Peak Expiratory Flow In Children Research Articles

Role of peak expiratory flow in the assessment and management of asthma in children

Peak expiratory flow (PEF) is a portable, reliable, and inexpensive method for lung function assessment. PEF can reflect expiratory airflow limitation and its variability can document reversibility, which provides an objective basis for the diagnosis of asthma in children. Short-term PEF monitoring can be an important aid in the management of acute asthma exacerbations, identification of possible triggers, and assessment of response to treatment. Long-term PEF monitoring can assist in the assessment of asthma control and warning of acute exacerbations, and this is useful for children with severe asthma. This article reviews the measurements, influencing factors, interpretation, and application of PEF, and its role in the diagnosis and management of asthma in children, to provide references for the clinical application of PEF in children.

Effects of Physical Therapist Intervention on Pulmonary Function in Children With Cerebral Palsy: A Systematic Review and Meta-Analysis.

The purpose of this study was to evaluate the effects of physical therapy on pulmonary function and respiratory muscle strength in children with cerebral palsy (CP). A search of 10 databases was conducted for this systematic review. Initially, there were no language, study design, or time frame restrictions. All studies assessing the effect of physical therapy on the respiratory system in children with CP were included. Two reviewers independently extracted and documented data. The data extracted included description of the intervention (duration, therapeutic method) and study results (change of spirometric parameters, respiratory muscle strength). The effects of physical therapist treatment were calculated using software. A total of 269 children aged 5 to 18 years from 10 studies were included. The included studies consisted of 5 different therapeutic methods (inspiratory muscle training [IMT], aerobic training, swimming, respiratory exercise, exercise with elastic bands). Physical therapist intervention led to a significant increase in the maximal expiratory pressure (MEP) (I2 = 0%), peak expiratory flow (I2 = 0%), and maximum oxygen consumption (I2 = 37%). A separate analysis of the most frequently used therapy (IMT) showed a positive effect on MEP (I2 = 0%) and maximal inspiratory pressure (I2 = 35%). Various forms of physical therapy have potential to demonstrate a positive effect on maximal inspiratory pressure, MEP, and peak expiratory flow in children with CP. There is no possibility to recommend the best method and duration of the physical therapy; however, it can be suggested that physical therapy should be applied for at least 4 weeks and include IMT. CP is one of the most common causes of physical disabilities in children, and pulmonary dysfunction is the leading cause of death in people with CP. Thus, it is warranted to seek different approaches that may improve pulmonary function in people with CP. This review has shown that various forms of physical therapy have potential to improve the pulmonary function of children with CP.

Effects of indoor environment and lifestyle on respiratory health of children in Chongqing, China

BackgroundThe prevalence of certain respiratory diseases of children in China appears to be on the rise in recent decades. This study aims to explore residential environmental factors that may affect respiratory diseases and lung function of children and to assess the effects of lifestyle (diet and exercise) on lung function.MethodsThe study was conducted in Chongqing, southwest of China in June, 2017. Information on respiratory diseases was obtained from 2,126 primary school children through a family questionnaire by purposive sampling. In addition, a random sample of 771 children participating in the family-questionnaire was selected for physical measurements and lung function test as well as lifestyle questionnaire survey. Chi-square test and multivariate logistic regressions were used to analyze the relationship between indoor environment and children’s respiratory diseases. The effects of indoor environment and lifestyle on lung function indices were analyzed by t-test, variance analysis, and univariate and multivariate linear regression methods.ResultsAmong residential environmental factors, indoor ventilation and air circulation were significant associated with children’s respiratory health outcomes. The use of air conditioning for more than 8 h/day in summer was a risk factor for asthma with an adjusted odds ratio (AOR) of 1.99, bronchitis (AOR =1.62), and allergic rhinitis (AOR =1.51). Ventilation for less than 12 h per day during summer increased the risk for allergic rhinitis (AOR =1.40). Children living in homes with an opened kitchen had the risk of developing allergic rhinitis 1.51 times higher than children living in homes with a closed kitchen. Indoor dampness and mold were significantly associated with increased risks for childhood asthma (AOR =2.16), bronchitis (AOR =1.55) and allergic rhinitis (AOR =1.55). The frequent use of hygienic incense and mosquito coils also increased the risk for asthma (AOR =2.58) and bronchitis (AOR =1.42) in children. The multiple linear regression results showed that frequent use of air fresheners reduced children’s peak expiratory flow (PEF) and small airway function (FEF25–75) after potential influencing factors were adjusted for. Analyses of lifestyle variables showed that increased lung function (FVC, FEV1, FEV3) was associated with increasing consumption of vegetable and fruit as well as increasing time of physical exercise.ConclusionsThis study identified the following residential risk factors for children’s respiratory diseases in Chongqing: poor indoor ventilation, home dampness and mold presence, and frequent use of hygienic incense and mosquito coils. Frequent use of air fresheners is associated with reduced lung function in children. High frequency consumption of vegetables, fruits and dairy products as well as daily exercise for more than 1 hour have positive effects on children’s lung development.

Calculation of Predicted Peak Expiratory Flow in Children with a Formula

To determine whether a child has asthma exacerbation, we should obtain the value of peak expiratory flow.

The association between ambient temperature and children's lung function in Baotou, China.

The objective of this study is to examine the association between ambient temperature and children's lung function in Baotou, China. We recruited 315 children (8-12 years) from Baotou, China in the spring of 2004, 2005, and 2006. They performed three successive forced expiratory measurements three times daily (morning, noon, and evening) for about 5 weeks. The highest peak expiratory flow (PEF) was recorded for each session. Daily data on ambient temperature, relative humidity, and air pollution were monitored during the same period. Mixed models with a distributed lag structure were used to examine the effects of temperature on lung function while adjusting for individual characteristics and environmental factors. Low temperatures were significantly associated with decreases in PEF. The effects lasted for lag 0-2 days. For all participants, the cumulative effect estimates (lag 0-2 days) were -1.44 (-1.93, -0.94) L/min, -1.39 (-1.92, -0.86) L/min, -1.40 (-1.97, -0.82) L/min, and -1.28 (-1.69, -0.88) L/min for morning, noon, evening, and daily mean PEF, respectively, associated with 1 °C decrease in daily mean temperature. Generally, the effects of temperature were slightly stronger in boys than in girls for noon, evening, and daily mean PEF, while the effects were stronger in girls for morning PEF. PM2.5 had joint effects with temperature on children's PEF. Higher PM2.5 increased the impacts of low temperature. Low ambient temperatures are associated with lower lung function in children in Baotou, China. Preventive health policies will be required for protecting children from the cold weather.

Effect of Inhaled MgSO4 on FEV1 and PEF in Children with Asthma Induced by Acetylcholine: A Randomized Controlled Clinical Trail of 330 Cases

To determine the response of nebulized magnesium sulfate on the lung function of acetylcholine-induced asthma children. Three hundred and thirty children of asthma with positive bronchial provocation test were randomly divided into three groups: magnesium sulfate, albuterol, and a combination of magnesium sulfate and albuterol. Lung function was compared between the three groups. Forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF) as percentage over predicted at 10 min and 20 min in albuterol and combination group were significantly improved when compared to magnesium group. The changes in FEV1 and PEF expressed as absolute and percentage over predicted was not statistically significant from baseline to 20 min in magnesium, albuterol, and combination of magnesium sulfate and albuterol. There was no significant adverse effect observed during the present study. Nebulized magnesium sulfate alone has a bronchodilatory effect in Ach-induced asthmatic children. The combination of MgSO4 and albuterol did not has a synergistic effect.

Correlation between peak nasal inspiratory flow and peak expiratory flow in children and adolescents

PEAK nasal inspiratory flow (PNIF) has been proposed as a simple method to evaluate nasal patency. Asthma and allergic rhinitis are commonly associated, and lower airway assessment can provide information concerning an objective interpretation of nasal function. TO determine whether the PNIF is correlated with peak expiratory flow (PEF) in children and adolescents. Cross-sectional study carried out in healthy students randomly chosen in 14 public schools of the city of Belo Horizonte. PNIF and PEF were assessed for each subject as the following characteristics: gender, height, weight and age. We created a linear regression model to explain the PNIF, in which we included all the variables with a p value ≤ 0.25 in a univariate analysis, and to calculate the relationship between the maximum PNIF and maximum PEF by the Spearman correlation coefficient. In total, 297 healthy subjects, aged between six and eighteen years were evaluated. A positive and significant correlation between PNIF and PEF was found. PEF is predictive of PNIF. However, these measures evaluate two distinct segments of the airways and should be both obtained for a more precise assessment of airflow limitation.

Correlation between peak nasal inspiratory flow and peak expiratory flow in children and adolescents

Correlation between peak nasal inspiratory flow and peak expiratory flow in children and adolescents

Acute Effects of Asian Dust Events on Respiratory Symptoms and Peak Expiratory Flow in Children with Mild Asthma

The aim of this study was to investigate the possible adverse effects of Asian dust events on respiratory health in asthmatic children. Fifty-two children with mild asthma were studied for eight consecutive weeks in the spring of 2004 (March 8 to May 2). During the study period, five Asian dust days were identified; we included a lag period of two days following each of the events. Subjects recorded their respiratory symptom diaries and peak expiratory flow (PEF) twice daily during the study period; and they underwent methacholine bronchial challenge tests. The subjects reported a significantly higher frequency of respiratory symptoms during the Asian dust days than during the control days. They showed significantly more reduced morning and evening PEF values, and more increased PEF variability (10.1%±3.5% vs. 5.5%±2.2%) during the Asian dust days than during the control days. Methacholine PC20 was not significantly different between before and after the study period (geometric mean: 2.82 mg/mL vs. 3.16 mg/mL). These results suggest that the short-term Asian dust events might be associated with increased acute respiratory symptoms and changes in PEF outcomes. However, there might be little long-term influence on airway hyperresponsiveness in children with mild asthma.

Correlations between pulse oximetry and peak expiratory flow in acute asthma

Few studies are available concerning correlations between pulse oximetry and peak expiratory flow in children and adolescents with acute asthma. Although the Global Initiative for Asthma states that measurements of lung function and oximetry are critical for the assessment of patients, it is not clear if both methods should necessarily be included in their evaluation. Since there is a significant difference in cost between pulse oximetry equipment and peak expiratory flow devices, we determined whether clinical findings and peak expiratory flow measurements are sufficient to determine the severity of acute asthma. The present prospective observational study was carried out to determine if there is correlation between pulse oximetry and peak expiratory flow determination in 196 patients with acute asthma aged 4 to 15 years diagnosed according to the Global Initiative for Asthma criteria. Patients experiencing their first or second wheezing episode, with fever, related acute or chronic diseases, and unable to perform the peak expiratory flow maneuver were excluded. Measurements of peak expiratory flow and pulse oximetry were performed at admission and after 15 min of each inhaled salbutamol cycle. Correlations obtained by linear regression using the Pearson correlation coefficients (r) were 0.41 (P < 0.0001), 0.53 (P < 0.0001), 0.51 (P < 0.0001), and 0.61 (P < 0.0001) at admission and after the first, second and third cycles of salbutamol, respectively. These correlations showed that one measure cannot substitute the other (Pearson's coefficient <0.7), probably because they evaluate different aspects in the airways, suggesting that peak expiratory flow should not be used alone in the assessment of acute asthma in children and adolescents.

Respiratory symptoms and peak expiratory flow in children with asthma in relation to volatile organic compounds in exhaled breath and ambient air.

Indoor volatile organic compounds (VOCs) have been associated with asthma, but there is little epidemiologic work on ambient exposures, and no data on relationships between respiratory health and exhaled breath VOCs, which is a biomarker of VOC exposure. We recruited 26 Hispanic children with mild asthma in a Los Angeles community with high VOC levels near major freeways and trucking routes. Two dropped out, three had invalid peak expiratory flow (PEF) or breath VOC data, leaving 21. Children filled out symptom diaries and performed PEF maneuvers daily, November 1999-January 2000. We aimed to collect breath VOC samples on asthma episode and baseline symptom-free days, but six subjects only gave samples on symptom-free days. We analyzed 106 breath samples by GC-MS. Eight VOCs were quantifiable in >75% of breath samples (benzene, methylene chloride, styrene, tetrachloroethylene, toluene, m,p-xylene, o-xylene, and p-dichlorobenzene). Generalized estimating equation and mixed linear regression models for VOC exposure-response relationships controlled for temperature and respiratory infections. We found marginally positive associations between bothersome or more severe asthma symptoms and same day breath concentrations of benzene [odds ratio (OR) 2.03, 95% confidence interval (CI) 0.80, 5.11] but not other breath VOCs. Ambient petroleum-related VOCs measured on the same person-days as breath VOCs showed notably stronger associations with symptoms, including toluene, m,p-xylene, o-xylene, and benzene (OR 5.93, 95% CI 1.64, 21.4). On breath sample days, symptoms were also associated with 1-h ambient NO(2), OR 8.13 (1.52, 43.4), and SO(2), OR 2.36 (1.16, 4.81). Consistent inverse relationships were found between evening PEF and the same ambient VOCs, NO(2), and SO(2). There were no associations with O(3). Given the high traffic density of the region, stronger associations for ambient than for breath VOCs suggest that ambient VOC measurements were better markers for daily exposure to combustion-related compounds thought to be causally related to acute asthma. Alternatively, the low sample size of symptom responses (15-21 responses per 108 breath samples) may have led to the nonsignificant results for breath VOCs.

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.

Effects of ambient air pollution on upper and lower respiratory symptoms and peak expiratory flow in children

Previous epidemiological studies have shown acute effects of increased amounts of ambient air pollution on the prevalence of respiratory symptoms in children with respiratory disorders. We investigated whether children with bronchial hyperresponsiveness (BHR) and relatively high serum concentrations of total IgE (>60 kU/L, the median value) are susceptible to air pollution. We collected data from children during three winters (1992-95) in rural and urban areas of the Netherlands. Lower respiratory symptoms (wheeze, attacks of wheezing, shortness of breath), upper respiratory symptoms (sore throat, runny or blocked nose), and peak expiratory flow were recorded daily for 3 months. The acute effects of airborne particulate matter with a diameter of less than 10 microm, black smoke, sulphur dioxide, and nitrogen dioxide were estimated by logistic regression. 459 (73%) of 632 children had complete data. Of these, 26% had BHR and relatively high (above median) serum total IgE, 36% had no BHR and total IgE of 60 kU/L or less, 15% had BHR and total IgE of 60 kU/L or less, and 23% had a total IgE of more than 60 kU/L but no BHR. In children with BHR and relatively high serum total IgE the prevalence of lower respiratory symptoms increased significantly by between 32% and 139% for each 100 microm/m3 increase in particulate matter, and between 16% and 131% for each 40 microm/m3 increase in black smoke, SO2, or NO2. Decrease in peak expiratory flow of more than 10% in that group was more common with increased airborne particulate matter and black smoke. There were no consistent positive or negative associations between increased air pollution and prevalence of respiratory symptoms or decrease in peak expiratory flow in the other three groups of children. Children with BHR and relatively high concentrations of serum total IgE are susceptible to air pollution. Although our odds ratios were rather low (range 1.16-2.39) the overall effect of air pollution on public health is likely to be substantial since these odds ratios refer to large numbers of people.

Diurnal Variation of Peak Expiratory Flow in Children with Cough Variant Asthma

Cough variant asthma (CVA) is thought to be a variant form of asthma in which cough is the sole clinical manifestation of airways hyperresponsiveness, a characteristic feature of asthma. Another characteristic feature of asthma includes an increased diurnal variation of peak expiratory flow (PEF) compared to normal subjects. To examine whether diurnal variation of PEF might also increase in children with CVA, we have examined the degree of diurnal variation of PEF in these children (n = 7) by measuring peak flow serially for a week, and compared it with those in mild to moderate asthma (n = 17) and in control children without cough (n = 8). In control children without cough, the average value of the mean diurnal variation of PEF was 10.4 ± 0.8%. In both groups of children with asthma and with CVA, there was a significant increase in the value (20.5 ± 1.3% and 23.6 ± 3.6%, respectively) compared to that in control children (p < 0.01 in both groups), although there was no significant difference between these 2 groups. These results show that mild, but significant airway obstruction is occurring in children with CVA, although clinical wheezing is not recognized. Serial measurements of diurnal variation of PEF may be helpful for the diagnosis of CVA in children.

Association between lower respiratory tract symptoms and falls in peak expiratory flow in children

Peak expiratory flow (PEF) measurements are increasingly recommended in childhood asthma management. However, few data are available on the temporal relationship between the onset of upper and lower respiratory tract symptoms and significant falls in PEF. We wanted to determine whether falls in PEF constitute a sensitive marker for clinical episodes of respiratory morbidity. We therefore analysed data on daily PEF and respiratory symptom recording from a 12 month longitudinal study in 192 children aged 7 and 8 yrs with current respiratory symptoms. Outcome measures were number of and relationship between: 1) episodes of fall in PEF (defined as a fall in PEF for more than 2 days to < 1.5 SD below individual mean morning PEF); and 2) upper and lower respiratory tract symptom events (defined as a respiratory symptoms score of > 3 units within three consecutive days). One hundred and eight six of the 192 children completed the study. For the group as a whole, the mean number of PEF episodes per subject was 3.5, and the mean number of symptom events 8.9, with 29% of symptom events being temporally associated with a PEF episode, and 40% of PEF episodes not being accompanied by a symptom event. Forty nine percent of PEF episodes were preceded by at least two consecutive days of either upper or lower respiratory symptoms. We conclude that falls in PEF alone were not a sensitive marker for episodes of respiratory morbidity. On almost half of the occasions where PEF did fall, morbidity could have been detected at least 2 days earlier using symptom reporting.(ABSTRACT TRUNCATED AT 250 WORDS)

Circadian rhythm of peak expiratory flow in children passively exposed and not exposed to cigarette smoke.

Because airway calibre shows a circadian rhythm and since exposure to passive smoking reduced lung function this study was undertaken to investigate whether passive smoking affects the circadian rhythm of peak expiratory flow (PEF) in schoolchildren. Twenty schoolchildren (12 boys and 8 girls, aged 10-11 years) exposed to passive smoking were matched for sex, age, and height with 20 children who had not been exposed to cigarette smoke. Exposure to passive smoking was assessed by questionnaire and by urinary cotinine concentrations. A portable spirometer was used to measure PEF at 16:00, 20:00, 22:00, 06:00, 08:00, and 12:00 hours on a consecutive Saturday and Sunday. The circadian changes in PEF were measured by the cosinor method. Both groups showed diurnal fluctuation in PEF values with a noticeable circadian rhythm. PEF peaks were the same in the two groups and occurred around 15:00 hours. The cosinor mean was approximately 10% lower in children exposed to passive smoking and the amplitude was approximately 60% higher than in the unexposed children. Passive smoking in children is associated with a reduction in the cosinor mean and an increase in the amplitude of the normal circadian rhythm of airway calibre. This increased PEF rhythm amplitude may be considered as an early indication of airway obstruction.

Time course of change in oxygen saturation and peak expiratory flow in children admitted to hospital with acute asthma.

The time course for recovery of the arterial oxygen saturation (SaO2) in acute childhood asthma is unknown. Serial measurements of SaO2 were made in 47 children during an acute attack of asthma that required admission to hospital. Adequate serial peak expiratory flow (PEF) measurements were possible in 28 children (mean age 8.3 years; group A), but not in the other 19 children (mean age 3.2 years; group B). Measurements of PEF and SaO2 were recorded twice daily before and 30 minutes after they had received salbutamol by nebuliser. Initial SaO2 values (mean (SD) %) were similar in groups A and B at 92.2 (3.5) and 92.4 (2.9). For the children in group A, PEF plateaued 36 hours after admission and SaO2 plateaued 12 hours later. Mean PEF improved after each dose of nebulised salbutamol during the first 36 hours, whereas mean SaO2 increased only after the first dose. SaO2 increased more rapidly in group B. Length of hospital stay was not related to initial SaO2 or PEF values. These data suggest that in children admitted to hospital for acute asthma arterial oxygen saturation is low at admission, recovers more slowly than airway function, reflects bronchodilatation with salbutamol only when SaO2 is low, and recovers more rapidly in younger children than in older children.