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.     

Variability of pulmonary function tests in cystic fibrosis

The aim of this study was to define the within-subject variability for tests of respiratory function in patients with cystic fibrosis (CF) within the day, from day to day and from week to week. Twenty-eight patients with CF (aged 9-19 years) and 23 healthy height matched controls (aged 9-18 years) had measurements made of spirometry, lung volumes, maximal flows at three lung volumes and maximal inspiratory and expiratory pressures at the mouth. Testings were done on nine occasions, three times within a day, on consecutive days at one week intervals. Each individual's variability was summarized both as the within-subject coefficient of variation (WCV) and within-subject standard deviation (WSD). Means of WSD and median WCV are reported for both the patients with CF and normal subjects. The within-subject variability of VC, FEV1, TLC, RV, and RV/TLC was more appropriately assessed by the use of WSD rather than WCV. The WSDs in the CF group were significantly more variable (P less than 0.005) than in the normals for VC and FEV1. WCV best summarized within-subject variation for FEF25-75, FRC, V25, V50max and V75max for which the CF subjects were significantly more variable (P less than 0.005). Individuals' variability was very consistent, therefore assessment of significant change could be made more accurately by predetermining the variability of that individual, rather than using group data. We stress the importance to consider increased variability from day to day and week to week in the interpretation of change in lung function in patients with CF, and provide reference values for accurate interpretation of serial pulmonary function test results.     

The effects of Bone Marrow transplantation on pulmonary function in children

The effects of current methods of bone marrow transplantation (BMT) on pulmonary function in children have not been extensively studied. We reviewed serial pulmonary function tests (PFTs) in 25 children (median age, 9 yr; range, 4—15) who received allogeneic (n = 14) or autologous (n = 11) BMT for neoplastic diseases at The Johns Hopkins Hospital. The PFTs were obtained before BMT and at 6 months (early) and 15 months (late) after transplant. In all but 6 patients, PFTs were normal before BMT. A mild transient decline in carbon monoxide diffusing capacity (D_LcO) was observed early after BMT but returned to baseline levels in the late post-BMT period. A trend towards worsening of PFTs with increasing age of patients was observed. The presence of graft-versus-host disease (GVHD) and pretransplant seropositivity for cytomegalovirus (CMV) were associated with significant decrements in several measurements of pulmonary function in the early post-BMT period. Patients given bulsulfan-containing preparative regimens tended to have less impairment of PFTs than those given other regimens using other combination high-dose chemotherapeutic agents or total body irradiation. These findings suggest that abnormalities in PFTs are common in the first months after BMT in pediatric patients but are not consistently associated with impairment of lung function when studied 15 months post-transplant. Pediatr Pulmonol. 1994;18:361–367. ©1994 Wiley-Liss, Inc.     

Pulmonary function in adolescents with ataxia telangiectasia

INTRODUCTION: Pulmonary complications are common in adolescents with ataxia telangiectasia (A-T), however objective measurements of lung function may be difficult to obtain because of underlying bulbar weakness, tremors, and difficulty coordinating voluntary respiratory maneuvers. To increase the reliability of pulmonary testing, minor adjustments were made to stabilize the head and to minimize leaks in the system. Fifteen A-T adolescents completed lung volume measurements by helium dilution. To assess for reproducibility of spirometry testing, 10 A-T adolescents performed spirometry on three separate occasions. RESULTS: Total lung capacity (TLC) was normal or just mildly decreased in 12/15 adolescents tested. TLC correlated positively with functional residual capacity (FRC), a measurement independent of patient effort (R2=0.71). The majority of individuals had residual volumes (RV) greater than 120% predicted (10/15) and slow vital capacities (VC) less than 70% predicted (9/15). By spirometry, force vital capacity (FVC) and forced expiratory volume in 1 sec (FEV1) values were reproducible in the 10 individuals who underwent testing on three separate occasions (R=0.97 and 0.96 respectively). Seven of the 10 adolescents had FEV1/FVC ratios>90%. CONCLUSION: Lung volume measurements from A-T adolescents revealed near normal TLC values with increased RV and decreased VC values. These findings indicate a decreased ability to expire to residual volume rather then a restrictive defect. Spirometry was also found to be reproducible in A-T adolescents suggesting that spirometry testing may be useful for tracking changes in pulmonary function over time in this population.     

Reference values for spirometry and their use in test interpretation: A Position Statement from the Australian and New Zealand Society of Respiratory Science

Traditionally, spirometry testing tended to be confined to the realm of hospital‐based laboratories but is now performed in a variety of health care settings. Regardless of the setting in which the test is conducted, the fundamental basis of spirometry is that the test is both performed and interpreted according to the international standards. The purpose of this Australian and New Zealand Society of Respiratory Science (ANZSRS) statement is to provide the background and recommendations for the interpretation of spirometry results in clinical practice. This includes the benchmarking of an individual's results to population reference data, as well as providing the platform for a statistically and conceptually based approach to the interpretation of spirometry results. Given the many limitations of older reference equations, it is imperative that the most up‐to‐date and relevant reference equations are used for test interpretation. Given this, the ANZSRS recommends the adoption of the Global Lung Function Initiative (GLI) 2012 spirometry reference values throughout Australia and New Zealand. The ANZSRS also recommends that interpretation of spirometry results is based on the lower limit of normal from the reference values and the use of Z‐scores where available.     

Spirometric lung volumes in the adult Pacific Islander population: comparison with predicted values in a European population

OBJECTIVE: Prediction equations for spirometric lung volumes have been developed mainly in Europe and North America and may not be relevant to Pacific Islanders. This study was undertaken to determine whether currently available prediction equations adequately describe spirometric lung volumes in the asymptomatic adult Pacific Islander population. METHODOLOGY: Healthy asymptomatic Pacific Island adults aged 15-70 years were recruited. Pulmonary function was measured in the laboratory at Green Lane Hospital, Auckland, New Zealand, in accordance with American Thoracic Society standards. Measured results were compared with predicted values derived from four sets of prediction equations relevant to, or currently used in, New Zealand. RESULTS: A total of 101 volunteers took part in the study; mean age 28 years (range 18-66 years), 39% male, body mass index = 32 (range 22-54). For forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC), when measured values were compared with reference values, the slopes of the regression lines were not significantly different from 1 and the intercepts were not significantly different from zero. Prediction equations derived for African-Americans did not provide a better fit than the prediction equations for Caucasians. Predictions were improved when ideal rather than actual bodyweight was used. CONCLUSION: Respiratory parameters (FEV1 and FVC) in healthy asymptomatic adult Pacific Islanders in New Zealand are adequately described by currently available prediction equations and no adjustment for ethnicity is required.     

New Danish reference values for spirometry

Introduction: International recommendations state that reference values for lung function should derive from cross‐sectional studies of healthy nonsmokers and be renewed from time to time because of cohort effect and newer, more accurate, technical equipment. In 1986, the Danish Lung Society published reference values for spirometry based on 570 individuals aged 30–70 years. Objectives: To produce new reference values for lung function and to extend the existing values by including individuals between 20 and 30 years of age and older than 70 years of age. Methods: Two similar but independent studies was used: The 2001–2003 examination of the Copenhagen City Heart Study and the 2003–2010 examination of the Copenhagen General Population Study. Of a total of 69 822 individuals, we included 11 288 healthy never‐smoking white individuals to produce the reference values: 6307 women and 4981 men, 20 years of age or older with adequate lung function. Results: We used sex‐stratified multiple linear regression analysis to find prediction formulas for forced expiratory volume in 1 s (FEV₁), forced vital capacity (FVC) and FEV₁/FVC adjusted for age and height. The cutoff value of normal lung function was defined as the fifth percentile (also named the 5% quantile) according to gender, age and height. The robustness of the data was tested and validated in several ways. Conclusion: Compared with the 1986 data, our 2001–2010 material contributes with a substantial number of individuals in the more extreme groups of age and height, and in general, our dataset shows that in most subgroups, the lung function level has improved during the last two decades. Please cite this paper as: Løkke A, Marott JL, Mortensen J, Nordestgaard BG, Dahl M and Lange P. New Danish reference values for spirometry. Clin Respir J 2013; 7: 153–167.     

New reference equations to improve interpretation of infant lung function

Rationale

With increasing use of infant pulmonary function tests (IPFTs) in both clinical and research studies, appropriate interpretation of results is essential.

Objectives

To investigate the potential bias associated with “normalising” IPF by expressing results as a ratio of body size and to develop reference ranges for tidal breathing parameters, passive respiratory mechanics (compliance [C_rs] and resistance [R_rs]) and plethysmographic functional residual capacity (FRC_p) for white infants during the first 2 years of life.

Methods

IPFTs were measured using the Jaeger BabyBody system and standardized protocols. Reference equations, adjusted for body size, age, and sex where appropriate, were created using multilevel modeling.

Results

The ratio of lung function to body length changes markedly with growth, thereby precluding its use for any outcome. While the ratio of tidal volume and C_rs to body weight remained relatively constant with growth, this was not the case for FRC_p. Even in healthy infants, a strong inverse relationship was observed between lung function/body weight and weight z‐score which could distort interpretation of results in growth‐restricted infants with lung disease, such as cystic fibrosis. Reference equations were derived from 153 healthy white infants on 232 test occasions (median age 35.5 weeks [range: 2.6–104.7]). Crown‐heel length was the strongest predictor of IPF.

Conclusions

When reporting IPF, use of size‐corrected ratios should be discouraged, with interpretation instead based on appropriate reference equations. The current equations are applicable to white infants and young children up to 2 years of age, studied using the same commercially available equipment. The extent to which these equations are applicable to infants and young children of other ethnic backgrounds or who are tested with different equipment needs to be established. Pediatr Pulmonol. 2013; 48:370–380. © 2012 Wiley Periodicals, Inc.     

河北省健康成人脉冲震荡肺功能正常参考值测定分析

目的：通过对我省健康成人肺功能脉冲震荡(impulse oscillometry system,IOS)的测定,探讨本地区肺功能测定中的 IOS 正常参考值。方法对409例来自我省不同职业的健康成人进行IOS 测定,按照欧洲呼吸协会的测定要求,观察参数包括呼吸总阻抗(Zrs),5 Hz、20 Hz 时的气道阻力 R5、R20,5 Hz 时的呼吸电抗(X5),中心阻力(Rc),外周阻力(Rp),(以上数据的单位为 kPa· L-1·s-1),弹性阻力等于惯性阻力时的响应频率(Fres),单位为1/S,R5实测/预测%及 R20实测/预测%。结果不同性别 IOS 参数 Zrs、Fres、Rc、Rp、R5、R20、X5差异有统计学意义(P <0.05), R5实/预%及 R20实/预%差异无统计学意义;与其他地区几所医院相比,IOS 参数 Zrs、Fres、Rc、Rp、R5、R20、X5差异有统计学意义;本研究参数与昆明地区非常接近。结论肺功能脉冲震荡测定技术能直观的反应呼吸阻抗以及各种阻力分布的情况,河北省健康成人 IOS 肺功能正常参考值与其他地区相比存在差异,各地区应有适合本地区的正常参考值。     

Clinical study on pulmonary diffusion function in patients with chronic liver disease

OBJECTIVE: To investigate the influence of chronic liver disease (CLD) on pulmonary diffusion function. METHODS: Arterial blood gas analysis, pulmonary function test, contrast-enhanced transthoracic echocardiography and technetium macro-aggregated albumin scanning were performed in 50 cirrhotic patients who underwent surgery on portal hypertension and liver transplantation. The severity of chronic liver disease (CLD) was evaluated by Child–Pugh–Turcotte (CPT) categorization and model for end stage liver disease (MELD) score from October 2008 to July 2009 in our surgical department and organ transplantation center. RESULTS: A-aDO₂ was increased with the aggravation of liver dysfunction. The pulmonary diffusion capacity for carbon monoxide (DLCO) differed significantly among the three groups, which was (90.8 ± 7.3)% in CPT A group, (82.8 ± 10.8)% in CPT B group, and (73.5 ± 8.3)% in CPT C group. A-aDO₂ correlated positively with CPT (r= 0.581, P= 0.000) as well as the MELD score (r= 0.696, P= 0.000), whereas DLCO was negatively correlated with CPT (r=−0.630, P= 0.000) and the MELD score (r=−0.708, P= 0.000). CONCLUSION: DLCO can be useful in the detection of pulmonary vascular abnormality of CLD. The MELD score may be a better criterion than the CPT score in assessing intrapulmonary vascular damage of CLD patients.     

Reference equations for pulmonary function tests in preschool children: a review

Recent developments in pulmonary function tests (PFTs) in preschool children (2-5 years of age) have meant that objective assessments of respiratory function are now possible for this age group. However, the application and interpretation of these tests may be limited by the relative paucity of appropriate reference equations. This review summarizes available preschool reference equations, identifies the current gaps and limitations in the methodologies and statistics used and proposes future directions for improving reference data. A PubMed search which included the MeSH terms (preschool [2-5years]), (respiratory function test), and (reference value) yielded 214 publications which were screened to identify 34 publications presenting 36 reference equations for seven techniques. There were considerable differences with respect to population characteristics, recruitment strategies, equipment and methodologies and reported parameters both within and between each measurement technique. Despite an increasing number of reference equations for PFT for preschool children, the extent to which these can be generalized to other populations may be limited in some cases by inclusion of relatively few children less than 5 years of age, a lack of details regarding the sample populations and measurement techniques and/or inappropriate statistical analysis. A fresh approach based on large sample sizes, clearly documented population characteristics, equipment and protocols, and more rigorous modern statistical methods both for developing reference equations and interpreting results could enhance clinical application of these tests. This in turn would maximize the tremendous opportunities to detect early lung disease offered by the recent surge in developing suitable tests for preschool children.     

Spirometric pulmonary function in 3- to 5-year-old children

Forced expiratory maneuvers are routinely used in children, 6 years of age and older for the diagnosis and follow-up of respiratory diseases. Our objective was to establish normative data for an extensive number of parameters measured during forced spirometry in healthy 3- to 5-year-old children. Children aged between 3 and 5 years were tested in 11 daycare centers. Usual parameters, including FEV1, FVC, PEF, FEF(25-75), FEF25, FEF50, FEF75, and Aex were measured and analyzed in relation to sex, age, height, and weight. In addition, the same analysis was performed for FEV0.5 and FEV0.75. One hundred sixty-four children were recruited for testing including 87 girls and 77 boys. Thirty-five were 3 years old, 63 were 4 years old, and 66 were 5 years old. Overall, 143 children (87%) accepted to perform the test and 128 children (78%) were able to perform at least two technically acceptable expiratory maneuvers. Analyses using different regression models showed that height was the best predictor for every parameter. In conclusion, the present study confirms that most healthy 3-5 years old children can perform valid forced expiratory maneuvers. In agreement with other studies, we found that height is the most important single predictor of various parameters measured on forced spirometry. The present study is the first to establish normative values for FEV0.75, as well as to demonstrate that Aex can be easily performed in the majority of children aged 3-5 years. These are likely important parameters of lung function in this age range.     

Pulmonary diffusing capacity at reduced alveolar volumes in children

The diffusing capacity, when normalized per liter of alveolar volume (D_L,CO/V_A) decreases in normal adults, whereas their total diffusing capacity (D_L,CO) increases as alveolar volume (V_A) increases. We studied these relationships in a group of normal children below 20 years of age. Diffusion variables were determined using the single breath technique. The effects of sex, age, and height on these relationships were estimated. D_L,CO increased and D_L,CO/V_A decreased as alveolar volume increased. D_L,CO and D_L,CO/V_A reference values at total lung capacity (TLC) appeared to be comparable to reference values at TLC in the literature. Reference values of D_L,CO and D_L,CO/V_A derived from measurements at various alveolar volumes also predict similar values at TLC. The advantage of our reference equations is their applicability to patients with restrictive lung disease. Actual D_L,CO/V_A can be compared with reference D_L,CO/V_A at actual (restrictive) TLC instead of reference D_L,CO/V_A at reference TLC. This comparison extends the evaluation of a diffusion disorder. Pediatr Pulmonol. 1996; 21:84–89. © 1996 Wiley-Liss, Inc.     

Influence of socioeconomic status on lung function and prediction equations in Indian children

The present study was carried out to assess the influence of socioeconomic status on lung functions and to suggest prediction equations for Indian children. For this purpose, 2,616 normal, healthy schoolchildren aged between 5-15 years were recruited. Boys were classified into three groups, i.e., high-income (HIG), middle-income (MIG), and low-income (LIG), while girls were classified into HIG and LIG groups, based on socioeconomic status (SES). Height, weight, chest circumference, body surface area (BSA), fat-free mass (FFM), and body fat were assessed. Forced expiratory volume in 1 sec (FEV1), forced vital capacity (FVC), FEV1/FVC ratio, and peak expiratory flow rate (PEFR) were measured. The results, before and after adjustment of physical characteristics, showed that anthropometry, body composition, and lung functions were significantly higher in HIG compared to MIG and LIG children, while in girls, no differences were observed in physical characteristics after adjustments. Multiple linear regression equations were developed to predict FEV1, FVC, and PEFR, using independent variables like age, height, fat-free mass, and SES. It is opined that these equations could be used as Indian reference equations for healthy children based on the SES.