Large Airway Obstruction Research Articles

Small airway inflammation in atypical asthma

BackgroundLess attention has been paid to the pathophysiological changes in atypical asthma such as cough variant asthma (CVA) and chest tightness variant asthma (CTVA). The obstruction of large and small airways is the important component in the development of asthma. We investigated whether small airway inflammation (SAI) induced small airway dysfunction (SAD) in these atypical asthmatics. MethodsSix hundred and eighty-six patients were enrolled and analyzed in the study. The partitioned airway inflammation was assessed by fractional exhaled nitric oxide (FeNO), such as FnNO, FeNO50, FeNO200, and calculated alveolar fraction of exhaled NO (CaNOdual). Correlations between exhaled NOs and SAD-related variables were assessed, whereas cell classification was evaluated by Spearman's rank tests. Classic asthma, CVA, and CTVA about potential risk were conducted using binary logistic regression models. ResultsThe whole airway inflammation increased in classic and atypical asthma than controls, whereas the central and peripheral airway inflammation in the CVA and CTVA groups increased compared with the classic asthma group. Smoking exposure was found to increase the central and peripheral airway inflammation in patients with asthma. The exhaled NO of FeNO50 and FeNO200 was associated with SAD in classic asthma, but not in CVA and CTVA. FeNO200 was the main risk (adjusted odds ratio [OR], 1.591; 95 % CI, 1.121–2.259; P = .009) in classic asthma and (adjusted OR, 1.456; 95 % CI, 1.247–1.700; P = .000) in CVA. The blood eosinophil levels were correlated with FeNO50 and FeNO200 in classic asthma and atypical asthma. ConclusionMore severe inflammatory process was present in central and peripheral airways in CVA and CTVA, which might reflect a pre-asthmatic state. SAI was the predominant risk factor in the development of asthma before SAD.

Early diagnosis of small airway disease in asymptomatic polishing sector workers of a leather factory

Background: The leather industry stands as one of India’s burgeoning sectors, boasting significant manpower. Workers in the finishing sector, particularly those involved in polishing, face heightened risks due to exposure to formaldehyde, aniline, and resins, which can lead to respiratory complications. Aims and Objectives: The aims and objectives of the study are to determine the small airway obstruction in asymptomatic finishing sector workers of a leather factory. Materials and Methods: The current study was a cross-sectional study conducted in a leather factory located in Chennai, Tamil Nadu. A random sample of 60 workers was drawn from different sectors of a leather factory. Basic demographic details, smoking history, nature of work, exposure to irritants along with duration, and respiratory symptoms were collected. All workers were subjected to spirometry as per ATS guidelines and the results were analyzed. Association between length (years) of exposure, respiratory symptoms, and spirometry impairment among the workers were analysed. Results: Out of 60 samples, 38 were exposed to irritants and 22 were not exposed to irritants. Out of 38, 25 had small airway disease, seven had large airway obstruction, one had a restrictive pattern, and five had normal spirometry. 42.1% of them were asymptomatic. Conclusion: Small airway obstruction is notably prevalent, especially among asymptomatic workers in the polishing sector. Prolonged exposure is associated with the development of large airway obstructive disease. This study underscores the importance of continuous monitoring for airway diseases in occupationally exposed workers, advocating for timely preventive and protective measures to curb disease progression.

Small airway dysfunction and obesity in asthmatic patients: a dangerous liaison?

Asthma is a chronic condition characterized by inflammation throughout the entire bronchial airways. Recent findings suggest that ventilation inhomogeneity and small airway dysfunction (SAD) play a particularly significant role in asthma development and clinical manifestations. Obesity is a considerable risk factor for asthma development and morbidity in children and adults. A growing body of evidence suggests that SAD is linked to more severe asthma and poor asthma control in obese patients. However, the knowledge about the relationship between peripheral airway compromise and obesity in asthma is limited, mainly because of the historical lack of access to non-invasive assessment methods for studying SAD. Conventional lung function measurements, like spirometry, cannot accurately assess small airway function. However, in recent years, new specialized tests available in outpatient settings have been found to distinguish SAD from large airway obstruction more accurately compared to spirometry. Therefore, understanding the degree of peripheral airway implication in the underlying pathology is critical for effective asthma control and therapeutic decisions. This review highlights recent findings on the impact of SAD on asthma patients who are obese. Additionally, it explores how new diagnostic methods, such as impulse oscillometry (IOS), may be used in outpatient settings to detect small airway impairment in obese asthma at an early stage, potentially leading to improved asthma treatment.

Clinical Utility of Peak Flow Meter in Asthma Diagnosis and Monitoring in Low- and Middle-Income Countries

Low- and middle-income countries (LMICs) suffer a disproportionate burden of asthma-related deaths. This may be attributed to the underdiagnosis and undertreatment. It remains unclear the extent to which the access to utility of peak flow meters (PFMs) affect the mortality rates recorded across LMICs. The purpose of this narrative review was to offer a comprehensive overview of PFMs’ clinical value for diagnosing and monitoring asthma in low- and middle-income nations. Using the standards for conducting a narrative review, this paper carried out a literature search on three major databases: Google Scholar, ResearchGate, and PubMed. Search terms were created from the variables present in the topic and strung together to find relevant literature. Exclusion criteria were used to ensure that the chosen articles were relevant after a trickle of articles was collected from various databases on the internet. There is limited knowledge about the clinical utility of PFM in LMICs despite the evidence that it can be used to demonstrate large airway obstruction. There is also limited access to the device in most health facilities and patients for self-monitoring. There is a need for more awareness on the usefulness of peak flow among doctors on the utility of the device for asthma diagnosis and monitoring. There is also a need for more research to assess the impact of the poor use of the device on asthma diagnosis, management, and overall outcome.

Review of the Pathologic Characteristics in Myhre Syndrome: Gain-of-Function Pathogenic Variants in SMAD4 cause a Multisystem Fibroproliferative Response.

Background: Myhre syndrome, caused by pathogenic variants in SMAD4, is characterized by compact body habitus with short stature, distinctive craniofacial appearance, stiff skin, cardiovascular abnormalities (valve stenosis, coarctation, hypoplasia, or stenosis of aorta), effusions of potential spaces (pericardium, pleura, peritoneum), restricted movement of the joints (including thorax), and hearing loss. Lung and airway disease has been reported, but not always well-defined, to include interstitial lung disease, large airway obstruction, and pulmonary arterial hypertension. Excessive fibroproliferation of tissues especially following trauma or surgical instrumentation has been recognized, although these may also present spontaneously. Method: We report the pathologic features of 1 new patient with progressive choanal stenosis, and 22 literature cases, including the expanded history of 5 patients (3 who died). Results: Examination of patient tissues documents cellular fibroproliferation and deposition of excessive extracellular matrix explaining some of the observed clinical features of Myhre syndrome. Conclusion: Excessive fibrosis is noted in multiple tissues, especially heart, lung, and upper and lower airways. Our research provides the first systematic review to provide a knowledge base of gross and pathologic findings in Myhre syndrome.

Clinical progress note: Noncardiac complications in adults with congenital heart disease.

Clinical progress note: Noncardiac complications in adults with congenital heart disease.

COMPARATIVE STUDY TO DETECT SITE OF OBSTRUCTION IN OBSTRUCTIVE AIRWAY DISEASES USING SPIROMETRY AND IMPULSE OSCILLOMETRY

Introduction: Chronic Obstructive Pulmonary Disease [COPD] is associated with predominantly smaller airways and lung parenchyma involvement, whereas, Asthma involves predominantly smooth muscles located in the larger airway. Spirometry involves flow volume studies which are effort and coordination dependent and Impulse Oscillometry [IOS] is done during spontaneous respiration and hence effort independent. We studied the site of airway obstruction in COPD and Asthma patients using both Impulse Oscillometry and flow volume loop and whether both methods of pulmonary function testing are comparable with each other. Aims: To study site of airway obstruction using Impulse Oscillometry and Flow volume loop in COPD and Asthma patients. Methodology: The study was performed in 50 patients who were either COPD or Asthma. The patients underwent spirometry and impulse oscillometry. Both the modalities were analyzed for detecting the site of obstruction as per the diagnosis. Results and Conclusion: As per IOS, all the patients having large airway obstruction were asthmatics, all patients with mixed airway disease were COPD and 97.1% patients having small airway obstruction were COPD. Spirometry could not detect site of obstruction in 5 (10%) patients, on the other hand IOS could detect site of obstruction in all the 50 (100%) patients. Hence, Oscillometry is a better tool to know site of obstruction as compared to Spirometry in patients of Asthma and COPD.

Use of flow volume curve to evaluate large airway obstruction.

The flow volume loop (FVL) is a graphic display of airflow against lung volumes at different levels obtained during the maximum inspiratory and expiratory maneuver. It is a simple and reproducible method of lung function assessment. A narrative review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. PubMed, EMBASE, Ovid MEDLINE and CINAHL databases were queried and reviewed for studies pertinent to the various FVLs abnormalities and their mechanisms from January 2020 to December 2020. We used the following search terms; flow-volume loop, upper airway obstruction, Obstructive airway disease, and spirometry. Assessing the shape of the flow-volume loop is particularly helpful in diagnosing and localizing upper airway obstruction. They are also helpful in identifying bronchodilator response to treatment. Characteristic FVLs is also seen in patients with obstructive or restrictive lung disorders. Spirometry should be interpreted using the absolute values for flows and volumes as well as the flow volume and volume time curves.

Forced expiratory volume in the third second and its derivatives for diagnosis of airway obstruction in obese patients

BackgroundSpirometry is a simple diagnostic tool for pulmonary diseases, as obstructive pulmonary disorders, especially in obese. Obesity is an increasing worldwide public health concern that contributes to many respiratory problems that affect both large and small airways. The traditional use of forced expiratory volume in the first second (FEV1) and FEV1/forced vital capacity (FVC) in defining large-airflow obstruction may be confined not only by the limitation of FVC maneuver, but also by the long time to reach plateau flow rate in geriatrics and in patients with moderate-to-severe airflow obstruction. FEV3 and its derivatives FEV1/FEV3 and FEV3/FVC are used for better diagnosis of obstruction, especially in deteriorated patients who cannot blow for more than or equal to 6 s even after their best trials. Regarding small-airway obstruction, FEV3/FEV6 abnormality may be used to diagnose it in the early stages, especially with obesity.AimTo compare the accuracy of FEV3, FEV1/FEV3, and FEV3/FEV6 with that of FVC, FEV1/FVC, and forced expiratory flow (FEF) 25–75% as indices for large-airway and small-airway obstruction in obese persons, in order to replace the ordinary spirometric maneuvers that are easier to perform.Patients and methodsIn this study, 95 patients were enrolled. All participants were classified according to BMI into normal, overweight, and obese groups. FEV1, FEV3, FEV6, FVC, FEV1/FVC%, FEV1/FEV3%, FEV3/FVC%, and FEV3/FEV6% were determined.ResultsFifty participants were males, 52.63%, and 45 were females, 47.37%. Acceptable accuracy of FEV1/FEV3 test for diagnosis of large-airway obstruction, if compared with FEV1/FVC. While FEV3/FVC test showed less-satisfied accuracy. FEV3/FEV6 failed to show an acceptable accuracy for diagnosis of small-airway obstruction when compared with FEF25–75%. Regarding the effect of BMI on spirometric values, FEV1/FVC (P = 0.027), FEV1/FEV3 (P = 0.029), and FEF25–75% (P = 0.002) were more significant in obese patients than overweight patients or normal participants. No differences in FEV3/FVC and FEV3/FEV6 were found among the various groups studied.ConclusionTargeting obese persons, FEV3 and its derivatives as FEV1/FEV3 and to a lesser extent FEV3/FVC can be used as substitutes for FVC and FEV1/FVC, respectively, for evaluation of large-airway obstruction, while FEV3/FEV6 cannot identify people with small-airflow obstruction.

Small-Airway Dysfunction is Involved in the Pathogenesis of Asthma: Evidence from Two Mouse Models.

BackgroundThere has been growing evidence of small-airway dysfunction in patients with asthma. Few studies have evaluated the mechanism of small-airway dysfunction in mouse models of asthma.PurposeWe explored the correlation between small-airway spirometric variables and large-airway function or inflammation in different endotypes of asthma.MethodsOvalbumin (OVA) sensitization/challenge was used to produce a type 2 (T2)-high asthma model, and OVA combined with ozone exposure (OVA + ozone) was used for the T2-low asthma model with increased neutrophils. Spirometry, airway responsiveness, cytokine levels in bronchoalveolar lavage fluid (BALF), and pathological analyses of lung slices stained with hematoxylin-eosin, periodic acid–Schiff, and Masson’s trichrome stain were all determined. Muc5ac expression in lung tissue was evaluated by the reverse transcription-polymerase chain reaction (RT-PCR), and alpha-smooth muscle actin was measured by immunohistochemistry.ResultsInflammatory cells infiltrated the lung tissue and inflammatory cytokines were increased in the BALF of both the OVA and OVA + ozone groups, compared with the control group. Peribronchial hypersecretion and collagen deposition were evident in the models. The OVA + ozone group showed greater neutrophilic infiltration and peribronchial smooth muscle proliferation than the OVA group. Large-airway obstruction, small-airway dysfunction, and airway hyperresponsiveness were confirmed in both models. Small-airway functional variables, such as MMEF (mean midexpiratory flow, average flow from 25 to 75% forced vital capacity [FVC]) and FEF50 (forced expiratory flow at 50% of FVC), were positively correlated with large-airway function and had a stronger negative correlation with airway inflammation, mucus secretion, and responsiveness than large-airway function.ConclusionSmall-airway dysfunction was evident in the two endotypes of asthma and was correlated with severe airway inflammation, mucus hypersecretion, and airway hyperresponsiveness. The small airways may be an important target in asthma treatment, and further research in the role of small-airway variables in the pathogenesis of asthma is warranted.

Outcomes of infants with severe bronchopulmonary dysplasia in the pediatric intensive care unit.

BackgroundSome infants with severe bronchopulmonary dysplasia (sBPD) are referred to higher‐level centers for multidisciplinary care, including the pediatric intensive care unit (PICU). However, information regarding these infants is limited in PICUs.MethodsWe investigated the characteristics and outcomes of preterm infants with sBPD referred to the PICU of a tertiary hospital. This retrospective cohort study included 14 preterm infants with sBPD who were transferred to the PICU beyond 40 weeks’ postmenstrual age (PMA) because of weaning failure, from January 1, 2014, to September 30, 2018.ResultsThe median age at referral was 47.1 weeks (range, 43.6–55.9 weeks), and the median length of stay in the previous neonatal intensive care unit was 154 days (range, 105.8–202.3 days) after birth. After referral the following major comorbidities were found in the patients: large airway malacia, n = 7 (50.0%); significant upper airway obstruction, n = 3 (21.4%); and pulmonary arterial hypertension, n = 8 patients (57.1%). Finally, eight patients (57.1%) were successfully extubated without tracheostomy. Final respiratory support of the patients was determined at a median PMA of 56 weeks (range, 48–63 weeks). Age at referral (P = 0.023) and large airway obstruction (P = 0.028) were significantly related to a decrease in successful extubation.ConclusionBased on a timely and individualized multidisciplinary approach, some of the prolonged ventilator‐dependent infants, even those beyond term age, could be successfully extubated.

Small Airway Disease in Pediatric Asthma: the Who, What, When, Where, Why, and How to Remediate. A Review and Commentary.

Asthma affects all portions of the airways. Small airways, however, comprise a substantial component of the conducting lung air flow. In asthma, inflammatory processes can affect the whole respiratory tract, from central to peripheral/small airways. The emphasis in adult and pediatric respiratory disease clinics is to focus on large airway obstruction and reversibility. This information, although valuable, underemphasizes a large portion of the conduction airway of asthmatics. Standard descriptions of asthma management focus on a multiple medication approaches. We particularly focused on the management of asthma in the international guidelines for the Global Initiative for Asthma (GINA). Overall, however, minimal attention is placed on the small airway pool in asthma medical management. We took the opportunity to thoroughly review and present specific data from the adult asthma literature which supported the concept that small airway abnormalities may play a role in the pathogenesis and clinical expression of asthma. Based on the conclusions of the adult asthma literature, we here present a thorough review of the literature as it relates to small airway disease in children with asthma. We used, collectively, individual data sources of data to expand the information available from standard diagnostic techniques, especially spirometry, in the evaluation of small airway disease. As the pharmacological approaches to moderate to severe asthma are advancing rapidly into the realm of biologics, we sought to present potential pharmacological options for small airway dysfunction in pediatrics prior to biological modifier intervention.

Correlation of Iron Levels with Asthma and Lung Function in Pediatric Patients with Sickle Cell Anemia

Introduction:Significant morbidity and mortality in patients with sickle cell disease (SCD) is attributed to the pulmonary sequalae of the disease. Patients with SCD often suffer airway hyper-reactivity, acute chest syndrome (ACS), chronic lung disease, pulmonary hypertension (PHTN), and obstructive sleep apnea (OSA). Recent literature has provided evidence supporting the strong association between asthma and airway hyper-reactivity in SCD. One of the factors linked to chronic inflammation and asthma is iron status. The present study examined whether iron levels are associated with pulmonary complications in pediatric patients with SCD. Method:Through retrospective review of electronic medical records (EMR) we evaluated patients with diagnosis of asthma and SCD. All patients with available PFT (3/21/2013-3/11/2020) and iron studies were included in the analysis. Chi square and ANOVA tests were used to explore relationships of respiratory conditions with lab data and relevant medical history. Results:The analysis reviewed information of 100 patients with SCD -- 56 males and 44 females The sample population had the following genotypes: 63% Hemoglobin (Hb) SS, 23% Hb SC, 2% Hb S Beta Zero Thalassemia, and 12% Hb S Beta Thalassemia. 38% of these patients were receiving treatment via hydroxyurea. The results generated found that patients with a large airway obstruction (LAO) had a marginally statistically significantly higher serum iron level than those with no LAO (p=0.067.) Patients with homozygous Hb S disease were four times as likely to have a history of ACS (p=0.004) than those without and were marginally significantly more likely to be SS and SB0Thal (p=0.052). Patients with history of ACS had a significantly higher mean iron saturation and lower total iron binding capacity (TIBC.) Patients with PHTN had significantly higher serum iron levels (p=0.029). Conclusion:Our findings reveal that while iron might play a more significant role in the development of PHTN and ACS in patients with SCD, the role in asthma is borderline in our sample. These findings, although of borderline statistical significance p=0.067, are clinically noteworthy. These results may open a new window for therapy targeted at maintaining iron in normal physiologic ranges to decrease pulmonary complications in patients with sickle cell anemia. Further studies with larger samples are necessary to clarify the meaning of our marginally significant findings. Disclosures No relevant conflicts of interest to declare.

Lung function testing assessment by impulse oscillometry in chronic lung disease

Abstract Impulse oscillometry (IOS) is a variant of forced oscillation technique described by Dubois 50 years ago, which allows us to measure the reactance of the airways and the resistance of the small and large airways during tidal breathing. It requires minimal patient cooperation from subjects who are unable to perform spirometry, like elders, children and patients with neurologic disorders. IOS can outline the diagnosis of obstructive airway disease, differentiate small airway obstruction from large airway obstruction. It is more sensitive than spirometry for peripheral airway disease in determining the severity of the disease, the exacerbations and evaluate the therapeutic response. Other applications include early evaluation of transplant rejection, cystic fibrosis, vocal cord disorder, bronchiectasis, hypersensitivity pneumonitis, obstructive sleep apnea.

A Comparative Study of Symptoms, Nasal Eosinophilia and Pulmonary Function Tests Before and After Short Term Treatment with Corticosteroid Nasal Spray in Patients with Allergic Rhinitis.

Allergic rhinitis has been on the rise because of urbanization and major population shift in addition to changes in the particulate matter in the atmosphere. Intranasal corticosteroid sprays are recommended as first-line prescription treatment in all cases of allergic rhinitis. The propensity of co-existing non-apparent lower airway hyper-responsiveness is also on the rise and must be evaluated. The aim of this study is to compare the symptomatic improvement, changes in nasal eosinophilia and asymptomatic airway hyper responsiveness before and after short term treatment with steroid nasal spray. Fifty patients meeting the inclusion criteria for allergic rhinitis with no symptoms of asthma underwent pulmonary function tests and assessment of symptoms before and after one-month treatment with inhalational steroid nasal spray (Fluticasone Furoate), in the standard adult dosage. Based on TNSS (Total nasal symptom score) and TOSS (Total ocular symptom score), all 50 patients showed significant improvement after treatment. Among 20 patients with > 50 eosinophils per high power field, 80% had 0-10 eosinophils per high power field on nasal smear after treatment. Among 40 patients with mild large airway obstruction, 37 showed significant improvement in FEV1 data. Also FEV1/FVC data showed significant improvement. Significant improvement (FEF25-75 > 50%) was also noticed in small airway disease after treatment among the 5 patients. The study showed that lower airway hyper responsiveness coexists with allergic rhinitis and treating allergic rhinitis with just steroid nasal spray assists in reducing the former, supporting the concept of Unified Airway Disease (UAD).

Prevalence and clinical correlates of small airway obstruction in patients with systemic sclerosis.

This study aims to assess the prevalence and clinical correlates of small airway obstruction (SAO) in patients with systemic sclerosis (SSc). Sixty-nine consecutive patients with SSc (63 women and 6 men) were included. Lung function tests, including assessment of lung diffusing capacity, were performed in all patients. Patients were considered to have SAO when the maximal expiratory flow at 25% of the forced vital capacity (MEF25) was lower than 60% as predicted. High-resolution computed tomography (HRCT) of the lung was performed in all patients with MEF25 < 60%. We assessed the relationship of SAO in our patients with large airway obstruction, decreased lung diffusing capacity, HRCT findings, disease duration, disease subtype, scleroderma-specific antibodies, and smoking. SAO was noticed in 46/69 (66.6%) of patients with SSc. Restrictive lung disease was found in 4/69 (5.8%), obstruction of large airways in 18/69 (26.1%), and decreased lung diffusing capacity in 47/69 (68.1%) of patients. No difference in gender, age, disease duration, disease subtype, and scleroderma-specific antibodies was found between patients with and without SAO. Eighteen out of forty-six (39.1%) patients with SAO had decreased forced expiratory volume in 1 sec (FEV1) and the Tiffeneau-Pinelli index, indicating presence of coexistent large airway obstruction. Twenty out of forty-six (43.5%) patients with SAO had associated decreased lung diffusing capacity, while 8/46 (17.4%) of patients had isolated SAO. HRCT patterns of interstitial lung disease (ILD) were found more frequently in patients with SAO and decreased lung diffusing capacity, compared with patients with SAO and normal diffusing capacity (75% vs 11.5%, p = 0.008). We have noticed that tobacco smokers among SSc patients with SAO have more common associated obstructive lung disease on spirometry (58.8% vs 15.4%, p = 0.004). On the other hand, isolated SAO and SAO associated with impaired diffusing capacity were equally frequent among smokers and non-smokers. Patients with SSc have commonly SAO. It can be considered clinical feature of undiagnosed asthma or chronic obstructive pulmonary disease (COPD), if isolated or associated with large airway obstruction, especially in tobacco smokers. On the other hand, SAO associated with decreased lung diffusing capacity was found to be not related to smoking, and may indicate a possible prominent bronchiolar involvement within SSc-related interstitial lung disease Key Points • Small airway obstruction in patients with systemic sclerosis can be considered a clinical feature of undiagnosed obstructive lung disease, if isolated or associated with large airway obstruction, especially in tobacco smokers. • Obstruction of small airways, associated with decreased lung diffusing capacity, may indicate a possible prominent bronchiolar involvement within systemic sclerosis-related interstitial lung disease.

Rare Manifestation of Idiopathic Tracheobronchopathia Osteochondroplastica: Misdiagnosed and Untreated Entity?

Tracheobronchopathia osteochondroplastica (TBPO) is a rare benign disease of unknown cause, in which multiple cartilaginous or bony submucosal nodules project into the trachea and proximal bronchi. It usually occurs in men in their fifth decade and can cause airway obstruction, bleeding and chronic cough; patients are more prone to post-obstructive pneumonia and chronic lung infection in some instances. We report a case of a 69-year-old female who presented with shortness of breath and lower extremity swelling over the past couple of weeks. Echocardiography (ECHO) was consistent with heart failure with preserved ejection fraction, and she was treated with diuretics accordingly. Imaging revealed persistent pleural effusions bilaterally, more pronounced on the right side. During the course of her hospitalization, the patient coded once and had to be resuscitated. She had bronchoscopy done and pathology was consistent with TBPO. In this condition, there are numerous osseous or cartilaginous submucosal nodules in the trachea and the main bronchus and nodules are formed due to the deposition of calcium phosphate that results in the proliferation of osseous and cartilaginous structures resulting in the obstruction of large airways. Treatment for the most part is supportive and resolves around bronchodilators for symptomatic relief.

Impact of a supervised training course on spirometry competency for primary care pediatricians

Objective Spirometry is the most commonly performed lung function test, and performance, adherence to acceptability and repeatability criteria, and accurate interpretation of results help optimize the test’s usefulness. This study aimed to measure the effects of spirometry training courses supported by the Italian Pediatric Respiratory Society (IPRS) on primary care pediatricians’ (PCP) knowledge of spirometry test quality, ability to interpret results, and overall degree of satisfaction with the course. Methods Of the six face-to-face courses, four lasted two days and two lasted one day: mean duration of theoretical lessons was five and four hours respectively; and practical sessions lasted eight and six hours, respectively. At the end of each course, participants took a learning test consisting of evaluating six flow-volume curves. Degree of satisfaction was assessed by asking participants to rank the relevance, quality, and usefulness of the course. Results 261 PCPs were involved, with most (67.43%) taking two-day courses. Nearly all participants correctly identified normal and restrictive patterns. Intrathoracic large-airway obstruction was the pattern most difficult to identify correctly (70.5% overall), whereas > 80% of the participants correctly classified artifacts, obstructive-restrictive, and obstructive patterns. Participants in longer courses reported significantly higher values on the learning score. The overall degree of satisfaction average ranged between “good” and “excellent”. Conclusions This pilot study showed the greater impact of two-day courses than one-day courses for training PCPs to properly interpret spirometry, confirming that a practical module lasting at least six hours is sufficient to deliver adequate training on spirometry for healthcare professionals.

The bridging bronchus: A comprehensive review of a rare, potentially life‐threatening congenital airway anomaly associated with cardiovascular defects

The bridging bronchus is a rare congenital airway anomaly in which the right upper lobe of the lung is supplied by the right main bronchus while the right lower lobe, and often the right middle lobe is supplied by an aberrant bronchus arising from the left main bronchus. The aberrant bronchus crosses (bridges) the lower part of the mediastinum, hence the term bridging bronchus (BB). This potentially life-threatening condition, usually accompanied by diffuse or focal airway stenosis, commonly presents with signs and symptoms related to large airway obstruction, such as respiratory distress, apnea, wheezing, stridor, and recurrent respiratory tract infections. Diagnosis of the BB is often challenging because the associated signs and symptoms mimic those of common conditions such as bacterial and viral bronchiolitis, bronchial asthma, cystic fibrosis, and foreign body aspiration. The BB is also often accompanied by congenital cardiovascular anomalies, including left pulmonary artery sling, atrial, and ventricular septal defects, tetralogy of Fallot, patent ductus arteriosus, and coarctation of the aorta. Patients presenting with the above signs and symptoms who are not responsive to standard treatment modalities, and have accompanying cardiovascular congenital anomalies should, therefore, be investigated for the BB. Herein, we review the anatomy, embryology, clinical presentation, differential diagnosis, imaging techniques and surgical management of the BB.

Status asthmaticus requiring extracorporeal membrane oxygenation associated with rhinovirus infection

Objective: Evolving research links human rhinovirus (HRV) with status asthmaticus (SA) as well as severe respiratory illness in patients with atopy and asthma. This case series reviews five episodes of HRV-associated SA that required extracorporeal membrane oxygenation (ECMO). Methods: Charts of four patients, five total episodes of ECMO, with SA secondary to HRV were reviewed in this IRB-approved case series. Outcomes included demographic information, past medical history, clinical parameters and spirometry. Results: Patients (three male, one female), mean age 9 years (range 7–12 years) at the time of admission, were African American, on Medicaid, carried a diagnosis of persistent asthma, and had documented non-adherence to prescribed, daily controller medications. One patient had passive smoke exposure. All patients had a mean IgE of 734 (range 12–2497) with seasonal allergic rhinitis was diagnosed in three patients. Cases occurred in spring (3/5) and fall (2/5). Venous/venous ECMO (4/5) or venous/arterial ECMO (1/5) was continued for a mean duration of 4.2 days (range 3–7 days). Spirometry after hospitalization had a mean FEV1 of 1.59 L (81% predicted, range 69%–91%), and an FEF25%–75% 1.13 L (47.5% predicted, range 41%–65%) at an average of 16.7 weeks post ECMO. Conclusions: This case series highlights the association between persistent, poorly controlled asthma and severe SA with HRV infection resulting in ECMO. Despite life-threatening illness, these patients did not demonstrate significant large-airway obstruction following infection. However, patients showed persistently abnormal small airway function, which could be a risk factor or early evidence of vulnerability to infection.