Lower Respiratory System Research Articles

Stability of influenza A virus in droplets and aerosols is heightened by the presence of commensal respiratory bacteria.

Aerosol transmission remains a major challenge for control of respiratory viruses, particularly those causing recurrent epidemics, like influenza A virus (IAV). These viruses are rarely expelled alone, but instead are embedded in a consortium of microorganisms that populate the respiratory tract. The impact of microbial communities and inter-pathogen interactions upon stability of transmitted viruses is well-characterized for enteric pathogens, but is under-studied in the respiratory niche. Here, we assessed whether the presence of five different species of commensal respiratory bacteria could influence the persistence of IAV within phosphate-buffered saline and artificial saliva droplets deposited on surfaces at typical indoor air humidity, and within airborne aerosol particles. In droplets, presence of individual species or a mixed bacterial community resulted in 10- to 100-fold more infectious IAV remaining after 1 h, due to bacterial-mediated flattening of drying droplets and early efflorescence. Even when no efflorescence occurred at high humidity or the bacteria-induced changes in droplet morphology were abolished by aerosolization instead of deposition on a well plate, the bacteria remained protective. Staphylococcus aureus and Streptococcus pneumoniae were the most stabilizing compared to other commensals at equivalent density, indicating the composition of an individual's respiratory microbiota is a previously unconsidered factor influencing expelled virus persistence.IMPORTANCEIt is known that respiratory infections such as coronavirus disease 2019 and influenza are transmitted by release of virus-containing aerosols and larger droplets by an infected host. The survival time of viruses expelled into the environment can vary depending on temperature, room air humidity, UV exposure, air composition, and suspending fluid. However, few studies consider the fact that respiratory viruses are not alone in the respiratory tract-we are constantly colonized by a plethora of bacteria in our noses, mouth, and lower respiratory system. In the gut, enteric viruses are known to be stabilized against inactivation and environmental decay by gut bacteria. Despite the presence of a similarly complex bacterial microbiota in the respiratory tract, few studies have investigated whether viral stabilization could occur in this niche. Here, we address this question by investigating influenza A virus stabilization by a range of commensal bacteria in systems representing respiratory aerosols and droplets.

SARS-CoV-2 infection unevenly impacts metabolism in the coronal periphery of the lungs.

COVID-19 significantly decreases amino acids, fatty acids, and most eicosanoidsSARS-CoV-2 preferentially localizes to central lung tissueMetabolic disturbance is highest in peripheral tissue, not central like viral loadSpatial metabolomics allows detection of metabolites not altered overallSARS-CoV-2, the virus responsible for COVID-19, is a highly contagious virus that can lead to hospitalization and death. COVID-19 is characterized by its involvement in the lungs, particularly the lower lobes. To improve patient outcomes and treatment options, a better understanding of how SARS-CoV-2 impacts the body, particularly the lower respiratory system, is required. In this study, we sought to understand the spatial impact of COVID-19 on the lungs of mice infected with mouse-adapted SARS2-N501Y MA30 . Overall, infection caused a decrease in fatty acids, amino acids, and most eicosanoids. When analyzed by segment, viral loads were highest in central lung tissue, while metabolic disturbance was highest in peripheral tissue. Infected peripheral lung tissue was characterized by lower levels of fatty acids and amino acids when compared to central lung tissue. This study highlights the spatial impacts of SARS-CoV-2 and helps explain why peripheral lung tissue is most damaged by COVID-19.

Integrated traditional Chinese and western medicine expert consensus on the diagnosis and treatment of combined allergic rhinitis and asthma syndrome

Combined allergic rhinitis and asthma syndrome (CARAS) refers to a common respiratory disease that occurs simultaneously with clinical or subclinical allergic symptoms of the upper respiratory tract (allergic rhinitis) and the lower respiratory tract (asthma). The incidence of CARAS is high and the quality of life of the patients is greatly affected. At present, treatment of this comprehensive disease is often carried out separately in the otorhinolaryngology and respiratory departments. One of the reasons is a lack of coordinated treatment consensus on the comprehensive management of this disease. As a common respiratory disease, this syndrome also has a profound clinical basis of traditional Chinese medicine in its diagnosis and treatment. Therefore, the Allergy Committee of Chinese Association of Integrative Medicine organized domestic experts in respiratory medicine, otolaryngology, allergy, pediatrics, traditional Chinese Medicine internal medicine and other related fields to discuss and summarize the etiology and anatomical characteristics, pathophysiology and pathogenesis, laboratory examination, diagnostic evaluation and differential diagnosis as well as treatment of both traditional Chinese medicine and western medicine, in order to provide integrated diagnosis and treatment opinions for this common integrative disease of upper and lower respiratory system in clinical practice.

Management of Linguatula serrata infestation in a dog from Greece: a case report

Linguatuliasis is caused by the Arthropod parasite Linguatula serrata (family: Linguatulidae) a parasite with worldwide distribution and zoonotic importance, especially in warm subtropical and temperate regions. Dogs, cats, foxes, jackals, and other carnivores are the final hosts of this Arthropod while any mammal could be a potential intermediate host of this parasite. Adults L. serrata live in the nasopharyngeal region and lower respiratory system, embed their body into the mucosa of nasal pharyngeal cavities. A two year old spayed female dog of undetermined breed, weighting 29 kg that lives in a mountain village called Sella (Prefecture of Achaia, Greece) in a semi-free form, was presented in a veterinary clinic of Patra with history of progressive cough and sneezing, which started about 2 weeks earlier. Along with the dog, the owner brought a parasite that was expelled from the dog’s nose during the intense cough and sneezing the same day. Macroscopic morphological aspects of the parasite, in the laboratory under stereoscope, revealed an arthropod 3,8cm in length identified as L. serrata, also commonly called tongue worm. The dog was treated with Macrocyclice lactone and lavage of nasal cavities. Humans can become infected in two ways: either as an intermediate host (visceral linguatuliasis) or as an accidental final host (nasopharyngeal linguatuliasis), usually as a result of consumption of raw or poorly cooked meat of an infected intermediate host.

Pathophysiology and clinical management of coronavirus disease (COVID-19): a mini-review.

An unprecedented global pandemic caused by a novel coronavirus named SARS-CoV-2 has created a severe healthcare threat and become one of the biggest challenges to human health and the global economy. As of July 2023, over 767 million confirmed cases of COVID-19 have been diagnosed, including more than 6.95 million deaths. The S protein of this novel coronavirus binds to the ACE2 receptor to enter the host cells with the help of another transmembrane protease TMPRSS2. Infected subjects that can mount an appropriate host immune response can quickly inhibit the spread of infection into the lower respiratory system and the disease may remain asymptomatic or a mild infection. The inability to mount a strong initial response can allow the virus to replicate unchecked and manifest as severe acute pneumonia or prolonged disease that may manifest as systemic disease manifested as viremia, excessive inflammation, multiple organ failure, and secondary bacterial infection among others, leading to delayed recovery, hospitalization, and even life-threatening consequences. The clinical management should be targeted to specific pathogenic mechanisms present at the specific phase of the disease. Here we summarize distinct phases of COVID-19 pathogenesis and appropriate therapeutic paradigms associated with the specific phase of COVID-19.

Impact of Electronic Cigarettes on the Upper Aerodigestive Tract: A Comprehensive Review for Otolaryngology Providers.

The use and effects of electronic (e)-cigarettes (e-cigs) are particularly relevant for otolaryngology providers as tobacco plays a major role in benign and malignant diseases of the upper aerodigestive tract. This review aims to (1) summarize the recent policies regarding e-cigs and important patterns of use and (2) serve as a comprehensive resource for clinical providers on the known biologic and clinical effects of e-cigs on the upper aerodigestive tract. PubMed/MEDLINE. We conducted a narrative review on (1) general information on e-cig use and informative findings in the lower respiratory system and a comprehensive review on (2) the effects of e-cigs on cell and animal models and the clinical implications of these products on human health as is relevant to otolaryngology. Although e-cigs are likely less harmful than conventional cigarettes, preliminary research on e-cigs suggest several deleterious effects including in the upper aerodigestive tract. Due to this, there has been increased interest in restricting e-cig usage, particularly among the adolescent population, and caution in recommending e-cigs to current smokers. Chronic e-cig use is likely to have clinical implications. It is critical for otolaryngology providers to be aware of the rapidly changing regulations and use patterns regarding e-cigs and how e-cigs influence human health, particularly with regards to the upper aerodigestive tract, to accurately council patients regarding potential risks and benefits of use.

The Effects of Asymptomatic Coronavirus Disease-2019 on Placenta at Third Trimester Pregnancy: A Comprehensive Study

Objective: By the time coronavirus disease-2019 (COVID-19) had been announced as pandemic, the disease was shown to have a great risk among pregnant woman if lower respiratory system is involved. We aimed to describe clinical characteristics of deliveries with asymptomatic COVID-19 infection, investigate transplacental transmission, and compare first-line histopathological findings with healthy controls. Material and Methods: We conducted a prospective cohort study of consecutive term deliveries at our tertiary hospital's obstetric unit between March and November 2021. Forty-five patients with asymptomatic reverse transcription-polymerase chain reaction (RT-PCR) positivity were matched with 45 controls with negative RT-PCR testing. All newborns of mothers with positive RT-PCR results for COVID19 underwent a nasopharyngeal swab following delivery, and Apgar scores of the newborns were extracted from pediatric charts. Placentas were transported and fixated in 10% formaldehyde solution before pathological evaluation. Results: There were no significant differences in Apgar scores, birth weights, head circumferences, birth height, and genders between the 2 groups. RT-PCR results were negative in all of the newborns, indicating no vertical transmission. Placental focal and global calcification, and choriamnionitis frequencies were similar between the groups, whereas placental fibrin deposits were significantly more frequent in the placentas of infected pregnancies. Conclusion: There was no evidence of vertical transmission and any characteristic feature in the placentas of pregnancies with asymptomatic COVID-19 infection. Although no significant clinical implication was found, increased perivillous fibrin deposition in the study group could be a baseline step for the progression of perinatal infection.

Investigation of Ultrafine Particle Deposition in Human Airway to the 9th Generation of Bronchial Tubes Using Computational Fluid and Particle Dynamics

The behavior of airborne particles in the human respiratory system is closely related to local tissue dosimetry and its associated health risks. The inhalation of these particles is known to be the origin of lung diseases, such as lung cancer, chronic obstructive pulmonary disease, and cardiovascular disease. To compensate for the difficulty of experiments involving volunteers, in silico studies using numerical models have been adopted as promising alternatives. Therefore, this study applied the computational fluid and particle dynamics technique to investigate the deposition of ultrafine particles in the human respiratory tract from the nostrils to the ninth generation of bronchi. A computational model was created using computed tomography images. The airflow patterns were simulated under steady and incompressible conditions at breathing flow rates of 7.5 and 15 L/min, respectively. The discrete phase was simulated for ultrafine particles with aerodynamic diameters of 2–100 nm. Consequently, the validation work confirmed the simulation accuracy for particle sizes > 25 nm. In the lower respiratory system, the total deposition fraction decreased as the particle size increased. In addition, the eighth generation is a focal point of the deposited particles, elucidated by the local deposition fraction. The results of this study will benefit further studies involving health risk assessments and drug delivery.

Порівняльний аналіз коефіцієнтів аеродинамічного носового опору за даними передньої та задньої активної риноманометрії

The paper deals with a comparative analysis of aerodynamic nose drag coefficients based on the data of front and rear active rhinomanometry. Functional disorders of nasal breathing in the future lead to further complications of the upper and lower respiratory system, reduce the quality of life and lead to other pathological conditions. The diagnosis of such disorders is complicated by the low prevalence of nasal breathing testing tools (rhinomanometers) in medical practice and the peculiarities of functional research methods, which are particularly related to the low repeatability of results and the lack of a clear correlation between diagnostic data and the patient's objective feelings. The obtained data on the total coefficients of aerodynamic nasal resistance, which are determined using the methods of front and rear active rhinomanometry, correspond quite clearly to each other within 12%. The values of the total coefficients of nasal resistance, obtained by the method of posterior rhinomanometry, in all typical cases differ to a lesser extent. The perspective of the work is to gather statistical data to determine the features of nasal breathing testing to obtain accurate personalized values of nasal resistance coefficients in different breathing modes, taking into account individual variability.

Mast cells promote viral entry of SARS-CoV-2 via formation of chymase/spike protein complex

The pulmonary pathological findings associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) result from the release of multiple proinflammatory cytokines, which causes the subsequential damage of the lungs. The current study was undertaken to investigate the responses of mast cells to viral inoculation and their contribution to host defenses from the point of view of viral entry. Pseudovirions, in which the spike glycoprotein of SARS-CoV-2 was incorporated, triggered activation of mast cells, and a mast cell-derived chymase, MCP2, formed a complex with spike protein, which promoted protease-dependent viral entry. According to the quantification results of viral entry, 10 μM quercetin, a mast cell stabilizer, potentially potently inhibited 41.3% of viral entry, while 100 μM chymostatin, which served as a chymase inhibitor, suppressed 52.1% of viral entry, compared to non-treated cells. Study using mast cell-deficient mice showed that the absence of mast cells may influence early viral loading in the upper respiratory tract, which consequently increases the risk of viral invasion into the lower respiratory system. Furthermore, mast cell-deficient mice exhibited ongoing infection in the late phase post-viral inoculation, while clearance of virus-positive cells was observed in wild-type mice. In conclusion, mast cells act as a multifaceted immune modulator that is equipped with both protective effects and pathogenic influences on viral entry of SARS-CoV-2. The utility of mast cell stabilizers and chymase inhibitors in the treatment of SARS-CoV-2-induced acute respiratory syndrome should be optimized regarding the infection stage and the risk of cytokine storm.

Diagnostic dilemma of Wegener’s granulomatosis and its effective management: A rare case report and update

Granulomatosis with Polyangiitis (GPA) is an uncommon condition belongs to the group of ANCA-associated necrotizing vasculitides. It is characterized by necrotizing granulomatosis of upper and lower respiratory system with coexisting glomerulonephritis. Its signs and symptoms are largely varied due to a wide spectrum of involvement sites. In the present case report, we describe a case of 26-year-old female presented to our centre with history of bilateral ear discharge, earache, and dry cough with a deviated mouth angle to left. Diagnostic work up was done and patient was treated with pulse methylprednisolone, plasmapheresis, and rituximab. Timely diagnosis and prompt initiation of the treatment has prevented the GPA progression and helped the patient to improve quickly. Currently, the patient is doing well and is in remission.

A case of primary COVID-19 pneumonia: plausible airborne transmission of SARS-CoV-2

BackgroundThe different clinical manifestations, from none to severe, and the variability in efficacy of SARS-CoV-2 diagnosis by upper respiratory tract testing, make diagnosis of COVID-19 and prevention of transmission especially challenging. In addition, the ways by which the virus can most efficiently transmit still remain unclear.Case PresentationWe report the case a 48-year-old man who presents primary COVID-19 pneumonia. He was initially admitted for cholecystitis but, upon review of his abdominal CT scan, a segmental zone of ground glass opacity was identified in the right lower lobe. A bronchoalveolar lavage proved positive to SARS-CoV-2 by RT-qPCR, even if he tested negative by oro-nasopharyngeal swab at admission and the day after he underwent bronchoscopy. The near absence of the virus in his saliva 2 days after, combined with a very sharp increase in salivary viral load on the third day, also rule out the possibility of prior viral replication in the upper airway and clearance. In addition, rapidly increasing bilateral alveolar lung infiltrates appeared as the upper respiratory tests begin to detect the virus.ConclusionsFor this patient to have developed primary COVID-19 pneumonia, a contagious aerosol must have traveled to the lower respiratory system. This case gives indirect but compelling evidence that aerosol may spread the virus. It also highlights the limitations of oral and nasal testing methods and the importance of anatomical considerations when studying infections by SARS-CoV-2.

Hamsters Expressing Human Angiotensin-Converting Enzyme 2 Develop Severe Disease following Exposure to SARS-CoV-2.

ABSTRACTThe rapid emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has created a global health emergency. While most human disease is mild to moderate, some infections lead to a severe disease characterized by acute respiratory distress, hypoxia, anosmia, ageusia, and, in some instances, neurological involvement. Small-animal models reproducing severe disease, including neurological sequela, are needed to characterize the pathophysiological mechanism(s) of disease and to identify medical countermeasures. Transgenic mice expressing the human angiotensin-converting enzyme 2 (hACE2) viral receptor under the control of the K18 promoter develop severe and lethal respiratory disease subsequent to SARS-CoV-2 intranasal challenge when high viral doses are used. Here, we report on SARS-CoV-2 infection of hamsters engineered to express the hACE2 receptor under the control of the K18 promoter. K18-hACE2 hamsters infected with a relatively low dose of 100 or 1,000 PFU of SARS-CoV-2 developed a severe and lethal disease, with most animals succumbing by day 5 postinfection. Hamsters developed severe lesions and inflammation within the upper and lower respiratory system, including infection of the nasal cavities causing marked destruction of the olfactory epithelium as well as severe bronchopneumonia that extended deep into the alveoli. Additionally, SARS-CoV-2 infection spread to the central nervous system (CNS), including the brain stem and spinal cord. Wild-type (WT) hamsters naturally support SARS-CoV-2 infection, with the primary lesions present in the respiratory tract and nasal cavity. Overall, infection in the K18-hACE2 hamsters is more extensive than that in WT hamsters, with more CNS involvement and a lethal outcome. These findings demonstrate the K18-hACE2 hamster model will be valuable for studying SARS-CoV-2.

Alveolar type II cells and pulmonary surfactant in COVID-19 era.

In this review, we discuss the role of pulmonary surfactant in the host defense against respiratory pathogens, including novel coronavirus SARS-CoV-2. In the lower respiratory system, the virus uses angiotensin-converting enzyme 2 (ACE2) receptor in conjunction with serine protease TMPRSS2, expressed by alveolar type II (ATII) cells as one of the SARS-CoV-2 target cells, to enter. ATII cells are the main source of surfactant. After their infection and the resulting damage, the consequences may be severe and may include injury to the alveolar-capillary barrier, lung edema, inflammation, ineffective gas exchange, impaired lung mechanics and reduced oxygenation, which resembles acute respiratory distress syndrome (ARDS) of other etiology. The aim of this review is to highlight the key role of ATII cells and reduced surfactant in the pathogenesis of the respiratory form of COVID-19 and to emphasize the rational basis for exogenous surfactant therapy in COVID-19 ARDS patients.

THE HISTOLOGICAL EFFECTS OF COVID-19 ON THE LOWER RESPIRATORY SYSTEM

Both histologically and anatomically, the respiratory system is a compound system having diverse functions. It fulfills the process of respiration that is regarded as gas exchange through conduction and filtration of air. The respiratory system is functionally divided into conducting and respiratory parts.Anatomically, the respiratory tract is categorized into the upper and lower respiratory tract. The lower respiratory tract represents the organs within the thorax such as the trachea, bronchi, bronchioles, alveolar duct, and alveoli which make up the lungs.The paired lungs are parts of the lower respiratory tract which are regularly presented microorganisms.Although COVID-19 affects different organs simultaneously it seriously affects the lower respiratory system, produces respiratory distress to affected individuals, and mostly produces histological changes in the respiratory tract. In terms of COVID-19 effects on the lower respiratory tract, the lungs are affected in most cases, and the review is largely focused on the lungs. The histological effects of COVID-19 on the lungs are different and reveal a broad spectrum of abnormalities.Diffuse alveolar damage (DAD) remained the principal lung histopathological finding in patients with COVID-19. DAD results from damage of the covering cells of the alveoli and endothelium ending with disarrangement of the blood-air barrier. Concerning the event of pulmonary injury, DAD is classified into three histopathological stages that are acute (exudative), subacute (organizing), and chronic (fibrotic) stage.Since there is no adequate information about the histological effects of COVID-19 on the lower respiratory system, this article aimed to review what is known about the histological effects of COVID-19 on the lower respiratory system. It summarizes the previous literature of published articles that examined the histological effects of COVID-19 on the lower respiratory system to display the present understanding of histological changes of the lower respiratory system associated with COVID-19. Further data about the histological effects of COVID-19 on the lower respiratory system is needed to adequately define the histopathological changes of the lower respiratory system associated with COVID-19.

COVID-19 Pandemic: Current Scenario, Challenges and Future Perspectives

Background: The new public health emergency of COVID-19 caused by a novel Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), which originated in Wuhan, Hubei province, China in December 2019, evolved into a pandemic in no time and is still in progression. The novel virus mainly targets the lower respiratory system, leading to viral pneumonia, with other associated complications of multi organ failure. Discussion: The bats, in particular Rhinolophus affinis, is a natural host of SARS-CoV-2 and the virus is considered to have spread to humans through yet controversial intermediate host pangolins. The incubation period ranges from 2-14 days and mode of person-to-person transmission is primarily via the direct contact with the infected person or through the droplets generated by the infected person during coughing or sneezing. The initiation of the infection process by SARS-CoV-2 virus is the invasion of lung type II alveolar cells via a receptor protein called angiotensin-converting enzyme 2 (ACE2) present on the cell membrane with glycosylated spike (S) viral protein that mediates host cell invasion. The main diagnostic tools employed are molecular methods based on nucleic acid detection engaging real-time quantitative polymerase chain reaction (RT-qPCR) and a new immunoassays based on antibodies IgM/IgG. Conclusion: Due to the lack of specific clinically approved anticovid-19 drugs or vaccines that could be used for its prevention or treatment, the current management approach is essentially supportive and symptomatic. The precautionary measures like, social distancing, cleaning hands with soap or sanitizers, using disinfectant solutions to decontaminate the surfaces of things and proper ventilation, wearing masks and other protective gears to curb transmission. The knowledge regarding COVID-19 therapies is still evolving and collaborative efforts are being put in to discover definitive therapies on different themes in the form of vaccines, repurposing drugs, RNA interference, docking studies, etc.

Plant-based Remedies with Reference to Respiratory Diseases – A Review

In the era of air pollutants, respiratory diseases are a very common diagnosis in children, adolescents, and adults. Disorders of the respiratory system can affect both upper and lower respiratory system, and cause an immense worldwide health, economical and psychological burden. Considerable attention is drawn to the use of plant-based products for the prevention and cure of health challenges, with respect of their eco-friendliness and very few side effects. Exposure to nature and active plant interaction is considered beneficial to physical and mental health. Plant-based drugs primarily target the immune and cardiovascular systems. Biologically active substances with different value can be identified from both terrestrial or marine botanicals, whose therapeutic abilities are an efficient control of an array of diseases. In view of the potential of plant agents to positively influence respiratory diseases, this review will provide the reader with recent objective findings in the field of plant therapy and pharmaceutical agents and their ability to alter the physical and psychological complications of airborne diseases.

Potential pharmacological Therapeutics options for COVID-19: Review

Unusual pneumonia result from unknown pathogen was emerged in December 2019 in a seafood market of Wuhan city in China. The pathogen was soon identified as a novel coronavirus (2019-nCoV), which is closely related to sever acute respiratory syndrome CoV (SARS-CoV) which has taken the world to the edge of health emergency. On 11th March 2020, COVID-19 was declared a pandemic by the World Health Organization. SARS-CoV-2 belongs to the family of Coronaviridae. Corona virus has been reported to cause similar morbific impacts on the lower respiratory system. Transmits occurs when people breathe in air contaminated by droplets and small airborne particles. Transmission can also occur if sprayed with contaminated fluids, in the eyes, nose or mouth. People remain contagious for up to 20 days, and can spread the virus even if they do not develop any symptoms. Although this disease primarily targets lungs, damages in other organs, such as heart, kidney, liver, and testis, may occur.

Latent class analysis to predict intensive care outcomes in Acute Respiratory Distress Syndrome: a proposal of two pulmonary phenotypes

BackgroundAcute respiratory distress syndrome remains a heterogeneous syndrome for clinicians and researchers difficulting successful tailoring of interventions and trials. To this moment, phenotyping of this syndrome has been approached by means of inflammatory laboratory panels. Nevertheless, the systemic and inflammatory expression of acute respiratory distress syndrome might not reflect its respiratory mechanics and gas exchange.MethodsRetrospective analysis of a prospective cohort of two hundred thirty-eight patients consecutively admitted patients under mechanical ventilation presenting with acute respiratory distress syndrome. All patients received standardized monitoring of clinical variables, respiratory mechanics and computed tomography scans at predefined PEEP levels. Employing latent class analysis, an unsupervised structural equation modelling method, on respiratory mechanics, gas-exchange and computed tomography-derived gas- and tissue-volumes at a PEEP level of 5cmH2O, distinct pulmonary phenotypes of acute respiratory distress syndrome were identified.ResultsLatent class analysis was applied to 54 respiratory mechanics, gas-exchange and CT-derived gas- and tissue-volume variables, and a two-class model identified as best fitting. Phenotype 1 (non-recruitable) presented lower respiratory system elastance, alveolar dead space and amount of potentially recruitable lung volume than phenotype 2 (recruitable). Phenotype 2 (recruitable) responded with an increase in ventilated lung tissue, compliance and PaO2/FiO2 ratio (p < 0.001), in addition to a decrease in alveolar dead space (p < 0.001), to a standardized recruitment manoeuvre. Patients belonging to phenotype 2 (recruitable) presented a higher intensive care mortality (hazard ratio 2.9, 95% confidence interval 1.7–2.7, p = 0.001).ConclusionsThe present study identifies two ARDS phenotypes based on respiratory mechanics, gas-exchange and computed tomography-derived gas- and tissue-volumes. These phenotypes are characterized by distinctly diverse responses to a standardized recruitment manoeuvre and by a diverging mortality. Given multicentre validation, the simple and rapid identification of these pulmonary phenotypes could facilitate enrichment of future prospective clinical trials addressing mechanical ventilation strategies in ARDS.

Low-dose radiation therapy: a treatment for pneumonia resulting from COVID-19

AbstractBackground:The Coronavirus disease 2019 (COVID-19) is spreading rapidly throughout the world. Lung is the primary organ which the COVID-19 virus affects and leads to pneumonia, an acute respiratory distress syndrome. COVID-19 infects the lower respiratory system, and the lung’s response to this infection is recruiting macrophages and monocytes leading to inflammation, this response causes widespread damage to the lung’s airways.Aim:The purpose of this study is to review studies of using low-dose radiation as a treatment for the inflammation of the tissue and pneumonia resulting from COVID-19. These studies were compared with the risk of developing lung cancer during performed dose for the treatment of COVID-19 in radiation therapy.Materials and methods:Our study focused on in vitro, in vivo and clinical reports of using low-dose radiation for the treatment of inflammation, pneumonia and COVID-19. The risk of lung cancer resulting from suggested dose in these studies was also evaluated.Conclusion:From the review of articles, we have found that low-dose radiation can lead to improvement in inflammation in different line cells and animals; in addition, it has been effective in treating inflammation and pneumonia caused by COVID-19 in human up to 80%. Since suggested doses do not remarkably increase the lung cancer risk, low-dose radiation can be an adjuvant treatment for COVID-19 patients.