Clinically useful spirometry in preschool-aged children: evaluation of the 2007 American Thoracic Society Guidelines

Perioperative and Anesthetic Considerations in Vascular Rings and Slings

Vascular rings represent an increasingly prevalent and diverse set of congenital malformations in which the aortic arch and its primary branches encircle and constrict the esophagus and trachea. Perioperative management varies significantly based on the type of lesion, its associated comorbidities, and the compromise of adjacent structures. Multiple review articles have been published describing the scope of vascular rings and relevant concerns from a surgical perspective. This review seeks to discuss the perioperative implications and recommendations of such pathology from the perspective of an anesthesia provider.

Heavy metal levels are positively associated with serum periostin and miRNA-125b levels, but inversely associated with miRNA-26a levels in pediatric asthma cases. A case-control study

BACKGROUND

The study investigated heavy metals levels [urinary cadmium (U-Cd), erythrocytic cadmium (E-Cd), urinary arsenic (U-As), and whole blood lead (WB-Pb)] in children with bronchial asthma (BA) and tested their associations with serum periostin, miRNA-125b and miRNA-26a levels, and with asthma severity clinically and laboratory [blood eosinophils count (BEC) and serum total immunoglobin E (IgE)]. Also, we tested cut-off points, for the studied parameters, to distinguish BA cases from healthy children.

METHODS

This case-control study included 158 children divided into control group; n = 72 and BA group; n = 86. Heavy metals were measured by an inductively coupled plasma-optical emission spectrophotometer. Serum periostin and IgE levels were measured by their corresponding ELISA kits. miRNAs relative expressions were estimated by RT-qPCR using the 2-ΔΔCT method.

RESULTS

Heavy metals, serum periostin, and miR-125b levels were significantly high in BA group (p < 0.001). Heavy metals levels correlated positively with serum periostin, miR-125b and IgE levels, BEC, and asthma severity. The reverse was observed regarding serum miR-26a levels. Receiver operating characteristics (ROC) curve analysis showed good to excellent abilities of U-Cd, E-Cd, U-As, WB-Pb, serum periostin, miRNA-125b, and miRNA - 26a, and total IgE levels to distinguish BA cases from healthy children.

CONCLUSIONS

Heavy metal toxicity in children is associated with BA severity, increased serum periostin and miRNA-125b levels, and decreased miRNA-26a levels. Specific measures to reduce children's exposure to heavy metals should be taken. Future research should consider blocking miRNA-125b action or enhancing miRNA-26a action to manage BA cases.

Does routine spirometry impact on clinical decisions and patient-related outcome measures of children seen in respiratory clinics: an open-label randomised controlled trial

INTRODUCTION

There is limited evidence on the efficacy of using spirometry routinely in paediatric practice for improving outcomes.

OBJECTIVE

To determine whether the routine use of spirometry alters clinical decisions and patient-related outcome measures for children managed by respiratory paediatricians.

METHODS

We undertook a parallel open-label randomised controlled trial involving children (aged 4-18 years) able to perform spirometry in a specialist children's hospital in Australia. Children were randomised to either routine use of spirometry (intervention) or clinical review without use of spirometry (control) for one clinic visit. The primary outcomes were the (a) proportion of children with 'any change in clinical decisions' and (b) 'change score' in clinical decisions. Secondary outcomes were change in patient-related outcome measures assessed by State-Trait Anxiety Inventory (STAI) and Parent-Proxy QoL questionnaire for paediatric chronic cough (PC-QoL).

RESULTS

Of 136 eligible children, 106 were randomised. Compared with controls, the intervention group had significantly higher proportion of children with 'any change in clinical decisions' (n=54/54 (100%) vs n=34/52 (65.4%), p<0.001) and higher clinical decision 'change score' (median=2 (IQR 1-4) vs 1 (0-2), p<0.001). Also, improvement was significantly greater in the intervention group for overall STAI score (median=-5 (IQR -10 to -2) vs -2.5 (-8.5, 0), p=0.021) and PC-QoL social domain (median=3 (IQR 0 to 5) vs 0 (-1, 1), p=0.017).

CONCLUSION

The routine use of spirometry in children evaluated for respiratory issues at clinical outpatient review is beneficial for optimising clinical management and improving parent psychosocial well-being.

REGISTRATION

Australia and New Zealand Clinical Trials Registry ACTRN12619001686190.

Long term outcomes in CDH: Cardiopulmonary outcomes and health related quality of life

BACKGROUND

With improvements in clinical management and an increase in CDH survivorship there is a crucial need for better understanding of long-term health outcomes in CDH.

AIM

To investigate the prevalence of cardiopulmonary health morbidity and health related quality of life (HRQoL) in CDH survivors.

METHODS

We included all studies (n = 65) investigating long-term cardiopulmonary outcomes in CDH patients more than 2 years published in the last 30 years. The Newcastle-Ottawa Scale and the CASP checklist for cohort studies were utilized to assess study quality. Results were reported descriptively and collated by age group where possible.

RESULTS

The incidence of pulmonary hypertension was highly variable (4.5-38%), though rates (%) appeared to diminish after 5 years of age. Lung function indices and radiological outcomes were frequently abnormal, and Health Related Quality of Life (HRQoL) reduced also. Long term diseases notably emphysema and COPD are not yet fully described in the contemporary literature.

CONCLUSION

This study underscores cardiopulmonary health morbidity and a reduced HRQoL among CDH survivors. Where not already available dedicated multidisciplinary follow-up clinics should be established to support these vulnerable patients transition safely into adulthood. Future research is therefore needed to investigate the risk factors for cardiopulmonary ill health and morbidity in CDH survivors.

TYPE OF STUDY

Systematic review of case control and cohort studies.

Spirometry reference equations for children from a Middle Eastern population

BACKGROUND

Spirometry is a clinically useful test that can be used to assess lung function among children. Different equations had been formulated to determine the spirometric reference values depending on several individual characteristics. However, the widely used equations do not produce perfect suitability for Middle Eastern children.

OBJECTIVES

This study aims to formulate Middle Eastern-specific equations that may be applicable for other populations in the region.

METHODS

The spirometric data were collected from Jordanian children between the ages of 6 and 17 years. The collected data were used to formulate customised reference equations for Middle Eastern children using generalised additive models for location, scale and shape. The newly formulated equation results were compared with Global Lung Initiative 2012 (GLI-2012) equations predicted values.

RESULTS

Spirometric values for 1576 healthy participants (870 males) were used to formulate the new equations. The assessment of z-scores produced by the present study equations and GLI-2012 indicated that the new equations were more suitable than GLI-2012 for Middle Eastern children. In-depth analysis of the results indicated that the suitability of GLI-2012 equations varied between different age points.

CONCLUSION

This study formulated new spirometric reference equations for Middle Eastern children that can improve the diagnosis and management of different respiratory conditions.

Impact of using spirometry on clinical decision making and quality of life in children: protocol for a single centre randomised controlled trial

INTRODUCTION

Although spirometry has been available for decades, it is underused in paediatric practice, other than in specialist clinics. This is unsurprising as there is limited evidence on the benefit of routine spirometry in improving clinical decision making and/or outcomes for children. We hypothesised that using spirometry for children being evaluated for respiratory diseases impacts on clinical decision making and/or improves patient-related outcome measures (PROMs) and/or quality of life (QoL), compared with not using spirometry.

METHODS AND ANALYSIS

We are undertaking a randomised controlled trial (commenced in March 2020) that will include 106 children (aged 4-18 years) recruited from respiratory clinics at Queensland Children's Hospital, Australia. Inclusion criteria are able to perform reliable spirometry and a parent/guardian who can complete questionnaire(s). Children (1:1 allocation) are randomised to clinical medical review with spirometry (intervention group) or without spirometry (control group) within strata of consultation status (new/review), and cough condition (present/absent). The primary outcome is change in clinical decision making. The secondary outcomes are change in PROM scores, opinions regarding spirometry and degree of diagnosis certainty. Intergroup differences of these outcomes will be determined by χ2 test or unpaired t-test (or Mann-Whitney if not normally distributed). Change in outcomes within the control group after review of spirometry will also be assessed by McNemar's test or paired t-test/Wilcoxon signed-rank test.

ETHICS AND DISSEMINATION

The Human Research Ethics Committee of the Queensland Children's Hospital approved the study. The trial results will be disseminated through conference presentations, teaching avenues and publications.

TRIAL REGISTRATION NUMBER

ACTRN12619001686190; Pre-results.

Applicability of GLI 2012 spirometry equation among preschool aged Jordanian

OBJECTIVES

The Validation of Global Lung Initiative (GLI 2012) equations is required prior to their application in clinical practice in different regions. This study validated the GLI 2012 equations in Middle Eastern preschool aged children, which was not previously conducted.

STUDY DESIGN

Spirometry measures were collected from 765 (54% males) healthy 3 to 5-year-old Jordanian children. z scores, percent predicted values, and frequency of measures below lower limit than normal (LLN) were calculated using GLI 2012 equations for Caucasians and Other or Mixed.

RESULTS

The mean of z-scores produced by GLI 2012 equation for Caucasians in FEV_0.75, FEV₁, FVC, FEV₁/FVC% and FEF25-75 in boys were 0.03, 0.02, -0.13, 0.26 and -0.08 respectively, while in girls it was -0.03, 0.01, 0.02, -0.01 and -0.04 respectively, and the mean of z-scores produced by GLI-2012 Other or Mixed equations in FEV₁, FVC, FEV₁/FVC% and FEF25-75 in boys were 0.56, 0.51, 0.09 and 0.12 respectively, and in girls it was 0.56, 0.67, -0.22 and 0.18 respectively. The frequency of measures below LLN as produced by Caucasians equation were not significantly different from the expected 5% in any of the spirometry parameters.

CONCLUSION

The GLI 2012 for Caucasians is a reasonable fit for Jordanian preschool aged children.

Non-invasive forced oscillometry to quantify respiratory mechanics in term neonates

BACKGROUND

To determine normative data by forced oscillation technique (FOT) in non-sedated normal term neonates and test the hypothesis that infants with transient tachypnea of the newborn (TTN) have higher resistance (R) and lower reactance (X) on day 1.

METHODS

Healthy term infants (n = 138) and infants with TTN (n = 17) were evaluated on postnatal days 1 through 3 (NCT03346343). FOT was measured with a mask using a TremoFlo C-100 Airwave System™. R, X, and area under the reactance curve (AX) were measured at prime frequencies 7-41 Hz for 8 s.

RESULTS

In all, 86% of control infants had adequate measurements (coherence >0.8, CV < 0.25) on day 1. Infants with TTN had higher resistance at 13 Hz (TTN 32.5 cm H₂O·s/L [95% CI 25.5-39.4]; controls 23.8 cm H₂O·s/L [95% CI 22.2 to 25.3], P = 0.007) and lower reactance from 17 to 37 Hz (TTN -35.1 to -10.5; controls -26.3 to -6.1, P < 0.05). In healthy controls, lung mechanics were unchanged from days 1 to 3. In TTN, lung mechanics normalized on days 2 and 3.

CONCLUSIONS

FOT is feasible in neonates and distinguishes normal control infants from those with TTN on postnatal day 1. Oscillometry offers a non-invasive, longitudinal technique to assess lung mechanics in newborns.

Interactions between ambient air pollution and obesity on lung function in children: The Seven Northeastern Chinese Cities (SNEC) Study

Children are vulnerable to air pollution-induced lung function deficits, and the prevalence of obesity has been increasing in children. To evaluate the joint effects of long-term PM₁ (particulate matter with an aerodynamic diameter ≤ 1.0 μm) exposure and obesity on children's lung function, a cross-sectional sample of 6740 children (aged 7-14 years) was enrolled across seven northeastern Chinese cities from 2012 to 2013. Weight and lung function, including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁), peak expiratory flow (PEF), and maximal mid-expiratory flow (MMEF), were measured according to standardized protocols. Average PM₁, PM_2.5, PM₁₀ and nitrogen dioxide (NO₂) exposure levels were estimated using a spatiotemporal model, and sulphur dioxide (SO₂) and ozone (O₃) exposure were estimated using data from municipal air monitoring stations. Two-level logistic regression and general linear models were used to analyze the joint effects of body mass index (BMI) and air pollutants. The results showed that long-term air pollution exposure was associated with lung function impairment and there were significant interactions with BMI. Associations were stronger among obese and overweight than normal weight participants (the adjusted odds ratios (95% confidence intervals) for PM₁ and lung function impairments in three increasing BMI categories were 1.50 (1.07-2.11) to 2.55 (1.59-4.07) for FVC < 85% predicted, 1.44 (1.03-2.01) to 2.51 (1.53-4.11) for FEV₁ < 85% predicted, 1.34 (0.97-1.84) to 2.04 (1.24-3.35) for PEF < 75% predicted, and 1.34 (1.01-1.78) to 1.93 (1.26-2.95) for MMEF < 75% predicted). Consistent results were detected in linear regression models for PM₁, PM_2.5 and SO₂ on FVC and FEV₁ impairments (P_Interaction < 0.05). These modification effects were stronger among females and older participants. These results can provide policy makers with more comprehensive information for to develop strategies for preventing air pollution induced children's lung function deficits among children.

Longitudinal Analysis of Pulmonary Function in Survivors of Congenital Diaphragmatic Hernia

OBJECTIVE

To analyze longitudinal trends of pulmonary function testing in patients with congenital diaphragmatic hernia (CDH) followed in our multidisciplinary clinic.

STUDY DESIGN

This was a retrospective cohort study of CDH patients born between 1991 and 2013. A linear mixed effects model was fitted to estimate the trends of percent predicted forced expiratory volume in 1 second (FEV₁pp), percent predicted forced vital capacity (FVCpp), and FEV₁/FVC over time.

RESULTS

Of 268 patients with CDH who survived to discharge, 119 had at least 1 pulmonary function test study. The FEV₁pp (P < .001), FVCpp (P = .017), and FEV₁/FVC (P = .001) decreased with age. Compared with defect size A/B, those with defect size C/D had lower FEV₁pp by an average of 11.5% (95% CI, 2.9%-20.1%; P = .010). A history of oxygen use at initial hospital discharge also correlated with decreased FEV₁pp by an average of 8.0% (95% CI, 1.2%-15.0%; P = .023).

CONCLUSIONS

In a select cohort of CDH survivors, average pulmonary function declines with age relative to expected population normative values. Those with severe CDH represent a population at risk for worsening pulmonary function test measurements who may benefit from recognition and monitoring for complications.

Change in capnogram waveform is associated with bronchodilator response and asthma control in children

BACKGROUND

Airway hyper-reactivity, inflammation and remodeling contribute to inhomogeneity of ventilation-perfusion ratio VA·/Q· in asthma. Short-term variations in V.A/Q· can cause changes in expired capnographic indices.

OBJECTIVES

To measure acute changes in the phase 3 slope of the volumetric capnogram after β2-agonist inhalation (ΔSIII), for comparison with airway response based on FEV1 (ΔFEV1), and asthma control.

SUBJECTS AND METHODS

After ethical approval and informed consent, 72 children aged 6-18 y, followed up for asthma underwent spirometry and capnography before and after β-agonist inhalation through a spacer, using a side-stream rapid infrared analyzer. Asthma control was assessed using the GINA questionnaire.

RESULTS

Children with positive reversibility tests (defined as ΔFEV1>12%) had a significantly higher ΔSIII (m ± SE: 87.4 ± 41.4) versus those with negative tests (31.3 ± 14.0%, P = 0.001). Uncontrolled asthma was associated with a significantly larger ΔSIII (103.4 ± 64.0%, n = 7) compared to partly controlled (52.0 ± 26.1, n = 24; P = 0.009) and controlled asthma (30.8 ± 16.3, n = 41; P = 0.003). Neither Bohr dead space nor ΔFEV1 were different between asthma control groups.

CONCLUSIONS

ΔSIII was significantly larger in children with positive response to β2-agonist, and in uncontrolled asthmatics. To our knowledge these are the first data on exhaled CO₂ phase III volumetric slope change and asthma control. The observed ΔSIII could be due to an increased ventilation of inhomogeneous peripheral lung units, and merits further evaluation as a potential phenotypic biomarker in asthma.

An open-label extension study of ivacaftor in children with CF and a CFTR gating mutation initiating treatment at age 2-5 years (KLIMB)

BACKGROUND

KIWI (NCT01705145) was a 24-week, single-arm, pharmacokinetics, safety, and efficacy study of ivacaftor in children aged 2 to 5 years with cystic fibrosis (CF) and a CFTR gating mutation. Here, we report the results of KLIMB (NCT01946412), an 84-week, open-label extension of KIWI.

METHODS

Children received age- and weight-based ivacaftor dosages for 84 weeks. The primary outcome was safety. Other outcomes included sweat chloride, growth parameters, and measures of pancreatic function.

RESULTS

All 33 children who completed KIWI enrolled in KLIMB; 28 completed 84 weeks of treatment. Most adverse events were consistent with those reported during KIWI. Ten (30%) children had transaminase elevations >3 × upper limit of normal (ULN), leading to 1 discontinuation in a child with alanine aminotransferase >8 × ULN. Improvements in sweat chloride, weight, and body mass index z scores and fecal elastase-1 observed during KIWI were maintained during KLIMB; there was no further improvement in these parameters.

CONCLUSIONS

Ivacaftor was generally well tolerated for up to 108 weeks in children aged 2 to 5 years with CF and a gating mutation, with safety consistent with the KIWI study. Improvements in sweat chloride and growth parameters during the initial 24 weeks of treatment were maintained for up to an additional 84 weeks of treatment. Prevalence of raised transaminases remained stable and did not increase with duration of exposure during the open-label extension.

Lung function tests to monitor respiratory disease in preschool children

Pulmonary function tests are routinely used in the diagnosis and follow-up of respiratory diseases. In preschool children assessment and evaluation of lung function has always been challenging but improved techniques that require only minimal collaboration allowed obtaining reliable and useful results even in this group of patients. In this review we will describe the different techniques used in clinical practice to measure lung function in preschool children.(www.actabiomedica.it)

Spirometry in Asthma Care: A Review of the Trends and Challenges in Pediatric Practice

BACKGROUND

Given the rising incidence of noncommunicable diseases (NCDs) globally, especially bronchial asthma, there is the need to reduce the associated morbidity and mortality by adopting an objective means of diagnosis and monitoring.

AIM

This article aims to review the trends and challenges in the use of spirometry for managing childhood bronchial asthma especially in developing countries.

METHODS

We conducted a literature search of published data on the use of spirometry for the diagnosis of childhood bronchial asthma with special emphasis resource-poor countries.

RESULTS

Guidelines for the diagnosis and treatment of childhood asthma recommend the use of spirometry, but this is currently underused in both tertiary and primary care settings especially in developing countries. Lack of spirometers and proper training in their use and interpretation of findings as well as a dearth of asthma guidelines remains core to the underuse of spirometry in managing children with asthma. Targeting education of health care staff was, however, observed to improve its utility, and practical implementable strategies are highlighted.

CONCLUSIONS

Spirometry is not frequently used for asthma diagnosis in pediatric practice especially in resource-poor countries where the NCD burden is higher. Strategies to overcome the obstacles are implementable and can make a difference in reducing the burden of NCD.

Association of perfluoroalkyl substances exposure with impaired lung function in children

Previous studies have demonstrated associations between serum levels of perfluoroalkyl substances (PFASs) and asthma or asthma related-biomarkers. However, no studies have reported a possible relationship between PFASs exposure and lung function among children. The objective of the present study is to test the association between PFASs exposure and lung function in children from a high exposure area by using a cross-sectional case-control study, which included 132 asthmatic children and 168 non-asthmatic controls recruited from 2009 to 2010 in the Genetic and Biomarkers study for Childhood Asthma. Structured questionnaires were administered face-to-face. Lung function was measured by spirometry. Linear regression models were used to examine the influence of PFASs on lung function. The results showed that asthmatics in our study had significantly higher serum PFAS concentrations than healthy controls. Logistic regression models showed a positive association between PFASs and asthma, with adjusted odds ratios (ORs) ranging from 0.99 (95% confidence interval [CI]: 0.80-1.21) to 2.76 (95% CI: 1.82-4.17). Linear regression modeling showed serum PFASs levels were significantly negatively associated with three pulmonary function measurements (forced vital capacity: FVC; forced expiratory volume in 1s: FEV₁; forced expiratory flow 25-75%: FEF_25-75) among children with asthma, the adjusted coefficients between lung function and PFASs exposure ranged from -0.055 (95%CI: -0.100 to -0.010) for FVC and perfluorooctane sulfonate (PFOS) to -0.223 (95%CI: -0.400 to -0.045) for FEF_25-75 and perfluorooctanoic acid (PFOA). PFASs were not, however, significantly associated with pulmonary function among children without asthma. In conclusion, this study suggests that serum PFASs are associated with decreased lung function among children with asthma.

Lung function and functional capacity in school age children

Abstract Introduction: Six-minute walk test (TC6’) and peak expiratory flow (PEF) can be influenced by variables like gender, age and body mass index (BMI). In the school context, these tests can identify losses caused by sedentary habits and/or manifestation of overweight/obesity. Nevertheless, although widely studied in the adult context, they have not been properly clarified in the child public. Objective: To assess the PEF and TC6’ between students in the public and private network and to correlate them with factors like age, gender and BMI. Methods: 39 male and female children between eight and ten years of age were selected for the study. The TC6’ was held at a sports court. The child was instructed to walk at maximum speed for six minutes and the PEF test took place in accordance to the recommendations by Pereira et al (1). Results: No significant correlation was found between the BMI and the PEF and TC6’ scores. No significant correlation was found between sex and PEF, with measures within normal parameters for the entire sample. The EPF measures did not influence the distance walked in the TC6’. A significant correlation was found between sex and distance walked in the TC6’ only among male children attending public schools. Conclusion: Both sex and BMI did not influence the PEF measures which, in turn, does not seem to have influenced the distance the sample walked in the TC6’. Also concerning the TC6’, only the children from public school reached the normal scores proposed in the literature.

[Quality scale for preschool spirometry interpretation]

Since 2007, there are international guidelines for implementation and interpretation of spirometry in preschool children. A percentage of these patients cannot obtain maneuvers that meet all eligibility criteria. The objective of this study was to develop a quality scale for interpreting these partially acceptable spirometry.

MATERIAL AND METHOD

Delphi methodology was used, which allows to reach consensus among experts analyzing a defined problem. We invited to participate pediatric pneumologists dedicated to lung function and who participated actively in scientific specialty societies in Chile. Successive rounds were conducted with questionnaires about criteria used to assess spirometry in preschool children. These criteria define the acceptability of spirometric maneuvers according to international guidelines. Proposed quality grades were “very good”, “good”, “fair” and “bad”.

RESULTS

Thirteen of the 15 invited experts accepted our invitation. In the first round 9 disagreed with the degree of “regular” quality. In the second round this was removed and 11 experts answered, 9 of them agreed with the use of this new version. The most contentious criterion was the end of expiration.

CONCLUSION

Most experts agreed with the final scale, using “very good”, “good” and “bad” judgments. This would help to improve the performance of spirometry in children between 2 and 5 years.

Associations of maternal and fetal 25-hydroxyvitamin D levels with childhood lung function and asthma: the Generation R Study

BACKGROUND

Exposure to low levels of vitamin D in fetal life might be a risk factor for childhood asthma.

OBJECTIVE

We examined whether 25-hydroxyvitamin D levels in mid-gestation and at birth were associated with higher airway resistance and inflammation, and increased risks of wheezing and asthma in school-age children.

METHODS

We performed a population-based prospective cohort study among 3130 mothers and their children. Maternal blood samples in mid-gestation and umbilical cord blood samples at birth were used to determine 25-hydroxyvitamin D levels. At age of 6, airway resistance (Rint) was measured by interrupter technique and airway inflammation by fractional exhaled nitric oxide (FENO) using NIOX chemiluminescence analyser. Wheezing and asthma were prospectively assessed by annual questionnaires until age 6.

RESULTS

Maternal levels of 25-hydroxyvitamin D in mid-gestation were not associated with Rint, FeNO, wheezing patterns, or asthma. Children in the lowest tertile of 25-hydroxyvitamin D levels at birth had a higher Rint (Z-score (95% confidence interval [95% CI]): -0.42 (-0.84, -0.01), P-value for trend< 0.05), compared to those in the highest tertile group. The effect estimate attenuated when child's current 25-hydroxyvitamin D level was taken into account [Z-score (95% CI): -0.55 (-1.08, 0.01)].

CONCLUSION AND CLINICAL RELEVANCE

Low levels of 25-hydroxyvitamin D at birth were associated with a higher airway resistance in childhood. Additional adjustment for child's current 25-hydroxyvitamin D level reduced the effect size of the association. Further studies are needed to replicate these findings and to examine mechanisms underlying the observed association and the long-term consequences.

Breastfeeding and asthma outcomes at the age of 6 years: The Generation R Study

BACKGROUND

Breastfeeding is associated with a lower risk of asthma symptoms in early childhood, but its effect at older ages remains unclear. We examined the associations of duration and exclusiveness of breastfeeding with asthma outcomes in children aged 6 years, and whether these associations were explained by atopic or infectious mechanisms.

METHODS

We performed a population-based prospective cohort study among 5675 children. Information about breastfeeding was collected by questionnaires. At age 6 years, we measured interrupter resistance (Rint) and fractional exhaled nitric oxide (FeNO). Information about wheezing patterns (early (≤3 years only), late (>3 years only), persistent (≤3 and >3 years)), and current asthma at 6 years was derived from repeated questionnaires.

RESULTS

Compared to children who were ever breastfed, those who were never breastfed had lower FeNO levels (sympercent (95% CI): -16.0 (-24.5, -7.5)) and increased risks of late and persistent wheezing (OR(95% CI): 1.69 (1.06, 2.69) and 1.44 (1.00, 2.07), respectively). Shorter duration of breastfeeding was associated with early wheezing and current asthma (1.40 (1.14, 1.73) and 2.19 (1.29, 3.71), respectively). Less exclusive breastfeeding was associated with early wheezing (1.28 (1.08, 1.53)). Breastfeeding duration and exclusiveness were not associated with FeNO or Rint. The associations were not explained by inhalant allergies, partly by lower respiratory tract infections in early life, and to a lesser extent by lower respiratory tract infections in later life.

CONCLUSIONS

Breastfeeding patterns may influence wheezing and asthma in childhood, which seems to be partly explained by infectious mechanisms.

Respiratory System Disease

Respiratory system involvement in cystic fibrosis is the leading cause of morbidity and mortality. Defects in the cystic fibrosis transmembrane regulator (CFTR) gene throughout the sinopulmonary tract result in recurrent infections with a variety of organisms including Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and nontuberculous mycobacteria. Lung disease occurs earlier in life than once thought and ideal methods of monitoring lung function, decline, or improvement with therapy are debated. Treatment of sinopulmonary disease may include physiotherapy, mucus-modifying and antiinflammatory agents, antimicrobials, and surgery. In the new era of personalized medicine, CFTR correctors and potentiators may change the course of disease.

Prediction equations for spirometry in four- to six-year-old children

OBJECTIVE

To generate prediction equations for spirometry in 4- to 6-year-old children.

METHODS

Forced vital capacity, forced expiratory volume in 0.5s, forced expiratory volume in one second, peak expiratory flow, and forced expiratory flow at 25-75% of the forced vital capacity were assessed in 195 healthy children residing in the town of Sete Lagoas, state of Minas Gerais, Southeastern Brazil. The least mean squares method was used to derive the prediction equations. The level of significance was established as p<0.05.

RESULTS

Overall, 85% of the children succeeded in performing the spirometric maneuvers. In the prediction equation, height was the single predictor of the spirometric variables as follows: forced vital capacity=exponential [(-2.255)+(0.022×height)], forced expiratory volume in 0.5s=exponential [(-2.288)+(0.019×height)], forced expiratory volume in one second=exponential [(-2.767)+(0.026×height)], peak expiratory flow=exponential [(-2.908)+(0.019×height)], and forced expiratory flow at 25-75% of the forced vital capacity=exponential [(-1.404)+(0.016×height)]. Neither age nor weight influenced the regression equations. No significant differences in the predicted values for boys and girls were observed.

CONCLUSION

The predicted values obtained in the present study are comparable to those reported for preschoolers from both Brazil and other countries.

Utility of measuring FEV0.75/FVC ratio in preschoolers with uncontrolled wheezing disorder

Uncontrolled wheezing disorder is common in preschoolers and disease control assessment is challenging as parents frequently overestimate the extent to which their child's disease is controlled. This is the first study of forced expiratory volume in t s (FEVt)/forced vital capacity (FVC) ratio measurements (i.e. FEV1/FVC, FEV0.75/FVC and FEV0.5/FVC) in wheezy preschoolers in relation to disease control. Our objective was to evaluate whether FEVt/FVC ratios less than the lower limit of normal (LLN; z-score <−1.64) were associated with uncontrolled wheezing disorder in preschoolers.

Valid FVC, FEV1, FEV0.75 and FEV0.5 values were obtained in 92 healthy and 125 wheezy (62% uncontrolled) children (3–5 years). Associations between spirometry value <LLN, disease classification (healthy/wheezy) and disease control classifications (controlled/uncontrolled disease) were estimated using logistic regression.

FEV0.75/FVC or FEV0.5/FVC ratios <LLN were associated with wheezing disorder (OR 9.78, 95% CI 3.70–25.88 and OR 6.64, 95% CI 2.24–19.66; all p<0.001). Only an FEV0.75/FVC ratio <LLN was associated with uncontrolled wheezing disorder (OR 2.53, 95% CI 1.12–5.68; p=0.025).

FEV0.75/FVC ratio is a useful surrogate outcome index to evaluate the control of the wheezing disease of preschoolers.

Feasibility of spirometry testing in preschool children

RATIONALE

The primary purpose of this study was to evaluate the feasibility of obtaining acceptable and reproducible spirometry data in preschool aged children (3-5 years) by technicians without prior experience with spirometry.

METHODS

Two technicians were trained to perform spirometry testing (ndd Easy on-PC) and to administer standardized questionnaires. Preschool aged children were enrolled from two Head Start centers and a local primary care clinic. Subjects were trained in proper spirometry technique and tested until at least two acceptable efforts were obtained or the subject no longer produced acceptable efforts.

RESULTS

200 subjects were enrolled: mean age 4.0 years (± 0.7 SD); age distribution: 51 (25.5%) 3 years old, 103 (51.5%) 4 years old, and 46 (23%) 5 years old. Fifty-six percent male and 75% Hispanic. One hundred thirty (65%) subjects produced at least one acceptable effort on their first visit: 23 (45%) for 3 years old, 67 (65%) for 4 years old, and 40 (87%) for 5 years old. The number of acceptable efforts correlated with age (r = 0.29, P < 0.001) but not gender. The mean number of acceptable efforts on the first visit was 2.66 (± 2.54 SD; range 0-10). One hundred twenty subjects (60%) had two acceptable efforts; 102 had FEV0.5 within 10% or 0.1 L and 104 had FVC within 10% or 0.1 L of best effort. The Asthma Health Screening Survey (AHSS) was 78% sensitive when compared to a specialist exam and 86% compared to a self-reported prior diagnosis of asthma.

CONCLUSIONS

Technicians without prior experience were able to obtain acceptable and reproducible spirometry results from the preschool aged children; the number of acceptable efforts correlated significantly with age.

Influence of Body Composition on Lung Function and Respiratory Muscle Strength in Children With Obesity

Background

Obesity affects lung function and respiratory muscle strength. The aim of the present study was to assess lung function and respiratory muscle strength in children with obesity and determine the influence of body composition on these variables.

Methods

A cross-sectional study was conducted involving 75 children (40 with obesity and 35 within the ideal weight range) aged 6 - 10 years. Body mass index, z score, waist circumference, body composition (tetrapolar bioimpedance), respiratory muscle strength and lung function (spirometry) were evaluated.

Results

Children with obesity exhibited larger quantities of both lean and fat mass in comparison to those in the ideal weight range. No significant differences were found between groups regarding the respective reference values for respiratory muscle strength. Male children with obesity demonstrated significantly lower lung function values (forced expiratory volume in the first second % (FEV₁%) and FEV₁/forced vital capacity % (FVC%) : 93.76 ± 9.78 and 92.29 ± 3.8, respectively) in comparison to males in the ideal weight range (99.87 ± 9.72 and 96.31 ± 4.82, respectively). The regression models demonstrated that the spirometric variables were influenced by all body composition variables.

Conclusion

Children with obesity demonstrated a reduction in lung volume and capacity. Thus, anthropometric and body composition characteristics may be predictive factors for altered lung function.

Foetal and infant growth patterns, airway resistance and school-age asthma

BACKGROUND AND OBJECTIVE

Preterm birth, low birth weight and rapid infant weight gain are associated with increased risks of asthma symptoms in childhood. The underlying mechanism may include persistently higher airway resistance (Rint). The aim of our study was to examine the associations of longitudinally measured foetal and infant growth characteristics with Rint and asthma outcomes in school-age children.

METHODS

This study was embedded in a population-based prospective cohort study in Rotterdam, The Netherlands. Foetal growth was estimated by ultrasound in the second and third trimesters. Infant growth was measured at birth, 3, 6 and 12 months. At age 6 years, Rint was measured, and information about wheezing and asthma was obtained by questionnaires. The number of subjects per analysis differed per available outcome (3954-5066 subjects).

RESULTS

Longitudinal growth analyses showed that school-age children with increased Rint had lower foetal length growth and weight gain, and lower infant length growth. Children with persistent wheezing until age 6 years and physician-diagnosed asthma had a higher Rint compared with children who never wheezed or without asthma (difference z-scores Rint: 0.58 (0.19, 0.97) and 0.55 (0.15, 0.95), respectively).

CONCLUSION

Rint in school-age children is influenced by foetal growth restriction and is associated with asthma outcomes. See article, page 574.

Diagnosis and management of asthma in preschoolers: A Canadian Thoracic Society and Canadian Paediatric Society position paper

Asthma often starts before six years of age. However, there remains uncertainty as to when and how a preschool-age child with symptoms suggestive of asthma can be diagnosed with this condition. This delays treatment and contributes to both short- and long-term morbidity. Members of the Canadian Thoracic Society Asthma Clinical Assembly partnered with the Canadian Paediatric Society to develop a joint working group with the mandate to develop a position paper on the diagnosis and management of asthma in preschoolers. In the absence of lung function tests, the diagnosis of asthma should be considered in children one to five years of age with frequent (≥8 days/month) asthma-like symptoms or recurrent (≥2) exacerbations (episodes with asthma-like signs). The diagnosis requires the objective document of signs or convincing parent-reported symptoms of airflow obstruction (improvement in these signs or symptoms with asthma therapy), and no clinical suspicion of an alternative diagnosis. The characteristic feature of airflow obstruction is wheezing, commonly accompanied by difficulty breathing and cough. Reversibility with asthma medications is defined as direct observation of improvement with short-acting ß2-agonists (SABA) (with or without oral corticosteroids) by a trained health care practitioner during an acute exacerbation (preferred method). However, in children with no wheezing (or other signs of airflow obstruction) on presentation, reversibility may be determined by convincing parental report of a symptomatic response to a three-month therapeutic trial of a medium dose of inhaled corticosteroids with as-needed SABA (alternative method), or as-needed SABA alone (weaker alternative method). The authors provide key messages regarding in whom to consider the diagnosis, terms to be abandoned, when to refer to an asthma specialist and the initial management strategy. Finally, dissemination plans and priority areas for research are identified.

Spirometry interpretation feasibility among pre-school children according to the European Respiratory Society and American Thoracic Society Guidelines

INTRODUCTION

Spirometry is the most used test to evaluate pulmonary function. Guidelines that defined acceptability and repeatability criteria for its implementation and interpretation among preschoolers were published in 2007. Our objective was to quantify the actual compliance with these criteria among pre-school patients.

METHODS

A review was performed on the baseline spirometry measured in patients aged 2 to 5 years in the Pediatric Respiratory Laboratory of the Pontificia Universidad Católica de Chile, who were admitted due to recurrent or persistent coughing or wheezing. Only those results obtained in patients who took the test for the first time were considered. They were analyzed by international standards.

RESULTS

A total of 93 spirometry results (mean age 57.4 ± 8.6 months, 48 males) were obtained, of which 44 (47%) met all acceptable criteria, 87 (93%) obtained expiratory time of ≥ 0.5seconds, and 67 (72%) of the patients had an end-expiratory flow of ≤10% from peak flow. The variation in the measurement of forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) was very low (intraclass correlation coefficient > 0.9).

CONCLUSION

It was possible to meet the acceptability and repeatability criteria for spirometry among pre-school children in our Center, which was similar to previous reports. As in older children, this test is fully recommended for pre-school children who require lung function studies.

Diagnosis and management of asthma in preschoolers: A Canadian Thoracic Society and Canadian Paediatric Society position paper

Asthma often starts before six years of age. However, there remains uncertainty as to when and how a preschool-age child with symptoms suggestive of asthma can be diagnosed with this condition. This delays treatment and contributes to both short- and long-term morbidity. Members of the Canadian Thoracic Society Asthma Clinical Assembly partnered with the Canadian Paediatric Society to develop a joint working group with the mandate to develop a position paper on the diagnosis and management of asthma in preschoolers. In the absence of lung function tests, the diagnosis of asthma should be considered in children one to five years of age with frequent (≥ 8 days/month) asthma-like symptoms or recurrent (≥ 2) exacerbations (episodes with asthma-like signs). The diagnosis requires the objective document of signs or convincing parent-reported symptoms of airflow obstruction (improvement in these signs or symptoms with asthma therapy), and no clinical suspicion of an alternative diagnosis. The characteristic feature of airflow obstruction is wheezing, commonly accompanied by difficulty breathing and cough. Reversibility with asthma medications is defined as direct observation of improvement with short-acting ß2-agonists (SABA) (with or without oral corticosteroids) by a trained health care practitioner during an acute exacerbation (preferred method). However, in children with no wheezing (or other signs of airflow obstruction) on presentation, reversibility may be determined by convincing parental report of a symptomatic response to a three-month therapeutic trial of a medium dose of inhaled corticosteroids with as-needed SABA (alternative method), or as-needed SABA alone (weaker alternative method). The authors provide key messages regarding in whom to consider the diagnosis, terms to be abandoned, when to refer to an asthma specialist and the initial management strategy. Finally, dissemination plans and priority areas for research are identified.

Bisphenol a exposure and the development of wheeze and lung function in children through age 5 years

IMPORTANCE

Bisphenol A (BPA), a prevalent endocrine-disrupting chemical, has been associated with wheezing in children, but few studies have examined its effect on lung function or wheeze in older children.

OBJECTIVES

To test whether BPA exposure is associated with lung function, with wheeze, and with pattern of wheeze in children during their first 5 years.

DESIGN, SETTING, AND PARTICIPANTS

A birth cohort study, enrolled during early pregnancy in the greater Cincinnati, Ohio, area among 398 mother-infant dyads. We collected maternal urine samples during pregnancy (at 16 and 26 weeks) and child urine samples annually to assess gestational and child BPA exposure.

MAIN OUTCOMES AND MEASURES

We assessed parent-reported wheeze every 6 months for 5 years and measured child forced expiratory volume in the first second of expiration (FEV1) at age 4 and 5 years. We evaluated associations of BPA exposure with respiratory outcomes, including FEV1, child wheeze, and wheeze phenotype.

RESULTS

Urinary BPA concentrations and FEV1 data were available for 208 children and urinary BPA concentrations and parent-reported wheeze data were available for 360 children. The mean maternal urinary BPA concentration ranged from 0.53 to 293.55 µg/g of creatinine. In multivariable analysis, every 10-fold increase in the mean maternal urinary BPA concentration was associated with a 14.2% (95% CI, -24.5% to -3.9%) decrease in the percentage predicted FEV1 at 4 years, but no association was found at 5 years. In multivariable analysis, every 10-fold increase in the mean maternal urinary BPA concentration was marginally associated with a 54.8% increase in the odds of wheezing (adjusted odds ratio, 1.55; 95% CI, 0.91-2.63). While the mean maternal urinary BPA concentration was not associated with wheeze phenotype, a 10-fold increase in the 16-week maternal urinary BPA concentration was associated with a 4.27-fold increase in the odds of persistent wheeze (adjusted odds ratio, 4.27; 95% CI, 1.37-13.30). Child urinary BPA concentrations were not associated with FEV1 or wheeze.

CONCLUSIONS AND RELEVANCE

These results provide evidence suggesting that prenatal but not postnatal exposure to BPA is associated with diminished lung function and the development of persistent wheeze in children.

Respiratory assessment in centronuclear myopathies

The centronuclear myopathies (CNMs) are a group of inherited neuromuscular disorders classified as congenital myopathies. While several causative genes have been identified, some patients do not harbor any of the currently known mutations. These diverse disorders have common histological features, which include a high proportion of centrally nucleated muscle fibers, and clinical attributes of muscle weakness and respiratory insufficiency. Respiratory problems in CNMs may manifest initially during sleep, but daytime symptoms, ineffective airway clearance, and hypoventilation predominate as more severe respiratory muscle dysfunction evolves. Respiratory muscle capacity can be evaluated using a variety of clinical tests selected with consideration for the age and baseline motor function of the patient. Similar clinical tests of respiratory function can also be incorporated into preclinical CNM canine models to offer insight for clinical trials. Because respiratory problems account for significant morbidity in patients, routine assessments of respiratory muscle function are discussed.

Interpretation of lung function in infants and young children with cystic fibrosis

The last decade has seen a significant advance in understanding about early lung disease in cystic fibrosis (CF). As studies that have measured lung function in preschool years are conducted in association with surveillance of infection, inflammation and early structural changes, and emerging longitudinal data become available, a better insight into the very early onset and nature of such lung disease is emerging. Interventions during the preschool years are increasingly viewed as being crucial to delaying and minimizing disease progression as this is the most important period of postnatal life in terms of lung development and airway remodelling. Lung function measurement in CF is potentially an important assessment tool and is used in routine clinical practice in several centres already. Results of studies from lung function tests that, on the basis of their underpinning physiology, are viewed as being best suited currently for the early detection of lung disease in CF are reviewed.

Bisphenol A exposure is associated with decreased lung function

OBJECTIVE

To examine the associations of bisphenol A (BPA) exposure with lung function measures and exhaled nitric oxide (FeNO) in children.

STUDY DESIGN

We performed a cross-sectional analysis of a subsample of US children age 6-19 years who participated in the 2007-2010 National Health and Nutrition Examination Survey. We assessed univariate and multivariable associations of urinary BPA concentration with the predicted pulmonary function measures for age, sex, race/ethnicity and height (forced expiratory volume in 1 second [FEV1], forced vital capacity [FVC], forced expiratory flow 25%-75%, and FEV1 divided by FVC) and with FeNO.

RESULTS

Exposure and outcome data were available for 661 children. Median BPA was 2.4 ng/mL (IQR: 1.3, 4.1). In multivariable analysis, a larger urinary BPA concentration was associated with significantly decreased percent predicted forced expiratory flow 25%-75% (%FEF2575) (3.7%, 95% CI 1.0, 6.5) and percent predicted FEV1 divided by FVC (%FEV1/FVC) (0.8%, 95% CI 0.1, 1.7) but not percent predicted FEV1, percent predicted FVC, or FeNO. A child in the top quartile of BPA compared with the bottom quartile had a 10% decrease in %FEF2575 (95% CI -1, -19) and 3% decrease in %FEV1/FVC (95% CI -1, -5).

CONCLUSIONS

BPA exposure was associated with a modest decrease in %FEF2575 (small airway function) and %FEV1/FVC (pulmonary obstruction) but not FEV1, FVC, or FeNO. Explanations of the association cannot rule out the possibility of reverse causality.

Spirometry in children

Respiratory disorders are responsible for considerable morbidity and mortality in children. Spirometry is a useful investigation for diagnosing and monitoring a variety of paediatric respiratory diseases, but it is underused by primary care physicians and paediatricians treating children with respiratory disease. We now have a better understanding of respiratory physiology in children, and newer computerised spirometry equipment is available with updated regional reference values for the paediatric age group. This review evaluates the current literature for indications, test procedures, quality assessment, and interpretation of spirometry results in children. Spirometry may be useful for asthma, cystic fibrosis, congenital or acquired airway malformations and many other respiratory diseases in children. The technique for performing spirometry in children is crucial and is discussed in detail. Most children, including preschool children, can perform acceptable spirometry. Steps for interpreting spirometry results include identification of common errors during the test by applying acceptability and repeatability criteria and then comparing test parameters with reference standards. Spirometry results depict only the pattern of ventilation, which may be normal, obstructive, restrictive, or mixed. The diagnosis should be based on both clinical features and spirometry results. There is a need to encourage primary care physicians and paediatricians treating respiratory diseases in children to use spirometry after adequate training.

Researching asthma across the ages: insights from the National Heart, Lung, and Blood Institute's Asthma Network

Clinical asthma studies across different age groups (ie, cross-age studies) can potentially offer insight into the similarities, differences, and relationships between childhood and adult asthma. The National Institutes of Health's Asthma Research Network (AsthmaNet) is unique and innovative in that it has merged pediatric and adult asthma research into a single clinical research network. This combination enhances scientific exchange between pediatric and adult asthma investigators and encourages the application of cross-age studies that involve participants from multiple age groups who are generally not studied together. The experience from AsthmaNet in the development of cross-age protocols highlights some of the issues in the evaluation of cross-age research in asthma. The aim of this review is to summarize these challenges, including the selection of parallel cross-age clinical interventions, identification of appropriate controls, measurement of meaningful clinical outcomes, and various ethical and logistic issues.

Quality of spirometry in 5-to-8-year-old children

INTRODUCTION

Although spirometry quality standards for children were proposed by American Thoracic Society/European Respiratory Society (ATS/ERS) in 2007, there is limited information on the percentage of children that fulfill these criteria during routine clinical testing, especially among 5-to-8-year-olds.

AIMS OF THE STUDY

to report the percentage of children that met the current 2007 ATS/ERS quality criteria; explore factors potentially associated with poor quality spirometry; and ascertain the repeatability of forced expiratory volume at 0.5 sec (FEV0.5 ), and at 1 sec (FEV1 ), as well as forced vital capacity (FVC).

METHODS

We evaluated the quality of spirometries without bronchodilator use performed at our laboratory in 2008 by 5-to-8-year-old children. FEV1 , FEV0.5 , FVC, back-extrapolated volume (BEV), forced expiratory time (FET), number of acceptable maneuvers, and repeatability, were computed and the percentage of tests that met the quality criteria standards was calculated. Based on our results, we propose a quality scoring system for spirometry for children that grades on a scale from A-to-F.

RESULTS

Three hundred seventy-six spirometries were reviewed. Mean age was 6.7 years; (53% males); 68% fulfilled the 2005 and 2007 ATS/ERS quality standards; >90% reached a repeatability ≤150 and ≤100 ml, or 10%, in FVC or FEV1 ; 87.2% reached FET ≥3 sec; 88% had a BEV ≤80 ml. The 90 percentile repeatability was 120 ml for FVC and FEV1 . Quality improved with age.

CONCLUSIONS

Our results support the proposal that a FET ≥3 sec, a BEV ≤80 ml, and repeatability in FEV1 and FVC ≤100 ml, or 10%, be taken into account as elements in quality control for spirometry in children.

Feasibility and reproducibility of spirometry and inductance plethysmography in healthy Brazilian preschoolers

RATIONALE

Preschoolers show peculiarities that reinforce the importance of assessing their pulmonary function. However, there are few data on the success rate and between-occasions reproducibility of pulmonary function tests in preschoolers, particularly in the Brazilian population.

OBJECTIVE

To assess the success rate and between-occasions reproducibility of the variables obtained by spirometry and respiratory inductive plethysmography in healthy children aged 4-6 years.

METHODS

Breathing pattern was assessed by plethysmography (tidal volume-V(T), respiratory rate-f, inspiratory duty cycle-Ti/Ttot, mean respiratory flow-V(T)/Ti, displacement of the rib cage-RC and phase relation during the total breath-PhRTB) and spirometry (forced vital capacity-FVC, forced expiratory volume in 0.5 sec-FEV0.5 and forced expiratory volume in first second-FEV1) in 47 healthy children, aged 4-6 years. To evaluate between-occasions reproducibility, 10 children (according to the sample size calculation) were reassessed after 3 weeks. Between-occasions reproducibility was evaluated by paired t-test, considering significant P < 0.05, Intraclass Correlation Coefficient (ICC) and coefficient of variation of method error (CV(ME)).

RESULTS

The results showed an 83% success rate for spirometry and a 98% success rate for plethysmography. Regarding reproducibility, there were no significant differences between the variables of any test. Spirometry ICC was above 0.80 and the CV(ME) was lower than 10%. The plethysmography ICC was between 0.61 and 0.95, and the CV(ME) was between 2% and 31%.

CONCLUSIONS

These results suggest a high success rate in performing the pulmonary function tests and good between-occasions reproducibility for spirometry and plethysmography in healthy preschoolers.

Novel end points for clinical trials in young children with cystic fibrosis

Cystic fibrosis (CF) lung disease commences early in the disease progression and is the most common cause of mortality. While new CF disease-modifying agents are currently undergoing clinical trial evaluation, the implementation of such trials in young children is limited by the lack of age-appropriate clinical trial end points. Advances in infant and preschool lung function testing, imaging of the chest and the development of biochemical biomarkers have led to increased possibility of quantifying mild lung disease in young children with CF and objectively monitoring disease progression over the course of an intervention. Despite this, further standardization and development of these techniques is required to provide robust objective measures for clinical trials in this age group.

Forced expiratory decay in asthmatic preschool children--is it adult type?

BACKGROUND

The forced expiratory decay in healthy preschool children portrays a convex shape that differs from the linear decay in the older healthy population. The "adult-type" expiratory decay during airway obstruction is concave. The study objective was to determine if the expiratory decay in young asthmatic children is "adult-type".

METHODS

Among 245 children (age 3-7 yrs), 178 had asthma (asthmatics) and 67 were non-asthmatic (controls). The expiratory flow decay was inspected by FEF25-75/FVC ratio (=1.0 when linear). Values were compared to those of our formerly studied (n = 108) healthy children. A meaningful obstruction in FEF25-75/FVC ratio was defined as 2-zScores from healthy. A meaningful response to bronchodilators was related to non-asthmatics.

RESULTS

In healthy subjects FEF25-75/FVC ratio declined with age from 1.73 ± 0.17 to 1.28 ± 0.11. Non-asthmatics portrayed ratio values similar to those of healthy subjects. In asthmatics, 118/178 displayed a convex to linear expiratory decay (FEF25-75/FVC = 1.33 ± 0.22). Sixty/178 asthmatics portrayed concavity (FEF25-75/FVC-0.79 ± 0.16) that appeared when FEF50 was 43.4 ± 12%healthy. Concavity appearance was also age-dependent (30.4% of 3-4 y old and 59.1% of 6-7 y). Vital-Capacity decreased in either decays, forming a visually petit curve. Most asthmatic children respond to bronchodilators by a meaningful elevation in FEF25-75/FVC values and by a visual change in the shape of the curve. Other common spirometry indices also increased meaningfully.

CONCLUSION

Most asthmatic preschool children portray convex to linear expiratory decay with diminished vital-capacity, resulting in a visually smaller than healthy curve, with seemingly normal expiratory decay. These curves may be misinterpreted as "normal" or as "no-cooperation" and may lead to misinterpretation. In response to bronchodilators, FEF25-75/FVC value increases in asthmatics and the curve changes from concave to linear or from linear to convex contour.

Spirometry testing in a population of Italian children: age and gender differences

AIM

To estimate how many asthmatic children underwent spirometry testing in one year in a large Italian region, and evaluate sociodemographic determinants.

METHODS

Data were retrieved from the administrative databases that store all pharmacological and diagnostic prescriptions issued to individuals living in the Lombardy Region. The analysis involved prescriptions dispensed to all 6-17 year olds (1,047,241 subjects) during 2008. Youths were identified as asthmatics by a previously validated strategy. Number of subjects having ≥1 spirometry claims was calculated, and factors associated with the probability of undergoing spirometry were evaluated by multivariate analysis.

RESULTS

A total of 40,528 (3.9%) asthmatic subjects were identified. Only 30% of them underwent ≥1 spirometry during 2008, with differences between local health units (range 22-45%) and degree of anti-asthmatic use (26-35%). Moreover, in a multivariate analysis, the chance of undergoing spirometry was greater in boys than in girls (OR=2.3).

CONCLUSIONS

A low percentage of asthmatic children, especially girls (who are more at risk of developing severe disease in adulthood), underwent spirometry during 1-year period. This highlights a low compliance with guidelines in the monitoring of childhood asthma. Educational intervention is needed in order to encourage use of spirometry in primary care settings.