Juerg Hammer

Management of acute bronchiolitis: can evidence based guidelines alter clinical practice?

Background: Acute bronchiolitis is the most common lower respiratory tract infection in infants and there is no evidence that drug treatment alters its natural course. Despite this, most Swiss paediatricians reported in 2001 prescribing bronchodilators and inhaled corticosteroids (ICS). This situation led to the creation of national guidelines followed by a tailored implementation programme. The aim of this study was to examine if treatment practices changed after the implementation of the new guidelines. Methods: A questionnaire on treatment of bronchiolitis was sent to all Swiss paediatricians before (2001) and after (2006) creation and implementation of national guidelines (2003–2005). Guidelines were created in collaboration with all paediatric pulmonologists and implemented carefully using a multifaceted approach. Results: Questionnaires were returned by 541 paediatricians (58%) in 2001 and by 639 (54%) in 2006. While both surveys showed a wide variation in the treatment of bronchiolitis between physicians, reported drug prescription decreased significantly between the two surveys. For outpatients, general use (for all patients) of bronchodilators dropped from 60% to 23%, and general use of ICS from 34% to 6%. For inpatients, general use of bronchodilators and ICS dropped from 55% to 18% and from 26% to 6%, respectively (all p<0.001). The decrease was evident in all regions, among hospital and primary care physicians, and among general paediatricians and paediatric pulmonologists. Conclusions: National guidelines together with a tailored implementation programme can have a major impact on medical management practices in a country.

Comparability of a hand-held nitric oxide analyser with online and offline chemiluminescence-based nitric oxide measurement

Practicability is crucial for successful implementation of fractional exhaled nitric oxide (FeNO) measurement into asthma management. The study aimed at comparing a conventional chemiluminescence NO analyser (EcoMedics®) with a hand‐held device (NIOX MINO®) and offline FeNO measurement using a commercially available system in an unselected cohort of children aged 6–16 yr. A secondary objective was to confirm FeNO stability over time in 15 samples from adult volunteers obtained using the offline system. Sixty‐six children (mean ± s.d. age 11.8 ± 3.0 yr) underwent single breath FeNO measurement in triplets with each device. Offline collected FeNO was measured after offline breath collection into a Mylar balloon and subsequent analysis using the chemiluminescence NO analyser. Variability and between‐method agreement were assessed, and stability over time within the Mylar balloons was tested by repeated hourly measurements. FeNO levels ranged from 2 to 113 p.p.b. Intra‐class correlation was excellent (r = 0.98, p < 0.001 for each pair). Bland–Altman plots and back‐transformation of logarithmic mean differences revealed fair agreement between methods. Stability over time was confirmed over 10 h both at room temperature and when stored under cooling conditions. FeNO values obtained using the chemiluminescence NO analyser, the portable NIOX MINO® system and the offline collection technique show between‐method agreement within clinically acceptable range.

Mannitol dry powder challenge in comparison with exercise testing in children.

Mannitol dry powder (MDP) challenge is an indirect bronchial provocation test, which is well studied in adults but not established for children.

Neuropsychological, behavioral, and adaptive functioning of Swiss children with congenital central hypoventilation syndrome.

This study collected data about developmental problems in a cohort of children with congenital central hypoventilation syndrome. In 2003, in Switzerland, 11 children with this disease were registered. Nine of them gave their informed consent to participate in the study and were examined. Clinical assessments were conducted, including examinations of neuropsychological, behavioral, and adaptive functions using Kaufman-Assessment Battery for Children, Child Behavior Checklist, and Vineland Adaptive Behavior Scales. The mean age (± standard deviation) was 7.5 ± 2.5 years. The cognitive tests showed problems in working memory functions with a near-to-normal full-range intelligence quotient (87.4 ± 23.3). The children showed normal values (t-values < 67) on problem scales of behavior, although 5 of the 9 children showed elevated values on the attention and on the social interaction problem scales. Adaptive function problems were identified in communication and daily living skills.

The Value of Exhaled Nitric Oxide in Predicting Bronchial Hyperresponsiveness in Children

Reduced attention span and motor skills in children limit the practicability of bronchial provocation tests. To assess exhaled nitric oxide (FeNO) as a surrogate for bronchial hyperresponsiveness (BHR) in children with possible reactive airway disease, FeNO was measured using the single-breath method in 169 successive outpatients 11 ± 5 years of age before lung function testing and subsequent bronchial provocation by exercise (n = 165) and methacholine (n = 134). Baseline forced expiratory volume in 1 second (FEV1) less than 80% of predicted and/or BHR were seen in 59%. FeNO correlated weakly with PD20 to methacholine (r = −0.24, p < 0.05), but not with the change in FEV1 due to exercise-induced bronchoconstriction (EIB) (r = 0.1, p > 0.05). The negative predictive value of FeNO less than 10 ppb for EIB was 94%, but overall accuracy for predicting BHR was low. Measurement of FeNO is not a substitute for bronchial provocation in children.

Prevalence and characteristics of tracheal cobblestoning in children

Tracheal follicular pattern or so‐called tracheal cobblestoning is a poorly described entity in the literature and is depicted as a nodular or lumpy appearance of the tracheal wall mucosa suggesting tracheal irritation from factors like gastro‐esophageal reflux (GERD) or pulmonary infection. The aim of the present study was to investigate the prevalence and characteristics of tracheal cobblestones in a large pediatric population.

Effect of mannitol dry powder challenge on exhaled nitric oxide in children

Background Fractional exhaled nitric oxide (FENO), a non-invasive marker of eosinophilic airway inflammation, is increasingly used for diagnostic and therapeutic decisions in adult and paediatric asthma. Standardized guidelines for the measurement of FENO recommend performing FENO measurements before rather than after bronchial provocation tests. Objective To investigate whether FENO levels decrease after a Mannitol dry powder (MDP) challenge in a clinical setting, and whether the extent of the decrease is influenced by number of MDP manoeuvres, baseline FENO, atopy and doctor diagnosed asthma. Methods Children aged 6–16 years, referred for possible reactive airway disease to a respiratory outpatient clinic, performed an MDP challenge (Aridol®, Pharmaxis, Australia). FENO was measured in doublets immediately before and after the challenge test using the portable NIOX MINO® device (Aerocrine, Stockholm, Sweden). We analysed the data using Kruskal-Wallis rank tests, Wilcoxon signed rank tests and multivariable linear regressions. Results One hundred and seven children completed both tests (mean±SD age 11.5±2.8 years). Overall, median (interquartile range) FENO decreased slightly by −2.5 ppb (−7.0, −0.5), from 18.5 ppb (10.5, 45.5) before the MDP challenge to 16.5 ppb thereafter (8.5, 40.5; p<0.001). In all participants, the change in FENO was smaller than one standard deviation of the baseline mean. The % fall in FENO was smaller in children with less MDP manoeuvres (e.g. higher bronchial responsiveness; p = 0.08) but was not influenced by levels of baseline FENO (p = 0.68), atopy (p = 0.84) or doctor diagnosed asthma (p = 0.93). Conclusion MDP challenge test influences FENO values but differences are small and clinically barely relevant.

Adenosine for salbutamol-induced supraventricular tachycardia.

Sir: Rapid onset of action, high success rate, and a short half-life are distinct advantages of adenosine for converting paroxysmal supraventricular tachycardia (SVT) to sinus rhythm. While shorted-lived sensations of dyspnea and chest pain commonly accompany the administration of adenosine, serious side effects are fortunately infrequent and mostly confined to cardiac arrhythmias and, rarely, bronchospasm. Consequently, higher grade AV blocks, sick sinus syndrome, and asthma are listed as contraindications for adenosine. Salbutamol-induced SVT occurring in the alert, spontaneously breathing asthmatic patient thus constitutes a therapeutic dilemma. We report our experience in two boys with salbutamol-induced SVT who were successfully converted with adenosine during asthma exacerbations. Neither of them had significant hypokalemia at the onset of SVT. One boy with brittle asthma had three episodes of SVT at 20, 22, and 24 months of age during therapy for status asthmaticus. The first episode was considered salbutamolinduced, and intravenous adenosine at 0.1 mg/kg was successful in all three instances without worsening of his asthma. In all three episodes he was receiving continuous inhalations of salbutamol, the first two while being mechanically ventilated in pressure-control mode. No changes were noted in tidal volumes. Unfortunately there was no end-tidal CO2 monitor in place at the time. The second boy suffered a salbutamol-induced SVT during an acute asthma exacerbation at the age of 6 years. At the time of the SVT episode he was awake, tachypneic, and saturating around 88% with 6 l/min of oxygen by facemask. No changes in respiratory parameters were observed after SVT termination with 0.1 mg/kg adenosine. Although adenosine may be safely administered in most children with a history of asthma [1, 2], rare case reports indicate that this drug has a potential for inducing bronchospasm in vulnerable individuals. Only two instances of adenosine administration in acutely asthmatic children with salbutamol-induced SVT have been reported so far, both apparently without adverse effects on asthmatic symptoms [3, 4]. Our experience suggests that salbutamol may provide protection from adenosine-related worsening of bronchospasm during asthma exacerbations. References

Ivacaftor in a young boy with the rare gating mutation S549R - use of lung clearance index to track progress: a case report

BackgroundIvacaftor acts as a potentiator of the cystic fibrosis transmembrane conductance regulator (CFTR) and increases the transepithelial chloride transport of CFTR in 9 of 10 known gating mutations causing cystic fibrosis. S549R is a rare gating mutation considered to be less sensitive to potentiators than all other gating mutations.Case presentationWe report our first experience with ivacaftor in an 8-year-old boy with the rare S549R gating mutation. Besides subjective clinical improvements, the sweat chloride level and the lung clearance index decreased impressively within a few weeks of treatment while forced expiratory volume in the first second values remained in normal range.ConclusionWe emphasize the value of measuring small airway function by lung clearance index as an outcome measure for new interventions targeting the correction of the CFTR defect at an age before traditional lung function parameters start to deteriorate.