Dyspnea is the most common symptom experienced by patients with chronic obstructive pulmonary disease (COPD). To avoid exertional dyspnea, many patients adopt a sedentary lifestyle which predictably ...leads to extensive skeletal muscle deconditioning, social isolation, and its negative psychological sequalae. This “dyspnea spiral” is well documented and it is no surprise that alleviation of this distressing symptom has become a key objective highlighted across COPD guidelines. In reality, this important goal is often difficult to achieve, and successful symptom management awaits a clearer understanding of the underlying mechanisms of dyspnea and how these can be therapeutically manipulated for the patients’ benefit. Current theoretical constructs of the origins of activity-related dyspnea generally endorse the classical demand–capacity imbalance theory. Thus, it is believed that disruption of the normally harmonious relationship between inspiratory neural drive (IND) to breathe and the simultaneous dynamic response of the respiratory system fundamentally shapes the expression of respiratory discomfort in COPD. Sadly, the symptom of dyspnea cannot be eliminated in patients with advanced COPD with relatively fixed pathophysiological impairment. However, there is evidence that effective symptom palliation is possible for many. Interventions that reduce IND, without compromising alveolar ventilation (
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), or that improve respiratory mechanics and muscle function, or that address the affective dimension, achieve measurable benefits. A common final pathway of dyspnea relief and improved exercise tolerance across the range of therapeutic interventions (bronchodilators, exercise training, ambulatory oxygen, inspiratory muscle training, and opiate medications) is reduced neuromechanical dissociation of the respiratory system. These interventions, singly and in combination, partially restore more harmonious matching of excessive IND to ventilatory output achieved. In this review we propose, on the basis of a thorough review of the recent literature, that effective dyspnea amelioration requires combined interventions and a structured multidisciplinary approach, carefully tailored to meet the specific needs of the individual.
Dyspnea, the most common symptom in chronic obstructive pulmonary disease (COPD), often becomes disabling in advanced stages of the disease. Chronic dyspnea erodes perceived health status and ...diminishes engagement in physical activity, often leading to skeletal muscle deconditioning, anxiety, depression, and social isolation. Broader understanding of the pathophysiologic underpinnings of dyspnea has allowed us to formulate a sound rationale for individualized management. This review examines recent research and provides historical context. The overarching objectives are to consider current constructs of the physiologic mechanisms of activity-related dyspnea and identify specific targets amenable to therapeutic manipulation in patients with COPD.
•Dyspnoea persists in many patients following COVID-19 infection.•COVID-19 patients with persistent dyspnoea have impaired spirometry and gas exchange.•COVID-19 patients with persistent dyspnoea have ...reduced exercise performance.
The purpose of this study was to examine the physiological mechanisms of persistent dyspnoea in COVID-19 survivors. Non-critical patients (n = 186) with varying degrees of COVID-19 severity reported persistent symptoms using a standardized questionnaire and underwent pulmonary function and 6-minute walk testing between 30 and 90 days following the onset of acute COVID-19 symptoms. Patients were divided into those with (n = 70) and without (n = 116) persistent dyspnoea. Patients with persistent dyspnoea had significantly lower FVC (p = 0.03), FEV1 (p = 0.04), DLCO (p = 0.01), 6-minute walk distance (% predicted, p = 0.03), and end-exercise oxygen saturation (p < 0.001), and higher Borg 0-10 ratings of dyspnoea and fatigue (both p < 0.001) compared to patients without persistent dyspnoea. We have shown that dyspnoea is a common persistent symptom across varying degrees of initial COVID-19 severity. Patients with persistent dyspnoea had greater restriction on spirometry, lower DLCO, reduced functional capacity, and increased exertional desaturation and symptoms. This suggests that there is a true physiological mechanism that may explain persistent dyspnoea after COVID-19.
Activation of inflammatory pathways promotes organ dysfunction in COVID-19. Currently, there are reports describing lung function abnormalities in COVID-19 survivors; however, the biological ...mechanisms remain unknown. The aim of this study was to analyze the association between serum biomarkers collected during and following hospitalization and pulmonary function in COVID-19 survivors.
Patients recovering from severe COVID-19 were prospectively evaluated. Serum biomarkers were analyzed from admission to hospital, peak during hospitalization, and at the time of discharge. Pulmonary function was measured approximately 6 weeks after discharge.
100 patients (63% male) were included (age 48 years, SD ± 14) with 85% having at least one comorbidity. Patients with a restrictive spirometry pattern (n = 46) had greater inflammatory biomarkers compared to those with normal spirometry (n = 54) including peak Neutrophil-to-Lymphocyte ratio (NLR) value 9.3 (10.1) vs. 6.5 (6.6), median (IQR), p = 0.027 and NLR at hospital discharge 4.6 (2.9) vs. 3.2 (2.9) p = 0.005 and baseline C-reactive protein value 164.0 (147.0) vs. 106.5 (139.0) mg/dL, p = 0.083). Patients with an abnormal diffusing capacity (n = 35) had increased peak NLR 8.9 (5.9) vs. 5.6 (5.7) mg/L, p = 0.029; baseline NLR 10.0 (19.0) vs. 4.0 (3.0) pg/ml, p = 0.002 and peak Troponin-T 10.0 (20.0) vs. 5.0 (5.0) pg/ml, p = 0.011 compared to patients with normal diffusing capacity (n = 42). Multivariable linear regression analysis identified predictors of restrictive spirometry and low diffusing capacity, but only accounted for a low degree of variance in pulmonary function outcome.
Overexpression of inflammatory biomarkers is associated with subsequent lung function abnormalities in patients recovered from severe COVID-19.
Abstract Background Systemic sclerosis-associated interstitial lung disease (SSc-ILD) is characterized by multiple symptoms and comorbidities. The cumulative impact of these deficits can be ...summarized using the concept of frailty; however, frailty has not been characterized in patients with SSc-ILD. Methods Patients with SSc-ILD and non-CTD fibrotic ILD were recruited from specialized clinics. Frailty was assessed using a 42-item patient-reported Frailty Index, calculated as the proportion of reported deficits divided by the total number of surveyed items. Frailty was defined as a Frailty Index >0.21. Unadjusted and multivariate analyses were used to identify correlates of frailty. Results The study cohort included 86 patients with SSc-ILD and 167 patients with non-CTD fibrotic ILD. The mean age in SSc-ILD was 60.5 years, 80% were women, and on average patients had mild to moderate restrictive lung function impairment (mean FVC 78%-predicted, DLCO 51%-predicted). The mean Frailty Index was 0.23 ± 0.15, with 55% of the SSc-ILD population meeting criteria for frailty. Dyspnea had the strongest association with the Frailty Index (r = 0.62, p < 0.001) and was the only variable independently associated with frailty on multivariate analysis. Frailty severity was similar in SSc-ILD and non-CTD fibrotic ILD, including with adjustment for differences in baseline cohort characteristics. Conclusion Frailty is highly prevalent in patients with SSc-ILD, indicating that chronological age significantly underestimates biological age in this population. Dyspnea is the variable with the strongest association with frailty in SSc-ILD; however, future studies are needed to identify additional modifiable determinants of frailty and the ability of frailty to predict outcomes in SSc-ILD.
Unexplained dyspnea presents a significant diagnostic challenge. Dyspnea arises when inspiratory neural drive (IND) to the respiratory muscles is increased and the respiratory system fails to meet ...this increased demand. Cardiopulmonary exercise testing (CPET) is a valuable tool to unravel the causes of exertional dyspnea in the individual. Moreover, analysis of breathing pattern, operating lung volumes and flow-volume loops allows characterization of abnormal dynamic mechanical response to increased IND - an important source of breathing discomfort. We illustrate the clinical utility of this approach which examines respiratory sensation, ventilatory control, respiratory mechanics and cardio-circulatory responses in cases of unexplained dyspnea.
Evaluation of the intensity and quality of activity-related dyspnea is potentially useful in people with chronic obstructive pulmonary disease (COPD). The present study sought to examine associations ...between qualitative dyspnea descriptors, dyspnea intensity ratings, dynamic respiratory mechanics, and exercise capacity during cardiopulmonary exercise testing (CPET) in COPD and healthy controls.
In this cross-sectional study, 261 patients with mild-to-very severe COPD (forced expiratory volume in 1 s, 62 ± 25%pred) and 94 age-matched controls (forced expiratory volume in 1 s, 114 ± 14%pred) completed an incremental cycle CPET to determine peak oxygen uptake (V˙O2peak). Throughout exercise, expired gases, operating lung volumes, and dyspnea intensity were assessed. At peak exercise, dyspnea quality was assessed using a modified 15-item questionnaire.
Logistic regression analysis revealed that among 15 dyspnea descriptors, only those alluding to the cluster "unsatisfied inspiration" were consistently associated with an increased likelihood for both critical inspiratory mechanical constraint (end-inspiratory lung volume/total lung capacity ratio ≥0.9) during exercise and reduced exercise capacity (V˙O2peak < lower limit of normal) in COPD (odds ratio (95% confidence interval), 3.26 (1.40-7.60) and 3.04 (1.24-7.45), respectively; both, P < 0.05). Thus, patients reporting "unsatisfied inspiration" (n = 177 (68%)) had an increased relative frequency of critical inspiratory mechanical constraint and low exercise capacity compared with those who did not select this descriptor, regardless of COPD severity or peak dyspnea intensity scores.
In patients with COPD, regardless of disease severity, reporting descriptors in the unsatisfied inspiration cluster complemented traditional assessments of dyspnea during CPET and helped identify patients with critical mechanical abnormalities germane to exercise intolerance.
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