studies evaluating physical activity (PA) in patients with chronic obstructive pulmonary disease (COPD) on long-term oxygen therapy (LTOT). Aim: To assess PA in hypoxemic COPD patients on LTOT. Methods: In this cross-sectional study, we compared lung function, arterial blood gases, respiratory and peripheral muscle strength, 6-min walking distance (6MWD), daily energy expenditure and steps, and health-related quality of life (HRQL) in COPD patients on LTOT (LTOT group) versus two groups of control patients not needing LTOT: with (HYPOX) and without (COPD) exercise-induced desaturations. Results: Groups did not differ as regards demographics, anthropometrics, peripheral or respiratory muscle strength. Compared to the other groups, LTOT patients had more severe airway obstruction and lung hyperinflation, greater number and severity of comorbidities, shorter 6MWD, as well as lower mean SpO2 during 6MWD and worse quality of life. LTOT patients had a lower daily energy expenditure, shorter time spent > 3.0 METs and longer sedentary time compared to the COPD group, and less daily steps compared to the other groups. No significant difference in any parameter of PA was found between COPD and HYPOX. In LTOT patients, daily steps showed a strong correlation with 6MWD, and a moderate correlation with airway obstruction, level of oxygenation, comorbidities and quality of life but not with peripheral and respiratory muscle strength. In COPD and HYPOX patients, daily steps were strongly correlated with 6MWD and level of oxygenation as assessed by PaO2/FiO2. There was no significant correlation between mean SpO2 and 6MWD in any group. Conclusion: COPD patients on LTOT perform less physical activity than patients not needing LTOT, both with and without exercise-induced desaturations. Patients with exercise-induced desaturations do not perform less physical activity than those without.