Persistent Airway Obstruction Research Articles

Polysomnographic outcomes following lingual tonsillectomy for persistent obstructive sleep apnea in down syndrome.

Lingual tonsil hypertrophy is a common cause of persistent airway obstruction in patients with Down syndrome (DS) following adenotonsillectomy (T&A); however, little is known about the effect of lingual tonsillectomy (LT) on polysomnographic outcomes in these patients. Our objective was to describe changes in sleep-related respiratory outcomes following LT in children with DS and persistent obstructive sleep apnea (OSA) following T&A. Retrospective case series. We included all children with DS who underwent polysomnography before and after LT at a tertiary care center from 2003 to 2013. Nonparametric analysis of variables was performed. Forty patients with DS underwent LT; 21 met inclusion criteria. The mean age at surgery was 9.3 ± 4.3 years and 47.6% were female. The median apnea-hypopnea index (AHI) was 9.1 events/hour (range, 3.8 to 43.8 events/hour) before surgery and 3.7 events/hour (range, 0.5 to 24.4 events/hour) after surgery. The median improvement in overall AHI and the obstructive AHI (oAHI) were 5.1 events/hour (range, -2.9 to 41) and 5.3 events/hour (range, -2.9 to 41), respectively (P <.0001). The mean oxygen saturation nadir improved from 84% to 89% (P =.004). The mean time with CO2 > 50 mm Hg, central index, and percentage of rapid eye movement sleep were not significantly different. After surgery, the oAHI was <5 events/hour in 61.9% and ≤1 in 19% of patients. In children with DS, persistent OSA after T&A and lingual tonsil hypertrophy, LT significantly improved AHI, oAHI, and O2 saturation nadir. We recommend that children with DS should be evaluated for lingual tonsil hypertrophy if found to have persistent OSA following T&A. 4 Laryngoscope, 2016 127:520-524, 2017.

Use of serial rigid bronchoscopy in the treatment of plastic bronchitis in children

AimPlastic bronchitis (PB) is a rare disorder characterized by formation of bronchial casts (BC) in the tracheobronchial tree with partial or complete airway obstruction. Although lysis of casts with several fibrinolytic agents has been reported, removal of BC with bronchoscope provides better clearance of airways. A retrospective study was performed to evaluate the use of serial rigid bronchoscopy (RB) in the treatment of PB in children. Patients and methodsBetween 2011 and 2015, children with partial or complete airway obstruction with PB were evaluated for age, gender, underlying disease, clinical findings, results of bronchoscopic interventions and histopathologic findings. ResultsFive patients with 14 RB interventions were evaluated. The mean age of the patients was 7.8years (min: 3years — max: 14years) and male–female ratio was 4:1. All of the patients were diagnosed as asthma and none of them had underlying cardiac disease. Suction of mucus plaques and bronchoalveolar lavage were performed in all patients with flexible bronchoscopy. Also, aerosolized tissue plasminogen activator was used in two patients. During follow-up serial RB was indicated in patients with persistent atelectasis and severe airway obstruction. The most common localization of BC was left main stem bronchus and bilateral cast formation was detected in 7 interventions. Although, removal of BC was challenging in two patients because of cast friability and fragmentation, most of the plugs were successfully removed with optical forceps and rigid suctioning. Two patients underwent repeated RB (min: 3 — max: 8) for recurrent symptoms. Histopathologic evaluation of BC revealed Charcot–Leyden crystals with inflammatory cells in all patients. The time interval between RB interventions was one to five months. ConclusionBC are tenacious mucus plugs which are firmly wedged to the tracheobronchial tree. The use of optical forceps with rigid suction provides adequate removal of BC during RB. Because of underlying disease, it is difficult to cure cast formation. Therefore, most of the patients require serial RB when they become unresponsive to standard therapy or develop partial or complete airway obstruction.

N-terminal-pro brain natriuretic peptide levels in children with allergic rhinitis

Persistent upper airway obstruction may lead to increased pulmonary arterial pressure (PAP). The aim of this study was to evaluate N-terminal pro brain natriuretic peptide (NT-proBNP) concentrations and PAP values in children with allergic rhinitis. Sixty-six patients with allergic rhinitis and 22 healthy children were prospectively enrolled in this study. Plasma NT-proBNP levels were measured at first admission and after treatment. Simultaneously, echocardiography was done to assess pulmonary arterial hypertension, and rhinitis symptom scores were recorded. The median age of the study group was 9.0 (5.0‒17.0) years; 26 were female. PAP was found to be normal in all the patients. There was a negative correlation between age and NT-proBNP levels (r = -0.452, P < 0.01). Nasal blockage levels affected NT-proBNP levels mildly (P = 0.067). No significant difference between before and after nasal steroid treatment was observed in NT-proBNP levels. These results suggest that NT-proBNP level and PAP may not be affected in children with allergic rhinitis, and primarily this influence may be associated with the severity of nasal obstruction.

Prevalence and Predictors of Adverse Events during Procedural Sedation Anesthesia-Outside the Operating Room for Esophagogastroduodenoscopy and Colonoscopy in Children

Procedural sedation/anesthesia outside the operating room for a variety of procedures is well described with an overall low adverse event rate in certain settings. Adverse event associated with procedural sedation/anesthesia outside the operating room for gastrointestinal procedures have been described, albeit in small, single-center studies with wide variance in outcomes. Predictors of such outcomes are unclear. We aimed to estimate the prevalence of adverse event in children undergoing procedural sedation/anesthesia outside the operating room for esophagogastroduodenoscopy, colonoscopy, or both to identify predictors of adverse event. Retrospective analysis of Pediatric Sedation Research Consortium database, a large data repository of pediatric patients aged 21 years old or younger undergoing procedural sedation/anesthesia outside the operating room during September 2007 to November 2011. Twenty-two of the 40 centers provided data pertaining to the procedure of interest. None. Primary outcome variable is any adverse event. Independent variables include: age (five groups), sex, American Societyof Anaesthesiologists status, procedure (esophagogastroduodenoscopy, colonoscopy, or both), provider responsible, medication used, location, and presence of coexisting medical conditions. Descriptive statistics used to summarize the data. Using multivariablelogistic regression model, odds ratio, 95% CI) were computed. A total of 12,030 procedures were performed (esophagogastroduodenoscopy, 7,970; colonoscopy, 1,378; and both, 2,682). A total of 96.9% of patients received propofol. Eighty-three percent were performed in a sedation unit. Prevalence of adverse event was 4.8%. The most common adverse event were persistent desaturations (1.5%), airway obstruction (1%), cough (0.9%), and laryngospasm (0.6%). No deaths or CPR occurred. Infants and children aged 5 years old or younger had a higher adverse event rate than older children (15.8%, 7.8% vs 4%). Regression analysis revealed age 5 years old or younger, American Society of Anaesthesiologists greater than or equal to 2, esophagogastroduodenoscopy ± colonoscopy, and coexisting medical conditions of obesity and lower airway disease were independent predictors of higher adverse event. Overall prevalence of any adverse event was 4.8%. Independent predictors of adverse events in procedural sedation/anesthesia outside the operating room in pediatric esophagogastroduodenoscopy/colonoscopy onoscopy were identified. Recognition of such risk factors may enable optimization of procedural sedation.

Alpha-1-antitrypsin deficiency: increasing awareness and improving diagnosis.

Alpha-1-antitrypsin deficiency (AATD) is a hereditary disorder that is characterized by a low serum level of alpha-1-antitrypsin (AAT). The loss of anti-inflammatory and antiproteolytic functions, together with pro-inflammatory effects of polymerized AAT contribute to protein degradation and increased inflammation resulting in an increased risk of developing chronic obstructive pulmonary disease (COPD) and emphysema, especially in smokers. AATD is a rare disease that is significantly underdiagnosed. According to recent data that are based on extrapolations, in many countries only 5-15% of homozygous individuals have been identified. Furthermore, the diagnostic delay typically exceeds 5 years, resulting in an average age at diagnosis of about 45 years. Although the American Thoracic Society/European Respiratory Society recommendations state that all symptomatic adults with persistent airway obstruction should be screened, these recommendations are not being followed. Potential reasons for that include missing knowledge about the disease and the appropriate tests, and the low awareness of physicians with regard to the disorder. Once the decision to initiate testing has been made, a screening test (AAT serum level or other) should be performed. Further diagnostic evaluation is based on the following techniques: polymerase chain reaction (PCR) for frequent and clinically important mutations, isoelectric focusing (IEF) with or without immunoblotting, and sequencing of the gene locus coding for AAT. Various diagnostic algorithms have been published for AATD detection (severe deficiency or carrier status). Modern laboratory approaches like the use of serum separator cards, a lateral flow assay to detect the Z-protein, and a broader availability of next-generation sequencing are recent advances, likely to alter existing algorithms.

A Delayed Finding of a Tracheal Cartilaginous Sleeve in a Patient with Pfeiffer Syndrome Type 2 and a Complex Airway History.

Persistent airway obstruction symptoms in a 2½-year-old boy with Pfeiffer syndrome were attributed to facial abnormalities, central and obstructive sleep apnea, and tracheomalacia from a vascular ring. These findings delayed the diagnosis of a tracheal cartilaginous sleeve. Life expectancy in tracheal cartilaginous sleeve is improved by tracheostomy. Tracheal cartilaginous sleeve should be considered and investigated through airway endoscopy in children with fibroblast growth factor receptor-related craniosynostosis syndromes.

Rates and predictors of uncontrolled bronchial asthma in elderly patients from western Romania.

PurposeBronchial asthma (BA) is a chronic inflammatory disorder of the airways, featuring variable and often reversible airflow limitations. An accurate assessment of BA control is difficult in practice, especially in the elderly, requiring the assessment of several clinical and paraclinical parameters that are influenced not only by asthma, but also by comorbidities. The purpose of this study was to evaluate the predictors of uncontrolled BA in a group of elderly patients from western Romania.Patients and methodsWe retrospectively evaluated 126 elderly patients (aged $ 65 years), who were consecutively evaluated in the Pulmonology Department of Victor Babes Hospital, Timisoara, Romania, between March 2009 and July 2012. We collected demographic data, performed pulmonary function testing and an asthma control test (ACT), and evaluated the level of BA control based on the 2012 Global Initiative for Asthma guidelines. Statistical processing of the data was done using the Epi Info and STATA programs.ResultsIn our study group, 36 (29%) patients were men and 90 (71%) were women; their mean age was 74.42±8.32 years (range: 65–85 years). A total of 14.28% of patients were smokers. About 30.15% of patients had an ACT score <19, 54.76% had an ACT score 20–24, and 15.09% had an ACT of 25. Moreover, 59.52% had normal spirometry results. Infectious exacerbations were found in 58.73% of patients. A history of allergies was demonstrated in 48.41% of patients, 34.12% had occupational exposure, and 82.53% of patients were treated with inhaled corticosteroids. Our results showed that 30.15% of patients had uncontrolled BA. We found six predictive factors for uncontrolled BA: infectious exacerbation, occupational exposure, mixed (obstructive and restrictive) ventilatory dysfunction, persistent airway obstruction on spirometry, duration of disease in months, and current smoking status. Infectious exacerbations, persistent airway obstructions, and occupational exposure were the most powerful predictors.ConclusionElderly patients represent an important group that is at risk for developing uncontrolled BA. Predictors may identify those elderly patients with uncontrolled BA and facilitate early medical interventions.

Chronic obstructive pulmonary disease in never-smoking dairy farmers.

Introduction : Work-related chronic obstructive pulmonary disease (COPD) represents a considerable part of the disease burden globally.Objective : To assess the COPD prevalence and characteristics in never-smoking dairy farmers.Materials and Methodology : We have conducted a cross-sectional study with 75 male dairy farmers aged 26 to 59 years, and compared them with equivalent number of male office workers similar by age, and duration of employment. Data on chronic respiratory symptoms, job history and daily activities were obtained by questionnaire. Lung functional testing of the examined subjects included baseline spirometry, and bronchodilator reversibility measurement.Results : Dairy farmers showed higher prevalence of overall respiratory symptoms, but significant difference was noticed for cough, phlegm, and dyspnea. Dairy farmers had more prevalent work-related respiratory symptoms, being significant for overall symptoms, cough, and phlegm. The mean baseline values of spirometric parameters were lower in dairy farmers, but significance was reported for FEV1/FVC%, MEF50, MEF75, and MEF25-75. Dairy farmers had significantly higher COPD prevalence than office controls (10.7% vs 2.7%, P = 0,049). Dairy farmers and office controls showed significant association between COPD and age over 45 years. Dairy farmers had a significant association between COPD and employment duration of over 20 years (P = 0.023), but also between COPD and work-related chronic respiratory symptoms (P = 0.041).Conclusion : The study findings favor the cause-effect association between job exposure to respiratory hazards, and development of persistent airway obstruction among dairy farmers.

Peri-operative adverse respiratory events in children.

Three quarters of all critical incidents and a third of all peri-operative cardiac arrests in paediatric anaesthesia are caused by adverse respiratory events. We screened for risk factors from children's and their families' histories, and assessed the usefulness of common markers of allergic sensitisation of the airway as surrogates for airway inflammation and increased risk for adverse respiratory events. One hundred children aged up to 16 years with two or more risk factors undergoing elective surgery were included in the study. Eosinophil counts, IgE level, specific IgE for D. pteronyssinus, cat epithelia and Gx2 (grass pollen) were measured for each child and adverse respiratory events (bronchospasm, laryngospasm, oxygen desaturation < 95%, severe persistent coughing, airway obstruction and postoperative stridor) were recorded. Twenty-one patients had an adverse respiratory event but allergic markers were poor predictors. Binary logistic regression showed a lack of predictive value of the eosinophil range and adverse respiratory events (p = 0.249). Receiver operating characteristic (ROC) curves for the presence of adverse respiratory events vs level of specific IgE antibody (to Gx2 (AUC 0.614), cat epithelia (0.564) and D. pteronyssinus (0.520)) demonstrated poor predictive values. However, the presence of risk factors was strongly associated with adverse respiratory events (p < 0.001) and a ROC-curve analysis indicated a fair capacity to predict adverse respiratory events (AUC 0.788). There was a significant difference (p = 0.001) between the presence of adverse respiratory events in patients with more than four (p = 0.006), compared with less than four (p = 0.001), risk factors. We conclude that while risk factors taken from the child's (or family) history proved good predictors of adverse respiratory events, immunological markers of allergic sensitisation demonstrated low predictive values. Pre-operative identification of children at high risk for an adverse respiratory event should rely on clinical, rather than immunological, assessment.

Risk factors associated with irreversible airway obstruction in nonsmoking adult patients with severe asthma.

Persistent airways obstruction (PAO) may affect some patients with severe asthma and may significantly worsen the prognosis. This study was designed to detect risk factors associated with persistent airflow limitation in nonsmoking adult patients with severe asthma. A total of 68 adults with severe asthma were recruited and followed prospectively for four to six weeks during the stable phase of disease. For all patients, at every visit spirometry with reversibility test was performed. Based on the results, patients were stratified into group 1 (reversible obstruction) or group 2 (PAO). In both cohorts, associations of postbronchodilatator forced expiratory volume in one second/forced vital capacity ratio (FEV1/FVC) with patients' age, gender, asthma duration, history of atopy and allergy, family history, medications, frequency of previous exacerbations, infections, hospitalizations, and artificial ventilation due to the asthma attack-related respiratory failure were investigated. Using a univariate logistic regression analysis, we have shown that older age, more than six exacerbations per year, artificial ventilation in the past, at least one hospitalization per year, the presence of atopic dermatitis, and exposure to domestic visible mold were all independent risk factors of PAO. Furthermore, multivariate regression analysis demonstrated that especially those with domestic exposure to visible molds, with very frequent exacerbations and with at least one hospitalization throughout the last year, were at risk for developing PAO. Domestic exposure to molds, hospitalization during the last year, and very frequent exacerbations were associated with PAO in patients with severe asthma. These factors may help in predicting fixed airflow limitation in nonsmoking patients with severe asthma.

Airway wall eosinophilia is not a feature of equine heaves

The objective of this study was to determine whether eosinophils infiltrate the airway wall of horses with heaves. Eosinophils were evaluated using paraffin embedded lung tissues from six heaves-affected horses in crisis and six aged-matched controls. Slides were stained using Luna's method and eosinophils enumerated using histomorphometric techniques. Total eosinophil counts (expressed per mm2 of basement membrane) were significantly higher in the airways of controls horses than in horses with heaves. Intraluminal, intraepithelial, and airway smooth muscle eosinophils counts were also increased in control horses. The results suggest that eosinophils do not contribute to the persistent airway obstruction in heaves.

Plasma connective tissue growth factor levels as potential biomarkers of airway obstruction in patients with asthma

BackgroundBronchial asthma is a chronic inflammatory disorder characterized by airway hyperresponsiveness and airflow limitation. Connective tissue growth factor (CTGF), one of the key profibrotic factors associated with transforming growth factor β, may be related to airway remodeling in asthma. However, no data are available on the association between plasma CTGF levels and clinical and physiologic parameters in patients with asthma. Recently, we developed a novel subtraction method for determination of plasma CTGF levels. ObjectiveTo investigate the utility of plasma CTGF level as a surrogate biomarker in asthma. MethodsPlasma CTGF levels were measured in 67 patients with stable asthma and 81 healthy volunteers, using the subtraction method. We evaluated correlations between plasma CTGF levels and clinical and physiologic parameters in patients with asthma. ResultsPlasma CTGF levels were higher in patients with asthma than in healthy volunteers. Asthmatic patients with a percentage of predicted forced expiratory volume in 1 second (FEV1) less than 80% had significantly higher levels of plasma CTGF than those with a percentage of predicted FEV1 of 80% or more. In patients with asthma, plasma CTGF levels had significantly negative correlations with forced vital capacity (FVC), FEV1, percentage of predicted FEV1, FEV1/FVC ratio, forced expiratory flow at 50% of the FVC (FEF50%), percentage of predicted FEF50%, forced expiratory flow at 75% of the FVC (FEF75%), and percentage of predicted FEF75%, parameters that reflect the degree of airway obstruction. Plasma CTGF levels were negatively correlated with Asthma Control Test scores, a patient-based index of clinical control of asthma. ConclusionPlasma CTGF may be a potential biomarker for stable asthma when evaluating the degree of persistent airway obstruction. Trial Registrationumin.ac.jp/ctr Identifier: UMIN000013081

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Introduction: Pediatric Sedation Anesthesia- Outside Operating Room (PSA-OOR) is well described with overall low adverse events (AE) in certain settings. AE associated with PSA-OOR for Gastro-Intestinal procedures have been described in small single center studies with wide variance in outcomes. Predictors of such outcomes are unclear. Estimating the incidence of AE in children undergoing PSA-OOR for Esophagogastroduodenoscopy (EGD), Colonoscopy (Col), or both may help identify the predictors of AE. Methods: Retrospective analysis of prospectively collected EGD and Col data from Pediatric Sedation Research Consortium (PSRC) database, a web-based collaborative from 40 North American institutions (09/07-11/11). Primary outcome variable is any AE. Independent variables include-Age (5 Groups), gender, ASA status (S), procedure (only EGD, only Col, or both), medication used, location performed and presence of co-existing medical conditions (CMC). Descriptive statistics used to summarize the data. Using multivariable logistic regression model, odds ratio (OR), and 95% Confidence Intervals (CI) were computed for each independent variable. Results: 12030 procedures were performed (EGD 7970, Col 1378, both 2682), Variables include: age (Gp I: < 1y: 222; Gp II:1-5y: 2081; Gp III: > 5-10y: 3464; Gp IV: >10-15y: 428; Gp V: > 15y: 1978), male (51%), ASA (S1: 25.7%, S2: 67%, S3 or greater: 6.6%), with CMC (32%), in Sedation Unit (83%), and Propofol (97%). Overall incidence of any AE was 4.8% (582); the most common AE were persistent desats (1.5%), airway obstruction (1%), cough (0.9%) & laryngospasm (0.6%). No deaths or cardiopulmonary resuscitation (CPR). Age Group as AE % (Gp I: 35/222 (15.7%); Gp II: 162/2081 (7.8%); Gp III: 140/3464 (4%); Gp IV: 173/4285 (4%); Gp V: 72/1978 (3.6%)). Regression analysis revealed: age (Gp 1: 4.1 odds ratio (OR), 2.6-6.5, 95% confidence interval (CI), p < 0.0001; Gp 2: 2.1, 1.6-2.9, p < 0.0001, Reference (Ref) Gp 5), ASA (S2: 1.3, 1.06-1.6, p < 0.01; S3 and greater: 3.02, 2.2-4.1, p < 0.0001, Ref S1), Procedure (EGD only: 1.9, 1.3-2.6, p <0.0002, both EGD & Col: 2.2,1.5-3.2, p <0.0001, Ref Col only), presence of CMC (Metabolic/Genetic: 2.3, 1.6 – 3.3, p <0.0001, Resp-Lower Airway: 1.3, 1.01-1.72, p= 0.04, Ref No CMC) were predictors of higher AE. Conclusions: In the selected data set from the PSRC, the overall AE rate was 4.8%. Our analysis indicates that younger age, higher ASA status, EGD procedure, and presence of certain CMC were independent predictors of higher AE. The majority of such AE were minor and reversible with none of them leading to death or disability when performed in institutions with well-organized sedation systems that were able to quickly recognize and rescue at risk patients.

Unsuspected mild emphysema in nonsmoking patients with chronic asthma with persistent airway obstruction

Unsuspected mild emphysema in nonsmoking patients with chronic asthma with persistent airway obstruction

Complex adult laryngotracheal reconstruction with a prefabricated flap: A case series

Laryngotracheal stenosis (LTS) can cause persistent or recurrent airway obstruction. Although there is extensive literature on surgical techniques to treat LTS at onset, there are few techniques described for complex adult LTS after failed prior airway surgery. We describe a procedure used successfully in 3 patients who required structural augmentation for complex LTS. Patients were treated with staged reconstruction using a prefabricated composite graft consisting of auricular cartilage and a radial forearm free flap. All patients underwent successful reconstruction with good wound healing and are tolerating oral diets. Two patients have been successfully decannulated. A delayed prefabricated graft using auricular cartilage in a radial forearm free flap is a viable surgical intervention in patients with complex adult LTS who are not candidates for conventional approaches.

Late diagnosis of double aortic arch: Consequences on long‐term follow‐up

Double aortic arch is the most common congenital anomaly of the aortic arch system, in which the trachea and esophagus are completely encircled by vascular segments of the aortic arch and its branches, often resulting in variable airway compression. One case of late diagnosis of this congenital malformation and long-term consequences of late surgical treatment with persistent tracheo-broncomalacia and dynamic airway obstruction is reported. This report emphasizes the importance of an early diagnosis to minimise the progressive airways damage and subsequent respiratory symptoms, that need an accurate medical follow-up.

Small-airways deposition of dornase alfa in children with asthma and persistent airway obstruction

Small-airways deposition of dornase alfa in children with asthma and persistent airway obstruction

Year in review 2012: Asthma and chronic obstructive pulmonary disease

Year in review 2012: Asthma and chronic obstructive pulmonary disease

Bronchodilator responsiveness in patients with chronic heart failure

ObjectiveThe aim of this study was to evaluate the effect of inhaled bronchodilators on pulmonary function and dyspnea in patients with chronic heart failure (HF). BackgroundConflicting data exist on whether bronchodilators may improve pulmonary function and dyspnea in patients with chronic HF. MethodsIn this retrospective observational study we analyzed data of 116 chronic HF outpatients with systolic dysfunction who underwent spirometry and Borg dyspnea measurements before and after inhalation of 400 μg salbutamol and 80 μg ipratropium. Patients with chronic obstructive pulmonary disease (COPD) or asthma were excluded. ResultsBronchodilators fully reversed airway obstruction (AO) in 25 of 64 (39.1%) patients with pre-bronchodilator AO. All spirometric measurements, except for forced vital and inspiratory capacities, improved significantly post-bronchodilation. Absolute and percent improvements in forced expiratory volume in 1 s (FEV1) were more pronounced in patients with persistent AO post-bronchodilation compared to those without AO (0.19 ± 0.18 L and 8.4 ± 7.3% versus 0.11 ± 0.12 L and 4.3 ± 4.0%, p < 0.05). Significant bronchodilator responsiveness of FEV1 (>200 mL and >12%) was noted in 12.1% and was more frequent in patients with persistent AO and fully reversible AO than in those without AO (23.1% and 16.0% versus 1.9%, p < 0.05). We measured a small, albeit significant improvement in dyspnea (0.7 ± 1.2 versus 0.9 ± 1.3, p = 0.002). ConclusionsInhaled bronchodilators may have an additional role in the management of patients with chronic HF because of their potential to improve pulmonary function, especially in those with AO. The clinical usefulness and possible adverse events of bronchodilators need to be further established.

Association of airway pentosidine levels with bronchodilator response mediated by salbutamol administration in asthmatic patients

BackgroundRecently, increased levels of pentosidine, an intermolecular cross-linking type of advanced glycation end products, are observed in the airways of asthmatic patients. This study was designed to determine whether differences in bronchodilator response among individuals with asthma are attributable to pentosidine levels in their airways. MethodsFifty-six asthmatic patients (21 with airway obstruction, 35 without airway obstruction) and 10 normal controls were included in this study. For asthmatic patients, we evaluated the spontaneous reversibility of airway obstruction or the reversibility that can be obtained after methacholine provocation. And we also measured pentosidine levels and percentage of sputum eosinophils in induced sputum, and exhaled nitric oxide (NO) levels. ResultsThe pentosidine levels did not significantly differ between the two asthmatic subgroups with and without airway obstruction. In asthmatic patients without airway obstruction, airway hyperresponsiveness to methacholine (PC20 methacholine) was significantly correlated with sputum eosinophils and exhaled NO levels. In contrast, PC20 methacholine was not significantly correlated with pentosidine levels. In asthmatic patients with or without airway obstruction, bronchodilator response was not significantly correlated with sputum eosinophils and exhaled NO levels. However, bronchodilator response was closely correlated with pentosidine levels (asthmatics without airway obstruction: r = −0.54, p = 0.002; asthmatics with airway obstruction: r = −0.48, p = 0.03). ConclusionsOur results showed that pentosidine might be a potential biomarker reflecting the reduced bronchodilator response in asthma. This study will provide new insights into the mechanisms underlying persistent airway obstruction.