Assessment of bronchodilator response by forced oscillation technique in preterm infants with evolving bronchopulmonary dysplasia

Inhaled bronchodilators are often given in preterm infants with evolving or established bronchopulmonary dysplasia. However, it is unclear which patients may benefit from it and when it is the best time to start treatment. The forced oscillation technique (FOT) is a noninvasive method for assessing lung mechanics that proved sensitive to airway obstruction reversibility in children and adults. FOT does not need patient cooperation, which is ideal for infants. Bedside tools for applying FOT in infants during spontaneous breathing and different respiratory support modes are becoming available. This case report illustrates for the first time that FOT has potential value in assessing airway obstruction reversibility in preterm infants, informing which infants may manifest a clinical benefit from the treatment with bronchodilators.

Clinical value of bronchodilator response for diagnosing asthma in steroid-naïve adults

Spirometry and testing for bronchodilator response have been recommended to detect asthma, and a bronchodilator response (BDR) of ≥12% and ≥200 mL has been suggested to confirm asthma. However, the clinical value of bronchodilation tests in newly diagnosed steroid-naïve adult patients with asthma remains unknown. We evaluated the sensitivity of BDR in FEV1 as a diagnostic test for asthma in a real-life cohort of participants in the Seinäjoki Adult Asthma Study (SAAS). In the diagnostic phase, 369 spirometry tests with bronchodilation were performed for 219 steroid-naïve patients. The fulfilment of each test threshold was assessed. According to the algorithm of the National Institute for Health and Care Excellence, we divided the patients into obstructive (FEV11/FVC<0.70) and non-obstructive (FEV1/FVC≥0.70) groups. Of the overall cohort, 35.6% fulfilled ΔFEV1≥12% and ≥200mL for the initial FEV1, 18.3% fulfilled ΔFEV1≥15% and ≥400 mL for the initial FEV1 and 36.1% fulfilled ΔFEV1≥9% of predicted FEV1 at least once. One-third (31%) of these steroid-naïve patients was obstructive (pre-bronchodilator FEV1/FVC<0.7). Of the obstructive patients, 55.9%, 26.5% and 48.5%, respectively, met the same thresholds. In multivariate logistic regression analysis, different thresholds recognized different kinds of asthma patients. In steroid-naïve adult patients, the current BDR threshold (ΔFEV1≥12% and ≥200 mL) has low diagnostic sensitivity (36%) for asthma. In obstructive patients, sensitivity is somewhat higher (56%) but far from optimal. If the first spirometry test with bronchodilation is not diagnostic but asthma is suspected, spirometry should be repeated, and other lung function tests should be used to confirm the diagnosis.

Certainties fading away: β-blockers do not worsen chronic obstructive pulmonary disease

For many years, β-blockers have been considered contraindicated in patients with heart failure (HF) and in those with bronchial asthma or even chronic obstructive pulmonary disease (COPD) although without clear evidence of asthma. Today, despite overwhelming evidence of the usefulness of β-blockers, especially in HF with reduced left ventricular ejection fraction (HFrEF), and in ischaemic heart disease, some reluctance persists in using these drugs when COPD coexists. Such resistance is due to the fear that a possible worsening of bronchospasm induced by β-blockers could induce negative effects greater than the benefits. The Guidelines of the European Society of Cardiology clearly suggest that: (i) implantation of a cardiac defibrillator (ICD) are not contraindicated in COPD without clear evidence of bronchial asthma; (ii) β-blockers are only ‘relatively’ contraindicated when there is certainty of bronchial asthma with a documented bronchodilator response to the β2 stimulant. Therefore, bronchial asthma is not an absolute contraindication to β-blockers. The cardiologist should not limit the diagnosis of COPD to clinical suspicion, but should rely on a spirometry examination associated with any bronchodilation tests. In any case, selective β1 blockers are preferred, starting at a basic dose, which ensure a better dilator response to bronchodilators and in any case cause less bronchospasm than non-selective β-blockers. Unfortunately, there is still some reluctance to the use of β-blockers in patients with COPD associated with HF, which should be eliminated.

Prevalence of Asthma-COPD Overlap in COPD and Severe Asthma Cohorts

Background: Asthma and chronic obstructive pulmonary disease (COPD) are airway diseases with similar clinical manifestations, despite differences in pathophysiology. Asthma-COPD overlap (ACO) is a condition characterized by overlapping clinical features of both diseases. There have been few reports regarding the prevalence of ACO in COPD and severe asthma cohorts. ACO is heterogeneous; patients can be classified on the basis of phenotype differences. This study was performed to analyze the prevalence of ACO in COPD and severe asthma cohorts. In addition, this study compared baseline characteristics among ACO patients according to phenotype.Methods: Patients with COPD were prospectively enrolled into the Korean COPD subgroup study (KOCOSS) cohort. Patients with severe asthma were prospectively enrolled into the Korean Severe Asthma Registry (KoSAR). ACO was defined in accordance with the updated Spanish criteria. In the COPD cohort, ACO was defined as bronchodilator response (BDR) ≥ 15% and ≥ 400 mL from baseline or blood eosinophil count ≥ 300 cells/μL. In the severe asthma cohort, ACO was defined as age ≥ 35 years, smoking ≥ 10 pack-years, and post-bronchodilator forced expiratory volume in 1 s/forced vital capacity < 0.7. Patients with ACO were divided into four groups according to smoking history (threshold: 20 pack-years) and blood eosinophil count (threshold: 300 cells/μL).Results: The prevalence of ACO significantly differed between the COPD and severe asthma cohorts (19.8% [365/1839] vs. 12.5% [104/832], respectively, P < 0.001). The numbers of patients in each group were as follows: Group A (smoking 10–20 pack-years and blood eosinophil count ≥ 300 cells/μL), 42 (9.1%); Group B (smoking 10–20 pack-years and eosinophil count < 300 cells/μL), 17 (3.7%); Group C (smoking ≥ 20 pack-years and eosinophil count ≥ 300 cells/μL), 341 (73.8%); and Group D (smoking ≥ 20 pack-years and eosinophil count < 300 cells/μL), 62 (13.4%). Age, sex, BDR, comorbidities, and medications significantly differed among the four groups.Conclusion: The prevalence of ACO differed between COPD and severe asthma cohorts. ACO patients can be classified into four phenotype groups, such that each phenotype exhibits distinct characteristics.

Normal limits for oscillometric bronchodilator responses and relationships with clinical factors

IntroductionWe aimed to determine normal thresholds for positive bronchodilator responses for oscillometry in an Australian general population sample aged ≥40 years, to guide clinical interpretation. We also examined relationships between bronchodilator responses and: respiratory symptoms, asthma diagnosis, smoking and baseline lung function.MethodsSubjects recruited from Sydney, Melbourne and Busselton, Australia underwent measurements of spirometry, resistance (Rrs6) and reactance (Xrs6) at 6Hz, before and after inhalation of salbutamol 200μg. Respiratory symptoms and/or medication use, asthma diagnosis and smoking were recorded. Threshold bronchodilator responses were defined as the 5th percentile of decrease in Rrs6 and 95th percentile increase in Xrs6 in a healthy subgroup.ResultsOf 1318 participants, 1145 (570 female) were analysed. The lower threshold for ΔRrs6 was −1.38 cmH2O.s.L−1 (−30.0% or −1.42 Z-scores) and upper threshold for ΔXrs6 was 0.57 cmH2O.s.L−1 (1.36 Z-scores). Respiratory symptoms and/or medication use, asthma diagnosis and smoking all predicted bronchodilator response, as did baseline oscillometry and spirometry. When categorised into clinically relevant groups according to those predictors, ΔXrs6 was more sensitive than spirometry in smokers without current asthma or COPD, approximately 20% having a positive response. Using absolute or Z-score change provided similar prevalences of responsiveness, except in COPD in whom responsiveness measured by absolute change was twice that for Z-score.DiscussionThis study describes normative thresholds for bronchodilator responses in oscillometry parameters, including intra-breath parameters, as determined by absolute, relative and Z-score changes. Positive bronchodilator response by oscillometry correlated with clinical factors and baseline function, which may inform clinical interpretation of oscillometry.