Ventilatory Limitation Research Articles

Cardiopulmonary Exercise Performance of Children Born Non-Extremely Preterm.

Data on exercise tolerance of children born non-extremely preterm are sparse. We aimed to explore the cardiopulmonary exercise testing (CPET) characteristics in this population. We studied 63 children (age 7-12 years) born at 290/7-366/7 weeks of gestation (34 were late preterm, 29 were preterm) and 63 age-matched, term-born controls. All performed spirometry and CPET (cycle ergometry). There were no differences in activity levels and spirometric parameters between the group of preterm-born children and controls. A peak oxygen uptake (VO2peak) of <80% was noted in 25.4% of the term-born and 49.2% of preterm-born children (p = 0.001). Term-born participants presented similar VO2peak to late-preterm children but higher than those born at <340/7 weeks of gestation (p = 0.002). Ventilatory limitation was noted in 4.8% of term and 7.9% of preterm participants, while only one preterm child presented cardiovascular limitation. Children born before 34 weeks of gestation had higher respiratory rates and smaller tidal volumes at maximum exercise, as well as lower oxygen uptake for the level of generated work. We conclude that school-age children born at 29-34 weeks of gestation may present decreased exercise performance attributed to an altered ventilatory response to exercise and impaired O2 utilization by their skeletal muscles rather than other cardiopulmonary limiting factors.

Nasofacial Groove Pedicled Flap for the Reconstruction of Lateral Alar Defect.

The repair of nasal alar defects is challenging for plastic surgeons, and there is currently no standard operation. Herein, the authors reported the clinical outcomes of a nasofacial groove pedicled flap for the reconstruction of alar defect. This retrospective study included patients who underwent the nasofacial groove pedicled flap for the reconstruction of alar defect between January 2018 and June 2020. Photographs of standard facial postures were taken before and after surgery to record the surgical results of the patients. The patient's medical history was reviewed retrospectively. Self-reported satisfaction of patients on scar morphology and reconstructive effect were evaluated with a questionnaire survey. There were 26 eligible patients enrolled, and all patients were followed up for more than 1 year after surgery. All flaps were free of ischemia and necrosis and healed well. No patient experienced restricted nostril ventilation. Eight patients underwent reoperation to trim the flap pedicle and the scar. Eight patients (8/26) reported "very satisfied," and 17 patients (17/26) reported "satisfied" with the repair effect and scar morphology. One patient went through multiple laser treatments to improve her scars but still remained visible hyperpigmentation. She was dissatisfied with postoperative flap pigmentation but was satisfied with the correction effect. The clinical results indicated that the nasal groove flap was safe for the treatment of the lateral alar defect, and the patients were satisfied with the clinical results. The authors believe that this flap can be used as an alternative method for repairing the lateral alar defect. Level -IV, therapeutic study.

ABOLITION OF SAGITTAL T7-T10 DYNAMICS DURING FORCED VENTILATION IN AIS PATIENTS WITH LENKE 1A CURVES

In healthy subjects, respiratory maximal volumes are highly dependent on the sagittal range of motion of the T7-T10 segment. In AIS, the abolition of T7-T10 dynamics related to the stiffness induced by the apex region in Lenke IA curves could harm ventilation during maximal breathing. The aim of this study was to analyze the dynamics of the thoracic spine during deep breathing in AIS patients and in healthy matched controls. This is a cross-sectional, case-control study. 20 AIS patients (18 girls, Cobb angle, 54.7±7.9°; Risser 1.35±1.2) and 15 healthy volunteers (11 girls) matched in age (12.5 versus 15.8 yr. mean age) were included. In AIS curves, the apex was located at T8 (14) and T9 (6). Conventional sagittal radiographs of the whole spine were performed at maximal inspiration and exhalation. The ROM of each spinal thoracic functional segment (T1-T7, T7-T10, T10-T12) and the global T1-T12 ROM were measured. In healthy subjects, the mean T1-T12 ROM during forced breathing was 16.7±3.8. AIS patients showed a T1-T12 ROM of 1.1±1.5 (p&lt;0.05), indicating a sagittal stiffness of the thoracic spine. A wide T7-T10 ROM (15.3±3.0) was found in healthy controls (91.6% of the T1–T12 ROM). AIS patients showed only 0.4±1.4 ROM at T7-T10 (36.4% of the T1-T12 ROM) (p&lt;0.001). There was a significant positive correlation between the magnitude of T7-T10 kyphosis in maximal exhalation and both FVC (% of predicted FVC) and FEV1. In conclusion, Lenke 1A AIS patients show a restriction of the thoracic spine motion with an almost complete abolition of T7-T10 ROM, a crucial segment for deep breathing. T7-T10 stiffness could explain the ventilatory limitations found in AIS patients.

Longitudinal Relationship Between Physical Activity Levels and Respiratory Function in Older Individuals : A Longitudinal Study

Aging causes various physical changes, including decreased respiratory function characterized by decreased lung elasticity, reduced chest wall compliance, and weakened respiratory muscles. This study explored the longitudinal impact of daily physical activity (PA) on respiratory function in elderly individuals aged ≥50 years in England. Using data from Waves 2 (2004–2005), 4 (2008–2009), and 6 (2012–2013), we examined the influence of different levels of PA on forced expiratory volume (FEV), forced vital capacity (FVC), and other respiratory measures. Participants were classified based on self-reported PA into three categories; “hard” (vigorous activity at least 1–3 times monthly), “middle” (moderate activity 1–3 times monthly), and “nothing” (no PA). The inclusion criteria required participants to be ≥50 years and to have valid respiratory measures. The exclusion criterion was the presence of significant respiratory or cardiovascular disease at baseline. We applied the Sequential Doubly Robust Estimator and SuperLearner ensemble methods in the analysis using inverse probability weighting to address follow up bias and found that vigorous PA significantly reduced the risk of FVC by 4.10-fold compared with no exercise. In addition, vigorous exercise was associated with a 0.63-fold reduction in the risk of restrictive ventilation disorders while moderate exercise approached significance for FVC (p = 0.08). No significant effects were found with obstructive ventilation impairment (FEV). Overall, vigorous PA appears to be crucial for maintaining respiratory function in older individuals, highlighting the importance of regular exercise in preventing respiratory decline and potentially extending a healthy lifespan. These results underscore the need to promote regular PA to improve quality of life and reduce the risk of respiratory disease.

Mechanistic analysis of Th2-type inflammatory factors in asthma.

The main pathological features of asthma are widespread chronic inflammation of the airways and restricted ventilation due to airway remodeling, which involves changes in a range of regulatory pathways. While the role of T helper type 2 (Th2)-related inflammatory factors in this process is known, the detailed understanding of how genes affect protein functions during airway remodeling is still lacking. This study aims to fill this knowledge gap by integrating gene expression data and protein function analysis, providing new scientific insights for a deeper understanding of the mechanisms of airway remodeling and for further development of asthma treatment strategies. In this study, the mechanism of Th2-related inflammatory factors in tracheal remodeling was studied through differentially expressed gene (DEG) screening, enrichment analysis, protein-protein interaction (PPI) network construction, machine learning, and the construction of a line graph model. Our study revealed that S100A14, KRT6A, S100A2, ABCA13, UBE2C, RASSF10, PSCA, PLAT, and TIMP1 may be the key genes for airway remodeling; epithelial-mesenchymal transition (EMT)-related genes GEM, TPM4, SLC6A8, and SNTB1 may be involved in airway remodeling due to asthma; IL6 may affect the occurrence of airway remodeling by binding to UBE2C protein or by regulating GEM genes, respectively; IL6 and IL9 may affect the occurrence of airway remodeling by regulating the downstream Toll-like receptor (TLR) signaling pathway and thus IL6 and IL9 may influence the occurrence of tracheal remodeling by regulating downstream TLR signaling pathways. This study further mined the asthma gene microarray database through bioinformatics analysis and identified key genes and important pathways affecting airway remodeling in asthma patients, providing new ideas to uncover the mechanism of airway remodeling due to asthma and then seek new therapeutic targets.

Improvement of Pulmonary Function and Reconstructed 3-Dimensional Lung Volume After Halo-Pelvic Traction Combined With Posterior Correction for Severe Rigid Spinal Scoliosis: A Multicenter Study.

Severe rigid spinal scoliosis (SRSS) leads to severe restrictive ventilation dysfunction. Currently, the reports about the influence of preoperative halo-pelvic traction (HPT) combined with correction surgery on pulmonary function in patients with SRSS were relatively few. This study aims to investigate (1) the influence of preoperative HPT on lung volume and pulmonary function, (2) the further influence of the following correction surgery on lung volume and pulmonary function, and (3) the relationship among deformity correction, pulmonary function test outcomes, and computed tomography-based lung volume. A total of 135 patients with SRSS who underwent preoperative HPT and followed low-grade osteotomy correction surgery were reviewed. Spinal parameters, including proximal thoracic curve, main thoracic curve (MTC), lumbar curve, coronal balance, thoracic kyphosis, lumbar lordosis, sagittal vertical axis, pulmonary function test outcomes (forced vital capacity [FVC], the percentage of predicted forced vital capacity [FVC%], forced expiratory volume in 1 second [FEV1], total lung capacity [TLC]), and lung volume (Vin), were analyzed before, after HPT and at the final follow-up, respectively. The mean FVC, FVC%, FEV1, and TLC increased from 1.67 L, 51.13%, 1.47 L, and 2.37 L to 1.95 L, 64.35%, 1.75 L, and 2.78 L, respectively, after HPT and further improved to 2.22 L, 72.14%, 1.95 L, and 3.15 L, respectively, at the final follow-up. The mean Vin increased from 1.98 L to 2.42 L after traction and further increased to 2.76 L at the final follow-up. The variation of MTC was correlated with the improvement of FVC (r = 0.429, P = .026), FVC% (r = 0.401, P = .038), FEV1 (r = 0.340, P = .043), and TLC (r = 0.421, P = .029) and the variation of Vin (r = 0.425, P = .015) before HPT and after surgery. Preoperative HPT can improve preoperative pulmonary function and enhance the preoperative lung volume. There were significant correlations among the variations of MTC, pulmonary function indexes, and lung volume before HPT and after surgery in patients with SRSS.

Agreement between two independent raters in identifying exercise oscillatory ventilation in patients with heart failure

Abstract Background Heart failure (HF) leads to several functional and ventilatory limitations, including exercise oscillatory ventilation (EOV), whose presence is associated with an adverse prognosis, with a risk more than 4 times higher for a cardiovascular event. Methods to identify the presence of EOV were created and are being reformulated based on the amplitude and duration in the oscillation of the ventilatory cycles. Despite the documented association between EOV and prognosis in HF, the diversity of methods and subjective interpretation can compromise the diagnosis and adequate risk stratification. Purpose To analyze the agreement of the EOV identification between two independent raters and compare the clinical characteristics of the patients with and without EOV. Methods A cross-sectional study was carried out using an electronic questionnaire containing graphs of exercise ventilation over time from treadmill cardiopulmonary stress tests (CPET) performed in patients with HF, with preserved or reduced left ventricular ejection fraction (LVEF). The graphs were interpreted by two cardiologists with extensive experience in performing CPET. The research was approved by the institution's ethics and research committee. Agreement was evaluated by Cohen Kappa statistics and the proportion of agreements between raters. Differences among variables according to the presence of EOV (identified by at least one of the raters) were analyzed with Mann-Whitney test. A two-sided p-value &amp;lt; 0.05 was considered significant for all analyses. Results The sample consisted of 31 patients (74% men, 56 years ± 10 years) with a LVEF of 44 ± 12%, 61% with reduced LVEF, 80% with NYHA functional classification I/II, and peak oxygen uptake (VO2peak) of 17.6 ± 4.3 mL/kg/min. The EOV identification by the raters revealed a moderate agreement, with Kappa of 0.56. The proportion of agreement was 84% (26 of 31 cases) and the specific agreement (presence of EOV) was 50% (5 of 10 cases) (Figure 1). Regarding the clinical characteristics of patients with and without EOV (Figure 2), the only variable with statistical difference was VO2peak, with lower values in the patients with EOV (14.9 versus 17.9 mL/kg/min; p = 0.019). Conclusion The agreement between two experienced raters was only moderate, which demonstrate that the identification of EOV remains challenging. The only clinical characteristics associated with presence of EOV in our sample was VO2peak, suggesting a poor prognosis in patients with HF and EOV.

Influence of kyphosis in ankylosing spondylitis on cardiopulmonary functions.

This paper aims at analyzing the characteristics of cardiopulmonary functions in the patients with ankylosing spondylitis (AS), and exploring the influence of global kyphosis (GK) on cardiopulmonary functions. Clinical data of 46 patients with AS and kyphosis, who had been admitted in our hospital from October 2021 to October 2022, were analyzed retrospectively. According to the to global kyphosis (GK) angle, 23 subjects were divided into Severe Group (GK > 95°), and 23 subjects were divided into in the Moderate Group (80° ≤ GK ≤ 95°). Cardiac structure and cardiopulmonary function parameters were compared between both groups, and the influences of GK Angle on other parameters were analyzed by Pearson or Spearman correlation analysis. The cardiac structure and function measurements in both groups were within the normal range. The pulmonary functions of both groups decreased to different extents. Correlation analysis showed that GK Angle was significantly negatively correlated with the left atrioventricular size (LAD, LVDD, LVSD) and diastolic function parameters (E/A, e'/a') in the patients with AS (P < .05); GK Angle was negatively correlated with restrictive ventilation parameters in the patients with AS (P < .05). The GK Angle of the patients with AS affects the cardiac structure and diastolic function. The larger the GK Angle is, the smaller the left and right at ventricle diameters are. In addition, GK Angle also affects the left ventricular diastolic function. GK Angle is related to the degree of pulmonary function impairment, and the larger the GK Angle is, the worse the pulmonary function it will be.

Paleoproductivity and deep-sea oxygenation in Cosmonaut Sea since the last glacial maximum: impact on atmospheric CO2

The paleoproductivity in the Southern Ocean plays a crucial role in controlling the atmospheric CO2 concentration. Here, we present the sediment record of gravity core ANT37-C5/6-07, which was retrieved from the Cosmonaut Sea (CS), Indian Ocean sector of the Southern Ocean. We found that the change in the oxygen concentration in the CS bottom water is strongly correlated with the atmospheric CO2 fluctuations since the Last Glacial Maximum (LGM). Based on the change in the export production, we reconstructed the evolution history of the deep-water ventilation/upwelling in the study area. During the LGM, a large amount of respiratory carbon was stored in the deep Southern Ocean due to the effect of the low export productivity and restricted ventilation. The oxygen concentration was also low at this time. Despite the increase in paleoproductivity, the biological pump efficiency remained at a low level during the Last Deglaciation. Vast quantities of CO2 were released into the atmosphere through enhanced upwelling. The recovery of ventilation during this period facilitated the supply of oxygen-rich surface water to the deep ocean. Moreover, signals were identified during the transitions between the Heinrich Stage 1 (HS1), Antarctic Cold Reverse (ACR), and Younger Drays (YD) periods. During the Holocene, the productivity increased overall, and the oxygen in the bottom water was consumed but still remained at a high level. This may have been caused by the enhanced ventilation and/or the prevalence of East Cosmonaut Polynya (ECP) near Cape Ann.

Ventilatory limitations in patients with HFpEF and obesity

Heart failure with preserved ejection fraction (HFpEF) patients have an increased ventilatory demand. Whether their ventilatory capacity can meet this increased demand is unknown, especially in those with obesity. Body composition (DXA) and pulmonary function were measured in 20 patients with HFpEF (69 ± 6 yr;9 M/11 W). Cardiorespiratory responses, breathing mechanics, and ratings of perceived breathlessness (RPB, 0–10) were measured at rest, 20 W, and peak exercise. FVC correlated with %body fat (R2 =0.51,P = 0.0006), V̇O2peak (%predicted,R2 =0.32,P = 0.001), and RPB (R2 =0.58,P = 0.0004). %Body fat correlated with end-expiratory lung volume at rest (R2 =0.76,P < 0.001), 20 W (R2 =0.72,P < 0.001), and peak exercise (R2 =0.74,P < 0.001). Patients were then divided into two groups: those with lower ventilatory reserve (FVC<3 L,2 M/10 W) and those with higher ventilatory reserve (FVC>3.8 L,7 M/1 W). V̇O2peak was ∼22% less (p < 0.05) and RPB was twice as high at 20 W (p < 0.01) in patients with lower ventilatory reserve. Ventilatory reserves are limited in patients with HFpEF and obesity; indeed, the margin between ventilatory demand and capacity is so narrow that exercise capacity could be ventilatory limited in many patients.

External Respiratory Function, Inflammation Markers, and Life Quality Depending on the Volume of Tuberculosis Lung Lesion

Tuberculosis is a common disease in many countries, so understanding of its impact on life quality and respiratory function as well as study of correlations of these parameters with biochemical markers of tuberculosis course and treatment effectiveness is important in evaluating new methods of treatment and prevention. Objective — to investigate the relationships between the function of external respiration, the level of Human-beta-defensin-1, ferritin, interleukin-6, quality of life and the volume of tuberculosis lung lesions. Materials and methods. 100 patients with pulmonary tuberculosis were included in the study. Patients were divided into groups depending on the volume of tuberculous lesions: Group 1 (n = 36) had lesions within one lung, Group 2 (n = 64) had lesions of both lungs. Examination of patients was carried out according to the current standards of providing medical care to tuberculosis patients. In addition, patients underwent determination of ferritin, interleukin-6 (IL-6), and Human-beta-defensin-1 (HBD-1) levels in the blood by ELISA test. Spirography was performed to determine the parameters of the function of external breathing. Interviews were provided using SF-36 questionnaire with the determination of the main indicators of quality of life. Statistical data processing was carried out using the Statistica 8.0. Results and discussion. Comparison of spirometry parameters between groups showed significantly lower respiratory function parameters in patients with bilateral tuberculous lesions compared to patients with unilate­ral lesions. A decrease in external respiratory function indicators was accompanied by a corresponding significant decrease in the quality of life, which was more pronounced in Group 2. The described changes occurred against the background of a significant increase in the studied biochemical markers in Group 2 compared to Group 1. Thus, the level of HBD-1 in Group 1 was (8.11 ± 1.78) pg/ml, in Group 2 it was (30.14 ± 3.89) pg/ml (p &lt; 0.05). Ferritin level in Group 1 was (94.19 ± 1.18) ng/ml, in Group 2 — (113.45 ± 4.77) ng/ml (p &lt; 0.05). The level of IL-6 in Group 1 was (81.43 ± 1.14) pg/ml, in Group 2 — (103.34 ± 3.46) pg/ml (p &lt; 0.05). When investigating the correlations between the levels of HBD-1, ferritin, IL-6 and quality of life indicators according to the SF-36 scale, reliable inverse relationships were found between all quality of life parameters and the levels of HBD-1 and ferritin. When investigating the correlations between the levels of HBD-1, ferritin, IL-6 and parameters of the function of external respiration, it was found that HBD-1 demonstrates negative reliable correlations with both volume and speed indicators (– 0.24…– 0.32). IL-6 shows negative relationships only in FVC (rs = – 0.42) and FEV1 (rs = – 0.41), however, these correlations are stronger compared to HBD-1. Conclusions. An increase in the volume of tuberculous lesions of the lungs leads to a more pronounced violation of the function of external breathing and, as a result, a decrease in the patients life quality. The described changes are accompanied by an increase in the levels of HBD-1, ferritin and IL-6, which makes the studied biomarkers promising predictors of deterioration of external respiratory function and quality of life. HBD-1 and ferritin demonstrated more pronounced correlations with parameters of life quality. The investigated markers have negative correlations with indicators of both restrictive and obstructive ventilation disorders.

Mechanisms of ventilatory limitation to maximum exercise in children and adolescents with chronic airway diseases.

Exercise intolerance is common in chronic airway diseases (CAD), but its mechanisms are still poorly understood. The aim of this study was to evaluate exercise capacity and its association with lung function, ventilatory limitation, and ventilatory efficiency in children and adolescents with cystic fibrosis (CF) and asthma when compared to healthy controls. Cross-sectional study including patients with mild-to-moderate asthma, CF and healthy children and adolescents. Anthropometric data, lung function (spirometry) and exercise capacity (cardiopulmonary exercise testing) were evaluated. Primary outcomes were peak oxygen consumption (VO2 peak), forced expiratory volume in 1 s (FEV1 ), breathing reserve (BR), ventilatory equivalent for oxygen consumption (VE /VO2 ) and for carbon dioxide production (VE /VCO2 ), both at the ventilatory threshold (VT1 ) and peak exercise. Mean age of 147 patients included was 11.8 ± 3.0 years. There were differences between asthmatics and CF children when compared to their healthy peers for anthropometric and lung function measurements. Asthmatics showed lower VO2 peak when compared to both healthy and CF subjects, although no differences were found between healthy and CF patients. A lower BR was found when CF patients were compared to both healthy and asthmatic. Both CF and asthmatic patients presented higher values for VE /VO2 and VE /VCO2 at VT1 when compared to healthy individuals. For both VE /VO2 and VE /VCO2 at peak exercise CF patients presented higher values when compared to their healthy peers. Patients with CF achieved good exercise capacity despite low ventilatory efficiency, low BR, and reduced lung function. However, asthmatics reported reduced cardiorespiratory capacity and normal ventilatory efficiency at peak exercise. These results demonstrate differences in the mechanisms of ventilatory limitation to maximum exercise testing in children and adolescents with CAD.

Dynamics of functional changes in the respiratory system after COVID-19-associated lung injury at one year after hospital discharge

Morphological examination reveals microcirculation disorders in combination with small areas of lung damage in the long term after COVID-19. Therefore, the function of the respiratory system should be assessed after COVID-19. Aim of this study was to evaluate the dynamics of respiratory dysfunction in patients with COVID-19-associated lung injury using a complex examination of lung function (spirometry, body plethysmography, and lung diffusion testing) one year after hospital discharge. Methods. 60 patients (38 men/22 women, aged 39 to 80 years) with a diagnosis of “COVID-19-associated interstitial process in the lungs” were examined. Lung function (spirometry, body plethysmography, and lung diffusion capacity testing) was examined in all patients twice, at 1 – 6 months (visit 1) and at 12 – 24 months (visit 2) after hospital discharge. Results. At visit 1, 60% of patients had restrictive pulmonary ventilation disorders. Obstructive ventilation disorders were detected in only 1 patient. Decreased lung diffusion capacity (D CO corr.) was found in 78% of patients. At visit 2, obstructive disorders were detected in 1 patient, and the frequency of restrictive ventilation disorders was 29%. Decreased DLCO corr. was noted in 57% of cases. The parameters of pulmonary ventilation and pulmonary gas exchange function differed significantly between visits. Significant correlations were found between changes in the functional parameters of the respiratory system and disorders identified at visit 1 after hospital discharge. Conclusion. Thus, there is a decrease in the lung diffusion capacity and the rate of restrictive ventilation disorders even one year after severe COVID-19-associated lung injury. However, our results suggest a marked improvement in respiratory system function over time.

Respiratory function of workers at some wood factories in Bac Tu Liem district, 2022

Objectives: This study aimed to assess the respiratory function status and associated factors among workers in wood factories in Bac Tu Liem district. Methods: A total of 80 workers from six woodworking establishments participated in this cross-sectional study. Respiratory symptom questionnaires based on ECCS-87 and ATS-DLD-78a were used to collect data on symptoms experienced within the past 12 months. Respiratory function measurements were also conducted during breaks and at the end of shifts. Results: Workers with 3-5 years of experience accounted for 63.8% of the total sample. The majority (92.5%) were exposed to harmful workplace factors for more than 8 hours per day. Only 13.8% reported using full personal protective equipment. Concentrations of respiratory particles and Total Suspended Particulate (TSP) in wood facilities exceeded allowable standards. Cough was the most commonly reported respiratory symptom, with a prevalence of 28.8%. Approximately 66.3% of subjects had normal respiratory function, while restrictive ventilation disorder accounted for the highest proportion of respiratory disorders at 21.3%. Statistical analysis revealed significant associations between respiratory dysfunction and work experience (OR=2.56, p&lt;0.01), duration of exposure to hazardous factors (OR=1.8, p&lt;0.05), use of personal protective equipment (OR=7.12, p&lt;0.05), and the occurrence of respiratory symptoms (OR=1.73, p&lt;0.01). Conclusions: workers in furniture manufacturing facilities in Bac Tu Liem district face exposure to high concentrations of total particles, respiratory particles, and toxic gases that surpass permissible standards. The study also found a significant relationship between respiratory dysfunction and employee characteristics. Keywords: Respiratory function, wood workers, wood factories.

An experimental study on the evolution of flame length and tilt angle under the joint effect of tunnel curved ceiling restriction and longitudinal ventilation

The model about flame length and fuel mass loss rate in this paper was developed based on the flame morphology with different longitudinal ventilation speeds when the flame was confined by the tunnel curved ceiling restriction. Secondly, after analyzing the experimental data, it was found that the air entrainment velocity was proportional to the 0.22nd power of longitudinal ventilation speed. Thirdly, the product of flame length and air entrainment velocity was proportional to the fuel mass loss rate, and the above models could better describe the characteristic evolution behaviors of flame length. Furthermore, the relation between fuel mass loss rate and longitudinal ventilation speed was established. Finally, this paper broadened the applicability of other scholars' flame tilt angle models, and found that the flame tilt angle is smaller when the flame is attached to the wall at the same wind speed. It is obvious that the above results supplement the classical tunnel-fire theory, which can be further applied to prevention and control of tunnel fire, and ultimately ensure building safety.

An Innovative Stent Consisting of Expanded Polytetrafluoroethylene and Ear Cartilage in Rhinoplasty For Asians: Application I of Dai's Exogenous Extension Stent Concept.

Restricted ventilation is common after rhinoplasty with an endogenous extension stent. The authors proposed an exogenous extension stent concept for Asian rhinoplasty patients to avoid this problem. Herein, we introduce an innovative stent in rhinoplasty for Asians, which is an application of this concept. An L-shaped expanded polytetrafluoroethylene is hand-carved, and the long arm is placed at the nose back to improve the flatness of the nose, while the short arm supports the nasal column to raise the nose tip. The prosthesis does not occupy nasal volume and therefore theoretically does not affect nasal ventilation. The fan-shaped ear cartilage was placed at the nasal tip to prevent visualization of the nasal tip. The safety and effectiveness of this method were verified through 20 years of clinical practice. The difficulty of learning and popularizing the method was tested through the course of rhinoplasty among 22 plastic surgeons. After 20 years of clinical practice, it was found that this stent could not only effectively improve the nasal dorsum and tip morphology, but also did not actually affect the nasal volume and thus did not affect the nasal ventilation of patients. Among the trainees in plastic surgery, we found that it was not difficult to learn this method of rhinoplasty and the trainees could complete the prosthesis carving well after standardized training. This stent consisting of expanded polytetrafluoroethylene and ear cartilage is suitable in rhinoplasty for Asians with significant advantages, one of which is that it has no risk of resulting in restricted nasal ventilation. Level IV.

Cinnamic acid mitigates methotrexate-induced lung fibrosis in rats: comparative study with pirfenidone

PurposeLung fibrosis is a heterogeneous lung condition characterized by excessive accumulation of scarred tissue, leading to lung architecture destruction and restricted ventilation. The current work was conducted to examine the probable shielding influence of cinnamic acid against lung fibrosis induced by methotrexate.MethodsRats were pre-treated with oral administration of cinnamic acid (50 mg/kg/day) for 14 days, whereas methotrexate (14 mg/kg) was orally given on the 5th and 12th days of the experiment. Pirfenidone (50 mg/kg/day) was used as a standard drug. At the end of the experiment, oxidative parameters (malondialdehyde, myeloperoxidase, nitric oxide, and total glutathione) and inflammatory mediators (tumor necrosis factor-α and interleukin-8), as well as transforming growth factor-β and collagen content, as fibrosis indicators, were measured in lung tissue.ResultsOur results revealed that cinnamic acid, as pirfenidone, effectively prevented the methotrexate-induced overt histopathological damage. This was associated with parallel improvements in oxidative, inflammatory, and fibrotic parameters measured. The outcomes of cinnamic acid administration were more or less the same as those of pirfenidone. In conclusion, pre-treatment with cinnamic acid protects against methotrexate-induced fibrosis, making it a promising prophylactic adjuvant therapy to methotrexate and protecting against its possible induction of lung fibrosis.

The characteristics of chest HRCT and pulmonary function tests in lung-onset primary sjogren's syndrome.

Interstitial lung disease (ILD) can manifest before the diagnosis of primary Sjögren's syndrome (pSS), however, the underlying mechanisms remain unclear. The aim of this study is to investigate the characteristics of lung-onset pSS using chest high-resolution computerized tomography (HRCT) and pulmonary function tests (PFTs). The data of 102 patients with pSS-ILD were retrospectively analyzed. The patients were divided into two groups: lung-onset group and the nonlung-onset group. The chest HRCT, PFTs, and clinical and laboratory data were evaluated and compared. Among the 102 patients with pSS-ILD, 59 (57.8%) were lung-onset and 43 (42.2%) were nonlung-onset. Chest HRCT in the lung-onset group showed higher percentage of usual interstitial pneumonia and nonspecific interstitial pneumonia, the difference did not reach statistical significance. The total HRCT score was higher in the lung-onset group, compared with the nonlung-onset group (2 [2, 3], vs. 2 [1, 2], p = .014). Total lung capacity (TLC) (%pred) [(75.4 ± 16.2) versus (82.8 ± 19.4), p = .049] and forced vital capacity (FVC) (%pred) [(82.2 ± 19.9) versus (91.6 ± 28.3), p = .050] were significantly lower in the lung-onset group, compared with the nonlung-onset group.Residual volume (RV)/TLC (%) significantly increased more than 40% in the lung-onset group (p = .015). Restricted ventilation disorder, small airway obstruction and reduced diffusing capacity of the lung for carbon monoxide/alveolar volume (%Pred) were more common in the lung-onset group (p = .038, p = .050, and p = .050, respectively). Correlation analysis showed that HRCT score was positively correlated with the interval between the onset of pulmonary symptoms and the diagnosis of ILD, serum CA125, and serum CEA. TCL (%pred), VC (%pred), FVC (%pred) were negatively correlated with serum CA125. Lung-onset is common in pSS patients with more severe lung function impairments. Serum biomarkers, such CA125, CEA, and ALB, were associated with the severity of lung damage.

Optical coherence tomography angiography characteristics of retinochoroidal and optic nerve head microcirculation in cryptogenic organizing pneumonia

BackgroundTo assess retinochoroidal and optic nerve head microcirculation alterations in cryptogenic organizing pneumonia. MethodsThirty cryptogenic organizing pneumonia patients in the resolution phase (group 1, 30 right eyes) and 33 healthy subjects (group 2, 33 right eyes) were compared. Patients had 40 mg/day corticosteroids for 8–10 days, and a pulmonary function test, which revealed only minimally restrictive ventilation features. After gathering demographic data, a comprehensive ophthalmological exam and optical coherence tomography angiography were performed three months following maximum disease resolution with corticosteroid therapy ResultsGroups 1 and 2 had mean ages of 54.37±14.87 and 49.61±12.36 years, respectively (P = 0.171). Despite the lack of statistical significance, superficial and deep capillary plexus vessel densities in all macular regions were lower in group 1, as were foveal avascular zone parameters (P>0.05). However, the outer retinal and choriocapillaris flows increased significantly in group 1, especially in select areas (P<0.001, for both). There were no significant differences in whole image (P = 0.346), inside disk (P = 0.438), or peripapillary (P = 0.185) optic nerve head vessel densities between the two groups; however, nasal (P<0.001) and inferior quadrant (P = 0.006) vessel densities differed significantly. Global retinal nerve fiber layer thickness did not differ significantly between groups 1 and 2 (112.83±14.71 versus 111.45±12.74 µm, respectively; P = 0.692). Group 1, however, had significantly higher superior, nasal, and inferior quadrant, and significantly lower temporal quadrant retinal nerve fiber layer thickness (P<0.001, for all). ConclusionsConcerning the impact of probable cryptogenic organizing pneumonia-induced hypoxia on ocular tissues, optical coherence tomography angiography assessments of retinochoroidal and optic nerve head microcirculation could be employed as a biomarker for cerebral microcirculation.

Effect of Compression Garments on the Ventilatory Function After Abdominoplasty.

The use of compression garments in the postoperative period of abdominoplasty seems to be a consensus, but the incidents of complications arising from this have been described, related to an increase in intraabdominal pressure and reduction of the femoral vein blood flow that may facilitate thromboembolic events. There are no studies that have evaluated the isolated effect of postoperative compression garments on respiratory function. The purpose of this study was to evaluate the effect of compression garments on respiratory function after abdominoplasty. Thirty-four female patients who underwent standard abdominoplasty were divided into 2 groups, the garment group (n = 18) and the no garment group (n = 16). Respiratory function assessment (with spirometry and manovacuometry) was performed in the preoperative and postoperative periods. Forced vital capacity assessment revealed a greater ventilatory restriction in the garment group. Forced expiratory volume in 1 second (FEV1) showed differences between the evaluation time points in the garment group; the intergroup comparisons showed that the no garment group had a lower FEV1. Slow vital capacity was evaluated with no significant differences found on both intergroup comparisons. The inspiratory capacity was reduced in the garment group, representing ventilatory restriction. Measurements of the maximum inspiratory pressure showed no significant differences between the groups. The maximum expiratory pressure showed significantly lower values on postoperative day 7 in the garment group. The use of compression garments after abdominoplasty impairs ventilatory function. Not wearing this type of garment can improve ventilation, decreasing the risk of pulmonary complications.