Assessing Airway Resistance Using Plethysmography as Lung Function Testing Among Asymptomatic Rheumatoid Arthritis Patients.

Pulmonary events in rheumatoid arthritis (RA) reflects the involvement of pleurae, lung interstitium, and airways. Overall, pulmonary manifestations are estimated to cause 10–20% of mortalities in RA. Respiratory system involvement as extra-articular presentations of RA is common among some Saudi patients. This study aims to evaluate specific airway conductance (sGaw), airway resistance (Raw), and specific airway resistance (sRaw), using plethysmography. Comparison for deployed methods is made by forced spirometer as an indicator for obstruction among patients with RA. The study sought to use the methods to enhance lung testing among RA patients. An analytical, hospital-based study was carried out at pulmonary function test laboratory, department of respiratory care King Saud Medical City (KSMC). RA patients were selected, with an age group of 18-75years. The tests for Forced spirometer and plethysmography were carried out to assess and analyze how the respiratory mechanism was impacted by the disease. Data collected was analyzed using Statistical Package for Social Sciences (SPSS), version 21. The obstructive and mixed ventilation patterns constituted 15%; the mean values of Raw and sRaw were significantly higher compared to mean values predicted for participants selected during the study, while sGaw was significantly lower compared to mean values predicted for participants selected. Monitoring of airway resistance parameters using plethysmography can be used as indicators of lung function testing among RA patients.

Quantification of Airway Conductance from Non-invasive Ventilatory Drive in Patients with Sleep Apnea

Upper airway conductance, the ratio of inspiratory airflow to inspiratory effort, quantifies the degree of airway obstruction in hypopneas observed in sleep apnea. We evaluated the ratio of ventilation to non-invasive ventilatory drive as a surrogate of conductance. Further, we developed and tested a refinement of non-invasive drive to incorporate the interactions of inspiratory flow, pressure, and drive in order to better estimate conductance. Hypopneas were compiled from existing polysomnography studies with esophageal catheterization in 18 patients with known or suspected sleep apnea, totaling 1517 hypopneas during NREM sleep. For each hypopnea, reference-standard conductance was calculated as the ratio of peak inspiratory flow to esophageal pressure change during inspiration. Ventilatory drive was calculated using the algorithm developed by Terrill et al and then mathematically modified according to the presence or absence of flow limitation in order to non-invasively estimate esophageal pressure. The ratio of ventilation to ventilatory drive and the ratio of peak inspiratory flow to estimated esophageal pressure were each compared to the reference standard for all hypopneas and for median values from individual patients. Hypopnea ventilation:drive ratios were of limited correlation with the reference standard (R2 = 0.17, individual hypopneas; R2 = 0.03, median patient values). Modification of drive to estimated pressure yielded estimated conductance, which strongly correlated with reference standard conductance (R2 = 0.49, individual hypopneas; R2 = 0.77, median patient values­). We conclude that the severity of airway obstruction during hypopneas may be estimated from non-invasive drive by accounting for mechanical effects of flow on pressure.

Wnt signaling in lung development, regeneration, and disease progression

The respiratory tract is a vital, intricate system for several important biological processes including mucociliary clearance, airway conductance, and gas exchange. The Wnt signaling pathway plays several crucial and indispensable roles across lung biology in multiple contexts. This review highlights the progress made in characterizing the role of Wnt signaling across several disciplines in lung biology, including development, homeostasis, regeneration following injury, in vitro directed differentiation efforts, and disease progression. We further note uncharted directions in the field that may illuminate important biology. The discoveries made collectively advance our understanding of Wnt signaling in lung biology and have the potential to inform therapeutic advancements for lung diseases.

Could Be % MMEF and sGaw Determinant Diagnostic Parameters Between Partial Reversibility and Reversibility in Evaluating Short-Acting Bronchodilator Response?

INTRODUCTION: By examining the relationship between changes in maximum mild-expiratory flow( MMEF) and specific airway conductance(sGaw), parameters with the change in FEV1 when evaluating the spirometer test and the bronchodilator response, we investigated their diagnostic contribution to the bronchodilator response in those with partial responses to FEV1. METHODS: The retrospective study sample consists of data from 112 patients between Jun 1, 2019, and Feb 1, 2020 who applied to the pulmonary function laboratory with a pre-diagnosis of bronchial hyperreactivity as well as body plethysmography test performed together with the reversibility test. RESULTS: MMEF% and ▲sGaw were linearly correlated with ▲FEV1 (respectively r = 0.752; p <0.001, r = 0.611; p <0.001). While there was a significant difference between ▲MMEF% and ▲sGaw between reversible, partially reversible, and irreversible groups (P <0.001), there was no significant difference in ▲sGaw between partial reversible and reversible groups in post-hoc comparisons (P> 0.05). In the binary logistic regression model created between the partially reversible and reversible groups, demographic characteristics, MMEF% and ▲sGaw variables, ▲MMEF was an independent predictor [OR: 1.132; 95% CI (1.036-1.238), p = 0.006]. The 24% threshold for absolute reversibility or partial reversibility calculated with MMEF% was significant, indicating significance at 86.2% sensitivity and 80.8% specificity (AUC: 0.811, 95% CI: 0.686-0.936; p <0.001). This value we found defined 81% of the partially reversible group as reversible. DISCUSSION AND CONCLUSION: We observed that ▲sGaw alone didn' have a determinant contribution for determining reversibility in bronchodilator response, which showed partial reversibility with respect to FEV1 change. We believe that ▲MMEF% can be an independent predictor between these two groups and the calculated threshold value of 24% can be used as a criterion for determining the reversibility in cases where FEV1 is not determinant.

Cardiorespiratory disorders in preschool aged children associated with aerogenic impact of benzene, phenol and formaldehyde

There was performed an examination of 437 pre-school aged children living in the conditions of the pollution of atmospheric air with benzene, phenol andformaldehyde. Children with the elevated blood content of benzene, phenol andformaldehyde were detected to be diagnosed as having chronic respiratory diseases and asteno-neurotic syndrome by 3 and 1.3 times more often, respectively, in contrast to the reference group. Cardiorespiratory disorders in children with the elevated content of benzene, phenol and formaldehyde are manifested by restrictive and mixed disorders of airway conductance followed by the increase in markers of proliferative cell activity (CA-72-4 and M 20), changes in the electrophysiologicalprocesses in cardiac muscle pronounced by the decreased electric ventricular systole (QT interval) followed by the decline of the content in blood of glutathione-S-transferase, zAMF, nitrogen oxide and the increase in the lipids hydroperoxide level, and creatine phosphokinase activity.

The short-term bronchodilator effects of the dual phosphodiesterase 3 and 4 inhibitor RPL554 in COPD

We investigated the short-term bronchodilator effects of RPL554 (an inhaled dual phosphodiesterase 3 and 4 inhibitor) combined with other bronchodilators in chronic obstructive pulmonary disease patients with reversibility (>150 mL to short-acting bronchodilators).Study 1 was a six-way, placebo-controlled crossover study (n=36) with single doses of RPL554 (6 mg), salbutamol (200 µg), ipratropium (40 µg), RPL554 (6 mg)+salbutamol (200 µg), RPL554 (6 mg)+ipratropium (40 µg) or placebo. Study 2 was a three-way crossover study (n=30) of tiotropium (18 µg) combined with RPL554 (1.5 or 6 mg) or placebo for 3 days. Forced expiratory volume in 1 s (FEV1), lung volumes and specific airway conductance (sGaw) were measured.In study 1, peak FEV1 change compared with placebo was similar with RPL554, ipratropium and salbutamol (mean 223, 199 and 187 mL, respectively). The peak FEV1 was higher for RPL554+ipratropium versus ipratropium (mean difference 94 mL; p<0.0001) and RPL554+salbutamol versus salbutamol (mean difference 108 mL; p<0.0001). In study 2 (day 3), both RPL554 doses caused greater peak FEV1 effects than placebo. The average FEV1(0–12 h) increase was greater with RPL554 6 mg only versus placebo (mean difference 65 mL; p=0.0009). In both studies, lung volumes and sGaw showed greater RPL554 combination treatment effects versus monotherapy.RPL554 combined with standard bronchodilators caused additional bronchodilation and hyperinflation reduction.

Measurement of tidal breathing flows in infants using impedance pneumography

Tidal breathing flow volume (TBFV) profiles have been used to characterise altered lung function. Impedance pneumography (IP) is a novel option for assessing TBFV curves noninvasively. The aim of this study was to extend the application of IP for infants and to estimate the agreement between IP and direct pneumotachograph (PNT) measurements in assessing tidal airflow and flow-derived indices.Tidal flow profiles were recorded for 1 min simultaneously with PNT and uncalibrated IP at baseline in 44 symptomatic infants, and after methacholine-induced bronchoconstriction in a subgroup (n=20).The agreement expressed as the mean deviation from linearity ranged between 3.9 and 4.3% of tidal peak inspiratory flow, but was associated with specific airway conductance (p=0.002) and maximal flow at functional residual capacity (V′maxFRC) (p=0.004) at baseline. Acute bronchoconstriction induced by methacholine did not significantly affect the agreement of IP with PNT. TBFV indices derived from IP were slightly underestimated compared to PNT, but were equally well repeatable and associated with baseline V′maxFRC (p=0.012 and p=0.013, respectively).TBFV profiles were consistent between IP and PNT in most infants, but the agreement was affected by reduced lung function. TBFV parameters were not interchangeable between IP and PNT, but had a similar association with lung function in infants.