Changes in pulmonary function after naturally acquired respiratory infection in normal persons

Changes in pulmonary function due to naturally occurring respiratory tract infection were examinated in 26 normal healthy volunteers during a period of 6 months. Forced expiratory maneuvers in each volunteer were recorded at 2-wk intervals throughout the study and daily during illness. Significant impairment of peak expiratory flow rate, forced vital capacity, forced expiratory volume in one second, and maximal mid-expiratory flow rate at 50% of the vital capacity was observed during infection, whereas changes in the maximal expiratory flow rate at 75% of vital capacity were nonsignificant. From these results, we conclude that large airways are certainly affected during uncomplicated respiratory infections in normal healthy persons and from the changes observed in FVC we suggest that more widespread involvement of the small airways may occur.     

Spirometric pulmonary function parameters of healthy Chinese children aged 3–6 years in Taiwan

Spirometry is a well‐known technique for evaluating pulmonary function, but few studies have focused on preschool children. The aim of this study was to determine reference values of forced spirometric parameters in young Chinese children, aged 3–6 years, in Taiwan. Spirometric measurements were performed at day care centers by experienced pediatricians. Of 248 children without a history of chronic respiratory illness, at least two valid spirometric attempts were obtained from 214 children (109 boys and 105 girls; age: 36–83 [mean = 61] months; height: 90–131 [mean = 111] cm). Values of forced expiratory volume in 1 sec (FEV₁) and 0.5 sec (FEV_0.5), forced vital capacity (FVC), peak expiratory flow rate (PEF), forced expiratory between 25% and 75% FVC (FEF_25–75), and forced expiratory flow rate at 25%, 50%, and 75% of FVC (FEF₂₅, FEF₅₀, and FEF₇₅) were derived and analyzed. There were significant positive correlations between study parameters and body height, body weight, and age. Height was the most consistently correlated measurement in both boys and girls. Although boys tended to have higher spirometric values than girls, we found significant differences only in FVC and FEV₁ between boys and girls aged 6 years. The regression equations of each parameter were obtained. In conclusion, spirometric pulmonary function tests are feasible in 3‐ to 6‐year‐old children. The obtained values and regression equations provide a reference for Chinese preschool children and may be of value in evaluating pulmonary function of children with respiratory problems in this age group. Pediatr Pulmonol. 2009; 44:676–682. © 2009 Wiley‐Liss, Inc.     

Impact of respiratory illness on expiratory flow rates in normal,asthmatic, and allergic children

We examined the effects of current respiratory illness (RI) on pulmonary function (PF) in 1,103 subjects who underwent spirometry at schools twice within a 4-month period. Before spirometry, subjects were asked if they had a "cold or other chest illness" during the previous month, and if so, whether they had fully recovered. Those who had not recovered were considered to have an RI.We found that children without RI at their first PF test who reported RI on retest had significantly lower forced expiratory volume in 1 sec (FEV(1)) (-0.8%), peak expiratory flow rate (PEFR) (-2.2%), forced expiratory flow between 25-75% of vital capacity (FEF(25-75)) (-3.5%), and forced expiratory flow at 75% of vital capacity (FEF(75)) (-5.1%) than those without RI on both test and retest. Restriction of subjects to those without a history of doctor-diagnosed asthma did not appreciably change these findings. Children with hay fever had significantly larger RI-associated decreases for FEV(1), FEF(25-75), and FEF(75), but not PEFR, than those without hay fever. Among asthmatic subjects, those with active asthma had larger RI-associated decreases in FEF(25-75) and FEF(75), but not PEFR, than those without asthma. There was limited evidence that small airway losses were greater in children less than 12.5 years old.We conclude that RI in children who are well enough to attend school may reduce expiratory flow rates. These effects are greater for children with active asthma or hay fever than in those without, and may be inversely related to age.     

Longitudinal pulmonary status of cystic fibrosis children with meconium ileus

Although meconium ileus (MI) is the earliest manifestation of cystic fibrosis (CF), and is associated with poorer growth, the longitudinal pulmonary progression of CF children with MI is not clear. To test the hypothesis that MI is associated with worse pulmonary outcomes, we prospectively compared from diagnosis to 12 years of age 32 CF children with MI to 50 CF children without MI who were diagnosed during early infancy through neonatal screening. Pulmonary outcome measures included respiratory symptoms, respiratory infections, pathogens, antibiotic usage, hospitalizations, quantitative chest radiology, spirometry, and lung volume determinations. Obstructive lung disease was defined as percent predicted spirometry values below the lower limits of normal. Longitudinal analyses revealed no significant differences in cough, wheezing, respiratory infections, prevalence of and median times to acquisition of Pseudomonas aeruginosa or Staphylococcus aureus, antibiotic usage, and chest radiograph scores between the two groups. However, MI children showed significantly worse forced expiratory volume in 1 sec (FEV(1)), forced vital capacity (FVC), forced expiratory flow between 25-75% of FVC (FEF(25-75)), % predicted FEV(1), % predicted FEF(25-75), and total lung capacity (TLC). These differences were particularly apparent beginning at age 8-10 years. MI children also had higher rates of and shorter median times to obstructive lung disease. Subgroup analyses showed MI children treated surgically and those treated medically had similar pulmonary outcomes. In conclusion, MI children have worse lung function and more obstructive lung disease than those without MI. Such abnormalities are accompanied by reduced lung volume. MI is a distinct CF phenotype with more severe pulmonary dysfunction.     

Forced expiratory parameters in healthy preschool children (3-6 years of age)

In a group of 173 healthy preschool children 3-6 years of age (body height, 90-130 cm; 102 boys and 71 girls) out of total 279 children examined, maximum expiratory flow-volume (MEFV) curves were recorded in cross-sectional measurements. The majority (62%) of preschool children were able to generate an MEFV curve as correctly as older children. From the curves, maximum expiratory flows at 25%, 50%, and 75 % of vital capacity (MEF(25), MEF(50), and MEF(75)), peak expiratory flow (PEF), forced expiratory volume in 1 sec (FEV(1)), forced vital capacity (FVC), and area delineated by MEFV curve (A(ex)) were obtained. The purpose of the study was to establish reference values of forced expiratory parameters in preschool children suitable for assessment of lung function abnormalities in respiratory preschool children. The values of the studied parameters increased nonlinearly and correlated significantly with body height (P < 0.0001); the correlation was much lower with age. A simple power regression equation was calculated for the relationship between each parameter and body height. A best-fit regression equation relating functional parameters and body height was a power function. Based on the obtained regression equations with upper and lower limits, we prepared tables listing reference values of forced expiratory parameters in healthy Caucasian preschool children, against which patients can be compared. No statistically significant gender differences were observed for MEF(25), MEF(50), MEF(75), PEF, FEV(1), FVC, and A(ex) by extrapolation. The reference values were close to those obtained in our older children. A decline of the ratios PEF/FVC, FEV(1)/FVC and MEF/FVC with increasing body height suggested more patent airways in younger and smaller preschool children.     

Respiratory outcomes in high-risk children 7 to 10 years after prophylaxis with respiratory syncytial virus immune globulin

PURPOSE: Respiratory syncytial virus infections have been implicated in the development of asthma. We evaluated the long-term effects of respiratory syncytial virus immune globulin, an effective prophylactic agent for the prevention of these infections in children, on respiratory and allergic outcomes in children at high risk of chronic airway disease. SUBJECTS AND METHODS: Thirteen children at high risk of respiratory disease (mean [+/-SD] age, 8.6 +/- 1.1 years) were evaluated using pulmonary function and allergy skin testing 7 to 10 years after they had received prophylaxis with respiratory syncytial virus immune globulin. For comparison, 26 high-risk control children (mean age, 8.5 +/- 0.9 years) were also evaluated. Health outcomes data were collected from all subjects.The children were matched for age and gestational age. There were more boys, and a lesser frequency of a lower respiratory tract infection with respiratory syncytial virus (P <0.001) in the group that had been treated prophylactically than in the controls. The ratio of the forced expiratory volume in 1 second to forced vital capacity was significantly better in children who had received immune globulin (median, 0.88; interquartile range, 0.81 to 0.91) than in the controls (median, 0.76; interquartile range, 0.67 to 0.86; P = 0.02). Children were also less atopic (2 of 13) in the respiratory syncytial virus immune globulin group than in the control group (13 of 26, P <0.04) and were less likely to have missed school (P = 0.006) or have had an asthma attack (P = 0.03). CONCLUSION: The results suggest that prophylaxis of respiratory syncytial virus infections in infancy may have long-term effects on respiratory and immunologic parameters relevant to the development of asthma. Larger-scale studies are needed.     

Population values of lung volumes and flows in children: effect of sex, body mass and respiratory conditions.

The functional relationship of gender, anthropometric measures and respiratory condition in predicting respiratory function in children was explored, using data collected in a random sample survey in Central Italy (2,176 subjects). Regression equations for the logarithmic transformation of the functional data were obtained, using sex, ln(height), ln(body mass index) (BMI) and ln(age) as predicting variables. The fit of the model was better for forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF) (R2 = 0.655, 0.603 and 0.312, respectively) than for maximal expiratory flows. Variables indicating the presence of respiratory conditions (recent respiratory infections, asthma, cough and/or phlegm) were forced in the models; only a marginal change in the predictions was observed. Data analysis while controlling for FVC, as a proxy for total lung capacity, revealed no substantial sex difference in airways; furthermore, airways size relative to lung size falls with increasing FVC in both sexes. In overweight subjects (BMI greater than 90th percentile) the relationship between height and lung volume was modified by sex, the coefficient for ln(height) being higher in girls and lower in boys. A comparison between equations from the present study and available reference data revealed that our population differs from standards derived from laboratory data and is more similar to those derived from population studies.     

Effect of viral infections on pulmonary function in patients with chronic obstructive pulmonary diseases

The effect of 100 separate viral infections of the respiratory tract on pulmonary function was evaluated prospectively over an eight-year period in 84 patients with chronic obstructive pulmonary diseases and in eight normal subjects. Some viral infections were associated with small acute declines in forced vital capacity and/or 1-sec forced expiratory volume of 25-300 ml. These declines were detectable only during the 90-day period after infection. The greatest abnormalities of pulmonary function followed infections with influenza virus, and the mean acute changes in 1-sec forced expiratory volume (-118.5 ml) were significantly greater than expected (-15.2 ml; P = 0.03). Smaller, statistically insignificant declines followed infections with parainfluenza virus, rhinovirus, adenovirus, and respiratory syncytial virus, and no changes were detectable after infections with coronavirus, herpes simplex virus, Mycoplasma pneumoniae, and Haemophilus influenzae. Long-term effects of influenza or other viral infections on the course of chronic obstructive pulmonary disease were not detected in this study population.     

Effects of indoor air pollution on lung function of primary school children in Kuala Lumpur

In a cross-sectional study of 7-12 year-old primary school children in Kuala Lumpur city, lung function was assessed by spirometric and peak expiratory flow measurements. Spirometric and peak expiratory flow measurements were successfully performed in 1,214 and 1,414 children, respectively. As expected, the main predictors of forced vital capacity (FVC), forced expiratory volume in one second (FEV1), forced expiratory flow between 25% and 75% of vital capacity (FEF25-75), and peak expiratory flow rate (PEFR) were standing height, weight, age, and sex. In addition, lung function values of Chinese and Malays were generally higher than those of Indians. In multiple regression models which included host and environmental factors, asthma was associated with significant decreases in FEV1, FEF25-75, and PEFR. However, family history of chest illness, history of allergies, low paternal education, and hospitalization during the neonatal period were not independent predictors of lung function. Children sharing rooms with adult smokers had significantly lower levels of FEF25-75. Exposures to wood or kerosene stoves were, but to mosquito repellents were not, associated with decreased lung function.     

Assessment of the usefulness of helium-oxygen maximal expiratory flow curves in epidemiologic studies of lung disease in children

Density dependence of maximal expiratory air flow (DD) has been used in adults as a test of early obstructive airway disease (OAD). Whether DD is useful as an epidemiologic tool to identify childhood risk factors for OAD is not known. In a population-based sample of 133 children 8 to 23 yr of age, we calculated density dependence at 50 and 25% of vital capacity (DD50 and DD25) (the ratios between maximal expiratory flow rates breathing helium-oxygen and air gas mixtures at each of these lung volumes), and the volume of isoflow (VisoV) (the lung volume, expressed as a percentage of vital capacity, at which maximal flow rates when breathing each gas mixture are equal), measured airway responsiveness using eucapnic hyperventilation with cold air, and obtained health and household information with questionnaires. Mean levels (+/- SD) of DD50, DD25, and VisoV were: 1.49 +/- 0.14, 1.37 +/- 0.18, and 10.7 +/- 10%. The DD50 significantly increased with age in these growing children (p less than 0.05), but DD50 was found to be significantly lower (1.42 +/- 0.14 versus 1.52 +/- 0.13; p less than 0.01) among children with nonspecific bronchial hyperresponsiveness. The DD50 also was significantly reduced among children with a history of a recent upper respiratory tract illness (URI) (p less than 0.01). There were no significant associations of DD with history of asthma, personal smoking, parental smoking, or respiratory illness during infancy. The reproducibility of DD50 was assessed on a subsample of 90 subjects in whom DD was measured during 2 surveys 1 yr apart.(ABSTRACT TRUNCATED AT 250 WORDS)     

Acute lower respiratory illness in childhood as a predictor of lung function and chronic respiratory symptoms

This study investigated the relationship of acute lower respiratory illness (LRI) to level and change in level of forced expiratory volumes in a cohort of 801 children, followed longitudinally for a maximum of 13 yr. The co-occurrence of respiratory illness before 2 yr of age and two or more LRI during a single surveillance year was associated with a 20.3% lower mean cross-sectional level of FEF25-75, and with reduced longitudinal change in level of FEF25-75. The effect of LRI on lung function was uniformly stronger for boys than for girls. Of the children with illness before 2 yr of age and two or more LRI, six of 14 were male asthmatics with mean levels of FEF25-75 that were lower than those of other asthmatic children. Pneumonia and/or hospitalization for respiratory illness prior to the onset of study were associated with lower cross-sectional levels of forced expiratory volumes at entry to the study, even when asthmatics/persistent wheezers were eliminated from the analysis (6.1% lower level of FEV1 for a nonasthmatic boy with previous hospitalization versus a nonasthmatic boy without hospitalization). In the longitudinal analysis, pneumonia and/or hospitalization were associated with slower increase in level of forced expiratory volumes, even after adjusting for "ever diagnosis of asthma/current any wheeze" (starting at the same leve, after eight years a boy with hospitalization would develop a 5.0% lower FEV1 than a boy without hospitalization). Acute LRI also was evaluated as a predictor of chronic respiratory symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)     

Particulate matter and lung function growth in children: a 3-yr follow-up study in Austrian schoolchildren.

The effects of particulate matter <10 microm in diameter (PM10) and other air pollutants on lung function were assessed in 975 schoolchildren, from eight communities in Lower Austria between 1994-1997. In each community, air pollution data were collected. Spirometry was performed twice a year. PM10 concentration (mean concentration between two subsequent lung-function measures in spring and autumn (summer interval) or between autumn and spring (winter interval)) showed a mean value of 17.36 microg x m(-3) in the summer interval and 21.03 microg m(-3) in the winter interval. A slower increase in the forced expiratory volume in one second (FEV1) and midexpiratory flow between 25 and 75% of the forced vital capacity (MEF25-75) with age in children exposed to higher summer PM10 was observed in the 3-yr study period. After adjusting for potential confounders (sex, atopy, passive smoking, initial height, height difference, site, initial lung function) an increase of summer PM10 by 10 microg x m(-3) was associated with a decrease in FEV1 growth of 84 mL x yr(-1) and 329 mL x s(-1) x yr(-1) for MEF25-75. Nitrogen dioxide and ozone also showed a negative effect on lung-function growth, confirming previous work. The authors concluded that long-term exposure to particulate matter <10 microm in diameter had a significant negative effect on lung-function proxy for the development of large (forced expiratory volume in one second) and small (midexpiratory flow between 25 and 75% of the forced vital capacity) airways, respectively, with strong evidence for a further effect of ozone and nitrogen dioxide on the development of forced vital capacity and forced expiratory volume in one second.     

The role of computer games in measuring spirometry in healthy and "asthmatic" preschool children

STUDY OBJECTIVES: To explore the role of respiratory interactive computer games in teaching spirometry to preschool children, and to examine whether the spirometry data achieved are compatible with acceptable criteria for adults and with published data for healthy preschool children, and whether spirometry at this age can assess airway obstruction. DESIGN: Feasibility study. SETTINGS: Community kindergartens around Israel and a tertiary pediatric pulmonary clinic. PARTICIPANTS: Healthy and asthmatic preschool children (age range, 2.0 to 6.5 years). INTERVENTION: Multi-target interactive spirometry games including three targets: full inspiration before expiration, instant forced expiration, and long expiration to residual volume. MEASUREMENTS AND RESULTS: One hundred nine healthy and 157 asthmatic children succeeded in performing adequate spirometry using a multi-target interactive spirometry game. American Thoracic Society (ATS)/European Respiratory Society spirometry criteria for adults for the start of the test, and repeatability were met. Expiration time increased with age (1.3 +/- 0.3 s at 3 years to 1.9 +/- 0.3 s at 6 years [+/- SD], p < 0.05). FVC and flow rates increased with age, while FEV1/FVC decreased. Healthy children had FVC and FEV1 values similar to those of previous preschool studies, but flows were significantly higher (> 1.5 SD for forced expiratory flow at 50% of vital capacity [FEF50] and forced expiratory flow at 75% of vital capacity [FEF75], p < 0.005). The descending part of the flow/volume curve was convex in 2.5- to 3.5-year-old patients, resembling that of infants, while in 5- to 6-year-old patients, there was linear decay. Asthma severity by Global Initiative for Asthma guidelines correlated with longer expiration time (1.7 +/- 0.4 s; p < 0.03) and lower FEF50 (32 to 63%; p < 0.001) compared to healthy children. Bronchodilators improved FEV1 by 10 to 13% and FEF50 by 38 to 56% of baseline. CONCLUSIONS: Interactive respiratory games can facilitate spirometry in very young children, yielding results that conform to most of the ATS criteria established for adults and published data for healthy preschool children. Spirometric indexes correlated with degree of asthma severity.     

Follow-up evaluation of a prevalence study for chronic bronchitis and chronic airway obstruction.

Follow-up of the prevalence study of respiratory symptoms and chronic airway obstruction was performed after a 6- to 7-year interval. One hundred fifteen of 117 subjects (98%) originally labeled "abnormal" (chronic bronchitis or asthma by history, or ratio of 1-sec forced expiratory volume to forced vital capacity less than 60 per cent), and 111 of a random sample of 116 subjects (96%) originally labeled "normal" were traced. Nineteen patients were dead, 14 "abnormal" subjects, and 5 "normal" subjects (P less than 0.01). Eighty-eight of the originally labeled "abnormal" subjects and 91 of the random "normal" sample could be retested by spirometry. Subjects with lower initial ratios of 1-sec forced expiratory volume to forced vital capacity tended to lose more 1-sec forced expiratory volume and forced vital capacity. Early identification of respiratory symptoms and spirometric abnormalities may identify persons at increased risk of death who could benefit from appropriate therapy.     

Performance of forced expiratory manoeuvre in children.

The negative expiratory pressure (NEP) method has been previously used to assess the performance of forced vital capacity (FVC) manoeuvre in normal adults. The aim of the present study is to assess whether flow limitation is achieved during FVC manoeuvres in children aged 6-14 yrs. NEP (-10 cmH2O) was successfully applied in 177 normal children, the portion of FVC over which expiratory flow did or did not change with NEP being taken as effort-dependent and effort-independent, respectively. In all children peak expiratory flow (PEF) and forced expiratory volume in one second (FEV1) increased with NEP, indicating that PEF was in the effort-dependent portion of FVC. This portion decreased significantly with age (50-20% of FVC from 6-14 yrs). It is suggested that this mainly reflects the poorer coordination of specialized motor acts in younger children because of incomplete morphological and functional maturation of the relevant central nervous system (CNS) mechanisms. The results indicate that most unexperienced children aged 6-14 yrs can perform acceptable forced vital capacity manoeuvres, eventually achieving flow limitation over a portion of the forced vital capacity that increases with age. The negative expiratory pressure method can be used for online assessment of the performance of forced vital capacity manoeuvres and evaluation of treatment-related effects.     

Changes in the forced expiratory spirogram in young male smokers.

Forced expiratory spirograms and peak expiratory flow were measured in 102 resident male medical students (60 nonsmokers and 42 smokers). Forced vital capacity; forced expiratory volume in 1 sec; forced expiratory volume in 1 sec expressed as a percentage of forced vital capacity; forced expiratory flows between 80 and 70 per cent, between 55 and 45 per cent, between 30 and 20 per cent, and between 15 and 5 per cent of the forced vital capacity; forced expiratory time for the last 0.5 liter of the forced vital capacity; and maximal mid-expiratory flow were determined from the forced expiratory spirogram. Peak expiratory flow, all forced expiratory flows (except the forced expiratory volume in 1 sec), and the ratio of forced expiratory volume in 1 sec to forced vital capacity were significantly lower, and forced expiratory time for the last 0.5 liter of the forced vital capacity was significantly higher in the heavy smokers (those who had smoked a lifetime total of more than 10,000 cigarettes) than the nonsmokers. The light smokers (those who smoked a lifetime total of fewer than 10,000 cigarettes) had values between those of nonsmokers and the heavy smokers. Thus, a definite dose-related response to smoking was seen. Flows at lower lung volumes showed greater percentage changes than flows at higher lung volumes. The forced expiratory flow between 30 and 20 per cent of the forced vital capacity was the most sensitive test for detecting abnormality in smokers. Among heavy smokers, 58 per cent had abnormally low forced expiratory flow between 30 and 20 per cent of the forced vital capacity, whereas only 47 per cent had abnormally low ratio of forced expiratory volume in 1 sec to forced vital capacity, and 32 percent had abnormally low maximal mid-expiratory flow. The results show that even subjects with short smoking histories may have changes in pulmonary function that probably reflect narrowing of small airways. Moreover, these changes can easily be detected by simple tests, such as evaluation of a forced expiratory spirogram.     

Lung Function in Young Adults Predicts Airflow Obstruction 20 Years Later

Objective

The burden of obstructive lung disease is increasing, yet there are limited data on its natural history in young adults. To determine in a prospective cohort of generally healthy young adults the influence of early adult lung function on the presence of airflow obstruction in middle age.

Methods

A longitudinal study was performed of 2496 adults who were 18 to 30 years of age at entry, did not report having asthma, and returned at year 20. Airflow obstruction was defined as an forced expiratory volume in 1 second/forced vital capacity ratio less than the lower limit of normal.

Results

Airflow obstruction was present in 6.9% and 7.8% of participants at years 0 and 20, respectively. Less than 10% of participants with airflow obstruction self-reported chronic obstructive pulmonary disease. In cross-sectional analyses, airflow obstruction was associated with less education, smoking, and self-reported chronic obstructive pulmonary disease. Low forced expiratory volume in 1 second, forced expiratory volume in 1 second/forced vital capacity ratio, and airflow obstruction in young adults were associated with low lung function and airflow obstruction 20 years later. Of those with airflow obstruction at year 0, 52% had airflow obstruction 20 years later. The forced expiratory volume in 1 second/forced vital capacity at year 0 was highly predictive of airflow obstruction 20 years later (c-statistic 0.91; 95% confidence interval, 0.89-0.93). The effect of cigarette smoking on lung function decline with age was most evident in young adults with preexisting airflow obstruction.

Conclusion

Airflow obstruction is mostly unrecognized in young and middle-aged adults. Low forced expiratory volume in 1 second, low forced expiratory volume in 1 second/forced vital capacity ratio, airflow obstruction in young adults, and smoking are highly predictive of low lung function and airflow obstruction in middle age.     

Lung function in children with Duchenne's muscular dystrophy.

Duchenne's muscular dystrophy (DMD), characterized by gradually developing muscular weakness, leads to respiratory symptoms and reduced lung function. We aimed to assess lung function in 25 patients with DMD in relationship to age and muscular function. The 25 boys, mean age 13 years, comprized patients in southern Norway with DMD, taking part in an epidemiological follow-up study. None had chronic respiratory disease. Lung function was measured by maximum expiratory flow-volume loops and whole body plethysmography, and repeated after 1 year (n= 14). Lung function was reduced compared to predicted values for healthy children. Forced expiratory volume in 1 sec (FEV1)% predicted and forced vital capacity (FVC)% predicted correlated (significantly) inversely to age. FEV1 and FVC decreased annually 5.61 and 4.2% of predicted, respectively. Absolute values of FVC (litres) and FEV1 (1 sec(-1)) increased until mean age 14 years, decreasing thereafter. Values in % predicted decreased steadily throughout the age range (6-19 years). Lung function correlated closely to upper limb muscle function.     

Cardiopulmonary responses of asthmatic children to exercise: analysis of systolic and diastolic cardiac function

The aim of this study was to evaluate aerobic exercise capacity, cardiac features and function in a group of asthmatic children who underwent medical treatment. Dynamic exercise testing was done to evaluate aerobic exercise capacity. Echocardiography was performed to identify the effects that asthma-induced pulmonary changes have on respiratory and cardiac function in these patients. The study involved 20 asthmatic children (aged 7-16 years) who were followed at our hospital and 20 age- and sex-matched, healthy control subjects. Sixteen of the asthma cases were moderate and four were severe. All 40 subjects underwent similar series of assessments: multiple modes of echocardiography, treadmill stress testing, pulmonary function testing. The means for forced expiratory volume in 1 sec, forced expiratory flow 25-75%, maximal voluntary ventilation and inspiratory capacity were all significantly higher in the control group. The patient group had significantly lower mean maximal oxygen uptake and mean endurance time than the controls but there were no significant differences between the groups with respect to respiratory exchange ratio or the ventilatory threshold. The control group means for ejection fraction, fractional shortening, left ventricular mass, and left ventricular mass index were significantly higher than the corresponding patient group results. Children with moderate or severe asthma have lower aerobic capacity than healthy children of the same age. The data suggest that most of these children have normal diastolic cardiac function, but exhibit impaired systolic function and have lower LVM than healthy peers of the same age.     

Cough ability measurements and recurrent respiratory symptoms in individuals with Ataxia Telangiectasia

Objectives: Ataxia-Telangiectasia (A-T) individuals often present with respiratory muscle weakness, causing recurrent respiratory system infections, asthma-like symptoms, and chronic cough life-threatening events. The cough flow volume maneuver may reveal powerless airflow needed for efficient cough. The study aims to explore cough ability in relation to the flow/volume maneuver. Methods: Data collected retrospectively from clinical charts of 35 A-T patients (age 12.7?±?4.9 years) included forced expiratory and cough flow/volume maneuvers performed on the same day. Analysis compared among the maneuvers matching indices, numbers of cough-spikes, flow rate decay, and the reference data of similar ages. Adjusted to age, BMI, and number of hospitalizations prior to the tests, values were correlated with the cough indices. Results: Cough peak-flow (C-PF) was propagated within 90?±?20?ms compared with peak expiratory flow (PEF?>?200?ms). C-PF measured values were higher than expiratory peak-flow measured values (3.27?±?1.53?L/s versus 3.02?±?1.52?L/s, respectively, but C-PF (%predicted) values were significantly lower than expiratory peak-flow (%predicted) (46?±?15 versus 68?±?20 %predicted, respectively, p?<?0.002). The number of spikes/maneuver was low when compared with reference (2.0?±?0.8 versus 6–12 spikes) and cough vital-capacity was lower than expiratory vital capacity (0.95?±?0.43 versus 1.03?±?0.47; p?<?0.01). Inefficient C-PF was more prevalent in patients suffering from recurrent respiratory illness. The length of wheelchair confinement duration mostly influenced the C-VC level. Conclusions: The cough flow–volume curve can be applied as a method to follow cough ability in patients with A-T who showed a significantly reduced cough capacity. Further studies are needed to establish if the findings may aid decisions regarding cough assistance.