Subjective Dyspnea Research Articles

FFP2 induced breathing resistance does not affect metabolism and well-being during brisk walking and stair climbing - a randomized controlled trial

ObjectivesN95 or Type II filtering face pieces (FFP2) are often worn during work hours or on public transportation to prevent airborne infection. The aim of this randomized controlled crossover study is to assess the impact of FFP2 induced breathing resistance on pulmonary function, blood gas values and discomfort during walking and stair climbing.MethodsN = 16 healthy adults (24.8 ± 2.2 years; 10 females, ) participated. Interventions included (1) six minutes of walking in a 16-meter-long hallway (612 m) and (2) eight minutes of stair climbing in a two-story staircase (420 stairs), both with and without a FFP2 (> 48 h wash-out). Spiroergometric data (Ventilation, breathing frequency, tidal volume, oxygen uptake and carbon dioxide exhalation (primary outcome), end tidal carbon dioxide- and oxygen pressure) and self-reported response (Perceived exertion, dyspnoea and pain) were assessed during activities. Blood gas analysis (capillary carbon dioxide- (pCO2) (primary outcome) and oxygen partial pressure (pO2), pH, lactate and base excess) was measured immediately after cessation of activities. Manipulation effects (FFP2 versus no mask) were tested using repeated measures analyses of variance.ResultsAnalysis showed no effect of FFP2 on pCO2 or other blood-gas parameters but on carbon dioxide exhalation during walking: (mean 1067, SD 209 ml/min) (mean 1908, SD 426 ml/min) (F(15) = 19.5; p < 0.001; ηp2 = 0.566) compared to no mask wearing (mean 1237, SD 173 ml/min; mean 1908, SD 426 ml/min). Ventilation was decreased and dyspnoea was increased by FFP2 during activities. FFP2 led to lower oxygen uptake and lower end tidal oxygen but higher end tidal carbon dioxide during stair climbing.ConclusionsFFP2 decreased ventilation based on slower breathing patterns and led to limitations in pulmonary gas exchange and increased subjective dyspnoea. However, invasive diagnostics revealed no signs of clinically relevant metabolic effects immediately after everyday physical activities.

Dyspnea in young subjects with congenital central hypoventilation syndrome

Dyspnea in young subjects with congenital central hypoventilation syndrome

The role and limitations of electronic medical records versus patient interviews for determining symptoms of, underlying comorbidities of, and medication use by patients with COVID-19.

Electronic medical records (EMRs) are important for rapidly compiling information to determine disease characteristics (eg, symptoms) and risk factors (eg, underlying comorbidities, medications) for disease-related outcomes. To assess EMR data accuracy, agreement between EMR abstractions and patient interviews was evaluated. Symptoms, medical history, and medication use among patients with COVID-19 collected from EMRs and patient interviews were compared using overall agreement (ie, same answer in EMR and interview), reported agreement (yes answer in both EMR and interview among those who reported yes in either), and κ statistics. Overall, patients reported more symptoms in interviews than in EMR abstractions. Overall agreement was high (≥50% for 20 of 23 symptoms), but only subjective fever and dyspnea had reported agreement of ≥50%. The κ statistics for symptoms were generally low. Reported medical conditions had greater agreement with all condition categories (n = 10 of 10) having ≥50% overall agreement and half (n = 5 of 10) having ≥50% reported agreement. More nonprescription medications were reported in interviews than in EMR abstractions, leading to low reported agreement (28%). Discordance was observed for symptoms, medical history, and medication use between EMR abstractions and patient interviews. Investigations using EMRs to describe clinical characteristics and identify risk factors should consider the potential for incomplete data, particularly for symptoms and medications.

Feasibility of Home-Based Pulmonary Rehabilitation of Pediatric Patients with Chronic Respiratory Diseases.

Chronic respiratory diseases in children deteriorate their daily life due to dyspnea and reduced lung function. We aimed to evaluate the feasibility of home-based pulmonary rehabilitation in pediatric chronic respiratory diseases. This prospective, single-arm, cohort study included children with chronic lung disease. They were instructed to perform home-based pulmonary rehabilitation 30 min/session, three sessions/week for three months. Pulmonary function test (PFT) using spirometry, respiratory muscle strength (RMT), cardiopulmonary exercise test (CPET), 6 min walk test (6MWT), dyspnea questionnaires, speech evaluation, and pediatric quality of life inventory (PedsQL) were assessed pre- and post-pulmonary rehabilitation. Compliance and satisfaction of the program were also evaluated. Twenty children (mean age: 11.2 ± 3.1 years) with chronic respiratory diseases without cardiopulmonary instability participated. The overall compliance was 71.1% with no related adverse events. After pulmonary rehabilitation, forced expiratory volume in one second (FEV1), peak expiratory flow (PEF), RMT, 6MWT, dyspnea questionnaire, speech rate, and PedsQL (child) significantly improved (p < 0.05), particularly better in the FEV1 < 60% group than in the FEV1 ≥ 60% group and in the high-compliance group (compliance ≥ 50%) than in the low-compliance group (compliance < 50%). Home-based pulmonary rehabilitation for children with chronic lung disease was feasible with high compliance and effective in terms of objective functions, subjective dyspnea symptom, and quality of life.

Assessment of mask use on oxygen saturation in adults and children with asthma.

Background: Mask use is recommended to reduce the transmission of severe acute respiratory syndrome coronavirus 2. The safety of mask use in adults and children with asthma is unknown. Objective: The objective of this study is to evaluate the effect of mask use on peripheral oxygen saturation (SpO₂) in those with and those without asthma. Methods: A two-stage cross-sectional study was performed. In the first stage, the SpO₂ concentration in adults and children with and without asthma was measured with the adults and children at rest during mask use. In the second stage, children years 6-17 performed a 6-minute walk test while wearing masks. The SpO₂ concentration was measured before the exercise and at 3 and 6 minutes into exercise. Subjective dyspnea was evaluated by using the Pediatric Dyspnea Scale (PDS). Results: In the first stage, SpO₂ levels in 393 subjects were analyzed. In the second stage, 50 pediatric subjects were included, 25 with and 25 without asthma. There was no difference in SpO₂ levels between those with and those without asthma in adults and children wearing masks while at rest, with median SpO₂ 98% in both groups. There was no difference in oxygen saturation or reported level of dyspnea between the children with asthma and children without asthma performing the 6-minute walk test while wearing masks. Median SpO₂ levels were at or near 99% in the asthma and non-asthma groups at all time points. Median PDS scores were similar between the asthma and non-asthma groups. Conclusion: Mask use did not affect SpO₂ in adults and children at rest or in children performing low-to-moderate intensity exercise. These findings were consistent in those with and without asthma.

Superior Trunk Block Is an Effective Phrenic-Sparing Alternative to Interscalene Block for Shoulder Arthroscopy: A Systematic Review and Meta-Analysis.

The interscalene block (ISB) is the standard regional anesthesia for shoulder arthroscopy. However, the superior trunk block (STB) is an alternative with a potentially safer profile. This meta-analysis aimed to compare the incidence and degree of hemidiaphragmatic paralysis and block efficacy of these techniques. We searched MEDLINE, EMBASE, Scopus, and Cochrane databases to identify randomized controlled trials (RCTs). The main outcome was total hemidiaphragmatic paralysis. We used the Grading of Recommendation, Assessment, Development, and Evaluation (GRADE) framework to assess the certainty of evidence. Four RCTs and 359 patients were included. The STB group showed lower total hemidiaphragmatic paralysis (RR 0.07; 95% CI 0.04 to 0.14;p<0.0001). The incidence of subjective dyspnea (p= 0.002) and Horner's syndrome (p<0.001) was significantly lower with STB relative to ISB. There was no significant difference between groups in block duration (p = 0.67). There was a high certainty of evidence in the main outcome as per the GRADE framework. Our findings suggest that STB has a better safety profile than ISB, resulting in lower rates of hemidiaphragmatic paralysis and dyspnea while providing a similar block. Therefore, STB could be preferred to ISB, especially in patients susceptible to phrenic nerve paralysis complications.

Relationship between Chronic Obstructive Pulmonary Disease Severity and Surface Electromyography Parameters during Fatigue Caused by Knee Extensor Contractions

Objective: Skeletal muscle dysfunction, which is characterized by decreased muscle strength and endurance, contributes to dyspnea during exercise in patients with chronic obstructive pulmonary disease (COPD), regardless of pulmonary function. This study analyzed skeletal muscle function in patients with COPD through surface electromyography (sEMG) evaluations and signal processing and attempted to determine whether sEMG parameters for muscle fatigue reflect the course of the disease. Methods: In 24 patients with COPD, maximal voluntary isometric contraction and ramp contraction were performed during isometric knee extension, and the sEMG activity of the rectus femoris muscle was measured. The patients were divided into three groups according to their modified Medical Research Council (mMRC) grade and Global Initiative for Chronic Obstructive Lung Disease (GOLD) stage. Patients with mMRC grades 0 and 1 were classified into group A, grade 2 into group B, and grades 3 and 4 into group C. Patients with GOLD stage 1 were classified into group I, stage 2 into group II, and stages 3 and 4 into group III. sEMG parameters were compared between groups using one-way analysis of variance. Results: There were significant differences in the minimum median frequency and fatigue index between the mMRC groups. However, the sEMG parameters did not differ significantly among the GOLD groups. Conclusion: Muscle fatigue differs according to the severity of subjective dyspnea in COPD. sEMG evaluations and signal processing can play supplementary roles in evaluating muscle endurance and predicting functional capacity in COPD.

Remdesevir Antiviral Therapy in Pregnant Women with COVID-19

Background: Coronavirus disease 2019 (COVID-19) is difficult to treat in pregnant women due to pregnancy itself and the lack of standard treatment for the disease. As of August 2021, the etiotropic drug remdesivir has been added to the prescription list for women during gestation. There are few publications in the global scientific community regarding the use of this antiviral drug in pregnant women. Moreover, there are only sporadic scientific studies in Kazakhstan, so the question remains open. Objectives: This study aimed to evaluate the efficacy of remdesivir in pregnant women with probable or confirmed COVID-19. Methods: The study comprehensively examined 120 pregnant women with severe to very severe COVID-19, who were divided into two groups of patients. The study group consisted of women who received remdesivir and standard therapy. The control group included patients who received standard therapy per the protocol. Results: Statistically significant age differences were observed between the main and control groups (P = 0.019). The differences detected were due to a higher frequency in the age group of 33 and 42 years in patients taking remdesivir than in the control group (P = 0.036). Women in the main group (Median = 9.00; Q1 - Q3 = 8.00 - 11.0) had longer hospital stays than the control group (Me = 8.00; Q1 - Q3 = 7.00 - 10.0). This was due to the more severe condition of the patients in this group. There were statistically significant differences in amniotic fluid changes according to ultrasound between the control and main groups (P = 0.013). When comparing the groups in pairs, amniotic fluid was more common in women who received remdesivir (P = 0.316) than in the control group. Our study found that a decrease in temperature to normal levels occurred earlier in the control group (68%) than in the main group. Further SpO2 increases of more than 95% were seen on days 3 - 4 in the main group (71%) and days 1 - 2 in the control group (43%). After three days, there was an improvement in respiratory rate (41.6%) and a reduction in subjective dyspnea (66.6%) in the main group. Conclusions: The study found that repeat mothers have a more severe course of COVID-19. The older age group and the third trimester of pregnancy are risk factors for progression to severe disease.

Analysing the Effects of Different Types of Exercise on Dyspnoea and Fatigue in Adults through COPD-Systematic Review and Meta-Analysis of Randomised Clinical Trials.

Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung condition, the main symptoms of which are dyspnoea and fatigue. Though exercise has been recommended for subjects with COPD, its benefits remain unclear. The aim of this study was to summarise, through a systematic review and meta-analysis, the available evidence on the effects of aerobic, resistance, stretching, and combined exercise on the main symptoms of COPD. Search was performed using the electronic databases PubMed and Web of Science. Randomised controlled trials (RCTs) with interventions based on aerobic, resistance and/or combined exercise published until July 2022 were identified. The effects were summarised based on standardised mean differences (95% confidence intervals) using random and fixed effect models. Eight studies were selected, including a total of 375 subjects. The results obtained showed that resistance exercise, aerobic exercise and combined exercise seem to improve dyspnoea and fatigue symptoms in COPD subjects. In general, we can conclude that exercise-based interventions appear to improve the main COPD symptoms and may benefit quality of life in this population.

Deduced Respiratory Scores on COVID-19 Patients Learning from Exertion-Induced Dyspnea.

Dyspnea is one of the most common symptoms of many respiratory diseases, including COVID-19. Clinical assessment of dyspnea relies mainly on self-reporting, which contains subjective biases and is problematic for frequent inquiries. This study aims to determine if a respiratory score in COVID-19 patients can be assessed using a wearable sensor and if this score can be deduced from a learning model based on physiologically induced dyspnea in healthy subjects. Noninvasive wearable respiratory sensors were employed to retrieve continuous respiratory characteristics with user comfort and convenience. Overnight respiratory waveforms were collected on 12 COVID-19 patients, and a benchmark on 13 healthy subjects with exertion-induced dyspnea was also performed for blind comparison. The learning model was built from the self-reported respiratory features of 32 healthy subjects under exertion and airway blockage. A high similarity between respiratory features in COVID-19 patients and physiologically induced dyspnea in healthy subjects was observed. Learning from our previous dyspnea model of healthy subjects, we deduced that COVID-19 patients have consistently highly correlated respiratory scores in comparison with normal breathing of healthy subjects. We also performed a continuous assessment of the patient's respiratory scores for 12-16 h. This study offers a useful system for the symptomatic evaluation of patients with active or chronic respiratory disorders, especially the patient population that refuses to cooperate or cannot communicate due to deterioration or loss of cognitive functions. The proposed system can help identify dyspneic exacerbation, leading to early intervention and possible outcome improvement. Our approach can be potentially applied to other pulmonary disorders, such as asthma, emphysema, and other types of pneumonia.

Direct Extubation to High-Flow Nasal Cannula versus Noninvasive Ventilation in Obese Subjects.

Patients who are obese have a higher risk of acute respiratory failure after extubation in the ICU. This study aimed to compare the extubation of subjects who were critically ill and obese to high-flow nasal cannula (HFNC) versus noninvasive ventilation (NIV) to determine whether HFNC can aid in reducing postextubation respiratory failure and the re-intubation rate. In this randomized controlled trial, subjects who were obese, defined as individuals with a body mass index ≥ 30 kg/m2, were randomly assigned to receive HFNC (n = 60) versus 60 subjects treated with NIV applied immediately after extubation. The primary outcome was the incidence of postextubation respiratory failure and re-intubation rate within 72 h. Secondary outcomes included oxygenation, breathing frequency, subjective dyspnea, ICU and hospital length of stay, and ICU mortality at day 28. Compared with NIV, HFNC reduced the risk of respiratory failure by 8.4%, 95% CI 6.2-12.8%. Even though the rate of re-intubation was lower in the HFNC group versus in the NIV group, no statistical significance was observed (11.6% vs 16.6%; difference 5%, 95% CI 2.5%-8.2%). In 48-h periods and 72 h after extubation, the mean PaO2 /FIO2 significantly increased in the HFNC group compared with the NIV group. Both groups had low dyspnea levels 72 h after extubation. No difference was detected between the groups in breathing frequency. In addition, the 2 groups had no significant difference in ICU and hospital length of stay. The HFNC and NIV groups had comparable hospital mortality rates. The multivariable logistic regression analysis revealed the presence of severe obesity, comorbidities, a higher severity score, and hypercapnia remained as factors associated with an increased risk of re-intubation. Postextubation application of HFNC may prevent respiratory failure in patients who are obese. (ClinicalTrials.gov registration NCT04035351.).

Use of inhaled ipratropium bromide to improve exercise-induced laryngeal obstruction cannot be recommended.

Exercise-induced laryngeal obstruction (EILO) is a common cause of exertional breathing problems in young adults. Current management generally consists of breathing advice, speech therapy, inspiratory muscle training or supraglottoplasty in highly motivated subjects with supraglottic collapse. Inhaled ipratropium bromide (IB) is a muscarinic receptor antagonist used to treat asthma that is suggested in a few reports to improve EILO symptoms. The aim of the present study was to investigate effects of inhaled IB in EILO diagnosed by continuous laryngoscopy exercise (CLE) test and classified by CLE scores. A randomised crossover trial was conducted at Haukeland University Hospital, Bergen, Norway, enrolling participants diagnosed with EILO defined by characteristic symptoms and CLE score ≥3 (range 0-12). Two consecutive CLE tests were performed within 2 weeks, one test with and one test without prior administration of inhaled IB in a randomised order. Main outcomes were the CLE score, dyspnoea measured using a modified BORG scale (range 0-10) and cardiopulmonary exercise data provided by the CLE test. 20 participants (14 females) aged 12-25 years participated, and all ran to exhaustion on both tests. Mean CLE score, BORG score and peak oxygen consumption were similar in tests performed with and without IB; mean differences (95% confidence interval) were 0.08 (-0.28-0.43), 0.35 (-0.29-0.99) and -0.4 (-1.9-1.1) mL·kg-1·min-1, respectively. Inhaled IB did not improve CLE score, dyspnoea or exercise capacity in subjects with EILO. The study does not support the use of inhaled IB to treat EILO.

Remdesivir Effects on COVID-19 Infection in Adult Patients

Introduction: Coronavirus disease 2019 (COVID-19) is a serious pandemic affecting the global world since 2019 with heavy impacts on the social, economy, and normal daily life; one of the promising antiviral treatment used frequently all over the world is the remdesivir. Aim: The aim was to study the effect of 3–5 days remdesivir treatment course, regarding its starting time on clinical status and the fate of patients with COVID-19, with monitoring of the side effects. Materials and Methods: A prospective observational study involved 90 patients with COVID-19 who received remdesivir 5 days course; all were hospitalized, diagnosed by computerised tomography (CT) chest and polymerase chain reaction (PCR) at Merjan Teaching Hospital from August 2020 to October 2020. Those 90 patients’ age ranged from 25 to 88 years. Sixty-two patients received convalescent plasma with remdesivir against 13 patients who not received it. Tocilizumab was added for 18 patients, whereas 57 were not treated with it. Clinical state (SpO2, subjective dyspnea, respiratory rate (RR), fever, and the type of O2 supplements) of the patients was assessed three times. Regarding the time of starting remdesivir treatment during the course of disease, patients were assessed in three groups: patients received remdesivir within &lt;10 days, patients received it between 10 and 15 days, and patients received it &gt;15 days. Mean of the duration of patients discharge was recorded. Results: It showed an extremely significant difference (P &lt; 0.001) between the discharged and both referred to respiratory care unit (RCU) and death patients. There were significant differences (P &lt; 0.05) in the clinical state (SpO2, subjective dyspnea, RR, fever, and the type of O2 supplements) of the patients in all three times of assessments with significant correlation (P &lt; 0.01) between means of the clinical state (SpO2 and subjective dyspnea score) and the fate (discharge, admission to RCU, and death) of patient who received it. There were no significant differences (P &gt; 0.05) between means of time of starting therapy and the fate of patients. At the same time, no significant differences (P &gt; 0.05) were seen in the mean of liver function test. There were no significant differences (P &gt; 0.05) between the fate of patients who received convalescent plasma with remdesivir, but a significant disadvantage (P &lt; 0.001) was seen in the fate of patient who received tocilizumab. Conclusion: We can conclude that remdesivir improves the clinical state of patients with COVID-19 regardless of the time of its starting during the course of disease.

ANTISYNTHETASE SYNDROME PRESENTING AS INTERSTITIAL LUNG DISEASE: A CASE OF ANCHORING BIAS DURING THE COVID-19 PANDEMIC

ANTISYNTHETASE SYNDROME PRESENTING AS INTERSTITIAL LUNG DISEASE: A CASE OF ANCHORING BIAS DURING THE COVID-19 PANDEMIC

Respiratory function and CT abnormalities among survivors of COVID-19 pneumonia: a nationwide follow-up study

IntroductionConsidering the pulmonary burden caused by acute COVID-19, questions remain of respiratory consequences after recovery. The aim of the study was to describe respiratory function of COVID-19 pneumonia survivors at...

Long-term follow-up of tuberculosis-destroyed lung patients after surgical treatment

BackgroundTo monitor dypsnea and mortality at 5 and 10 years, respectively, after surgical treatment of tuberculosis-destroyed lung (TDL) patients.MethodsTDL patients treated surgically at Beijing Chest Hospital from November 2007 to June 2019 were monitored in this observational study. Follow-up assessments of respiratory function indicators and survival conducted 5 and 10 years post-surgery led to patient grouping based on mMRC score into a dyspnea group (mMRC ≥ 1) and a non-dyspnea group (mMRC = 0). Cox regression analysis detected effects of patient demographics, clinical characteristics, surgical factors and respiratory function on 5 year post-surgical survival.ResultsBy study completion (June 30, 2020), 32 of 104 patients were lost and 72 completed follow-up for a study total of 258.9 person-years. 45 patients (62.5%, 45/72) had mMRC scores of 0, while 12 (16.7%, 12/72), 21 (36.2%, 21/58) and 27 (60.0%, 27/45) patients exhibited dyspnea by 1, 3 and 5 years post-surgery, respectively. Low lung carbon monoxide diffusion score (DLCO% pred) and scoliosis contributed to dyspnea occurrence.ConclusionsMost TDL patients lacked subjective dyspnea signs post-surgery, while dyspnea rates increased with time. Preoperative low lung diffusion function and Scoliosis were associated with factors for postoperative dyspnea. Surgical treatment increased TDL patient survival overall.

A Case Report of Korean Medical Intervention in a Patient with Myasthenia Gravis after Myasthenia Crisis

Objective: This study reports on the management of a patient with myasthenia gravis (MG) following myasthenic crisis (MC) using Korean medicine.Methods: A 77-year-old Class Ⅴ MG patient was treated with acupuncture, moxibustion, and Korean herbal medicine. A manual muscle test was used to derive a Medical Research Council (MRC) score and the patient’s subjective view of his dyspnea was measured to assess MG symptoms.Results: The MRC grade indicated significant deterioration after 65 days of treatment, although there was no change in the patient’s subjective dyspnea assessment. But no other MG or MC complications occurred.Conclusion: This study suggests that Korean medicine could be used for the management of Class Ⅴ MG patients.

The Objective and Subjective Outcome of Bullectomy in Patients of Bullous Lung Disease: A Prospective Study

Background: This study aimed to evaluate the outcome of bullectomy in patients with bullous lung by comparative analysis of their preoperative and postoperative pulmonary function parameters and subjective dyspnea score.&#x0D; Materials and Methods: The study included 42 cases of bullous lung disease, who underwent open or video-assisted thoracoscopic surgery (VATS) bullectomy at our hospital from November 2019 till January 2022. All patients were subjected to set protocol which included preoperative comprehensive history and physical examination, chest X-ray, lung CT, and pulmonary function tests. Postoperative evaluation included 3 monthly follow-up for three visits, with clinical assessment for subjective dyspnea score and pulmonary function tests (PFTs). Preoperative and postoperative comparisons of parameters were made using the student’s paired t-test to calculate the statistical significance.&#x0D; Results: Primary bullous lung disease was the most common underlying lung pathology in our population, followed by COPD. Spontaneous pneumothorax was the most common presenting feature, and the most patients presented in their fourth decade of life with a history of smoking.&#x0D; All cases underwent VATS/open bullectomy. Most patients were discharged on the 4th postoperative day. Statistically, significant improvement was seen in mean FEV1 (forced expiratory volume in 1st second), FVC (forced vital capacity), and FEV1/FVC. FEV1 appeared to be the most reliable indicator of postoperative progress. The subjective dyspnea score improved in a statistically meaningful way. Diffuse parenchymal disease patients had a higher rate of complications. Our research found no evidence of mortality.&#x0D; Conclusion: We conclude that surgery remains the standard treatment for bullous lung disease. Most of the patients who got benefitted are those having localized disease with remaining normal parenchyma. Statistically significant improvement in subjective and objective parameters is seen in all cases. Those with the diffuse emphysematous disease need careful selection given their high complication rate.

Clinical characterization and possible pathophysiological causes of the Deventilation Syndrome in COPD

In daily routine, many COPD patients report early onset augmented dyspnea following use of NIV (Deventilation Syndrome, DVS) as a negative side-effect. The aim of this study is the clinical characterization and concrete definition of DVS. This monocenter prospective observational study collected demographic, physiologic and symptomatic data from 67 in-patients with severe COPD Gold III–IV and chronic hypercapnic failure before, during and after use of an established NIV. During their inpatient follow-up, we examined patients during the first hour after termination of nocturnal NIV. DVS was defined by the authors as an increase of ≥ 2 points on the Borg scale during the first 30 min in patients who reported repeated dyspnea after the use of NIV. We monitored cardiovascular and respiratory data and measured diaphragm excursion. Subjective dyspnea was documented by use of the Borg scale and questionnaires. In addition, respirator and demographic data were collected. DVS occurred in 58% of our COPD patient collective, showing predominant emphysema phenotype. Patients with DVS were more severely ill than non-DVS concerning bronchial obstruction (FEV1 0.6 vs. 0.8 l, p < 0.05) and hypercapnia during spontaneous breathing (pre NIV pCO2: 54.5 vs. 49.3 mmHg, p < 0.02). DVS patients showed significantly higher respiratory rates (RR) (20.1 vs. 18.1/min p < 0.05) after termination of NIV. This trial characterizes and defines early onset augmented dyspnea after the use of NIV, referred to as DVS. It is hereby brought to attention as a frequent side effect of long-term home ventilation and possible pathophysiologic mechanisms are elucidated.

Mechanism of Dyspnea during Exercise in Children with Corrected Congenital Heart Disease.

This study will evaluate cardiorespiratory and peripheral muscle function and their relationship with subjective dyspnea threshold after the surgical correction of congenital heart disease in children. Thirteen children with surgically repaired congenital heart disease were recruited. Each participant performed an incremental exercise test on a cycle ergometer until exhaustion. Gas exchanges were continuously sampled to measure the maximal aerobic parameters and ventilatory thresholds. The functional capacity of the subjects was assessed with a 6 min walk test. At the end of the exercise test, isokinetic Cybex Norm was used to evaluate the strength and endurance of the knee extensor muscle in the leg. Dyspnea was subjectively scored with a visual analog scale during the last 15 s of each exercise step. Oxygen consumption measured at the dyspnea score/VO2 relationship located at the dyspnea threshold, at which dyspnea suddenly increased. Results: The maximal and submaximal values of the parameters describing the exercise and the peripheral muscular performances were: VO2 Peak: 33.8 ± 8.9 mL·min−1·kg−1; HR: 174 ± 9 b·min−1; VEmax: 65.68 ± 15.9 L·min−1; P max: 117 ± 27 W; maximal voluntary isometric force MVIF: 120.8 ± 41.9 N/m; and time to exhaustion Tlim: 53 ± 21 s. Oxygen consumption measured at the dyspnea threshold was related to VO2 Peak (R2 = 0.74; p < 0.01), Tlim (R2 = 0.78; p < 0.01), and the distance achieved during the 6MWT (R2 = 0.57; p < 0.05). Compared to the theoretical maximal values for the power output, VO2, and HR, the surgical correction did not repair the exercise performance. After the surgical correction of congenital heart disease, exercise performance was impeded by alterations of the cardiorespiratory function and peripheral local factors. A subjective evaluation of the dyspnea threshold is a reliable criterion that allows the prediction of exercise capacity in subjects suffering from congenital heart disease.