Function Of Respiratory System Research Articles

Model of qualification for physical therapy program: experiences from the Mental Health Support Centre in Tarnowskie Góry, Poland.

IntroductionIn terms of physical and mental health benefits, psychiatric rehabilitation requires diverse therapeutic activities offered by an interdisciplinary team. In order for patients to be able to fully participate in social life, it is necessary to strengthen health-promoting activities, control the symptoms and side effects of pharmacological treatment, effectively manage resources and counteract interpersonal and environmental barriers caused by disability. Physical activity and exercise programs answer both psychosocial and biological aspects of health leading to higher self-efficacy, lower self-perceived stigma, longer lifespan and overall better quality of lifeObjectivesThe aim of this study is to present qualification process of adult patients for physical therapy program at the Mental Health Support Centre’s (Centrum Wsparcia Zdrowia Psychicznego, CWZP) daily rehabilitation unit in Tarnowskie Góry.MethodsAdult patients with diverse diagnoses (schizophrenia, affective disorders, anxiety disorders or organic mental disorders) and varied degree of functioning who met the admission criteria were accepted to the ward for a period of 12 weeks. During the stay, a wide range of therapeutic activities was offered, including individual psychological support, group work, art therapy, relaxation sessions, culinary/ dietary workshops, individual training and general fitness group exercises, as well as cognitive training (also via computer-based programs). Due to the COVID-19 epidemic, some of the activities have been limited.ResultsPhysical exercises, just as any treatment, should be offered in appropriate doses. Patients with mental disorders, especially severe mental illnesses, experience many barriers in engaging in physical activity and are under a greater risk of sedentary lifestyle. Thus, for the qualification, exercise tolerance assessment was performed in the form of 6-min Walk Test (6MWT) with Borg scale for subjective fatigue. Through aerobic capacity and endurance assessment patients’ respiratory system, cardiovascular system, and neuromuscular system functions can be evaluated. Functional fitness was assessed through 3 elements of Senior Fitness Test (SFT) (Back Scratch test, Up and go test, Chair Sit-and-Reach test) along with Romberg Test to evaluate the static and dynamic balance as well as flexibility of the upper and lower body.ConclusionsProperly planned and carried out qualification for the physical therapy program allows to adjust the activities to the needs of the patient. Additionally, it can be a tool to evaluate the achieved results at the end of the rehabilitation process.Disclosure of InterestNone Declared

Kineziterapija pagerina COVID-19 liga persirgusių asmenų kvėpavimo funkcijas, pusiausvyrą ir fizinį pajėgumą

The Coronavirus disease (COVID-19) is an infection caused by the coronavirus SARS-CoV-2. Although most patients with COVID-19 develop a mild form, approximately 14 per cent get a severe form of the disease, which requires hospitalisation and additional oxygen supply, and 5 per cent require to be treated in the intensive care unit. The patients who fell ill with COVID-19 and have disturbed biosocial functions are provided with rehabilitation services. Still, there is a lack of research that would reveal the effect of physiotherapy on respiratory system function, physical capacity, and balance. The study aims to evaluate the effect of physiotherapy on patients with COVID-19 disease. 15 participants (the mean age 56.00 ± 4.61 years) who had moderate COVID-19 disease and were hospitalised at least 30 days before the study participated in the research. All participants received physiotherapy for 4 weeks, 5 times a week, each session lasting 30 minutes. Participants were evaluated twice, before the study and after 4 weeks. The assessment methods included spirometry (forced vital capacity [FVC] and forced expiratory volume in the first second after maximal inspiration [FEV1]), the measurement of chest excursion, the assessment of balance on the Berg scale, and the assessment of physical capacity with a 6-minute walk test. After physiotherapy intervention, FVC (p<0.05) and FEV1 (p<0.05) increased, Berg test results improved (p<0.05). It can be concluded that four-week physiotherapy, including breathing and balance exercises, can be used as an effective rehabilitation tool for individuals who have recovered from COVID-19 disease.

Effect of hyperoxic inhalations for athletes of different sports, including those who had COVID-19, when training in the middle altitude

To identify hyperoxic inhalations on the functional state of the cardiorespiratory system of athletes of different sports, who have previously had COVID-19, when training in the middle altitude. The study included 64 elite athletes during the preparatory period. The studies were conducted in Kislovodsk in the middle altitude (1240 meters) on the Maloe Sedlo mountain, in the conditions of training camps. We studied the parameters of heart rate variability and functional state of cardiovascular and respiratory systems. Hyperoxic inhalations were performed with the JAY-10 oxygen concentrator (LONGFIAN SCITECH CO., LTD., China). The oxygen concentration in the mixture was 93±3%, capacity - 5 l/min, exposure time - 20 min. Athletes specializing in sports with predominantly anaerobic lactate and mixed mechanism of energy supply, respectively experiencing hypoxia in the process of their athletic activity during training can experience hypoxia at rest as well. The state of hypoxia during exercise in the middle altitude in such athletes is shown in heart rate variability indices (high values of heart rate and stress index, low power of high frequency waves), low saturation, increased oxygen uptake from the blood microcirculation system. The use of oxygen therapy in athletes promotes positive dynamics of the functional state, consisting in a reduced stress of regulatory mechanisms, strengthened tone of the parasympathetic nervous system in the heart rate regulation, increased economization of the central hemodynamics' parameters, improved functions of the external respiratory system. Application of hyperoxic inhalations during intense exercise in the middle altitude has a favorable effect on the functional state of the cardiorespiratory system in all the studied sports, especially in athletes who have previously had COVID-19.

Вопросы ранней диагностики и своевременной коррекции дыхательных нарушений при боковом амиотрофическом склерозе (обзор литературы)

Amyotrophic lateral sclerosis (ALS) is a rare severe progressive neurodegenerative disease with upper and lower motor neuron lesions, manifested by weakness of somatic muscle tissue with disorder of vital functions and leading to early disability and fatal outcome of patients. Regardless of the disease form, patients with ALS experience breathing and swallowing disorders. Hypercapnic respiratory failure (HRF) most commonly develop in patients as a consequence of respiratory muscle weakness. Instrumental diagnostic methods are currently used along with the assessment of the HRF clinical picture in ALS. Pulse oximetry and spirometry are the basic means of assessing the respiratory system function. Cardio-respiratory monitoring and arterial blood gas test play an auxiliary role in the diagnosis. To correct respiratory disorders, respiratory support is used with the help of artificial ventilation devices connected through various masks (non-invasive) or through a tracheostomy (invasive). In recent years, it has been proven that early diagnosis and correction of respiratory disorders contribute to prolonging the life of patients with ALS and improving its quality. The review presents the main development mechanisms of respiratory disorders in ALS, clinical and instrumental methods of their diagnosis, methods of correction, as well as criteria for the start of respiratory support. KEYWORDS: amyotrophic lateral sclerosis, respiratory disorders, lung ventilation, pulmonary support, neurodegeneration, NIV, ALV. FOR CITATION: Ermilov E.A., Isaeva N.V. Issues concerning early diagnosis and timely correction of respiratory disorders in amyotrophic lateral sclerosis (literature review). Russian Medical Inquiry. 2023;7(8). (in Russ.). DOI: 10.32364/2587-6821-2023-7-8-4.

The evolution, form and function of the human respiratory system.

This paper presents an updated view on the morphological and functional significance of the human respiratory system in the context of human evolutionary anatomy. While usually the respiratory system is treated either from a craniofacial perspective, mostly in the context of nasal evolution and air-conditioning, or from a postcranial perspective featuring on overall thoracic shape changes, here we pursue a holistic perspective on the form, function, integration, and evolutionary change of the entire organismal system in hominins. We first present a brief review of the most important morphological structures, their function, and its potential integration and interaction with the nasal cavity and thoracic skeleton. This is followed by an overview of the most important improvements in methods for the comparative study in recent humans and fossil hominins. We then overview and list a compendium of hominin fossil material currently available for the study. We propose four functional categories of hominin respiratory system configurations that differ potentially with respect to size, shape, biomechanics and/or bioenergetics. Finally, we discuss these and speculate on possible ways for future research into an anatomical system that, despite its under-investigated status, is central to the understanding of the form and functions of the hominin organism and its paleobiology.

The Use of Terrain Cure in the Treatment and Rehabilitation of Patients with Cardiovascular Diseases: a Review

INTRODUCTION. The review is devoted to the study of one of the modern complex methods of treatment and rehabilitation of patients with cardiovascular diseases – terrain cure which includes elements of therapeutic physical training, climatotherapy and provides for dosed physical activity in the form of hiking in rough terrain, climbing in mountainous areas on specific, marked routes under the supervision of a doctor. It is a method of exercise therapy that improves endurance, cardiovascular, respiratory and nervous system function, metabolism, as well as the muscles of the limbs and trunk. AIM. To highlight the mechanisms of the complex action of terrain cure, combining elements of climatotherapy and metered physical activity for the most optimal use in patients with pathology of the cardiovascular system, including those with excess body weight. MATERIAL AND METHODS. The analysis of publications in the electronic databases PubMed and the Russian Scientific Citation Index by keywords: terrain cure , metered physical activity, climatotherapy, rehabilitation, cardiovascular diseases. The date of the last search is August 9, 2022. CONCLUSION. The world and domestic scientific and practical experience of the use of terrain cure testifies to its high efficiency and an increase in the adaptive and compensatory potential of the patient's body, the safety of using this method in both preventive and therapeutic and rehabilitation programs, due to the main mechanisms of its rehabilitative action. Taking into account its wide availability, cost-effectiveness and additional therapeutic effects when in contact with the terrain, it seems advisable to expand the introduction of the terrain cure and use it for preventive purposes not only in sanatorium–resort conditions, but also in the urban environment – parks and other recreation areas of citizens.

Comprehensive bioinformatics analysis reveals biomarkers of DNA methylation-related genes in varicose veins.

Background: Patients with Varicose veins (VV) show no obvious symptoms in the early stages, and it is a common and frequent clinical condition. DNA methylation plays a key role in VV by regulating gene expression. However, the molecular mechanism underlying methylation regulation in VV remains unclear. Methods: The mRNA and methylation data of VV and normal samples were obtained from the Gene Expression Omnibus (GEO) database. Methylation-Regulated Genes (MRGs) between VV and normal samples were crossed with VV-associated genes (VVGs) obtained by weighted gene co-expression network analysis (WGCNA) to obtain VV-associated MRGs (VV-MRGs). Their ability to predict disease was assessed using receiver operating characteristic (ROC) curves. Biomarkers were then screened using a random forest model (RF), support vector machine model (SVM), and generalized linear model (GLM). Next, gene set enrichment analysis (GSEA) was performed to explore the functions of biomarkers. Furthermore, we also predicted their drug targets, and constructed a competing endogenous RNAs (ceRNA) network and a drug target network. Finally, we verified their mRNA expression using quantitative real-time polymerase chain reaction (qRT-PCR). Results: Total three VV-MRGs, namely Wnt1-inducible signaling pathway protein 2 (WISP2), Cysteine-rich intestinal protein 1 (CRIP1), and Odd-skipped related 1 (OSR1) were identified by VVGs and MRGs overlapping. The area under the curves (AUCs) of the ROC curves for these three VV-MRGs were greater than 0.8. RF was confirmed as the optimal diagnostic model, and WISP2, CRIP1, and OSR1 were regarded as biomarkers. GSEA showed that WISP2, CRIP1, and OSR1 were associated with oxidative phosphorylation, extracellular matrix (ECM), and respiratory system functions. Furthermore, we found that lncRNA MIR17HG can regulate OSR1 by binding to hsa-miR-21-5p and that PAX2 might treat VV by targeting OSR1. Finally, qRT-PCR results showed that the mRNA expression of the three genes was consistent with the results of the datasets. Conclusion: This study identified WISP2, CRIP1, and OSR1 as biomarkers of VV through comprehensive bioinformatics analysis, and preliminary explored the DNA methylation-related molecular mechanism in VV, which might be important for VV diagnosis and exploration of potential molecular mechanisms.

Effectiveness of Rehabilitation on Functional Changes of the Respiratory System in Persons with Severe and Critical Form of Covid-19 Disease

Background. It has been established that the disease of Covid-19 negatively affects the functions of the respiratory system of individuals. Since the disease appeared relatively recently, there are not many studies examining the functional state of the respiratory system of individuals after Covid-19 infection, but it is known that individuals who have suffered from a severe or critical form of the Covid-19 disease are diagnosed with many different complications. The aim. To assess the effectiveness of rehabilitation for functional changes in the respiratory system of persons suffering from a severe and critical form of the Covid-19 disease. Methods. 20 persons (11 men and nine women) aged 54.95±5.02 years who suffered from a severe or critical form of the Covid-19 disease participated in the study. Testing was done twice, before and after rehabilitation. During the study, the subjects’ respiratory system function was evaluated (Stange-Hench sample, respiratory rate, chest excursion, spirometry (VC, FEV, FEV1). Results. After rehabilitation, the parameters of the Stange and Hench functional tests, respiratory rate, chest excursion and Vital Capacity improved. Conclusion. It was established that after 20 days of rehabilitation, the respiratory system function of persons suffering from a severe or critical form of the Covid-19 disease improved. Keywords: Covid-19, Stange and Hench sample, respiratory rate, chest excursion, spirometry.

Pulmonary Functions and Respiratory Symptoms of Wheat Flour Mill Workers in The Duhok District

Exposure to flour dust in flour mill factories may cause diverse lung diseases with different severity of symptoms ranging from simple irritation to allergic rhinitis or occupational asthma; long-term exposure to flour dust can cause chronic lung problems. The aim of this study is to examine the effect of exposure to flour dust on the respiratory system and pulmonary function of wheat flour mill workers in the Duhok district. A cross-sectional study was performed among 63 workers who had direct contact with wheat flour mills. The data were collected using a well-structured questionnaire, anthropometric measurements, and digital spirometry. The workers’ mean age ± (SD) was 29.79 ± 10.60 years. The current study showed the predicted Forced vital capacity (FVC) mean ± (SD) 105.34 L (±) 25.96 L, and the predicted Forced expiratory volume in one second (FEV1) mean ± (SD) 97.90 L (±) 18.65 L, and the predicted FEV1/FVC mean ± (SD) 95.82 L (±) 17.61 L. About 43(68.3%) of workers were normal,10(15.9%) had mild pulmonary obstruction followed by moderate restriction, 5(7.9%), and 3(4.8%) had mild pulmonary restriction. The mild obstructive disorder is more among normal Body Mass Index (BMI) persons, while restrictive disorders are more among overweight workers. This study showed no significant statistical association between PFTs and respiratory symptoms (sneezing, rhinorrhea, change of voice, dyspnea and cough), BMI, and the duration of working in the wheat flour mills.

Patología respiratoria. Clasificación y estrategia diagnóstica

The identification and differential diagnosis of respiratory disease requires knowledge of the associated signs and symptoms. A patient's comprehensive medical history must be taken, which should list the presence or absence of symptoms such as cough, expectoration, dyspnea, chest pain, or hemoptysis, among others. The physical examination must be conducted according to the established order of inspection, palpation, percussion, and auscultation and should not only focus on the thorax. Obtaining all this information will serve to guide the patient's diagnosis and request additional tests that better establish the disease and its prognosis, both through imaging tests and respiratory system function tests.

Deep Chest: Computer Vision and Deep Learning for Lung Disease Detection

Lung disease is one of the most common medical conditions in the world. Pulmonary diseases happen when there are problems with any part of the lungs. Lung infections can affect the air ways of respiratory function, and it may affect the ability to breathe and the good functionality of the human respiratory system. Studying different lung diseases and categorizing them is one of the most interesting areas of research in recent years. Deep learning techniques in the field of computer vision along with medical engineering have recently achieved impressive results. In this work we used three deep learning models for classifying the lung diseases and analyzed the result to find the best model among them. The obtained result shows higher validation accuracy for the deep learning models and this lead to conclude that the method is suitable for predicting Lung diseases.

The Benefits of Inspiratory Muscle Training in Heart Failure Patients – A Systematic Review

Background: Patients with heart failure (HF) have impaired function of respiratory system and frequently experience dyspnea. Inspiratory muscle training (IMT) offers an alternative way of exercise with a lot of benefits for HF patients. Aim: The aim of this review was to summarize and to reveal the effects of IMT in HF patients. Methods: Electronic searches were performed using Pubmed Database, Physiotherapy Evidence Database (PEDro) and Cochrane Library. Inclusion criteria were: RCTs, patients with HF, full text articles after 2010 and at least one intervention group with IMT. Methodological quality was assessed using the PEDro (Physiotherapy Evidence Database) scale. Results: Nineteen articles met the inclusion criteria and were included in this review. In most studies training protocols involved 3 to 7 sessions per week with intensity ≤30-60% of maximal inspiratory pressure (MIP), for a total duration of 4-12 weeks. Respiratory muscle strength improved in 11/12 studies, peripheral muscle strength in 4/5 studies, exercise capacity (peak VO2, VE/VCO2 slope) in 4/10, pulmonary function (FEV1, FEV1/FVC, FVC) in 0/5, functional capacity (6MWT) in 6/8, echocardiography parameters in 1/6, quality of life and dyspnea in 9/16. Control groups followed sham IMT, usual care, no intervention, intervention without exercise, or aerobic training, which could explain in some cases the conflicting results. Conclusions: IMT is beneficial for HF patients and should be included as a complementary method in cardiac rehabilitation programs. The optimal characteristics of ΙΜΤ as well as the benefits when combined with common forms of exercise need further research.

The Outcome of Allogeneic Hematopoietic Stem Cell Transplantation From Different Donors in Recipients With Mucopolysaccharidosis.

There is limited information regarding hematopoietic stem cell transplantation (HSCT) for mucopolysaccharidosis (MPS) IV and VI. This study examined the full donor chimerism, specific lysosomal enzyme levels, and the survival of different MPS children after HSCT from various donor sources and compared the prognosis. A total of 42 children with MPS underwent HSCT, 9 cases were type I, 14 were type II, 15 were type IV, and 4 were type VI. A total of 24 patients received peripheral blood stem cells (PBSC) and 18 patients received umbilical cord blood (UCB). Patients who received PBSC were conditioned with intravenous (IV) busulfan every 6 h for a total of 16 doses, IV cyclophosphamide (CY, 200 mg/kg), and antihuman thymocyte globulin (ATG, 10 mg/kg). While conditioning regimen of patients who received UCB was adjusted to ATG (preposed, pre-) + busulfan + fludarabine + Cy, which includes IV ATG (pre-, 6 mg/kg), IV busulfan every 6 h for a total of 16 doses, IV fludarabine (200 mg/m2) and CY (200 mg/kg). Also, 95.2% (40 of 42) of patients achieved full donor chimerism, and all patients’ specific lysosomal enzyme levels reached normal. The estimated overall survival (OS) at 1 year was 92.9%. There was no significant difference in 1-year OS between patients who received PBSC transplantation and those who received UCB grafts (87.5% vs. 100%, p = 0.0247). The incidence of acute and chronic GVHD did not differ between them. The incidences of pneumonia in PBSC recipients and UCB recipients were 45.8 and 33.3%, respectively, but there few patients suffering from respiratory failure (4.2 and 5.6%, respectively) due to pneumonia. The incidence of cytomegaloviremia was also high in both groups, 58.3 and 44.4% respectively, However, no patient developed CMV disease. All deaths (3 of 42) occurred in patients receiving PBSC grafts, and there was no death in patients receiving UCB grafts. There was no death after transplantation in patients with MPS IV and VI. In addition, respiratory and nervous system functions were improved, whereas valvular heart disease was improved in some patients but progressed in more patients after transplantation. In summary, HSCT is a good therapeutic option for MPS, not only for patients with MPS I or II but also for those with MPS IV or VI. The specific lysosomal enzyme levels can be completely restored to normal, which is the basis for patients to resolve a broad range of clinical outcomes. Moreover, UCB with suitable HLA (HLA-match above 7/10 and 4/6) is a suitable donor source for MPS. Patients who underwent UCB transplantation using the conditioning regimen ATG (pre-) + busulfan + fludarabine + Cy can achieve a higher proportion of full donor chimerism and survival with less severe complications. HSCT can improve organs function in patients with MPS, but it is still worth exploring.

Cyclic visualization of the respiratory stages in teaching human physiology to english-speaking students

In the course of Human Physiology, students of different specialties learn cyclic processes reflecting the work of the cardiovascular, respiratory, female reproductive systems and sleep as well. Visualization of the cyclic processes is essential for better understanding of the organization and functioning of these systems and finding pathological deviations with formation of defective cycles.
 The objective of the work is to analyze the application of the visualization of the respiratory stages into the educational process. Dynamics of the physiological processes at various stages of respiration with the help of schematic visual figures allows effective formation of the students’ systemic understanding of the respiratory system functions and its interrelations with the cardiovascular system. These enable to apply the acquired theoretical knowledge while solving clinical situational tasks and formation of professional competence.

Approbation of the program of physical occupational therapy of young men who specialize in Greco-Roman wrestling after treatment of coronavirus disease

According to the results of the analysis of scientific-methodical, special and reference literature, the members of the research group established, that the issue of development (testing) of modern pedagogical technologies of physical occupational therapy, therapy of boys and girls who specialize in wrestling after the treatment of coronavirus disease is devoted to an insufficient number of scientific and methodological works, which requires further research and emphasizes the relevance and practical component of the chosen field of study.
 The main purpose of the study is to test the program of physical occupational therapy for young people aged 14-15, who specialize in Greco-Roman wrestling after treatment of coronavirus disease. The following methods were used in the process of research and analytical work: analysis and synthesis (abstraction), induction (deduction), modeling, mathematical and statistical (correlation analysis, factor analysis), etc.
 As a result of empirical research, members of the research group tested the program of physical occupational therapy for 14-15 year olds who specialize in Greco-Roman wrestling after treatment of coronavirus disease. Analyzing the results obtained, we found that the above experimental program provided accelerated recovery, as well as physical (special physical), psychological, technical and tactical training of young people aged 14-15, who specialize in Greco-Roman wrestling. In addition, the experimental program of physical occupational therapy for young people of the studied category, adapted to today's requirements, provided qualitative changes in their state of health, which was confirmed: activation of resorption of the inflammatory pneumonic center; intensification of bronchial drainage function; leveling of existing adhesions in the lungs; normalization of pulmonary hemodynamics; increasing the stimulation of immunological and nonspecific resistance of athletes; accelerating the regenerative processes of the broncho-pulmonary system, improving the function of the external respiratory system, etc.

3D numerical simulation of hot airflow in the human nasal cavity and trachea

Background and objectiveThe primary function of the human respiratory system is gas and moisture exchange, and conditioning inhaled air to prevent damage to the lungs and alveoli. In a fire incident, exposed soft tissues contract and the respiratory system may be severely damaged, possibly leading to respiratory failure and even respiratory arrest. The purpose of this study is to numerically simulate hot airflow in the human upper airway and trachea to investigate heat and moisture transfer and induced thermal injuries. MethodsFor analysis, the airflow is assumed to be laminar and steady, and simulations have been carried out at volume flow rates of 5 and 10 L/min, inlet temperatures of 70–240 °C, and relative humidity up to 40%. The mucous layer and surrounding tissues are incorporated into the conducting zone of the model. The blood perfusion is considered at different rates up to 5(Kg/m3.s) to regulate the temperature, and the vapor concentration is coupled with the energy equation. ResultsThe temperature and humidity distribution on the airway wall were calculated for all the studied conditions in order to find the mild and severe burn for different inhaled air temperatures. At the inlet temperatures of 70 and 100 °C, there are mild burns in several nasal cavity regions. At the higher temperatures of 160 and 200 °C, these areas suffer from severe burns and mild burns occur at the superior parts and nasopharynx. Rapid evaporation and tissue destruction will be observed if anyone breathes the 240 °C air. ConclusionsThe results show that the hot inlet temperatures drop below 44 °C when passing through the upper airway, and the lower airway was not affected. Increasing the inlet temperature from 70 to 240 °C extends the burns from mild to severe and the affected areas from the beginning of the nasal cavity to the pharynx.

Lung aeration, ventilation, and perfusion imaging.

Lung imaging is a cornerstone of the management of patients admitted to the intensive care unit (ICU), providing anatomical and functional information on the respiratory system function. The aim of this review is to provide an overview of mechanisms and applications of conventional and emerging lung imaging techniques in critically ill patients. Chest radiographs provide information on lung structure and have several limitations in the ICU setting; however, scoring systems can be used to stratify patient severity and predict clinical outcomes. Computed tomography (CT) is the gold standard for assessment of lung aeration but requires moving the patients to the CT facility. Dual-energy CT has been recently applied to simultaneous study of lung aeration and perfusion in patients with respiratory failure. Lung ultrasound has an established role in the routine bedside assessment of ICU patients, but has poor spatial resolution and largely relies on the analysis of artifacts. Electrical impedance tomography is an emerging technique capable of depicting ventilation and perfusion at the bedside and at the regional level. Clinicians should be confident with the technical aspects, indications, and limitations of each lung imaging technique to improve patient care.

Assessment of Heterogeneity in Lung Structure and Function During Mechanical Ventilation: A Review of Methodologies.

The mammalian lung is characterized by heterogeneity in both its structure and function, by incorporating an asymmetric branching airway tree optimized for maintenance of efficient ventilation, perfusion, and gas exchange. Despite potential benefits of naturally occurring heterogeneity in the lungs, there may also be detrimental effects arising from pathologic processes, which may result in deficiencies in gas transport and exchange. Regardless of etiology, pathologic heterogeneity results in the maldistribution of regional ventilation and perfusion, impairments in gas exchange, and increased work of breathing. In extreme situations, heterogeneity may result in respiratory failure, necessitating support with a mechanical ventilator. This review will present a summary of measurement techniques for assessing and quantifying heterogeneity in respiratory system structure and function during mechanical ventilation. These methods have been grouped according to four broad categories: (1) inverse modeling of heterogeneous mechanical function; (2) capnography and washout techniques to measure heterogeneity of gas transport; (3) measurements of heterogeneous deformation on the surface of the lung; and finally (4) imaging techniques used to observe spatially-distributed ventilation or regional deformation. Each technique varies with regard to spatial and temporal resolution, degrees of invasiveness, risks posed to patients, as well as suitability for clinical implementation. Nonetheless, each technique provides a unique perspective on the manifestations and consequences of mechanical heterogeneity in the diseased lung.

Perspectives on the Structure and Function of the Avian Respiratory System: Functional Efficiency Built on Structural Complexity

Among the air-breathing vertebrates, regarding respiratory efficiency, the avian respiratory system rests at the evolutionary zenith. Structurally, it is separated into a lung that serves as a gas exchanger and air sacs that mechanically ventilate the lung continuously and unidirectionally in a caudocranial direction. Largely avascular, the air sacs are delicate, transparent, compliant and capacious air-filled spaces that are not meaningfully involved in gas exchange. The avian lungs are deeply and firmly attached to the vertebrae and the ribs on the dorsolateral aspects, rendering them practically rigid and inflexible. The attachment of the lung to the body wall allowed extreme subdivision of the exchange tissue into minuscule and stable terminal respiratory units, the air capillaries. The process generated a large respiratory surface area in small lungs with low volume density of gas exchange tissue. For the respiratory structures, invariably, thin blood-gas barrier, large respiratory surface area and large pulmonary capillary blood volume are the foremost adaptive structural features that confer large total pulmonary morphometric diffusing capacities of O2. At parabronchial level, the construction and the arrangement of the airway- and the vascular components of the avian lung determine the delivery, the presentation and the exposure of inspired air to capillary blood across the blood-gas barrier. In the avian lung, crosscurrent-, countercurrent- and multicapillary serial arterialization systems that stem from the organization of the structural parts of the lung promote gas exchange. The exceptional respiratory efficiency of the avian respiratory system stems from synergy of morphological properties and physiological processes, means by which O2uptake is optimized and high metabolic states and capacities supported. Given that among the extant animal taxa insects, birds and bats (which accomplished volancy chronologically in that order) possess structurally much different respiratory systems, the avian respiratory system was by no means a prerequisite for evolution of powered flight but was but one of the adaptive solutions to realization of an exceptionally efficient mode of locomotion.

Haploinsufficiency of Col5a1 causes intrinsic lung and respiratory changes in a mouse model of classical Ehlers-Danlos syndrome.

The Ehlers‐Danlos syndromes (EDS) are inherited connective tissue diseases with primary manifestations that affect the skin and the musculoskeletal system. However, the effects of EDS on the respiratory system are not well understood and are described in the literature as sporadic case reports. We performed histological, histomorphometric, and the first in‐depth characterization of respiratory system function in a mouse model of classical EDS (cEDS) with haploinsufficiency of type V collagen (Col5a1+/−). In young adult male and female mice, lung histology showed reduced alveolar density, reminiscent of emphysematous‐like changes. Respiratory mechanics showed a consistent increase in respiratory system compliance accompanied by increased lung volumes in Col5a1+/− compared to control mice. Flow–volume curves, generated to mimic human spirometry measurements, demonstrated larger volumes throughout the expiratory limb of the flow volume curves in Col5a1+/− compared to controls. Some parameters showed a sexual dimorphism with significant changes in male but not female mice. Our study identified a clear respiratory phenotype in the Col5a1+/− mouse model of EDS and indicated that intrinsic respiratory and lung changes may exist in cEDS patients. Their potential impact on the respiratory function during lung infections, other respiratory disease processes, or insults may be significant and justify further clinical evaluation.