Spontaneous pneumomediastinum – a rare cause of chest pain and dyspnoe in children

Introduction. Spontaneous pneumomediastinum is a very rare condition in children. Nevertheless it should be considered in the differential diagnosis in patients who present with chest pain and dyspnoe.Aim. The aim of our study was to describe clinical presentation, management and outcomes of the paediatric patients with spontaneous pneumomediastinumMaterial and Methods. This was a retrospective analysis of the charts of all the patients who were admitted to the Department of Pneumonology, Paediatric Allergy and Clinical Immunology in a ten year period from 01.01.2011 till 31.12.2020 in whom spontaneous pneumomediastinum was diagnosed.Results. There were 11 children (7 females) with spontaneous pneumomediastinum. The median age of the children was 11 years (range 3 to 17.5 years). Most of the children presented to the hospital with chest pain, three children complained of the neck swelling and four children developed dyspnoe. Three children with the primary spontaneous pneumomediastinum had a history of physical exercise prior to the onset of symptoms. The secondary spontaneous pneumomediastinum occurred in two children with asthma and 4 children with pneumonia. Genetic material of human Bocavirus was identified in 3 cases. In 81.8% of children pneumomediastinum was accompanied by subcutaneous emphysema and in one case, in a child with severe pneumonia and respiratory insufficiency caused by Bocavirus with pneumorrhachis. In 10 children computed tomography was performed, bronchoscopy in 4 and esophagoscopy in two children. There was no evidence of esophageal rupture or bronchial tree rupture in any of our patients. Three children with pneumonia and pneumomediastinum developed respiratory insufficiency, two of these were treated with mechanical ventilation and one with High Flow Nasal Cannula oxygen therapy. All the children received oxygen. In one child surgical procedure was performed and the drain was inserted into mediastinal space in order to decompress it. Outcome was favourable in all children. Mean time to recovery was 10.6 ± 1.2 days. There was no recurrence of symptoms in any of our patients.Conclusions. Spontaneous pneumomediastinum in most cases is a benign condition, sporadically however it may progress rapidly, leading to respiratory insufficiency and warrant invasive management.

Alveoli form directly by budding led by a single epithelial cell

Oxygen passes along the ramifying branches of the lung's bronchial tree and enters the blood through millions of tiny, thin-walled gas exchange sacs called alveoli. Classical histological studies have suggested that alveoli arise late in development by a septation process that subdivides large air sacs into smaller compartments. Although a critical role has been proposed for contractile myofibroblasts, the mechanism of alveolar patterning and morphogenesis is not well understood. Here we present the three-dimensional cellular structure of alveoli, and show using single-cell labeling and deep imaging that an alveolus in the mouse lung is composed of just 2 epithelial cells and a total of a dozen cells of 7 different types, each with a remarkable, distinctive structure. By mapping alveolar development at cellular resolution at a specific position in the branch lineage, we find that alveoli form surprisingly early by direct budding of epithelial cells out from the airway stalk between enwrapping smooth muscle cells that rearrange into a ring of 3-5 myofibroblasts at the alveolar base. These alveolar entrance myofibroblasts are anatomically and developmentally distinct from myofibroblasts that form the thin fiber partitions of alveolar complexes ('partitioning' myofibroblasts). The nascent alveolar bud is led by a single alveolar type 2 (AT2) cell following selection from epithelial progenitors; a lateral inhibitory signal transduced by Notch ensures selection of only one cell so its trailing neighbor acquires AT1 fate and flattens into the cup-shaped wall of the alveolus. Our analysis suggests an elegant new model of alveolar patterning and formation that provides the foundation for understanding the cellular and molecular basis of alveolar diseases and regeneration.

Simulation of Air Motion in Human Lungs during Breathing. Dynamics of Liquid Droplet Precipitation in the Case of Medicine Drug Aerosols

The paper deals with numerical simulation of the air flow in the full human bronchial tree. In their previous studies, the authors developed an analytical model of the full human bronchial tree and a method of stage-by-stage computation of the respiratory tract. A possibility of using the proposed method for a wide range of problems of numerical simulations of the air flow in human lungs is analyzed. The following situations are considered: 1) steady inspiration (with different flow rates of air) for circular and “starry” cross sections of bronchi (“starry” cross sections models some lung pathology); 2) steady expiration; 3) unsteady inspiration; 4) precipitation of medical drug aerosol droplets in human bronchi. The results predicted by the proposed method are compared with results of other researchers and found to be in good agreement. In contrast to previous investigations, the air flow in the full (down to alveoli) bronchial tree is studied for the first time. It is shown that expiration requires a greater pressure difference (approximately by 30%) than inspiration. Numerical simulations of precipitation of medical drug aerosol droplets in the human respiratory tract show that aerosol droplets generated by a standard nebulizer do not reach the alveoli (the droplets settle down in the lower regions of the bronchi).

Plastic bronchitis associated with influenza A virus in children with asthma

Plastic bronchitis (PB) is a rare and potentially fatal disease characterized by acute progressive dyspnea caused by bronchial casts in the bronchial tree. We analyzed two children with asthma and PB who presented with high fever, cough and dyspnea. Both cases showed acute onset and rapid disease progression. Laboratory examination revealed that both children were infected with influenza A virus. Emergency fiberoptic bronchoscopy was performed within 20 hours of admission. Immediately after removing the bronchial casts, their dyspnea symptoms improved significantly, and they recovered after comprehensive treatment with antiviral drugs, antibiotics and glucocorticoids. When children with asthma have acute progressive and difficult-to-relieve dyspnea after infection with influenza A virus, clinicians should be aware of the possibility of PB and perform bronchoscopy as soon as possible to facilitate early diagnosis and treatment and improve patient prognosis.

Deep learning for anatomical interpretation of video bronchoscopy images

Anesthesiologists commonly use video bronchoscopy to facilitate intubation or confirm the location of the endotracheal tube; however, depth and orientation in the bronchial tree can often be confused because anesthesiologists cannot trace the airway from the oropharynx when it is performed using an endotracheal tube. Moreover, the decubitus position is often used in certain surgeries. Although it occurs rarely, the misinterpretation of tube location can cause accidental extubation or endobronchial intubation, which can lead to hyperinflation. Thus, video bronchoscopy with a decision supporting system using artificial intelligence would be useful in the anesthesiologic process. In this study, we aimed to develop an artificial intelligence model robust to rotation and covering using video bronchoscopy images. We collected video bronchoscopic images from an institutional database. Collected images were automatically labeled by an optical character recognition engine as the carina and left/right main bronchus. Except 180 images for the evaluation dataset, 80% were randomly allocated to the training dataset. The remaining images were assigned to the validation and test datasets in a 7:3 ratio. Random image rotation and circular cropping were applied. Ten kinds of pretrained models with < 25 million parameters were trained on the training and validation datasets. The model showing the best prediction accuracy for the test dataset was selected as the final model. Six human experts reviewed the evaluation dataset for the inference of anatomical locations to compare its performance with that of the final model. In the experiments, 8688 images were prepared and assigned to the evaluation (180), training (6806), validation (1191), and test (511) datasets. The EfficientNetB1 model showed the highest accuracy (0.86) and was selected as the final model. For the evaluation dataset, the final model showed better performance (accuracy, 0.84) than almost all human experts (0.38, 0.44, 0.51, 0.68, and 0.63), and only the most-experienced pulmonologist showed performance comparable (0.82) with that of the final model. The performance of human experts was generally proportional to their experiences. The performance difference between anesthesiologists and pulmonologists was marked in discrimination of the right main bronchus. Using bronchoscopic images, our model could distinguish anatomical locations among the carina and both main bronchi under random rotation and covering. The performance was comparable with that of the most-experienced human expert. This model can be a basis for designing a clinical decision support system with video bronchoscopy.

Gas Flow in Occluded Respiratory Tree: A New Matrix-Based Approach

Studies suggest that both the size of airways and the number of bifurcations of the respiratory tree provide the best structural design to accomplish its function. However, constrictions and occlusions due to inflammation and pulmonary edema of the airways can inhibit normal air flowing through the respiratory tree, affecting gas exchange. It results in heterogeneity in gas exchange (and pulmonary perfusion) with adverse risk factors. In this study, we propose a methodology based on the airway tree admittance (reciprocal of impedance) to study this problem. This methodology is distinct from the traditional quantification, based on overall impedance using lump parameter models, and applies to a matrix formed by admittances of each airway of the entire conducting part of the bronchial tree. The generated system admittance matrix is highly sparse in nature, and thus to solve the same system, a modified block-based LU decomposition method is proposed to improve the space-time trade-off. Our approach enables the determination of the local ventilation pattern and reduces the mis-evaluation, mainly in the cases that characterize the early-stage obstructive disorders. The key finding of the present study is to show that how the position and intensity of local obstruction in an airway can affect the overall as well as regional ventilation which can lead to impaired gas exchange.

Neonatal repair of total anomalous pulmonary venous connection accompanied by unilateral lung agenesis and Goldenhar syndrome: a case report

Background Total anomalous pulmonary venous connection accompanied by unilateral lung agenesis and Goldenhar syndrome is extremely rare. Case presentation We present a case of total anomalous pulmonary venous connection accompanied by unilateral lung agenesis and Goldenhar syndrome in a patient who was diagnosed based on transthoracic echocardiography and computed tomography. We observed complete absence of the lung, the bronchial tree, and vascular structures on the right side, with abnormal drainage of the left pulmonary veins into the innominate vein. The patient showed clear clinical evidence of pulmonary venous obstruction and underwent surgery 3 days after birth. The pulmonary venous chamber containing the vertical vein was anastomosed to the left atrium using 7–0 PDS running sutures via a median sternotomy. Echocardiography and computed tomography performed 1 year postoperatively revealed no pulmonary venous obstruction. Conclusion We report a rare case of total anomalous pulmonary venous connection accompanied by unilateral lung agenesis and Goldenhar syndrome, which was successfully repaired 3 days after birth. A median sternotomy is a safe and effective approach for surgical repair of congenital heart disease with unilateral lung agenesis. Repair of the supra cardiac total anomalous pulmonary connection using the vertical vein is feasible in patients with a small pulmonary venous chamber.

Flexible bronchoscopy in foreign body removal in the pediatric population: A Systematic Review

Background: Foreign body aspiration (FBA) in the tracheobronchial tree is a common problem in the pediatric population. Rigid bronchoscopic procedure is currently the gold standard method for treatment in pediatric patients, whereas recent reports present flexible bronchoscopy as an alternative method. The aim of this study was to summarize all available evidence regarding the application and the success rate of flexible bronchoscopy in foreign body (FB) removal. Methods: Systematic review of the use of flexible bronchoscopy as the first-line treatment in FBA cases in PubMed from 2001 to 2021. Results: Out of 243 citations, 23 studies were included on the use of flexible bronchoscopic procedure as a treatment of choice in 2,587 children with FBA. The FBs were successfully removed in 2,254/2,587 (87.1%) patients with a low complication rate. The majority of FBs retrieved were organic materials 1,073/1,370 (78.3%), and they were most commonly lodged in the right bronchial tree 708/1,401 (50.5%). General anesthesia was applied in most studies (14/23) before proceeding to a flexible bronchoscopy and laryngeal mask airways (LMAs) were mostly used (10/23 studies) to secure the airway during the procedure. Ancillary equipment, usually forceps 1,544/1808 (85.4%) assisted in the FB retrieval. Conclusion: The use of flexible bronchoscopy is shown to be a feasible and safe alternative therapeutic procedure in FBA cases. There is a need for development of extraction equipment and techniques to assist the procedure. Finally, future studies focusing on the comparison between clinical outcomes of flexible and rigid bronchoscopies are necessary.

A Soft Pneumatic Two-Degree-of-Freedom Actuator for Endoscopy

The rise of soft robotics opens new opportunities in endoscopy and minimally invasive surgery. Pneumatic catheters offer a promising alternative to conventional steerable catheters for safe navigation through the natural pathways without tissue injury. In this work, we present an optimized 6 mm diameter two-degree-of-freedom pneumatic actuator, able to bend in every direction and incorporating a 1 mm working channel. A versatile vacuum centrifugal overmolding method capable of producing small geometries with a variety of silicones is described, and meter-long actuators are extruded industrially. An improved method for fiber reinforcement is also presented. The actuator achieves bending more than 180° and curvatures of up to 0.1 mm−1. The exerted force remains below 100 mN, and with no rigid parts in the design, it limits the risks of damage on surrounding tissues. The response time of the actuator is below 300 ms and therefore not limited for medical applications. The working space and multi-channel actuation are also experimentally characterized. The focus is on the study of the influence of material stiffness on mechanical performances. As a rule, the softer the material, the better the energy conversion, and the stiffer the material, the larger the force developed at a given curvature. Based on the actuator, a 90 cm long steerable catheter demonstrator carrying an optical fiber is developed, and its potential for endoscopy is demonstrated in a bronchial tree phantom. In conclusion, this work contributes to the development of a toolbox of soft robotic solutions for MIS and endoscopic applications, by validating and characterizing a promising design, describing versatile and scalable fabrication methods, allowing for a better understanding of the influence of material stiffness on the actuator capabilities, and demonstrating the usability of the solution in a potential use-case.