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Background: Low back pain (LBP) is a common musculoskeletal disorder, and respiratory exercise is considered a nonsurgical management method. Therefore, this systematic review and meta-analysis aims to estimate the results of randomized controlled trials on the effect of respiratory training in reducing LBP and its dose relationship. Methods: The present study was conducted from January 2020 to January 2022, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (2020). Relevant studies were searched in multiple databases including PubMed, Web of Science, the Cochrane Library, EBSCO, Scopus, ScienceDirect, Wan Fang and China Knowledge Network, ClinicalTrials.gov, and Google Scholar, using a combination of MeSH/Emtree terms and free-text words. The heterogeneity of the studies was assessed using the I2 statistic. Results: A total of 14 publications were included in the meta-analysis, with a total sample size of 698 individuals, aged 60–80 years. Respiratory exercise was effective in relieving LBP (standardized mean difference = −0.87, P <.00001) and improving physical disability (standardized mean difference = −0.79, P <.00001). The type of breathing and the total duration of breathing exercises were found to be the source of heterogeneity in this study by subgroup analysis. Subgroup analysis revealed that the most significant effect sizes of breathing resistance exercise to reduce LBP and the most significant effect sizes of breathing relaxation techniques to alleviate physical disability were performed 3 to 5 times per week and period >4 weeks. Respiratory exercise reducing LBP and improving functional disability was most effective when the total duration of the intervention was >500 minutes. Funnel plots showed that the results of the 2 overall studies were reliable without publication bias. Conclusions: Respiratory exercise can effectively reduce LBP and improve physical disability. Therefore, these exercises can be regarded as a part of a LBP management plan. We recommend an exercise program with 30 to 50 minutes, 3 to 5 times per week, and >4 weeks of breathing resistance exercise program as the most effective for treating LBP. [ABSTRACT FROM AUTHOR]

Background: Chronic obstructive pulmonary disease (COPD) is associated with airflow limitation resulting from a combination of small airway disease (SAD) and parenchymal destruction. Although various diagnostic methods for SAD exist, access to these tools can be limited. Objectives: This study aimed to explore the correlation between handgrip strength (HGS) and SAD in COPD patients. Design: Cross-sectional prospective study. Methods: HGS was measured using a hand dynamometer. SAD was evaluated using impulse oscillometry, with results reported as the difference between respiratory resistance at 5 and 20 Hz (R5–R20). SAD was defined as R5–R20 ⩾0.07 kPa/L/s. The receiver operator characteristic (ROC) curves, sensitivity, and specificity values were calculated to determine the optimal cutoff value of HGS for predicting SAD. Results: Sixty-four patients (90.6% male) were included. The average age was 72.1 ± 8.3 years, and body mass index was 23.4 ± 4.2 kg/m2. FEV1 was 71.6 ± 21.3%, and HGS was 30.2 ± 8.1 kg. R5–R20 was 0.11 ± 0.08 kPa/L/s. SAD was found in 64.1% of patients. A negative correlation between HGS and R5–R20 was observed (r = −0.332, p = 0.007). The best cutoff value for HGS in detecting SAD was determined to be 28.25 kg, with a sensitivity of 73.9%, specificity of 65.9%, and an area under ROC curve of 0.685 (95% CI 0.550–0.819, p = 0.015). Conclusion: SAD is common in COPD patients, and HGS is significantly negatively correlated with SAD. This tool might serve as an alternative or adjunctive assessment for small airway dysfunction in COPD patients. Registration: This study was registered with ClinicalTrials.gov with number NCT06223139. Plain language summary: Association of handgrip strength with small airway disease in COPD In chronic obstructive pulmonary disease (COPD), the condition of small airways (those less than 2 mm wide) is closely linked to disease severity. Small airway disease (SAD) leads to reduced lung function, increased retention of excess gas in the lung, and poorer health in COPD patients. While various diagnostic methods exist for SAD, they may not always be accessible. This study investigated handgrip strength as a potential alternative way to assess SAD. Our findings show a significant negative correlation between handgrip strength and SAD in COPD patients. This suggests that handgrip strength could be used alongside existing methods to evaluate small airway dysfunction in these patients. [ABSTRACT FROM AUTHOR]

Background: The current morphological condition of an individual is described by a somatotype, which is a three-number scale. The endomorph, mesomorph and ectomorph components are presented in the same sequence, and each number corresponds to one of the three basic components of body composition. Methods: We recruited 50 healthy male subjects with a mean age of 24.10 ± 4.55 yrs. Somatotype was determined by the Heath and Carter method. Impulse oscillometry was performed followed by spirometry according to the European Respiratory Society (ERS) or American Thoracic Society (ATS) guidelines. Resistance at 5 Hz (R5) %pred, R20%pred, R5–R20, X5%pred, X20, area of reactance (Ax) and resonant frequency (Fres) were obtained by doing impulse oscillometry. Slow vital capacity (SVC), forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC ratio and maximum mid-expiratory flow (MMEF) were assessed by doing spirometry. Results: Endomorphs (0.05 (0.00–0.09) vs 0.01 (0.00–0.04); P < 0.0001) and mesomorphs (0.04 (0.000.09) vs 0.01 (0.00–0.04); P = 0.002) had significantly higher R5–R20 than ectomorphs. Similarly, endomorphs (0.32 (0.07–0.82) vs 0.15 (0.08–0.35); P = 0.001) and mesomorphs (0.28 (0.17–0.64) vs 0.15 (0.08–0.35); P = 0.015) also showed significantly higher Ax than ectomorphs, Fres of endomorphs (15.37 (8.43–21.85) vs 10.08 (8.94–14.30); P < 0.0001) and mesomorphs (14.32 (10.24–20.86) vs 10.08 (8.94-14.30); P < 0.0001) were significantly high than ectomorphs. Moreover, spirometric measures reveal significant variation in which mesomorphs had significantly higher values of % predicted of FVC than ectomorphs (92.49 ± 7.211 vs 83.86 ± 7.861; P = 0.042) and the ratio of FEV1 to FVC was significantly higher in ectomorphs than in endomorphs (89.00 ± 5.80 vs 85.04 ± 5.73; P = 0.03). Conclusion: Peripheral airway dysfunction was observed in endomorphs and mesomorphs as compared to ectomorphs. Mesomorphs had a relatively higher FVC that may be due to their greater muscular strength.

Background: The current morphological condition of an individual is described by a somatotype, which is a three-number scale. The endomorph, mesomorph and ectomorph components are presented in the same sequence, and each number corresponds to one of the three basic components of body composition. Methods: We recruited 50 healthy male subjects with a mean age of 24.10 ± 4.55 yrs. Somatotype was determined by the Heath and Carter method. Impulse oscillometry was performed followed by spirometry according to the European Respiratory Society (ERS) or American Thoracic Society (ATS) guidelines. Resistance at 5 Hz (R5) %pred, R20%pred, R5–R20, X5%pred, X20, area of reactance (Ax) and resonant frequency (Fres) were obtained by doing impulse oscillometry. Slow vital capacity (SVC), forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC ratio and maximum mid-expiratory flow (MMEF) were assessed by doing spirometry. Results: Endomorphs (0.05 (0.00–0.09) vs 0.01 (0.00–0.04); P < 0.0001) and mesomorphs (0.04 (0.000.09) vs 0.01 (0.00–0.04); P = 0.002) had significantly higher R5–R20 than ectomorphs. Similarly, endomorphs (0.32 (0.07–0.82) vs 0.15 (0.08–0.35); P = 0.001) and mesomorphs (0.28 (0.17–0.64) vs 0.15 (0.08–0.35); P = 0.015) also showed significantly higher Ax than ectomorphs, Fres of endomorphs (15.37 (8.43–21.85) vs 10.08 (8.94–14.30); P < 0.0001) and mesomorphs (14.32 (10.24–20.86) vs 10.08 (8.94-14.30); P < 0.0001) were significantly high than ectomorphs. Moreover, spirometric measures reveal significant variation in which mesomorphs had significantly higher values of % predicted of FVC than ectomorphs (92.49 ± 7.211 vs 83.86 ± 7.861; P = 0.042) and the ratio of FEV1 to FVC was significantly higher in ectomorphs than in endomorphs (89.00 ± 5.80 vs 85.04 ± 5.73; P = 0.03). Conclusion: Peripheral airway dysfunction was observed in endomorphs and mesomorphs as compared to ectomorphs. Mesomorphs had a relatively higher FVC that may be due to their greater muscular strength. [ABSTRACT FROM AUTHOR]

Introduction: The important parameters for evaluating the performance of particle filtering respirators in international standards are the filtration efficiency and respiratory resistance of the mask filter against airflow passage. To improve nanofiber filtration efficiency while creating the least breathing difficulty for the wearer, various research has been or is being conducted worldwide. This study investigated the effect of using polyacrylonitrile (PAN) nanofiber composite membrane and montmorillonite clay nanoparticles (MMT) in enhancing particle-filtering respirators’ filter performance, achieving higher filtration efficiency while maintaining optimal respiratory resistance conditions. Material and Methods: First, PAN polymer solution containing zero, 1%, 2%, 3%, and 5% MMT nanoparticles was prepared, and then PAN/MMT nanofiber composite membrane was synthesized in an electrospinning machine. Filtration efficiency was measured in diameter range of 0.3, 0.5, 1, and 3 microns using sodium chloride aerosol. Additionally, filter breathing resistance was measured at flow rates of 30, 85, and 95 liters per minute. Results: The efficiency of synthesized composite nanofilters for particle purification can be improved by adding MMT nanoparticles to PAN nanofibers. Optimal MMT concentration was found to be 2%. This addition resulted in an increase in filtration efficiency for particles with sizes of 0.3, 0.5, 1, and 3 microns by 4.2%, 4.88%, 3.77%, and 2.75% respectively without causing significant difference in respiratory resistance. Improved filtration efficiency can be attributed to enhanced morphology of composite nanofilters resulting from addition of MMT nanoparticles. Adding 2% MMT nanoparticles to PAN nanofibers resulted in uniform distribution and smaller fiber dimensions which did not significantly affect Packing density and porosity. Conclusion: If 2% of MMT nanoparticles are added to PAN nanofibers and used to produce particle respirators, resulting respirator will exhibit a 4.2% increase in particle filtration efficiency without increasing breathing difficulty for user. This result can help protect users from particulate pollutants in air pollution conditions.

Objective: To analyze the impact of repeated forced spirometry maneuvers on oscillometry parameters of healthy children.Methods: This is a cross-sectional study with healthy children (6-12 y old) from schools in Florianopolis-SC/Brazil. Good health condition was confirmed through questionnaires, health history, and normal spirometry. Spirometry maneuvers and impulse oscillometry were conducted according to the American Thoracic Society guidelines. The school children were grouped according to the number of spirometry maneuvers performed: 1) 3 maneuvers; 2) 4 maneuvers and 3) 5 to 8 maneuvers. The following oscillometry values were considered: at rest (T0); after the first spirometry maneuver (T1); and after the last maneuver (T2), according to the groups' allocation. The mixed model ANOVA was applied to verify the interaction of oscillometry parameters in all 3 moments and groups. The Friedman test was used for analysis of Fres (p < 0.05).Results: In 149 school children (mean age: 9.13 y old ± 1.98), there was a significant increase in Z5, R5, R20, and X5 values at rest and after the first spirometry maneuver, and values at rest and after the last maneuver in all groups. The effects on analyzed variables were significant in Z5 (F: 12.35; gl: 2; p < 0.001), R5 (F: 11.14; df: 2, p < 0.001), R20 (F: 7.53; df: 2, p < 0.001), and X5 (F: 4.30; df: 2, p = 0.014).Conclusion: There were changes in respiratory mechanics after spirometry, like the increase in baseline Z5, R5, R20, and X5 after the first forced spirometry maneuver, and in comparison to the last maneuver obtained. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Determining the respiratory system's mechanical properties with minimal patient effort has been an important field of investigation addressing patients unable to perform pulmonary function testing and in light of the preventive measures due to the recent pandemic. The current study aimed to present an alternative method for total respiratory resistance measurement during tidal breathing, compare it with airway resistance (Raw), measured by body plethysmography, and validate the procedure in three groups of subjects with normal, constrictive and obstructive respiratory patterns in spirometry. PATIENTS AND METHODS: We developed an alternative method of assessing total respiratory resistance during quiet breathing. After manufacturing the appropriate hardware apparatus, we applied a steady extrinsic resistance (R) for 100-200 m/s during tidal breathing. theoretical mathematical model allowed measurement of total respiratory resistance (Rtot) during inspiration (Rin) and expiration (Rex). To validate the method, 15 individuals were enrolled and assigned to the normal, obstructive and restrictive groups based on their spirometry patterns. All groups participated in two sets of measurements, the plethysmographic and novel method. Finally, respiratory resistance measurements were compared between groups and methods. RESULTS: The method was successfully developed, and Rtot measurements were recorded in five normal subjects and in five obstructive and restrictive subjects. Mean Rin and mean Rex were 4.99 cm H2O/L/sec and 4.42 cm H2O/L/sec in the healthy, 4.87 cm H2O/L/sec, and 6.63 cm H2O/L/sec in the obstructive and 5.97 cm H2O/L/sec and 4.12 cm H2O/L/sec in the restrictive group, respectively. Rex was notably higher than Rin in the obstructive group and was positively correlated with Raw (p<0.005, r=0.47). CONCLUSIONS: This method provides the theoretical background for a plausible alternative tool for accessing a mechanical parameter of the respiratory system, which is easy to perform and requires only passive patient cooperation while enabling rough differentiation between obstructive and restrictive disorders. The model's feasibility potential in a real-life setting was studied in a small sample, and additional implementation and validation of the method in a larger population are guaranteed. [ABSTRACT FROM AUTHOR]

Observational evidence suggests that mask-wearing mitigates transmission of COVID-19; at the same time high respiratory resistance leads to an unwillingness to wear masks. This paper proposed a respiratory drive structure to reduce the air resistance of a mask. This structure provides different shapes during expiration and inspiration while focusing on filtering dust, bacteria, or viruses. Meanwhile, the assembled system on the mask can be disassembled and replaced. Then porous media simulation is used to verify the model effect. Experimental results of a new mask show that the ventilation resistance is reduced by 20%, and the bacterial filtration efficiency meets the requirements of YY 0469–2011. [ABSTRACT FROM AUTHOR]

Zhonghao Tang,1,* Minjing Li,1,* Guokun Chu,1 Yan Mou,1 Qi Chen,2 Huili Zhu1 1Department of Pulmonary Medicine, Huadong Hospital, Fudan University, Shanghai, 200040, People’s Republic of China; 2Department of Pulmonology Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, People’s Republic of China*These authors contributed equally to this workCorrespondence: Huili ZhuDepartment of Pulmonary Medicine, Huadong Hospital, Fudan University, Shanghai, 200040, People’s Republic of ChinaEmail zhuhuili001@126.comQi ChenDepartment of Pulmonology Medicine, Shuguang Hospital Affiliated to Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, People’s Republic of ChinaEmail chenqiywl@shutcm.edu.cnObjective: To explore the correlation of respiratory resistance in stable COPD patients measured by broadband 3-dimensional impulse oscillometry (3D-IOS) and traditional pulmonary function test (PFT). To access the diagnostic value of 3D-IOS in COPD.Methods: A total of 107 COPD patients and 61 healthy subjects as controls were chosen to collect and statistically analyze the data of R5, R5–R20, R20, X5 and Fres measured by broadband 3D-IOS and FEV1%pred, FVC%pred and FEV1/FVC by PFTs. The diagnostic value of broadband 3D-IOS parameters in COPD was evaluated by receiver operating characteristic curve (ROC). 3D-colored images used to show dynamic changes of respiratory resistance in COPD.Results: The COPD group showed significant increases in R5, R20, R5–R20 and Fres, and a decrease in X5 (P< 0.05). With the increase of GOLD grade, R5, R5–R20 and Fres increased whereas X5 decreased (P< 0.05). Compared with FEV1%pred, FVC%pred and FEV1/FVC in the COPD group, R5, R5–R20 and Fres were negatively collated (P< 0.05), whereas X5 was positively collated (P< 0.01). R20 was uncorrelated with the traditional lung function parameters (P> 0.05). Fres and FEV1/FVC (r=− 0.467), and X5 and FEV1%pred (r=0.412) showed the strongest correlation. The AUC of R5, R5–R20, X5 and Fres was 0.7808, 0.7659, 0.8947 and 0.9095, respectively. Typical 3D-colored images of COPD displayed a green pattern in the inhalation phase and yellow–red–blue graduation in the expiration phase.Conclusion: R5, R5-R20, X5 and Fres measured by broadband 3D-IOS can reflect the change of respiratory resistance in COPD. And they have good correlation with the traditional lung function parameters (FEV1%pred, FVC%pred, FEV1/FVC). Fres has the highest diagnostic accuracy. Comprehensive analysis of R5, R5–R20, Fres and X5 helps to determine the degree of respiratory obstruction in COPD. X5 and Fres can reflect changes in lung tissue compliance. 3D-colored images can visually show the change of respiratory resistance and reactance in COPD.Keywords: 3-dimensional impulse oscillometry, respiratory resistance, pulmonary function test, chronic obstructive pulmonary disease

Abstract Introduction Airway resistance and reactance, measured by forced oscillometry, are used to measure the airway obstruction in patients with asthma. Objectives This study aimed to investigate the oscillometric bronchodilator responses in treated and untreated asthma and evaluate its association with airway inflammation and disease duration. Materials and methods This study included 30 nonsmoking patients with mild to moderate treated asthma, 25 patients with newly diagnosed untreated asthma and 29 control subjects. Spirometric and oscillometric measurements were performed before and after inhalation of 400 µg salbutamol. Disease duration was defined as the number of years since asthma diagnosis. Results At airway resistance of 5 Hz (R5) and 20 Hz (R20), bronchodilator responses in patients with untreated and treated asthma were greater than those in control subjects. In patients with untreated asthma, higher fractional exhaled nitric oxide concentration (FeNO) levels were strongly correlated with greater reversibility of R20 (rs = −0.621, P < 0.001). In patients with treated asthma, there was no significant association between FeNO and oscillometric reversibility, whereas longer disease duration was significantly associated with lesser bronchodilator response at R20 (rs = 0.441, P < 0.05). Treated asthma patients with longer disease duration (≥10 years) showed significantly higher post‐bronchodilator R5 and R20 than the treated asthma patients with shorter disease duration (

The aim of the work was to conduct experimental studies aimed at determining the protection factor of the filter respirator with forced air supply by volunteers in different modes of operation and to establish the dependence of the amount of air supplied by the fan from the air purification device to the filter’s resistance. Simulation studies to determine the protective effectiveness of the filter respirator on the testers were performed according to the procedure for determining the penetration coefficient of test aerosol – sodium chloride, as the ratio of the submask concentration of test aerosol to the ambient concentration formed in a special chamber that meets the requirements of DSTU EN 13274. Determination of the amount of air supplied by the air purification unit to the submask space and assessment of the value of positive pressure inside the mask was performed according to the procedure described in DSTU EN 12941: 2004. As a result of simulated laboratory tests to determine the protective effectiveness of filter respirators with forced air supply to the testers, it was found that the average result of the protection factor of the test samples ranged from 99.93 to 99.97, which meets the requirements of DSTU EN 12941: 2004. In addition, it was found that the amount of air treated by the fan of the air purification device for clean filters is 165 and 215 dm3/min for operating modes “Normal” and “Turbo”, while for the polluted filters it is reduced to 131 and 185 dm3/min, respectively. During the study, the compliance of the value of excess pressure in the submask space with the requirements of DSTU EN 12941: 2004, which should not exceed 2.5 mbar, was confirmed. It is also determined that the stability of the technical parameters of the air purification device is maintained in the specified range when charging the “Dinogy Li-Pol 11000mAh 14.8V 4S 25C” brand battery not less than 12 V to ensure the current value of not less than 1.6 A. The practical value of the results lies in determining the duration of protective action of the filter respirator, the choice of filter resistance to establish the scope and modes of operation in the developed personal respiratory protection equipment.

Noemi Porojan-Suppini, Ovidiu Fira-Mladinescu, Monica Marc, Emanuela Tudorache, Cristian Oancea Department of Pulmonology, Center for Research and Innovation in Personalized Medicine of Respiratory Diseases, University of Medicine and Pharmacy “Victor Babeș”, Timișoara, RomaniaCorrespondence: Ovidiu Fira-MladinescuDepartment of Pulmonology, University of Medicine and Pharmacy “Victor Babeș”, Str. Gheorghe Adam nr. 13, Timișoara 300310, RomaniaTel +40 745608856Email mladinescu@umft.roAbstract: Over the past decades, impulse oscillometry (IOS) has gained ground in the battery of pulmonary function tests. Performing the test requires minimal cooperation of the patient; therefore, it is a useful tool, especially in evaluating lung mechanics in children, elderly patients, and those who cannot perform spirometry. Oscillometry has also been used in both clinical and research departments. Studies were published mainly in asthma regarding detection of bronchodilator response and the therapeutic response to different drugs. Furthermore, it has been shown to be a sensitive technique to evaluate disease control. Other studied diseases were COPD, interstitial lung diseases, small airway disease, impairment of lung function due to exposure to occupational hazards or smoking, central airways obstruction, cystic fibrosis, monitoring lung mechanics during mechanical ventilation and sleep, neuromuscular diseases, lung transplant, and graft function. The aim of this review is to present the utility of oscillometry on the previously mentioned clinical fields.Keywords: oscillometry, pulmonary function tests, respiratory resistance, respiratory impedance

Abstract Background Alveolar recruitment maneuvers enable easily reopening nonaerated lung regions via a transient elevation in transpulmonary pressure. To evaluate the effect of these maneuvers on respiratory resistance, we used an oscillatory technique during mechanical ventilation. This study was conducted to assess the effect of the alveolar recruitment maneuvers on respiratory resistance under routine anesthesia. We hypothesized that respiratory resistance at 5 Hz (R5) after the maneuver would be decreased after the lung aeration. Methods After receiving the ethics committee’s approval, we enrolled 33 patients who were classified with an American Society of Anesthesiologists physical status of 1, 2 or 3 and were undergoing general anesthesia for transurethral resection of a bladder tumor within a 12-month period from 2017 to 2018. The recruitment maneuver was performed 30 min after endotracheal intubation. The maneuver consisted of sustained manual inflation of the anesthesia reservoir bag to a peak inspiratory pressure of 40 cmH2O for 15 s, including 5 s of gradually increasing the peak inspiratory pressure. Respiratory resistance was measured using the forced oscillation technique before and after the maneuver, and the mean R5 was calculated during the expiratory phase. The respiratory resistance and ventilator parameter results were analyzed using paired Student’s t-tests, and p

BackgroundOscillometry has been employed widely as a non-invasive and standardized measurement of respiratory function in children and adults; however, limited information is available on infants.AimsTo establish the within-session variability of respiratory impedance (Zrs), to characterize the degree and profile of intra-breath changes in Zrs and to assess their impact on conventional oscillometry in newborns.Methods109 healthy newborns were enrolled in the study conducted in the first 5 postpartum days during natural sleep. A custom-made wave-tube oscillometry setup was used, with an 8–48 Hz pseudorandom and a 16 Hz sinusoidal signal used for spectral and intra-breath oscillometry, respectively. A resistance-compliance-inertance (R-C-L) model was fitted to average Zrs spectra obtained from successive 30-s recordings. Intra-breath measures, such as resistance (Rrs) and reactance (Xrs) at the end-expiratory, end-inspiratory and maximum-flow points were estimated from three 90-s recordings. All natural and artifact-free breaths were included in the analysis.ResultsWithin-session changes in the mean R, C and L values, respectively, were large (mean coefficients of variation: 10.3, 20.3, and 26.6%); the fluctuations of the intra-breath measures were of similar degree (20–24%). Intra-breath analysis also revealed large swings in Rrs and Xrs within the breathing cycle: the peak-to-peak changes amounted to 93% (range: 32–218%) and 41% (9–212%), respectively, of the zero-flow Zrs magnitude.DiscussionIntra-breath tracking of Zrs provides new insight into the determinants of the dynamics of respiratory system, and highlights the biasing effects of mechanical non-linearities on the average Zrs data obtained from the conventional spectral oscillometry.

Surgical masks are widely used for the prevention of respiratory infections. However, the risk of heat stroke during intense work or exercise in hot and humid environment is a concern. This study aimed to examine whether wearing a surgical mask increases the risk of heat stroke during mild exercise in such environment. Twelve participants conducted treadmill exercise for 30 min at 6 km/h, with 5% slope, 35°C ambient temperature, and 65% relative humidity, while wearing or not a surgical mask (mask and control trials, respectively). Rectal temperature (Trec), ear canal temperature (Tear), and mean skin temperature (mean Tskin) were assessed. Skin temperature and humidity of the perioral area of the face (Tface and RHface) were also estimated. Thermal sensation and discomfort, sensation of humidity, fatigue, and thirst were rated using the visual analogue scale. Trec, Tear, mean Tskin, and Tface increased during the exercise, without any difference between the two trials. RHface during the exercise was greater in the mask trial. Hot sensation was greater in the mask trial, but no influence on fatigue and thirst was found. These results suggest that wearing a surgical mask does not increase the risk of heat stroke during mild exercise in moist heat. [ABSTRACT FROM AUTHOR]

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Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive condition with unknown aetiology that causes the lung parenchyma to scar incessantly, lowering the quality of life and hastening death. In this investigation, we studied the anti-fibrotic activity of Geneticin (a derivative of gentamycin) using in vitro and in vivo models. The TGF-β-mediated differentiation model was adopted to investigate (fibrotic marker's levels/expression) the anti-fibrotic activity of geneticin (GNC) in in-vitro scenarios (LL29 and DHLF cells). In vivo , the bleomycin (BLM)-induced pulmonary fibrosis model was employed by administering BLM intratracheally. Post 14 days of BLM administration, animals were treated with geneticin (6.25, 12.5, and 25 mg·kg−1) for another 14 days, and their therapeutic effect was investigated using a spectrum of techniques. RTqPCR and western-blot results revealed that geneticin treatment significantly attenuated the TGF-β/BLM mediated fibrotic cascade of markers in both in-vitro and in-vivo models respectively. Further, the BLM-induced pulmonary fibrosis model revealed, that geneticin dose-dependently reduced the BLM-induced inflammatory cell infiltrations, and thickness of the alveoli walls, improved the structural distortion of the lung, and aided in improving the survival rate of the rats. Picrosirus and Masson's trichrome staining indicated that geneticin therapy reduced collagen deposition and, as a result, lung functional characteristics were improved as assessed by flexivent. Mechanistic studies have shown that geneticin reduced fibrosis by attenuating the TGF-β/Smad through modulating the AMPK/SIRT1 signaling. These findings suggest that geneticin may be a promising therapeutic agent for the treatment of pulmonary fibrosis in clinical settings. [ABSTRACT FROM AUTHOR]

In the community setting, assessing spirometry in school-aged children is often limited by the unavailability of respirology technicians at the point-of-care. We developed a new technique called the Rapid Expiratory Occlusion Method (REOM) that measures respiratory resistance during normal breathing, without specialized training. The aim was to examine the concordance between respiratory resistance measured with the REOM and respiratory resistance measured by oscillometry on the tremoflo. Children aged 6-17 yr, with or without asthma, received respiratory resistance testing on the tremoflo, then on the REOM. Three to five replicates with a coefficient of variation ≤15% were obtained on each instrument; the primary outcome was the concordance between the average respiratory resistance on the REOM and that measured at 5Hz (R5) on the tremoflo. Thirty-two children (11 girls; 21 boys) were enrolled with a mean age of 11.2 (range 6-17) yr; after excluding two children not meeting reproducibility criteria, 9 healthy controls, 15 controlled asthmatics, and 6 poorly controlled asthmatics were included. Resistance measured on the REOM showed a strong correlation with R5 measured on the tremoflo (P < 0.0001) with no significant differences on the Bland-Altman analyses. Children and their parents found the REOM easy to use and would consider for home use if recommended by their doctor. With the high concordance between resistance values measured on the REOM and that on the tremoflo combined with perceived ease of use, the REOM appears as a promising means for measuring lung function, thus supporting further testing of other psychometric properties. [ABSTRACT FROM AUTHOR]

Abstract Introduction Products based on inhaled corticosteroid (ICS)/long-acting β2 agonist (LABA) combinations may provide different clinical benefits. This study was conducted to compare the rapid effects of three such combination products: formoterol/fluticasone (FFC) aerosol (pMDI), formoterol/budesonide (FBC) dry powder inhaler (DPI), and vilanterol/fluticasone furoate (VFC) DPI. Methods The study design was a three-armed, randomized, crossover study. Patients included in the study had stable moderate asthma, defined as an Asthma Control Questionnaire (ACQ) score ≤ 0.75, and were undergoing step 2 or 3 asthma treatment as defined by JGL2015. Subjects were treated with fluticasone propionate inhaled via Diskus® during a 2-week washout period before randomization. At visit 2, subjects were randomly assigned in a 1:1:1 ratio to FFC, FBC, or VFC, and evaluated for changes in pulmonary function over time. At visits 3 and 4, the treatment was switched to another ICS/LABA combination in a crossover manner after a 1-week washout period. Spirometry was performed pre-dose and at 3, 10, and 30 min post-dose, and forced oscillation was implemented pre-dose and at 1, 7, 15, and 60 min post-dose. Results Fifteen outpatients (63.3 ± 9.5 years, ACQ: 0.13 ± 0.19) completed the study. ∆FEV1 at 3 min did not significantly differ among the three groups. Significant increases in FEV1 and %FEV1 from baseline were observed in the FFC (p = 0.004, 0.003), FBC (p = 0.014, 0.011), and VFC (p = 0.032, 0.023) groups at 30 min. Improvements in respiratory resistance at 5–20 Hz from baseline at 60 min, resonant frequency, respiratory system reactance at 5 Hz, and low-frequency reactance area from baseline were observed at 1 min in the FFC group (p = 0.014, 0.002, 0.027, 0.018, respectively). Conclusion FFC administered using a pMDI showed favorable delivery to peripheral airways and significantly more rapid action promptly after inhalation as compared with other ICS/LABA preparations inhaled using a DPI, thus broadening the potential therapeutic options for asthma. Trial Registration Number UMIN000029379. Funding Kyorin Pharmaceutical Co., Ltd.

Introduction: Airway resistance and reactance, measured by forced oscillometry, are used to measure the airway obstruction in patients with asthma. Objectives: This study aimed to investigate the oscillometric bronchodilator responses in treated and untreated asthma and evaluate its association with airway inflammation and disease duration. Materials and methods: This study included 30 nonsmoking patients with mild to moderate treated asthma, 25 patients with newly diagnosed untreated asthma and 29 control subjects. Spirometric and oscillometric measurements were performed before and after inhalation of 400 µg salbutamol. Disease duration was defined as the number of years since asthma diagnosis. Results: At airway resistance of 5 Hz (R5) and 20 Hz (R20), bronchodilator responses in patients with untreated and treated asthma were greater than those in control subjects. In patients with untreated asthma, higher fractional exhaled nitric oxide concentration (FeNO) levels were strongly correlated with greater reversibility of R20 (rs = −0.621, P < 0.001). In patients with treated asthma, there was no significant association between FeNO and oscillometric reversibility, whereas longer disease duration was significantly associated with lesser bronchodilator response at R20 (rs = 0.441, P < 0.05). Treated asthma patients with longer disease duration (≥10 years) showed significantly higher post‐bronchodilator R5 and R20 than the treated asthma patients with shorter disease duration (<10 years). Conclusion: The present study provides further evidence of an association between airway inflammation and variable airway obstruction in asthma patients and indicates that long‐term disease duration could be related to poorly reversible airway resistance in patients with mild to moderate asthma. [ABSTRACT FROM AUTHOR]

BACKGROUND: Limited studies have examined the implications of Second-Hand Smoke (SHS) on lung function; majority used traditional diagnostic lung function tests requiring forced respiratory manoeuvres. Aim of our study was to assess the immediate effects of exposure to SHS on the respiratory mechanics during tidal breathing. METHODS: 20 healthy non-smokers 18-45-years-old participated in four exposure sessions; 10 minutes in 250 μg/m³ PM2.5 (10/250), 20 minutes in 250 μg/m³ PM2.5 (20/250), 10 minutes in 500 μg/m³ PM2.5 (10/500) and 20 minutes in 500 μg/m³ PM2.5 (20/500). A pre and an immediately post exposure IOS measurement were obtained. Differences in Impulse Oscillometry (IOS) parameters pre and post exposure for each session were assessed with paired t-tests or Wilcoxon tests. Differences between exposure sessions were assessed with mixed linear models. Analysis was performed in Stata 14. RESULTS: Statistically significant differences were observed in IOS parameters in all exposure sessions, with most changes observed in 10/500 and least in 20/500 session. Analysis between sessions showed significantly different results between 20/250 compared to 10/250 session in many IOS parameters, while 10/500 differed statistically significantly to 10/250 only in R10 inspiratory. CONCLUSIONS: Present study is the first to show that acute exposure of healthy non-smokers to SHS leads to alterations of resting breathing mechanics, successfully captured by IOS. Alterations were expressed by increased Resistance of peripheral and central airways, findings suggestive of a likely broncho-constrictive response to the irritative inhalant. A mild, linear effect of exposure duration was found, while no clear effect was observed for the level of exposure. [ABSTRACT FROM AUTHOR]

Porojan-Suppini N, Fira-Mladinescu O, Marc M, Tudorache E, Oancea C. Ther Clin Risk Manag.2020;16:1139–1150. On page 1146, Other Diseases – Graft Function, Lung Transplant, Sickle-Cell Disease section, “A recent Chinese study, performed on 156 lung-transplanted patients, shows that Oscillometry identified physiological changes associated with grade 2 acute cell rejection that were not observed on spirometry and it’s usefor graft monitoring after a lung transplant.100” should read “A recent study, performed on 156 lung-transplanted patients, shows that Oscillometry identified physiological changes associated with grade 2 acute cell rejection that were not observed on spirometry and it’s use for graft monitoring after a lung transplant.100” The authors apologize for this error. Read the original article

Independently from the chronic anxiety disorder, patients could feel nervousness and anxiety due to surgical stress during preoperative period. Preoperative anxiety could lead to various complications owing to autonomous nerve system activation. We targeted to examine the effects of preoperative anxiety on bronchospasm. In the study, 20-50 years old ASA I patient to be given elective endoscopic urologic operations were included. Totally 124 patients were evaluated during preoperative period. The patients were interviewed before the operation to determine their anxiety levels (Beck Anxiety Scale). Patients were grouped according to anxiety state. 58 anxious patients (Study Group) and 66 non-anxious (Control Group) were compared according to bronchospasm, wheezing, SpO2 paucity and ETCO2 extent. Incidence of bronchospasm and wheezing were found more in the patient group having preoperative anxiety (p [Med-Science 2017; 6(4.000): 746-749]

The effects of asthma on affect have been noted for some time, but little is known about associated brain processes. We therefore examined whether emotion-induced bronchoconstriction, airway inflammation, and asthma control are related to specific patterns of brain activity during processing negative affective stimuli. Fifteen adults with asthma viewed alternating blocks of distressing film clips (negative condition), affectively neutral film clips (neutral condition), and a crosshair image (baseline condition) while undergoing blood oxygenation level-dependent (BOLD) functional MRI (fMRI). Block-design fMRI analysis evaluated the BOLD response to "negative-baseline" and "neutral-baseline" contrasts. Airway response to these film clips was also assessed with impulse oscillometry in a separate session. Measures of airway inflammation [fractional exhaled nitric oxide (FENO)] and asthma control [Asthma Control Questionnaire (ACQ)] were additionally obtained. A whole brain voxel-based regression analysis of contrast maps was performed against respiratory resistance increase during negative and neutral films, FENO, and ACQ. Peak airway obstruction to negative affective stimulation was associated with stronger activation of the anterior and middle cingulate gyrus, including the dorsal anterior cingulate cortex (dACC). Stronger airway inflammation and lower asthma control were associated with reduced activation to negative stimuli in the superior frontal gyrus, middle cingulate gyrus, and supplementary motor area. Activation of the dACC in negative-affect-induced airway obstruction could be part of an integrated defensive response to critical environmental change. In addition, reduced frontal and limbic activation during processing of negative affect may reflect consequences of pathophysiological processes for CNS functioning. NEW & NOTEWORTHY This functional magnetic resonance imaging study shows, for the first time, that the degree of airway constriction due to negative affective stimuli in asthma is associated with stronger response to these stimuli in the dorsal anterior and middle cingulate cortex. Asthma patients with stronger airway inflammation and reduced asthma control also show reduced activation in a number of cortical and subcortical areas relevant for affective processing and breathing control. [ABSTRACT FROM AUTHOR]

Lung function is an important tool in the diagnosis and monitoring of patients with asthma at all ages. Airway obstruction is a typical feature of asthma and it can be assessed with several lung function techniques. Spirometry, respiratory resistance and reactance, and lung volumes are available to measure it at different ages and in children. The assessment of a bronchodilator response is always recommended to show the reversibility of the obstruction. Poor lung function is a predictor of poor asthma outcome and a low Forced Expiratory Volume in the first second of expiration percent predicted measured with spirometry, has been shown to be associated with a higher risk of having an exacerbation during the following year independently of the presence of asthma symptoms. In severe asthma lung function assessment is used to distinguish different phenotypes, children with severe asthma have worse airflow limitation prior to administration of a bronchodilator than children with non severe asthma. Airway resistance and reactance are indirect measurements of airway obstruction and they can be measured with the forced oscillation technique, which is feasible also in non-collaborative children. This technique can be more informative in discriminating patients with asthma from healthy controls and is able to indicate a more peripheral involvement of the airways. The role of this technique in severe asthma is still debated. In conclusion lung function is useful in the clinical management of children with severe asthma.

Objective: To compare early pulmonary function tests (PFTs) in neonates with critical congenital heart disease (CHD) compared to a historical reference group., Design: Infants > 37 weeks gestation with critical CHD were studied within the first few days of life and prior to cardiac surgery and compared to data from a published reference group. Passive respiratory resistance (Rrs) and compliance (Crs) were measured with the single breath occlusion technique following specific acceptance criteria. The study was powered for a 30% difference in Rrs., Results: PFTs in 24 infants with CHD were compared to 31 historical reference infants. There was no difference in the Rrs between the groups. The infants with CHD had a significantly decreased Crs (1.02 ± 0.26 mL/cmH2O/kg versus 1.32 ± 0.36; (p < 0.05; mean ± SD))., Conclusions: Further prospective studies are required to quantify early PFTs in infants with CHD of different phenotypes., Competing Interests: The authors have no conflicts of interest to disclose. The study sponsors had no role in any of the following: 1) study design; 2) the collection, analysis, and interpretation of data; 3) the writing of the report; or 4) the decision to submit the manuscript for publication.

Introduction: Products based on inhaled corticosteroid (ICS)/long-acting β2 agonist (LABA) combinations may provide different clinical benefits. This study was conducted to compare the rapid effects of three such combination products: formoterol/fluticasone (FFC) aerosol (pMDI), formoterol/budesonide (FBC) dry powder inhaler (DPI), and vilanterol/fluticasone furoate (VFC) DPI.Methods: The study design was a three-armed, randomized, crossover study. Patients included in the study had stable moderate asthma, defined as an Asthma Control Questionnaire (ACQ) score ≤ 0.75, and were undergoing step 2 or 3 asthma treatment as defined by JGL2015. Subjects were treated with fluticasone propionate inhaled via Diskus® during a 2-week washout period before randomization. At visit 2, subjects were randomly assigned in a 1:1:1 ratio to FFC, FBC, or VFC, and evaluated for changes in pulmonary function over time. At visits 3 and 4, the treatment was switched to another ICS/LABA combination in a crossover manner after a 1-week washout period. Spirometry was performed pre-dose and at 3, 10, and 30 min post-dose, and forced oscillation was implemented pre-dose and at 1, 7, 15, and 60 min post-dose.Results: Fifteen outpatients (63.3 ± 9.5 years, ACQ: 0.13 ± 0.19) completed the study. ∆FEV1 at 3 min did not significantly differ among the three groups. Significant increases in FEV1 and %FEV1 from baseline were observed in the FFC (p = 0.004, 0.003), FBC (p = 0.014, 0.011), and VFC (p = 0.032, 0.023) groups at 30 min. Improvements in respiratory resistance at 5-20 Hz from baseline at 60 min, resonant frequency, respiratory system reactance at 5 Hz, and low-frequency reactance area from baseline were observed at 1 min in the FFC group (p = 0.014, 0.002, 0.027, 0.018, respectively).Conclusion: FFC administered using a pMDI showed favorable delivery to peripheral airways and significantly more rapid action promptly after inhalation as compared with other ICS/LABA preparations inhaled using a DPI, thus broadening the potential therapeutic options for asthma.Trial Registration Number: UMIN000029379.Funding: Kyorin Pharmaceutical Co., Ltd. [ABSTRACT FROM AUTHOR]

Introduction: Following reports of respiratory symptoms among service members returning from deployment to South West Asia (SWA), an expert panel recommended pre-deployment spirometry be used to assess disease burden. Unfortunately, testing with spirometry is high cost and time-consuming. The airflow perturbation device (APD) is a handheld monitor that rapidly measures respiratory resistance (APD-Rr) and has promising but limited clinical data. Its speed and portability make it ideally suited for large volume pre-deployment screening. We conducted a pilot study to assess APD performance characteristics and develop normative values.Materials and Methods: We prospectively enrolled subjects and derived reference equations for the APD from those without respiratory symptoms, pulmonary disease, or tobacco exposure. APD testing was conducted by medical technicians who received a 10-min in-service on its use. A subset of subjects performed spirometry and impulse oscillometry (iOS), administered by trained respiratory therapists. APD measures were compared with spirometry and iOS.Results: The total study population included 199 subjects (55.8% males, body mass index 27.7 ± 6.0 kg/m2, age 49.9 ± 18.7 yr). Across the three APD trials, mean inspiratory (APD-Ri), expiratory (APD-Re), and average (APD-Ravg) resistances were 3.30 ± 1.0, 3.69 ± 1.2, and 3.50 ± 1.1 cm H2O/L/s. Reference equations were derived from 142 clinically normal volunteers. Height, weight, and body mass index were independently associated with APD-Ri, APD-Re, and APD-Ravg and were combined with age and gender in linear regression models. APD-Ri, APD-Re, and APD-Ravg were significantly inversely correlated with FEV1 (r = -0.39 to -0.42), FVC (r = -0.37 to -0.40), and FEF25-75 (r = -0.31 to -0.35) and positively correlated with R5 (r = 0.61-0.62), R20 (r = 0.50-0.52), X5 (r = -0.57 to -0.59), and FRES (r = 0.42-0.43). Bland-Altman plots showed that the APD-Rr closely approximates iOS when resistance is normal.Conclusion: Rapid testing was achieved with minimal training required, and reference equations were constructed. APD-Rr correlated moderately with iOS and weakly with spirometry. More testing is required to determine whether the APD has value for pre- and post-deployment respiratory assessment. [ABSTRACT FROM AUTHOR]

Objectives: International guidelines recommend the use of long-acting bronchodilators for the treatment of chronic obstructive pulmonary disease (COPD), but the usefulness of short-acting bronchodilator assist use for stable COPD remains uncertain. The purpose of the present study was to objectively demonstrate the effects of assist use of procaterol, a short-acting β2-agonist, on the respiratory mechanics of stable COPD patients treated with a long-acting bronchodilator using forced oscillation technique (FOT) and conventional spirometry. We also confirmed the length of time for which procaterol assist could significantly improve the pulmonary function.Methods: We enrolled 28 outpatients with mild to severe COPD (Global Initiative for Obstructive Lung Disease stages I-III), who had used the same long-acting bronchodilator for longer than 3 months and who were in stable condition. All measures were performed using both FOT and spirometry sequentially from 15 min to 2 h after inhalation.Results: Compared to baseline, inhaled procaterol assist use modestly but significantly improved spirometric and FOT measurements within 2 h after inhalation. These significant effects continued for at least 2 h. -Significant correlations were found between parameters -measured by spirometry and those measured by FOT.Conclusions: Procaterol assist use modestly but significantly improved pulmonary function determined by spirometry and respiratory mechanics in patients with stable COPD treated with long-acting bronchodilators. Thus, inhaled procaterol has the potential for assist use for COPD. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: The forced oscillation technique (FOT) is a particularly useful test of the mechanical properties of the respiratory system that has an increasingly important role in lung function laboratories. There is general agreement in the literature that the determination of reference values is of utmost importance in the clinical use of the FOT. Objective: Our aim was to present reference values for whole‐breath FOT measurements, establish which anthropometric variables were more predictive of impedance parameters, and provide all the details to adequately adopt these reference equations in individual laboratories. Methods: We prospectively evaluated a randomly selected non‐smoking sample of the adult Brazilian population (288 subjects, 144 males and 144 females aged 20‐86 years). The volunteers were separated by sex and divided into six groups based on decade of age. Sex‐specific linear prediction equations were developed by multiple regression analysis using age, body mass and height as explanatory variables. Results: Age introduced a slight, but significant, reduction of resistance in men (P < .001) and women (P < .001). In general, significantly higher values of resistance were observed in females (P < .0001). Among the anthropometric variables analyzed, height was the best predictor for all parameters studied. Conclusion: This study provides an original frame of reference for the FOT in Brazilian males and females aged 20‐86 years. Height was the best predictor of respiratory impedance parameters. Details contributing to an adequate adoption of these reference equations elsewhere by transference and verification are also provided. [ABSTRACT FROM AUTHOR]

The mechanisms whereby anticholinergics improve asthma outcomes, such as lung function, symptoms, and rate of exacerbation, can be numerous. The most obvious is by affecting the contraction of airway smooth muscle (ASM). The acetylcholine released from the cholinergic nerves is the most important bronchoconstrictor that sets the baseline degree of contractile activation of ASM in healthy individuals. Although the degree of ASM's contractile activation can also be fine-tuned by a plethora of other bronchoconstrictors and bronchodilators in asthma, blocking the ceaseless effect of acetylcholine on ASM by anticholinergics reduces, at any given moment, the overall degree of contractile activation. Because the relationships that exist between the degree of contractile activation, ASM force, ASM shortening, airway narrowing, airflow resistance, and respiratory resistance are not linear, small decreases in the contractile activation of ASM can be greatly amplified and thus translate into important benefits to a patient's well-being. Plus, many inflammatory and remodeling features that are often found in asthmatic lungs synergize with the contractile activation of ASM to increase respiratory resistance. This review recalls that the proven effectiveness of anticholinergics in the treatment of asthma could be merely attributed to a small reduction in the contractile activation of ASM. [ABSTRACT FROM AUTHOR]

Background: We have previously shown that when asthmatics go supine, fluid shifts out of the legs, accumulates in the thorax, and exacerbates lower airway narrowing. In the retrospective analysis of our previous work presented here, we test the hypothesis that the sensitivity of this process relates inversely to baseline caliber of the lower airways.Methods: Eighteen healthy (six women) and sixteen asthmatic subjects (nine women) sat for 30 min, and then lay supine for 30 min. While supine, lower body positive pressure (LBPP, 40 mm Hg) was applied to displace fluid from the legs similar in amount to the overnight fluid shift. Respiratory resistance and reactance at 5 Hz (R5 and X5) and leg and thoracic fluid volumes (LFV and TFV) were measured at the beginning and end of the supine period.Results: With LBPP, healthy, and asthmatic subjects had similar changes in the LFV and TFV (p = 0.3 and 0.1, respectively). Sensitivity to fluid shift, defined by ΔR5/ΔTFV, was larger in the asthmatics than in the healthy subjects (p = 0.0001), and correlated with baseline R5 in the supine position in the asthmatics (p = 0.7, p = 0.003). No such association was observed in the healthy subjects (p = 0.6). In the asthmatics, women showed a greater reduction in X5 than men with LBPP (p = 0.009).Conclusions: Smaller baseline airway caliber, as assessed by larger R5, was associated with increased sensitivity to fluid shift in the supine position. We conclude that asthmatics with narrower small airways such as obese asthma patients, women with asthma and those with severe asthma may be more sensitive to the effects fluid shift while supine as during sleep.

A child suspected of exercise-induced laryngeal obstruction and asthma is examined by laryngoscopy and respiratory resistance (Rrs) after exercise challenge. Immediately at exercise cessation, the visualized adduction of the larynx in inspiration is reflected in a paroxystic increase in Rrs. While normal breathing has apparently resumed later on during recovery from exercise, the pattern of Rrs in inspiration is observed to reoccur following a deep breath or swallowing. The procedure may thus help diagnosing the site of exercise-induced obstruction when laryngoscopy is not available and identify re-inducers of laryngeal dysfunction.

Background:: The forced oscillation technique (FOT) is useful for studying pulmonary function in children, as well as in school children with asthma. However, the standard values for respiratory resistance (Rrs) in Asian school children remain unknown. We evaluated the standard Rrs using a type of FOT, impulse oscillometry (IOS), in healthy Japanese children at elementary and junior high schools. Methods:: A total of 795 children (age range: 6-15 years; mean age ± SD: 11.1 ± 2.4 years; 404 boys, 391 girls) at elementary and junior high schools participated in the study. Of the 795 children, we evaluated the Rrs of 537 children aged 6-15 years (mean ± SD: 10.8 ± 2.4 years) using IOS. Results:: Regression analyses with three IOS parameters, Rrs at 5 Hz (R5), Rrs at 20 Hz (R20), and Rrs difference between 5 Hz and 20 Hz (R5-R20), for age, height, weight, and degree of obesity as independent variables demonstrated the strongest correlation between each parameter and children’s height. All parameters decreased with increasing height. Using the lambda-mu-sigma (LMS) method, we created standard curves for the Rrs values based on height. Conclusions:: Our standard curves could be useful for diagnosis and control evaluation of childhood asthma.

Background: We have previously shown that when asthmatics go supine, fluid shifts out of the legs, accumulates in the thorax, and exacerbates lower airway narrowing. In the retrospective analysis of our previous work presented here, we test the hypothesis that the sensitivity of this process relates inversely to baseline caliber of the lower airways. Methods: Eighteen healthy (six women) and sixteen asthmatic subjects (nine women) sat for 30min, and then lay supine for 30min. While supine, lower body positive pressure (LBPP, 40mm Hg) was applied to displace fluid from the legs similar in amount to the overnight fluid shift. Respiratory resistance and reactance at 5Hz (R5 and X5) and leg and thoracic fluid volumes (LFV and TFV) were measured at the beginning and end of the supine period. Results: With LBPP, healthy, and asthmatic subjects had similar changes in the LFV and TFV (p = 0.3 and 0.1, respectively). Sensitivity to fluid shift, defined by ΔR5/ΔTFV, was larger in the asthmatics than in the healthy subjects (p = 0.0001), and correlated with baseline R5 in the supine position in the asthmatics (p = 0.7, p = 0.003). No such association was observed in the healthy subjects (p = 0.6). In the asthmatics, women showed a greater reduction in X5 than men with LBPP (p = 0.009). Conclusions: Smaller baseline airway caliber, as assessed by larger R5, was associated with increased sensitivity to fluid shift in the supine position. We conclude that asthmatics with narrower small airways such as obese asthma patients, women with asthma and those with severe asthma may be more sensitive to the effects fluid shift while supine as during sleep. [ABSTRACT FROM AUTHOR]

The forced oscillation technique (FOT) can provide unique and clinically relevant lung function information with little cooperation with subjects. However, FOT has higher variability than spirometry, possibly because strategies for quality control and reducing artifacts in FOT measurements have yet to be standardized or validated. Many quality control procedures rely on either simple statistical filters or subjective evaluation by a human operator. In this study, we propose an automated artifact removal approach based on the resistance against flow profile, applied to complete breaths. We report results obtained from data recorded from children and adults, with and without asthma. Our proposed method has 76% agreement with a human operator for the adult data set and 79% for the pediatric data set. Furthermore, we assessed the variability of respiratory resistance measured by FOT using within-session variation (wCV) and between-session variation (bCV). In the asthmatic adults test data set, our method was again similar to that of the manual operator for wCV (6.5 vs. 6.9%) and significantly improved bCV (8.2 vs. 8.9%). Our combined automated breath removal approach based on advanced feature extraction offers better or equivalent quality control of FOT measurements compared with an expert operator and computationally more intensive methods in terms of accuracy and reducing intrasubject variability. NEW & NOTEWORTHY The forced oscillation technique (FOT) is gaining wider acceptance for clinical testing; however, strategies for quality control are still highly variable and require a high level of subjectivity. We propose an automated, complete breath approach for removal of respiratory artifacts from FOT measurements, using feature extraction and an interquartile range filter. Our approach offers better or equivalent performance compared with an expert operator, in terms of accuracy and reducing intrasubject variability. [ABSTRACT FROM AUTHOR]

The Douglas bag technique is reviewed as one in a series of articles looking at historical insights into measurement of whole body metabolic rate. Consideration of all articles looking at Douglas bag technique and chemical gas analysis has here focused on the growing appreciation of errors in measuring expired volumes and gas composition, and subjective reactions to airflow resistance and dead space. Multiple small sources of error have been identified and appropriate remedies proposed over a century of use of the methodology. Changes in the bag lining have limited gas diffusion, laboratories conducting gas analyses have undergone validation, and WHO guidelines on airflow resistance have minimized reactive effects. One remaining difficulty is a contamination of expirate by dead space air, minimized by keeping the dead space <70 mL. Care must also be taken to ensure a steady state, and formal validation of the Douglas bag method still needs to be carried out. We may conclude that the Douglas bag method has helped to define key concepts in exercise physiology. Although now superceded in many applications, the errors in a meticulously completed measurement are sufficiently low to warrant retention of the Douglas bag as the gold standard when evaluating newer open-circuit methodology. [ABSTRACT FROM AUTHOR]

[Display omitted] • Both experimental and numerical simulation were conducted to study the role of each mask layer in particle size–dependent filtration and respiratory resistance. • By using scanning electron microscopy images of a commercial three-layer mask, four representative models were constructed, in which the computational fluid dynamics of multiphase flow were performed. • Numerical simulation was then verified by comparing the data measured in this study and other theoretical works. The three-layer surgical mask was recognized by the World Health Organization as an effective-protection tool for reducing SARS-CoV-2 transmission during the COVID-19 pandemic; however, the contribution of each layer of this mask to the particle size–dependent filtration performance resistance remains unclear. Here, both experimental work and numerical simulation were conducted to study the role of each mask layer in particle size–dependent filtration and respiratory resistance. By using scanning electron microscopy images of a commercial three-layer mask, composed of two spun-bond and one melt-blown nonwoven polypropylene fabric layers, four representative models were constructed, in which the computational fluid dynamics of multiphase flow were performed. The pressure drop of all models under different flow conditions was measured next. Numerical simulation was then verified by comparing the experimental results in the present study and other theoretical works. The filtration efficiency of the spun-bond polypropylene nonwoven fabric layer was much lower than that of the melt-blown nonwoven polypropylene fabric layer for the particle diameter in the range of 0.1–2.0 μm. Both the spun-bond and melt-blown nonwoven polypropylene fabric layers demonstrated extremely low filtration efficiency for particles was<0.3 μm in diameter, with the maximum filtration efficiency being only 30%. The present results may facilitate rational design of mask products in terms of layer number and structural design. [ABSTRACT FROM AUTHOR]