深圳地区学龄前儿童用力肺活量测定的可行性及正常预计值公式

目的探讨学龄前儿童用力肺活量测定的可行性,并建立儿童常规用力肺活量的正常参考值。方法对深圳地区3~6岁正常儿童343例(男性184例,女性159例),采用意大利COSMED公司生产的COSMED流量传感仪,参考美国胸科协会可接受曲线标准,测定用力肺活量(FVC)、0.5 s用力呼气容积(FEV0.5)、0.75 s用力呼气容积(FEV0.75)、1 s用力呼气容积(FEV1)、0.5s用力呼气容积占用力肺活量比值(FEV0.5/FVC)、0.75 s用力呼气容积占用力肺活量比值(FEV0.75/FVC)、1 s用力呼气容积占用力肺活量比值(FEV1/FVC)、最大呼气中段流量(FEF25%~75%)、最高呼气流量(PEF)、最高吸气流量(PIF)、呼气时间(FET100%)等11个指标,并对各实测指标作多元逐步线性回归及曲线回归,得出回归方程式。比较本方程与国外Nystad方程对指定身高、体重、年龄的儿童的差异。结果所有儿童测试的总成功率为81.3%,其中3~岁、4~岁、5~岁、6~岁各年龄段测试的成功率分别为69.9%、70.8%、92.3%、91.6%;217例(77.7%)可以完成至少2条可接受的曲线。FVC、FEV0.5、FEV0.75、FEV1、FEF25%~75%、PEF、PIF在各年龄组间差异均有统计学意义(P均<0.01);大多数肺功能指标与身高、体重和年龄均呈密切正相关,男性儿童的大多数肺功能指标与身高的关系最为密切,而女性儿童的大多数肺功能指标则与年龄的关系最为密切。所有儿童的呼气时间为(1.61±0.52)s(x-±s),5百分位数为0.9 s,受试儿童中有18例(6.5%)呼气时间<1 s。建立了各肺功能指标的多元回归方程。结论利用儿童心理特点,通过形象比喻、竞赛游戏的方法进行用力肺活量的测定在中国的学龄前儿童中也是可行的。男性儿童肺功能指标受身高变化影响大于体重和年龄变化;女性儿童肺功能指标受年龄变化影响大于身高和体重变化;首次建立了中国深圳地区学龄前儿童用力肺活量正常值及其回归方程式。     

Sex influences on lung function and medication in childhood asthma

AIM: To evaluate possible sex differences in prevalence, diagnosis and treatment of asthma, and influence on lung function associated with asthma severity in a population-based birth cohort (BAMSE) of 4089 children. METHODS: At 4-y follow-up, 92% responded to a questionnaire on symptoms of asthma, current medication and doctor's diagnosis of asthma. A total of 2965 children participated in clinical testing, including measurements of peak expiratory flow (PEF), and were assigned to groups of asthma or no asthma by reported airway symptoms. RESULTS: Children in asthma groups had lower PEF readings compared to healthy children. This effect was most pronounced for both sexes in the persistent group (boys p<0.05, girls p<0.001) and for girls in the transient group (p<0.01). A doctor's diagnosis of asthma did not significantly differ between boys and girls, but significantly more boys than girls had inhaled corticosteroids, even when stratifying by frequency of symptoms. CONCLUSION: These results suggest that when 4-y-old children are stratified according to common diagnostic criteria, girls have a larger effect on PEF of asthma symptoms and are less frequently treated compared to boys.     

Normal values for simple lung function tests in South African Asian children

Normal lung function values have frequently been shown to be racially specific. This study of 1072 boys and girls establishes normal standards for peak expiratory flow rate, forced expiratory volume in 1 s, and forced vital capacity in Asian (Indian) children aged 5-14 years. These values are compared with those of American white and black children and of Indian and British Asians.     

Peak inspiratory flows in children with cystic fibrosis

OBJECTIVE: To show that in children with moderately severe cystic fibrosis lung disease: (i). inspiratory flow may be reduced; and (ii). peak inspiratory flow may be predicted from height, expiratory flow analysis or body mass index. METHODS: All children attending the Royal Children's Hospital, Melbourne, between May and July, 2001 who had cystic fibrosis, were aged > 5 years, were able to perform spirometry reproducibly and who had a forced expiratory volume in 1 s < 60% predicted were prospectively enrolled. Height, weight, peak inspiratory flow, forced expiratory volume in 1 s and forced vital capacity were recorded. Linear regression analysis was performed. RESULTS: The age range was 9.4-19.9 years. Sixteen boys and 11 girls were studied. All children had a peak inspiratory flow > 0.5 L/s. There was a significant relationship between peak inspiratory flow and forced vital capacity (R2 = 0.50) especially in boys (R2 = 0.65). In boys, peak inspiratory flow was significantly related to forced expiratory volume in 1 s (R2 = 0.47). There was no relationship between peak inspiratory flow and predicted values of expiratory flow, age, height, weight or body mass index. Logistic regression was used to predict the probability that peak inspiratory flow was < 2.0 L/s for a given forced vital capacity. If the forced vital capacity is > 2.5 L, peak inspiratory flow is likely to be > 2.0 L/s. CONCLUSIONS: In children with significant cystic fibrosis lung disease, peak inspiratory flow is likely to be > 0.5 L/s, which is required to activate dry powder inhalers. If the forced vital capacity is < 2.5 L, the peak inspiratory flow may be < 2.0 L/s, and a metered dose inhaler and spacer should be considered. Further studies that investigate the relationship between expiratory flow and peak inspiratory flow against an internal resistance are needed.     

The necessity of building population specific prediction equations for clinical assessment of pulmonary function tests

Fitting adequate prediction equations for pulmonary function test (PFT) parameters is crucial in the analysis of lung function tests and their interpretation. Our work aimed at studying the necessity of building population specific prediction equations, rather than using prediction equations built-in in commercial equipment. We used as an example results of studies carried out among Israeli schoolchildren. Second to sixth grade children (7–13 years old), 1064 boys and 1211 girls, were studied in Tel-Aviv. PFT (forced vital capacity, forced expiratory volume in 1st second, peak expiratory flow, forced expiratory flow in 50% volume, forced expiratory flow in 75% volume) performed by these children were adjusted for height, weight and age, for each sex separately, by a multiple regression procedure. Predicted PFT parameters of 300 boys and 301 girls aged 7–13 years, living along the southern shore of Israel, were calculated using the equations built for the same aged Tel-Aviv children as well as the prediction equations built-in in the spirometer used. The ratios between the observed PFT parameters in the southern children and their expected values, using the Israeli population specific equations, were around 1.00. Using the built-in equations resulted in ratios around 0.90. Conclusion The development of population specific prediction equations for PFT parameters is necessary. Such equations should be used both in clinical assessment to minimize misclassification (healthy/sick child) and in epidemiological studies. Received: 13 July 1998 / Accepted in revised form: 30 November 1998     

"Ethnic" variation in childhood lung function may relate to preventable nutritional deficiency

This study aimed to define the differences in lung function between British Caucasian and rural eastern Indian children, and to test the hypothesis that nutrition could account for such "ethnic" variation. To exclude confounders, a rural Indian setting was identified and children were screened for respiratory illness before lung function and nutritional characteristics were measured. Regression equations for this population have already been published. In this study, the lung function differences between rural eastern Indian ( n = 391) and mean predicted lung function for Caucasian children were characterized, matched for height and sex. In addition, stepwise multiple regression models were fitted to investigate the relative associations of lung function differences with body mass index (BMI), occipitofrontal circumference and age. Although the largest differences in the forced expiratory volume in 1 s (FEV 1 ) [girls 28.7 (27.3-30.1), boys 23.4 (22.2-24.6)] and forced vital capacity [girls 27.9 (26.4-29.4), boys 30.7 (29.6-31.9)] [values as mean difference in % predicted (95% confidence intervals)] ever reported between two populations were observed, differences in peak expiratory flow rate (PEFR) were small. BMI was strongly associated with inter-racial differences for FEV 1 for both sexes (boys β= -0.227, girls β= -0.353, p ≤0.001) and PEFR for girls ( β= -0.200, p ≤0.05) ( β= standardized coefficient).

Conclusion: Preventable nutritional factors may play a causal role in determining the FEV 1 differences between rural Indian and Caucasian children. As peak FEV 1 in youth influences respiratory morbidity in later life, it is important to define specific nutrient 1 deficiencies that may relate to poor FEV growth in these children.     

支气管可逆性试验对哮喘儿童治疗的指导意义

目的：观察哮喘治疗期间不同临床症状患儿肺功能的变化,探讨支气管可逆性试验对儿童哮喘治疗的指导意义。方法：417例哮喘患儿通过吸入沙美特罗/氟替卡松治疗时间3个月以上。复诊时根据患儿症状分为无症状组（n=215）、单咳组（n=89）、阵咳组（n=72）和喘咳组（n=41）。34例正常儿童作为对照组。应用沙丁胺醇泵雾化进行支气管可逆性试验,试验前后行肺功能检测。结果：各个哮喘组沙丁胺醇雾化后肺功能异常率较雾化前均明显降低,FEV1%/预测值雾化后均较雾化前显著升高（P<0.05）。雾化前单咳组、阵咳组、喘咳组肺功能异常率均较对照组显著增高,FEV1%/预测值均较对照组显著降低（P<0.05）;雾化前各个不同症状哮喘组间肺功能异常率及FEV1%/预测值差异有统计学意义（P<0.05）。雾化后阵咳组、喘咳组肺功能异常率明显高于对照组（P<0.05）,其他各组与对照组比较差异无统计学意义;雾化后喘咳组FEV1%/预测值明显低于对照组,其他各组与对照组比较差异无统计学意义。不同症状的4个哮喘组支气管可逆性试验阳性率均高于对照组（P<0.05）;各个哮喘组间可逆性试验阳性率比较,除无症状组与单咳组差异无统计学意义外,其余各组间差异均有统计学意义（P<0.05）。结论：儿童哮喘治疗期间不同症状者肺功能存在差异;支气管可逆性试验结合肺功能检查有利于哮喘控制的评估和治疗指导。     

6～14岁健康儿童呼出气体一氧化氮水平及其与肺功能的相关性

目的探讨沈阳地区6～14岁健康儿童呼出气体一氧化氮(FeNO)水平与其年龄、身高、体质量、体质量指数(BMI)及肺功能各参数之间的相关性。方法随机测定沈阳地区200名6～14岁健康儿童(男102名,女98名)FeNO水平及其肺功能,采用SAS 8.2软件进行统计学分析。结果受试儿童总体FeNO水平中位数(四分位间距)为13.0 ppb(8.0～19.0 ppb),其中男童13.0ppb(10.0～19.5 ppb),女童为13.5 ppb(10.0～17.0 ppb),不同性别比较差异无统计学意义(P>0.05);FeNO与肺功能各参数[用力肺活量(FVC)、第1秒用力呼气量(FEV1)、FEV1/FVC、呼气峰流速(PEF)]亦无相关性(R2=0.016 0、0.013 9、0.014 4、0.007 5);FeNO水平与身高、年龄、体质量、BMI均无相关性(R2=0.062 3、0.044 0、0.098 3、0.037 2)。结论健康儿童FeNO中位数为13.0ppb[8.0～19.0 ppb],FeNO与性别、年龄、身高、体质量、BMI无相关性,与肺功能各参数之间亦无相关性,但二者密不可分,是全面评价儿童哮喘的呼吸道炎症的无创方法。     

The importance of spirometry in the assessment of childhood asthma.

OBJECTIVE--To assess the pulmonary function of children with asthma at the time of a routine follow-up visit when they were judged to be clinically well. DESIGN--Pulmonary function tests were performed on children with a previous diagnosis of asthma. None had had any symptoms for at least 6 weeks. All had normal Wright peak flow rates and normal findings at physical examination. SETTING--General pediatric and pediatric pulmonary clinic at a municipal hospital in the Bronx, NY. PATIENTS--Sixty-five children with asthma who fit the above criteria. All were able to perform spirometry adequately. Their mean (+/- SD) age was 11 +/- 3 years, and their median age was 10 years. SELECTION PROCEDURES--All clinic patients were screened as possible participants. The 65 patients were deemed eligible, and were willing and able to perform spirometry. INTERVENTIONS--None. MEASUREMENTS AND RESULTS--The group's mean (+/- SD) forced expiratory volume in 1 second/forced vital capacity ratio was 80% +/- 8%, and their mean mid-maximal expiratory flow was 66% +/- 23% of the predicted value. Of the 65 patients, 11 (17%) had forced expiratory volume in 1 second/forced vital capacity ratios of less than 72%, and 35 (54%) had a mid-maximal expiratory flow of less than 65% of the predicted value. CONCLUSION--Failure to perform spirometry in children with asthma results in underdiagnosis of airflow obstruction. This may result in obstruction persisting into adulthood and/or progression to hyperinflation.     

Comparative effect of triamcinolone, nedocromil and montelukast on asthma control in children: A randomized pragmatic study

Asthma severity can be judged by measurements of symptoms, lung function, and medication requirements. The objective was to compare the effect of a 4-wk monotherapy with low-dose triamcinolone, montelukast and nedocromil on asthma control, lung function, eosinophil blood count, and bronchial hyper-reactivity in children with mild to moderate asthma allergic to dust mite. Two hundred fifty-six children, aged 6-18 yr, with mild to moderate asthma, participated in an 8-wk study. This was a three-arm, randomized no blinding or placebo pragmatic trial comparing the effect of triamcinolone acetonide (400 microg/day), inhaled nedocromil and montelukast sodium on clinical parameters of asthma [score, forced expiratory volume in 1 s (FEV(1))], PC20H, and eosinophil blood count. Two hundred forty-six children completed the study. After 4 wk of treatment with triamcinolone and montelukast, FEV(1) and PC20H significantly increased, and mean total symptoms score and mean number of eosinophil count in serum significantly decreased. Triamcinolone had a stronger effect on PC20H than montelukast. Nedocromil improved total asthma symptoms score and lung function. There was a reduction in the daytime and night-time symptom scores after treatment with all three drugs. Triamcinolone and montelukast had a stronger effect on asthma symptoms than nedocromil. There were statistically significant differences in reduction of nocturnal asthma symptoms between the triamcinolone and nedocromil groups (p < 0.001) and between montelukast and nedocromil (p = 0.001) groups, but not between the triamcinolone and montelukast groups. There was a reduction in beta-agonists use after treatment with all three drugs, with the strongest effect of triamcinolone. The study showed the strongest effect of low-dose inhaled steroids on clinical symptoms, lung function, bronchial hyper-reactivity and eosinophil blood count when compared to other asthma medications.     

Body composition and respiratory function in healthy non-obese children

BACKGROUND: The purpose of the present paper was to evaluate the role that body composition plays in lung function, among healthy children and adolescents. METHODS: Cross-sectional study was undertaken using sex- and age-stratified sampling among healthy children and adolescents aged 6-18 years. Spirometry was performed on every child who fulfilled inclusion criteria. Fat mass (FM) and fat-free mass (FFM) were calculated from triceps skinfold thickness and arm circumference. Multiple logistic regression was used to obtain adjusted prevalence odds ratios (OR) and 95% confidence intervals (95%CI) between low pulmonary function (PF) of schoolchildren and body composition expressed in FM and FFM. Calculations of OR imply that the outcome is dichotomous (low PF/normal PF), therefore those children who had parameters of pulmonary function below the 25th percentile were classed as cases and the rest of the subjects were considered as controls. RESULTS: A total of 2408 children were included; 1270 (53%) of them were male and 1138 (47%), female. Among boys the increase of FFM was associated with an increase of forced expiratory volume in 1 s (FEV1). Among girls the increase of FFM was associated with an increase of FEV1, forced vital capacity, and peak expiratory flow. The increase in FM was associated with a decrease of spirometric parameters in both genders, with a stronger effect among boys. CONCLUSIONS: The present study confirms the negative effect of body fat on the PF of children and adolescents, even though obese subjects were excluded. The effect is different between boys and girls.     

Exhaled carbon monoxide in childhood asthma.

OBJECTIVES: Oxidative stress and inflammation induce the expression of heme oxygenase-1, which produces carbon monoxide (CO), and nitric oxide synthase, which produces nitric oxide (NO). Exhaled CO and NO levels are elevated in asthmatic patients and are decreased after corticosteroid treatment, suggesting that they may be useful as noninvasive markers of airway inflammation. STUDY DESIGN: We measured forced expiratory volume in the first second, PC(20), and exhaled CO and NO levels in 29 children (18 boys, mean age 11.5 +/- 0.53 years) with asthma of different severity and 40 nonsmoking children without asthma (21 boys, mean age 8.1 +/- 0.35 years). We also studied whether upper respiratory tract infections were associated with elevated exhaled CO. RESULTS: Exhaled CO levels (ppm) were significantly higher (2.17 +/- 0.21) in children with persistent asthma compared with those in children with infrequent episodic asthma (1.39 +/- 0.18, P <.05) and healthy children (1.01 +/- 0.12, P <.001). The CO levels in children with infrequent episodic asthma and the normal control group, however, were not different. In contrast, exhaled NO levels (ppb) were higher in children with persistent asthma (24.2 +/- 5.9, P <.001) and infrequent episodic asthma (14.5 +/- 3.73, P <.05) than in normal subjects (5.1 +/- 0.24), but no significant difference was seen between the 2 asthmatic groups. In healthy children with upper respiratory tract infections (n = 12), exhaled CO concentrations were significantly elevated (2.16 +/- 0.33) during the acute symptomatic phase. No correlation was found between exhaled CO and forced expiratory volume in the first second or PC(20). CONCLUSIONS: Noninvasive measurement of exhaled CO may provide complementary data for assessment of asthma control in children. However, elevated CO levels are nonspecific and may be found in association with an acute viral illness.     

Long-term trajectories of lung function and risk factors in children with bronchial asthma北大核心CSCD

目的建立支气管哮喘(哮喘)患儿肺功能长期变化的发展轨迹, 确定哮喘患儿出现长期肺功能损伤的危险因素。方法采用回顾性队列研究, 纳入2019年1月至12月在首都儿科研究所附属儿童医院定期随诊, 并完成肺功能检测的14岁以上哮喘患儿, 收集其肺功能资料及临床信息。采用潜变量增长模型(LCGM)拟合哮喘患儿肺功能发展轨迹, 建立不同的轨迹组, 组间比较采用t检验、方差分析或χ2检验, 确定肺功能长期变化危险因素采用多分类Logistic回归分析。结果共纳入哮喘患儿173例, 年龄6~17岁, 获得肺功能测定1 160例次。拟合4条1秒率(FEV1/FVC)潜分类轨迹:持续高水平组、高于平均水平组、低于平均水平组、持续低水平组, 其病例数分别为27例(15.6%)、66例(38.1%)、66例(38.1%)、14例(8.1%)。不同轨迹组患儿的FEV1/FVC在每一年龄组间的差异均有统计学意义(均P<0.05)。持续高水平组各年龄段的FEV1/FVC均在90%以上, 其余各轨迹组FEV1/FVC随年龄变化整体呈下降趋势, 低于平均水平组的FEV1/FVC在青春期后下降至80%以下;持续低水平组的FEV1/FVC均值在学龄期后即下降至80%以下, 至青春期接近70%。最大用力呼气中段流量(MMEF)的轨迹和波动情况与FEV1/FVC相似。危险因素分析显示, 与持续高水平组相比, 典型哮喘患儿肺功能轨迹处于低于平均水平组的风险是咳嗽变异性哮喘患儿的11.940倍(P=0.008);多重致敏患儿的肺功能轨迹处于低于平均水平组的风险是单一致敏的7.462倍(P=0.015);未规律用药患儿肺功能处于持续低水平组的风险是规律用药者的6.337倍(P=0.035);男童肺功能轨迹处于低于平均水平组的风险是女童的6.186倍(P=0.002)。结论 6~17岁哮喘患儿的长期肺功能变化可确定4条不同轨迹:持续高水平、高于平均水平、低于平均水平、持续低水平;近半数患儿的长期肺功能轨迹处于低水平, 较多患儿在青春期, 少数患儿在学龄期出现持续性气流受限;典型哮喘、多重致敏、未规律用药、男性是哮喘患儿长期肺功能降低的危险因素。     

东北地区学龄期儿童肺通气功能预计方程式建立的前瞻性研究

目的 建立东北地区6~<16岁儿童肺通气功能参数的预计方程式。 方法 前瞻性选择辽宁、吉林和黑龙江三省健康儿童504名,其中男242名,女262名,采用德国耶格MasterScreen Pneumo肺功能仪测定其肺通气功能。以用力肺活量（forced vital capacity,FVC）、第１秒用力呼气容积（forced expiratory volume in one second,FEV₁）、一秒率（FEV₁/FVC）、外推容积（back-extrapolated volume,BEV）等10项参数实测值为因变量,以年龄、身高和体重为自变量,通过多元逐步回归建立不同性别儿童的回归方程。采用相对预测误差平均值评价预计方程式的适用性。 结果 9~<10岁和15~<16岁男童的身高、FVC和FEV₁高于女童,9~<10、10~<11、11~<12和13~<14岁男童的FEV₁/FVC低于女童（P<0.05）。相关性分析显示,除FEV₁/FVC和BEV/FVC外,其他参数均与年龄、身高和体重呈显著正相关（P<0.001）。进一步回归分析显示,年龄和身高是大部分参数的影响因素,而体重较少被纳入回归方程。与不同研究的预计方程式比较,该次构建的回归方程对该研究群体有较好的适用性。 结论 该研究建立了东北地区6~<16岁儿童肺通气功能主要参数的预计方程式,为临床上准确判定肺功能异常奠定基础。 引用格式:     

Respiratory function in childhood following repair of oesophageal atresia and tracheoesophageal fistula.

AIM: To determine the relation between respiratory function in infancy and at school age in children who have undergone oesophageal atresia and tracheoesophageal fistula repair, and assess the value of infant respiratory function testing; and to examine the effect of bronchodilators. METHOD: Fourteen children (6 girls, and 8 boys) who had undergone respiratory function testing in infancy were retested at school age (7-12 years). Measurements included lung volume, airways resistance, peak flow, and spirometry. Clinical problems were investigated by questionnaire. Twelve children had repeat measurements after taking salbutamol. RESULTS: Predominant complaints were non-productive cough and dysphagia, but even those children with major problems in infancy reported few restrictions at school or in sport or social activities. Respiratory function and clinical findings at school age appeared unrelated to status in infancy, such that even the patients with severe tracheomalacia requiring aortopexy did not have lung function testing suggestive of malacia at school age. Most patients showed a restrictive pattern of lung volume which would appear to result from reduced lung growth after surgery rather than being a concomitant feature of the primary congenital abnormality. Although six children reported wheeze and four had a diagnosis of asthma, only one responded to salbutamol. This suggests that a tendency to attribute all lower respiratory symptoms to asthma may have led to an overdiagnosis of this condition in this patient group. CONCLUSION: Respiratory function testing in infancy is of limited value in medium term prognosis, but may aid management of contemporary clinical signs. In children respiratory function testing is valuable in assessing suspected asthma and effects of bronchodilators.     

Reduction in pulmonary function and increased frequency of cough associated with passive smoking in teenage athletes

Previous studies have suggested that passive smoking (involuntary inhalation of tobacco smoke by nonsmokers) reduces small airways function. We evaluated the exposure to passive smoking and its effects on pulmonary function and symptoms in a group of 12- to 17-year-old high school athletes (N = 209; 119 boys and 90 girls) at their annual presport participation physical examinations. A structured interview was used to assess pulmonary symptoms, personal smoking habits, and passive cigarette smoke exposure. All athletes performed forced expiratory maneuvers on a portable spirometer. We measured forced vital capacity, forced expiratory volume in 1 second, and forced expiratory flow 25% to 75% (FEF25-75). The best of three FEF25-75 measured was used. Less than 70% of predicted FEF25-75 was considered abnormal. Of the 209 athletes, 7.7% were active smokers and were excluded. Of the remaining 193 athletes, 68.4% were currently exposed to passive smoking. We found a fourfold increase in incidence of low FEF25-75 and/or cough in athletes exposed to passive smoking compared with athletes not exposed: 18 of 132 exposed athletes (13.6%) had low FEF25-75 and/or cough compared with two of 61 unexposed athletes (3.3%) who had low FEF25-75 and cough (P = .02). Boys were more frequently exposed to passive smoking than girls (74% of boys [80/108] v 61% of girls [52/85] ), but the effects were more pronounced in girls. These data show a relationship between exposure to passive smoking and early pulmonary dysfunction in young athletes. The frequent exposure to passive smoke and the high prevalence of dysfunction in this population, generally considered to be healthy, is of particular concern.     

脉冲振荡肺功能支气管舒张试验阳性标准的确定

目的探讨在使用脉冲振荡肺功能（IOS）检测时,如何判断支气管舒张试验阳性。方法随机抽取发作期哮喘患儿156例,均进行最大呼气流量一容积和IOS测定,然后进行支气管舒张试验。以第一秒用力呼气容积（FEV1）和最大呼气中段流量（MMEF）作为金标准,分别计算IOS主要参数,即呼吸总阻抗（Zrs）、气道总粘性阻力（R5）、电抗（X5）在不同改善率水平时其对诊断的敏感度与特异度,并计算两种肺功能主要参数间的回归方程。结果吸入支气管舒张剂后,患儿肺功能显著改善,两种肺功能主要参数的改善率均存在显著相关（P〈0．01）,其中X5改善率与最大呼气流量-容积曲线参数改善率相关性最强（相关系数分别为0．676、0．571）,Zrs次之。无论使用FEV1改善率≥15％,还是使用MMEF改善率≥30％作参照,IOS参数以Zrs、R5下降≥20％,X5下降≥30％作为舒张试验阳性有着较高的敏感度和特异度。回归方程结果显示,与FEV,改善15％、MMEF改善30％对应的Zrs、R5、X5的降低率分别为21．7％、21．3％;19．9％、19．5％;30．1％、29．6％。结论用IOS进行支气管舒张试验,只有在Zrs、R5下降≥20％,X5下降≥30％时,才能考虑作为试验阳性。     

Asthma from Childhood to Adult Age

ABSTRACT. Twenty young men with a mean age 24.9 years, who had moderate to severe asthma during childhood, underwent a follow-up examination of their clinical status and pulmonary function. Comparison was made with data obtained at a mean age of 10.9 years. Eight of twenty showed a clinical improvement and 12 no change in their asthma. During childhood 12 of 20 boys had been on longterm ACTH or corticosteroid treatment. In the present study no one was given systemic steroid treatment. The static lung volumes (VC, TLC, FRC RV) were within normal limits for children and adults. In spite of clinical improvement, the expiratory flow rates (FEV₁, FEV%) were still significantly reduced ( p <0.005). Thus, the clinical improvement was not accompanied by a corresponding improvement in expiratory flow rates.     

A doctor's ability to assess the severity of childhood asthma by simple clinical features

Aims: To ascertain whether the severity of childhood asthma can be reliably assessed by simple clinical features, 94 newly diagnosed, school-aged asthmatic children were investigated. Methods: The study included parental interviews, physical examination, skin prick tests, lung function studies, including a brief visual interpretation of the flow-volume curve, and a 6-min exercise challenge test on a treadmill, which was used as a reference. Results: Baseline lung function studies showed a concave-shaped flow-volume curve in 40 (43%) patients, reduced maximal mid-expiratory flow (MMEF) in 25 (27%) and a reduced ratio of forced expiratory volume in 1 s to forced vital capacity (FEV₁/FVC) in 14 (15%). The drop in peak expiratory flow (PEF) after exercise ranged from 0 to 79% of the baseline (mean 21.3%) and exceeded 12.5% in 52 (55%) patients. There was a small but significant correlation between the baseline FEV₁/FVC and MMEF values and the response to exercise (r=-0.39 and -0.35; p=0.000, respectively), but when studied by linear regression analysis, the response to exercise was best predicted by the past symptom rate and a concave pattern in the pre-test maximal expiratory flow-volume curve. The values of traditional lung function tests or age, atopy, duration of symptoms or history of exercise-induced wheezing did not remain in the model.

Conclusions: These results show that the severity of asthma in school-aged children can be predicted at the first visit based on the past rate of symptoms and a visual interpretation of the maximal expiratory flow-volume curve.     

Adverse pulmonary responses to aspirin and acetaminophen in chronic childhood asthma

Because aspirin (ASA) is often reported to have an adverse effect on pulmonary function in children with chronic asthma, acetaminophen is commonly used as an ASA substitute in these children. To study acetaminophen effects on pulmonary functions, double-blind, oral challenges of ASA (600 mg), acetaminophen (600 mg), or lactose were administered on separate days to 25 chronic asthmatics, ten boys and 15 girls, ranging in age from 8 to 18 years (mean age +/- 1 SD: 12.5 +/- 2.8 years). No patient had a past history of adverse reactions to either drug. Forced expiratory volume in 1 second (FEV1), peak expiratory flow rate (PEFR), maximal mid-expiratory flow rate (FEF25-75), forced vital capacity (FVC), maximal voluntary ventilation (MVV), and flow volume curves were measured at base line and 1/2, 1, 2, 3, and 4 hours after ingestion of drug or placebo. Persistent decreases from base line FEV1 (greater than 20%) or FEF25-75 (greater than 30%) occurred in four ASA- and two acetaminophen-challenged patients. One ASA-sensitive patient was placebo intolerant; another reacted to acetaminophen. The acetaminophen responses were of less intensity than the ASA responses. Analysis of group mean pulmonary function responses to ASA, acetaminophen, and lactose showed no significant difference among the three agents at any time. Aspirin should be used cautiously in asthmatic children. Acetaminophen appears to be an adequate, although not completely, innocuous ASA substitute.