Prefrontal cortex activation during incremental inspiratory loading in healthy participants.

We aimed to investigate whether changes in prefrontal cortex (PFC) oxyhemoglobin (O2Hb) and deoxyhemoglobin (HHb) associates with inspiratory muscle effort during inspiratory threshold loading (ITL) in healthy participants. Participants performed an incremental ITL. Breathing pattern, partial pressure of end-tidal CO2 (PETCO2), mouth pressure and O2Hb and HHb over the right dorsolateral PFC, sternocleidomastoid (SCM), and diaphragm/intercostals (Dia/IC) were monitored. Fourteen healthy participants (8 men; 29 ± 5 years) completed testing. Dyspnea was higher post- than pre-ITL (5 ± 1 vs. 0 ± 1, respectively; P<0.05). PFC O2Hb increased (P < 0.001) and HHb decreased (P = 0.001) at low loads but remained stable with increasing ITL intensities. PFC total hemoglobin increased at task failure compared to rest. SCM HHb increased throughout increasing intensities. SCM and Dia/IC total hemoglobin increased in the at task failure compared to rest. PETCO2 did not change (P = 0.528). PFC is activated early during the ITL but does not show central fatigue at task failure despite greater dyspnea and an imbalance of SCM oxygen demand and delivery.

Investigation of perfusion defects by Q-SPECT/CT in patients with mild-to-moderate course of COVID-19 and low clinical probability for pulmonary embolism.

OBJECTIVE: Pulmonary embolism is a severe source of mortality and morbidity in patients with severe and critical coronavirus disease 2019. It is not yet clear whether the tendency to thrombosis is increased in the mild-to-moderate course of COVID-19. Our research aims to show the clinical benefit of Q-SPECT/CT in diagnosing PD in outpatients treated with mild-to-moderate course of COVID-19 and to determine the frequency of perfusion defects in these patients having relatively lower risk. METHODS: All patients who underwent Q-SPECT/CT with suspicion of embolism were examined retrospectively. Only patients with low clinical probability and mild-to-moderate course of COVID-19 for PE were included in the study. The patients were evaluated comparatively as those with and without perfusion defects. Patients were divided into laboratory suspicion, clinical suspicion, or clinical and laboratory suspicion. RESULTS: In outpatients with mild-to-moderate COVID-19 with low clinical probability for PE, PD without CT abnormality was detected with a rate of 36.6% with Q-SPECT/CT performed for complaints of high D-dimer and/or dyspnea. None of the patients had PD at more proximal level than the segment level. PD with no concomitant CT abnormality was observed with a rate of 56.5% in patients with both clinical and laboratory suspicion. For D-dimer = 0.5 mg/dL cut-off sensitivity is 85%, for D-dimer = 1.5 mg/dL cut-off specificity 81%. CONCLUSION: Thrombosis tendency is also present in outpatients with mild-to-moderate COVID-19, and these patients should also be offered anticoagulant prophylaxis during the COVID-19 period.

Association of high-resolution computed tomography score with ventilator weaning and 28-day mortality of patients with acute respiratory distress syndrome.

OBJECTIVE: This study was performed to explore the association of the high-resolution computed tomography (HRCT) score with ventilator weaning and 28-day mortality of patients with acute respiratory distress syndrome (ARDS). METHOD: In total, 197 patients treated for ARDS from October 2004 to December 2015 were retrospectively analyzed. Univariate analysis and multifactor regression analysis were used to determine the relationship of the HRCT score with ventilator weaning and 28-day mortality. Curve-fitting analysis and threshold analysis were further used to explore the association of the HRCT score with ventilator weaning and 28-day mortality. RESULTS: The multifactor regression analysis showed that the HRCT score was significantly associated with a lower rate of ventilator weaning and a higher risk of 28-day mortality in patients with ARDS. HRCT scores of 257.0 and 243.2 were the thresholds for ventilator weaning and 28-day mortality, respectively. When the HRCT score was below the threshold, every 1-point increase in the HRCT score was associated with a 4.6% decrease in the ventilator weaning rate and a 4.6% increase in the 28-day mortality rate. CONCLUSION: The HRCT score was associated with ventilator weaning and 28-day mortality with a threshold of 257.0 and 243.2 points, respectively.

Choosing an Adequate Test to Determine Fitness for Air Travel in Obese Individuals.

BACKGROUND: Air travel is physically demanding and, because obesity is rising, physicians increasingly need to assess whether such patients can fly safely. Our aim was to compare the diagnostic accuracy of two routinely used exercise tests, 50-m walk test and 6-min walk test, and hypoxic challenge testing (HCT) in obese individuals. We further explored the diagnostic potential of perceived dyspnea as measured with the Borg scale because this is often recorded subsequent to walking tests. METHODS: In this prospective study, we examined 21 obese participants (10 women, age 51 ± 15 [mean  ±  SD], BMI 36 ± 5  kg/m2). The most prevalent comorbidity was COPD (n = 11). The reference standard for in-flight hypoxia, defined as oxygen saturation below 90%, was established in an altitude chamber. Diagnostic accuracy of each index test was estimated by area under the receiver operating characteristic curve (AUC). RESULTS: Of the 21 participants, 13 (9 with COPD) were identified with in-flight hypoxia. HCT was the only test separating the reference groups significantly with AUC 0.87 (95% CI,  0.62-0.96). Neither of the walking tests predicted noticeably above chance level: 50 m walk test had an AUC of 0.63 (0.36-0.84) and 6MWT had an AUC of 0.64 (0.35-0.86). We further observed good prognostic ability of subjective dyspnea assessment when recorded after 6MWT with an AUC of 0.80 (0.55-0.93). CONCLUSIONS: In-flight hypoxia in obese individuals can be predicted by HCT but not by simple walking tests.

Influence of Hemoglobin Level on Muscle and Physical Functions, Activities of Daily Living, and Quality of Life in Patients With Hematological Malignancies.

PURPOSE: Patients with hematological malignancies often present with reduced muscle and physical functions, which are caused by the disease or related treatment. Moreover, patients with hematological malignancies rapidly develop low hemoglobin levels, and this may affect muscle and physical functions. This study aimed to identify the influence of hemoglobin levels on muscle and physical functions in patients with hematological malignancies. METHODS: Using a cross-sectional study design, this study included 60 patients with hematological malignancies (mean age = 68.0 ± 10.2 years, women 56.7%) who were hospitalized for chemotherapy- and radiotherapy-related side effects and underwent examination for skeletal muscle mass (SMM), muscle strength, physical function, activities of daily living (ADLs), psychological status, and quality-of-life (QOL), including physical symptoms. Participants were divided into 3 groups according to tertiles of hemoglobin levels: low (n = 19), middle (n = 20), and high (n = 21). Evaluation items were compared among the 3 groups. RESULTS: There was no significant difference among the 3 groups in terms of SMM. The low hemoglobin group showed significantly higher values of fatigue and dyspnea and lower values of muscle strength, ADLs, and QOL than the high hemoglobin group. CONCLUSIONS: Hemoglobin levels did not affect SMM; however, muscle weakness, decrease in physical function, physical symptoms such as fatigue and dyspnea, and decline in ADLs and QOL were observed in patients with low hemoglobin levels.

Assessment of Clinical and Echocardiographic Findings of Pregnant Women with Dyspnea.

BACKGROUND In the present study we evaluated clinical and echocardiography findings of pregnant women with dyspnea. MATERIAL AND METHODS Pregnant women with and without dyspnea and admitted to the Gynecology and Obstetrics Clinic of a tertiary hospital between December 2017 and June 2018 were enrolled in this case-control study. All patients underwent echocardiography in the third trimester (≥27 weeks). Pregnant women who were older than 18 years, who had dyspnea, and who were in the third trimester of their pregnancy (≥27 weeks) were included in the study. RESULTS Left ventricle end-diastolic diameter (LVEDd) was 47.38±3.68 mm in the study group and 43,70±8,84 mm in the control group (P=0.041). On the other hand, left ventricle end-systolic diameter (LVESd) was determined to be 30.86±3.90 mm in the study group and 34,45±6,56 mm in the control group (P=0.013). Systolic pulmonary artery pressure (sPAP), calculated through tricuspid insufficiency and analyzed, was found to be 24.69±9.10 mmHg in the study group and 20.39±6.80 mmHg in the control group (p=0.038). CONCLUSIONS When echocardiography findings of pregnant women with dyspnea were analyzed, it was determined that their left ventricle end-diastolic diameter (LVEDd), left ventricle end-systolic diameter (LVESd), and systolic pulmonary artery pressure (sPAP), calculated through tricuspid insufficiency, were higher than those of women in the control group, although they were within normal limit range. Therefore, we recommend that women with dyspnea should see a cardiologist and undergo an echocardiogram test so that the cardiac causes of dyspnea can be clinically revealed.

Intercostal muscle oxygenation during expiratory load breathing at rest.

BACKGROUND: During acute bronchial obstruction, despite a higher work of breathing, blood supply and oxygen availability may be reduced in intercostal muscles because of mechanical constraints. This hypothesis was assessed in healthy subjects breathing with and without expiratory load (ETL). METHODS: Eleven men (24 ± 2 years) breathed at rest for 5 min in unloaded condition and for 20 min through a 20-cmH2O ETL. Tissue saturation index (TSI) and changes (Δ) in concentration of total and oxy-haemoglobin ([tHb] and [O2Hb]) were measured in the seventh intercostal space by near-infrared spectroscopy. RESULTS: [tHb] and [O2Hb] decreased with ETL (-5.16 µM and -3.54 µM; p < 0.05). TSI did not vary. Negative correlations were observed between Δ[O2Hb] and changes in expiratory flow rate (ΔVt/Te) and between ΔTSI and Δ V˙E (r = -0.78 and -0.74; p ≤ 0.01). CONCLUSION: Despite decreases in Hb concentrations, saturation in oxygen was not reduced with ETL in intercostal muscles, suggesting a satisfactory ventilatory and/or hemodynamic arrangement.

Diagnostic and prognostic properties of procalcitonin in patients with acute dyspnea: Data from the ACE 2 Study.

BACKGROUND: Procalcitonin (PCT) concentrations increase during bacterial infections and could improve diagnosis of pneumonia and risk stratification in patients with acute dyspnea. METHODS: PCT concentrations were measured <24 h of admission in 310 patients with acute dyspnea and compared to C-reactive protein (CRP) and white blood cells (WBC) in the total cohort and the subset of patients with concomitant acute heart failure (HF). RESULTS: We diagnosed pneumonia in 16 out of 140 patients with acute HF (11%) and in 45 out of 170 patients with non-HF-related dyspnea (27%). PCT concentrations were higher in patients with pneumonia vs. patients without pneumonia, both among acute HF patients (median 2.79 [Q1-3 0.18-5.80] vs. 0.10 [0.07-0.14] ng/mL, p < .001) and non-HF patients (0.22 [Q1-3 0.13-0.77] vs. 0.07 [0.05-0.10] ng/mL, p < .001). CRP and WBC were also higher in patients with pneumonia in both groups, but among acute HF patients, only PCT concentrations were associated with pneumonia in multivariate analysis. In patients with acute HF, receiver-operating statistics area under the curve (ROC-AUC) to diagnose pneumonia was 0.90 (95% CI 0.81-0.98) for PCT, 0.84 (0.73-0.94) for CRP, and 0.72 (0.57-0.87) for WBC. The corresponding ROC-AUCs among patients with non-HF-related dyspnea were 0.88 (0.82-0.93), 0.94 (0.90-0.98), and 0.79 (0.72-0.87), respectively. During a median follow-up of 823 days (Q1-3 471-998) 114 patients died, and PCT and CRP, but not WBC concentrations were associated with all-cause mortality. CONCLUSION: In acute HF patients, PCT concentrations were superior to CRP and WBC to diagnose concurrent pneumonia.

The prognostic value of mid-regional pro-adrenomedullin in the evaluation of acute dyspnea.

INTRODUCTION: Acute dyspnea is a common chief complaint among patients who visit an emergency room and presents diagnostic challenges for clinicians in both identifying the etiology and determining the clinical severity. The study of biomarkers in the prognostication and risk stratification of these patients has been increasing, including the investigation of the prognostic value for mid-regional pro-adrenomedullin (MR-proADM). Areas covered: In this review, the authors cover what is known about MR-proADM testing in patients presenting with acute dyspnea and the supporting evidence of its prognostic value in common conditions in medical patients with acute dyspnea, including acute heart failure, community acquired pneumonia, acute exacerbation of chronic obstructive pulmonary disease, and acute pulmonary embolism. Expert commentary: Numerous studies have proposed MR-proADM as a more accurate, prognostic tool in the evaluation of acute dyspnea than other biomarkers and consensus risk scores such as Sequential Organ Failure Assessment (SOFA) and quick SOFA (qSOFA). The authors review recent prospective studies, systematic reviews, and meta-analyses that demonstrate its prognostic value and role in risk stratification, including its use in biomarker-based triage algorithms as part of the diagnostic evaluation of the acutely dyspneic patient.

Fibroblast growth factor 23 in patients with acute dyspnea: Data from the Akershus Cardiac Examination (ACE) 2 Study.

BACKGROUND: Circulating fibroblast growth factor 23 (FGF23) concentrations have been linked to left ventricular remodeling and unfavorable cardiovascular outcomes, but whether FGF23 is associated with heart failure (HF) diagnosis and outcome in unselected patients with dyspnea is unknown. Accordingly, we assessed the diagnostic and prognostic properties of FGF23 in patients presenting to the emergency department with acute dyspnea. METHODS AND RESULTS: FGF23 was measured in 314 patients admitted with acute dyspnea and the diagnostic and prognostic merit was compared to that of N-terminal pro-B-type natriuretic peptide (NT-proBNP). The diagnosis of acute HF was adjudicated by two independent physicians. Circulating FGF23 concentrations on hospital admission were higher in patients with acute HF vs. patients with non-HF related dyspnea: median 3.60 (IQR 1.24-8.77) vs. 1.00 (0.43-2.20) pmol/L; P<0.001. The receiver-operating statistics area under the curve for acute HF diagnosis was 0.750 (0.699-0.797) for FGF23 and 0.853 (0.809-0.890) for NT-proBNP. Adjusting for clinical risk indices and cardiac biomarkers in multivariate Cox regression analysis, admission FGF23 concentrations were associated with mortality in the total study population (hazard ratio [HR] per 1 SD in lnFGF23 1.74 [1.40-2.16]). FGF23 also reclassified patients into their correct risk strata on top of clinical variables significantly associated with outcomes in the total cohort (net reclassification index 0.386 [0.161-0.612]). In patients with acute HF, both admission FGF23 and NT-proBNP concentrations were associated with mortality. CONCLUSION: Circulating FGF23 concentrations provide incremental prognostic information to established risk indices in patients with acute dyspnea, but do not improve diagnostic accuracy over NT-proBNP measurements.

Nebulized opioids for the palliation of dyspnea in terminally ill patients.

PURPOSE: The use of nebulized opioids for the palliation of dyspnea in terminally ill patients is reviewed. SUMMARY: More than 50% of patients with advanced diseases experience dyspnea during their final stages of life. Systemically administered opioids are recommended for the management of dyspnea in these patients, but adverse effects may limit their use. Nebulization offers an alternative route for administering opioids, providing relief of dyspnea while minimizing adverse events. An extensive literature search was conducted to identify publications evaluating nebulized opioids for the palliation of dyspnea in patients at end-of-life. Ten studies that evaluated nebulized morphine, fentanyl, hydromorphone, and morphine-6-glucuronide were reviewed; 1 of these studies evaluated 4 different opioids. Of these 10 studies, 2 had double-blind, placebo-controlled, randomized crossover designs; 1 was retrospective, and the remaining 7 were prospective studies. A total of 181 patients, all adults, were evaluated. Subjective improvement in dyspnea from baseline was observed in 9 of the 10 studies. Nebulized morphine 20 mg every 4 hours was the most common opioid studied. Other doses of nebulized opioids included fentanyl 25 and 100 µg and hydromorphone 5 mg. Nine studies reported subjective improvement of dyspnea from baseline after administering nebulized opioids. Six studies evaluated objective outcomes and showed decreased respiratory rate (morphine, fentanyl, and hydromorphone) and heart rate (hydromorphone) and increased oxygen saturation (fentanyl). Mild-to-moderate adverse effects such as claustrophobia due to nebulizer mask, drowsiness, cough, and bitter taste were described. CONCLUSION: Nebulized opioids may provide subjective relief of dyspnea in terminally ill patients with mild-to-moderate adverse effects.

Effects of a simple prototype respiratory muscle trainer on respiratory muscle strength, quality of life and dyspnea, and oxidative stress in COPD patients: a preliminary study.

BACKGROUND: The aim of this study was to evaluate the efficiency of a simple prototype device for training respiratory muscles in lung function, respiratory muscle strength, walking capacity, quality of life (QOL), dyspnea, and oxidative stress in patients with COPD. METHODS: Thirty COPD patients with moderate severity of the disease were randomized into three groups: control (n=10, 6 males and 4 females), standard training (n=10, 4 males and 6 females), and prototype device (n=10, 5 males and 5 females). Respiratory muscle strength (maximal inspiratory pressure [PImax] and maximal expiratory pressure [PEmax]), lung function (forced vital capacity [FVC], percentage of FVC, forced expiratory volume in 1 second [FEV1], percentage of FEV1 [FEV1%], and FEV1/FVC), 6-minute walking distance (6MWD), QOL, and oxidative stress markers (total antioxidant capacity [TAC]), glutathione (GSH), malondialdehyde (MDA), and nitric oxide (NO) were evaluated before and after 6 weeks of training. Moreover, dyspnea scores were assessed before; during week 2, 4, and 6 of training; and at rest after training. RESULTS: All parameters between the groups had no statistical difference before training, and no statistical change in the control group after week 6. FVC, FEV1/FVC, PImax, PEmax, QOL, MDA, and NO showed significant changes after 6 weeks of training with either the standard or prototype device, compared to pre-training. FEV1, FEV1%, 6MWD, TAC, and GSH data did not change statistically. Furthermore, the results of significant changes in all parameters were not statistically different between training groups using the standard and prototype device. The peak dyspnea scores increased significantly in week 4 and 6 when applying the standard or prototype device, and then lowered significantly at rest after 6 weeks of training, compared to pre-training. CONCLUSION: This study proposes that a simple prototype device can be used clinically in COPD patients as a standard device to train respiratory muscles, improving lung function and QOL, as well as involving MDA and NO levels.

Pro- and Antioxidant Systems in the Lower Portion of Rat Brainstem during Hydroxybutyrate-Induced Pathological Periodic Breathing.

Activities of superoxide dismutase and catalase characterizing antioxidant status of the nervous tissue and its resistance to free radical oxidation were measured in the brainstem of rats with hydroxybutyrate-induced pathological periodic breathing. Hydroxybutyrate modified the pro- and antioxidant status in the brainstem respiratory center. It markedly inhibited catalase activity; in rats without the signs of periodic breathing, hydroxybutyrate up-regulated superoxide dismutase activity and to a lesser extent increased the resistance of the membrane structures in the medulla oblongata to induction of free radical oxidation. In rats with periodic breathing pattern, hydroxybutyrate induced more pronounced increase in the sensitivity of membrane structures in the medulla oblongata to induction of free radical oxidation.

Evaluation of exhaled nitric oxide's ability to predict methacholine challenge in adults with nonobstructive spirometry.

BACKGROUND: Compared with methacholine challenge, exhaled nitric oxide is less expensive, is performed as a simpler point-of-care maneuver, and may provide treatment guiding information. OBJECTIVE: To determine whether exhaled nitric oxide levels can predict the outcome of methacholine challenge in patients without obvious baseline obstruction. METHODS: This retrospective database and medical record review included adults presenting to a tertiary care center from November 1, 2009, through August 31, 2013, who underwent methacholine challenge and exhaled nitric oxide measurement within 2 weeks of each other. Database extraction identified age, sex, body mass index, baseline corticosteroid use, testing indication, forced expiratory volume in 1 second (FEV1), and testing results. Individuals taking corticosteroid-containing medication or who had an FEV1 less than the lower limit of normal at baseline were excluded. RESULTS: A total of 1,322 individuals were identified, with 774 meeting the eligibility criteria. A total of 123 methacholine challenges (16%) had positive results. Fractional exhaled nitric oxide was statistically higher in those with positive methacholine challenge results (mean [SD], 41.9 [54.5] ppb vs 25.2 [19.7] ppb; P < .01). Receiver operating characteristic curve revealed an area under the curve of 0.572 (P < .01), suggesting a poor correlation between exhaled nitric oxide level and methacholine challenge outcome. Fractional exhaled nitric oxide of greater than 50 ppb has a sensitivity, specificity, positive predictive value, and negative predictive value of 12%, 89%, 17%, and 84%, respectively, for a positive methacholine challenge result. CONCLUSION: In this large, retrospective cohort of corticosteroid-naive pulmonary patients with normal FEV1 on baseline spirometry, exhaled nitric oxide poorly predicts the outcome of a methacholine challenge.

Short-term exposure to high ambient air pollution increases airway inflammation and respiratory symptoms in chronic obstructive pulmonary disease patients in Beijing, China.

BACKGROUND: Few studies have investigated the short-term respiratory effects of ambient air pollution in chronic obstructive pulmonary disease (COPD) patients in the context of high pollution levels in Asian cities. METHODS: A panel of 23 stable COPD patients was repeatedly measured for biomarkers of airway inflammation including exhaled nitric oxide (FeNO) and exhaled hydrogen sulfide (FeH2S) (215 measurements) and recorded for daily respiratory symptoms (794person-days) in two study periods in Beijing, China in January-September 2014. Daily ambient air pollution data were obtained from nearby central air-monitoring stations. Mixed-effects models were used to estimate the associations between exposures and health measurements with adjustment for potential confounders including temperature and relative humidity. RESULTS: Increasing levels of air pollutants were associated with significant increases in both FeNO and FeH2S. Interquartile range (IQR) increases in PM2.5 (76.5µg/m(3), 5-day), PM10 (75.0µg/m(3), 5-day) and SO2 (45.7µg/m(3), 6-day) were associated with maximum increases in FeNO of 13.6% (95% CI: 4.8%, 23.2%), 9.2% (95% CI: 2.1%, 16.8%) and 34.2% (95% CI: 17.3%, 53.4%), respectively; and the same IQR increases in PM2.5 (6-day), PM10 (6-day) and SO2 (7-day) were associated with maximum increases in FeH2S of 11.4% (95% CI: 4.6%, 18.6%), 7.8% (95% CI: 2.3%, 13.7%) and 18.1% (95% CI: 5.5%, 32.2%), respectively. Increasing levels of air pollutants were also associated with increased odds ratios of sore throat, cough, sputum, wheeze and dyspnea. CONCLUSIONS: FeH2S may serve as a novel biomarker to detect adverse respiratory effects of air pollution. Our results provide potential important public health implications that ambient air pollution may pose risk to respiratory health in the context of high pollution levels in densely-populated cities in the developing world.

Actualización en el diagnóstico y tratamiento de la tuberculosis pulmonar / Update on the diagnosis and treatment of pulmonary tuberculosis

La tuberculosis (TB) sigue siendo la enfermedad infecciosa humana más importante que existe. El diagnóstico actual de la TB sigue basándose en la presentación clínica, los hallazgos radiográficos y los resultados microbiológicos; todos ellos con problemas de sensibilidad o especificidad. Es por ello que el futuro más inmediato pasa por las técnicas microbiológicas rápidas moleculares, sobre todo el GeneXpert (más sensible que la baciloscopia y con capacidad de detectar resistencia a la rifampicina) y el GenoType. El tratamiento actual de la TB sigue siendo el mismo de 6 meses utilizado desde hace décadas. Los intentos por acortar este tratamiento están fracasando en la actualidad. En los últimos años se han descrito nuevos fármacos que podrían contribuir al tratamiento de la TB en un futuro cercano, y que ya se utilizan en la TB con multifarmacorresistencias (AU)

Tuberculosis (TB) remains the most important human infectious disease. Currently, the TB diagnosis is still based on the clinical presentation, radiographic findings and microbiological results; all of which have sensitivity or specificity issues. For that reason, the immediate future involves rapid molecular microbiological techniques, in particular GeneXpert (which is more sensitive than bacilloscopy and is able to detect rifampicin resistance) and GenoType. The current six-month treatment for TB has remained unchanged for decades. Attempts to shorten this treatment have failed. In recent years, new drugs have been reported that could contribute to TB treatment in the near future, and are already being used in multi-drug-resistance TB (AU)

Contraste radiológico oral en la cavidad pleural / Oral radiological contrast in the pleural cavity

No disponible

Systemic inflammation and higher perception of dyspnea mimicking asthma in obese subjects.

BACKGROUND: There are a variable number of obese subjects with self-reported diagnosis of asthma but without current or previous evidence of airflow limitation, bronchial reversibility, or airway hyperresponsiveness (misdiagnosed asthma). However, the mechanisms of asthma-like symptoms in obesity remain unclear. OBJECTIVES: We sought to evaluate the perception of dyspnea during bronchial challenge and exercise testing in obese patients with asthma and misdiagnosed asthma compared with obese control subjects to identify the mechanisms of asthma-like symptoms in obesity. METHODS: In a cross-sectional study we included obese subjects with asthma (n = 25), misdiagnosed asthma (n = 23), and no asthma or respiratory symptoms (n = 27). Spirometry, lung volumes, exhaled nitric oxide levels, and systemic biomarker levels were measured. Dyspnea scores during adenosine bronchial challenge and incremental exercise testing were obtained. RESULTS: During bronchial challenge, patients with asthma or misdiagnosed asthma reached a higher Borg-FEV1 slope than control subjects. Moreover, maximum dyspnea and the Borg-oxygen uptake (V'O2) slope were significantly greater during exercise in subjects with asthma or misdiagnosed asthma than in control subjects. The maximum dyspnea achieved during bronchial challenge correlated with IL-1ß levels, whereas peak respiratory frequency, ventilatory equivalent for CO2, and IL-6 and IL-1ß levels were independent predictors of the Borg-V'O2 slope during exercise (r(2) = 0.853, P < .001). CONCLUSIONS: A false diagnosis of asthma (misdiagnosed asthma) in obese subjects is attributable to an increased perception of dyspnea, which, during exercise, is mainly associated with systemic inflammation and excessive ventilation for metabolic demands.

Effect of experimental modulation of mood on perception of exertional dyspnea in healthy subjects.

In many diseases across a range of pathologies (e.g., cardiopulmonary, neuromuscular, and cancer), chronic dyspnea, particularly on exertion, is a major debilitating symptom often associated with clinical anxiety/depression. This study aims to explore the interaction between mood state and exertional dyspnea in a healthy population. Following familiarization, 20 healthy subjects (27-54 years old) performed six 5-min treadmill tests on three separate days. On each day subjects viewed randomly assigned images designed to induce positive, negative, or neutral mood states (International Affective Picture System). For each condition, at minute intervals, subjects rated dyspnea (sensory and affective domains) in the first test and mood (valence and arousal domains) in the second test. Oxygen uptake (V̇O2 , liters/min), carbon dioxide production (V̇CO2, liters/min), ventilation (V̇E, liters/min), respiratory frequency (f(R), beats/min), and heart rate (HR, bpm), were measured throughout the exercise. V̇O2, V̇CO2, V̇E, HR, and f(R) were not statistically significantly different among the three mood states (P > 0.05). Mood valence was significantly higher with parallel viewing of positive (last 2-min mean ± SE = 6.9 ± 0.2) compared with negative pictures (2.4 ± 0.2; P < 0.001). Both sensory and affective domains of dyspnea were significantly higher during negative (sensory: 5.6 ± 0.3; affective: 3.3 ± 0.5) compared with positive mood (sensory: 4.4 ± 0.4, P < 0.001; affective: 2.1 ± 0.4, P = 0.002). These findings suggest that positive mood alleviates both the sensory and affective domains of exertional dyspnea in healthy subjects. Thus the treatment of anxiety/depression in dyspenic populations could be a worthwhile therapeutic strategy in increasing symptom-limited exercise tolerance, thereby contributing to improved quality of life.