IPPB-assisted coughing in neuromuscular disorders

In neuromuscular disorders, reduced peak cough flows (PCFs) are considered to increase the risk of respiratory complications such as pneumonia or chronic atelectasis. Different methods were described to improve PCF. However, these studies were primarily carried out in adults, and there is limited information regarding the use and efficacy of these methods in children with respiratory muscle weakness. The aim of this study was to investigate whether hyperinsufflation with an intermittent positive-pressure breathing (IPPB) device is effective in cough augmentation in pediatric patients. Spirometry (forced inspiratory vital capacity, FIVC; forced expiratory volume in 1 sec, FEV1), respiratory muscle pressures (peak inspiratory pressure, PIP; peak expiratory pressure, PEP), and PCF were measured in 29 schoolchildren with various neuromuscular disorders. IPPB-assisted hyperinsufflation was taught individually to increase lung volumes (maximum insufflation capacity, MIC) above FIVC. The impact of hyperinsufflation on peak cough flow was documented. In 28/29 patients, IPPB-assisted hyperinsufflation enhanced FIVC from 0.68 +/- 0.40 l to an MIC of 1.05 +/- 0.47 l (P < 0.001). Unassisted PCF was 119.0 +/- 57.7 l/min, and increased to 194.5 +/- 74.9 l/min (P < 0.001) in 27/29 patients. This effect was similar in young patients (ages 6-10 years) and older patients (aged >10 years). Augmentation of lung volumes from FIVC to MIC correlated with an increase of PCF (R = 0.42, P < 0.05). IPPB-assisted hyperinsufflation improves PCF in pediatric neuromuscular disorders. The results suggest that this technique can be used to improve clearance of airway secretions and therefore reduce respiratory morbidity in children with NMD.     

Spirometry reference values for Navajo children ages 6–14 years

Spirometry is the most important tool in diagnosing pulmonary disease and is the most frequently performed pulmonary function test. Since respiratory disease is the single greatest cause for morbidity and mortality on the Navajo Nation, the purpose of this study was to create new age and race‐specific pulmonary nomograms for Navajo children. Five hundred fifty‐eight healthy children, ages 6–14 years, attending Navajo Nation elementary schools in Arizona, were asked to perform spirometry to develop population‐specific and tribe‐specific nomograms for forced vital capacity (FVC), forced expiratory volume in 1 sec (FEV1), and FEV1 Ratio (FEV1/FVC). Spirometry tests from 284 girls and 274 boys met American Thoracic Society quality control standards. Lung function values, except for FEV1/FVC, all increased with height. The lower limit of the normal range for FEV1/FVC was 80%. The spirometry reference equations from the healthy boys and girls were developed. Height and the natural log of height were significant predictors of FEV1, FVC, and FEF_25–75% in the gender‐specific models. The resulting population‐specific spirometry reference equations should be used when testing Navajo children ages 6–14 years. However, the use of the NHANES III spirometry reference equations for Caucasian children may not result in significant misclassification in clinical settings providing that a maximal effort is given by the Navajo child being tested. Pediatr Pulmonol. 2009; 44:489–496. © 2009 Wiley‐Liss, Inc.     

Spirometry in 5-year-olds--validation of current guidelines and the relation with asthma

INTRODUCTION: Spirometry is more frequently measured in younger children. Our primary aim was to validate 2005 ATS-ERS Task Force standards for spirometry in adults and older children among a population of 5-year-old children. Our secondary aim was to relate spirometry to asthma symptoms. METHODS: Children were participants in a longitudinal cohort study where asthma symptoms and spirometry were assessed. RESULTS: Of the 827 children assessed, spirometry was obtained in 638 (85 with wheeze). A back-extrapolated volume/FVC ratio of <5% was achieved in 99% of children, the best two FVC were < or =150 ml of each other in 89% and three efforts were obtained within six attempts in 88%. The best two FVC were within 10% of each other in 82% of children. Only 13% achieved a forced expiratory time (FET) of > or =3 sec, whereas 80% had an FET of > or =1 sec. All criteria (including FET > or =1 s and FVC < or =10%) were met in 400 (65%) of the 638 children. Most spirometric indices were reduced in association with current wheeze and a history of asthma; children with current wheeze had a mean reduction of 0.65 FEV(1) z score compared to healthy children, P < 0.001. An FEV(1) z score of -1.0 had 82% sensitivity but only 50% specificity for current wheeze, the corresponding numbers for an FEF(50) z score of -1.0 being 79% and 71%. CONCLUSIONS: The standards for spirometry are mostly achieved in this age group but are not necessarily valid and require revision. Reliable spirometry is feasible in 5-year-old children where reduced measurements are associated with asthma symptoms and in whom FEF(50) appears to be the most discriminatory variable.     

Changes in spirometry over time as a prognostic marker in patients with Duchenne muscular dystrophy.

Duchenne muscular dystrophy (DMD) causes a progressive impairment of muscle function leading to hypercapnic respiratory failure. Most studies of respiratory function in DMD have been cross-sectional rather than longitudinal, and these data have not been related to survival. We retrospectively studied 58 patients with DMD with at least 2 yr of follow-up spirometry and known vital status. Spirometry was abnormal at entry: median FEV(1) 1.60 L (range 0.4 to 2.6 L), FVC 1.65 L (range 0.45 to 2.75 L), FVC 64% predicted (range 29 to 97%). Individual rates of change of vital capacity varied, with a median annual change of -0.18 L (range 0.04 to -0.74 L), -8.0% predicted FVC (range 2 to -39%). During the study 37 patients died; the median age of death, calculated by Kaplan-Meier analysis, was 21.5 yr (range 15 to 28.5 yr). The age when vital capacity fell below 1 L was a strong marker of subsequent mortality (5-yr survival 8%). The maximal vital capacity recorded and its rate of decline (however expressed) predicted survival time. Repeated spirometric measurement provides a simple and relatively powerful means of assessing disease progression in these patients and should be considered when planning treatment trials.     

Spirometry in an unselected group of 6-year-old children: the DARC birth cohort study

This study presents reference equations for spirometric parameters in 6-year-old children and evaluates the ability of spirometry to discriminate healthy children from children with asthma. Baseline spirometry and respiratory symptoms were assessed in 404 children participating in a longitudinal birth cohort study. Children with known asthma, possible asthma and a control group also performed bronchodilator measurements. At least two acceptable flow-volume curves at baseline were obtained by 368/404 children (91%). The two best values for FEV1 and FVC were within 5% of each other in 88% and 83% of children, respectively. Linear regression analyses for 242 children included in the reference population demonstrated height to be the main predictor of all spirometric indices except FEV1/FVC. FEV1, FEV75, and FVC correlated reasonably to anthropometric data in contrast to flow parameters. Gender differences were found for FEV1, FVC, and FEV75, but not for flow parameters. Asthma was diagnosed in 25/404 children. Baseline lung function in healthy children and children with asthma overlapped, although asthmatic children could be discriminated to some extent. Bronchodilator tests showed a difference in Delta FEV1(mean) between healthy children and children with asthma (3.1% vs. 6.1%, P < 0.05). At a cut-off point of Delta FEV1 = 7.8%, bronchodilator tests had a sensitivity of 46% and a specificity of 92% for current asthma. Spirometry including bronchodilator measurements was demonstrated to be feasible in 6-year-old children and reference values were determined. Spirometry aids the diagnosis of asthma in young children, but knowledge on sensitivity and specificity of these measurements is a prerequisite.     

How accurate is spirometry at predicting restrictive pulmonary impairment?

OBJECTIVE: To determine the accuracy with which spirometric measurements of FVC and expiratory flow rates can diagnose the presence of a restrictive impairment. DESIGN: The pulmonary function tests of 1,831 consecutive white adult patients who had undergone both spirometry and lung volume measurements on the same visit over a 2-year period were analyzed. The probability of restrictive pulmonary impairment, defined as a reduced total lung capacity (TLC) below the lower limit of the 95% confidence interval, was determined for each of several categoric classifications of the spirometric data, and additionally for each of several interval levels of the FVC and the FEV1/FVC ratio. SETTING: A large clinical laboratory in a university teaching hospital using quality-assured and standardized spirometry and lung volume measurement techniques according to American Thoracic Society standards. RESULTS: Two hundred twenty-five of 1,831 patients (12.3%) had a restrictive defect. The positive predictive value of spirometry for predicting restriction was relatively low; of 470 patients with a low FVC on spirometry, only 41% had restriction confirmed on lung volume measurements. When the analysis was confined to the 264 patients with a restrictive pattern on spirometry (ie, low FVC and normal or above normal FEV1/FVC ratio), the positive predictive value was 58%. Conversely, spirometry had a very favorable negative predictive value; only 2.4% of patients (32 of 1,361) with a normal vital capacity (VC) on spirometry had a restrictive defect by TLC measurement. The probability of a restrictive defect was directly and linearly related to the degree of reduction of FVC when the FVC was < 80% of predicted (p = 6.002). Combining the FVC and the FEV1/FVC ratio improved the predictive ability of spirometry; for all values of FVC < 80% of the predicted amount, the likelihood of restrictive disease increased as the FEV1/FVC ratio increased. CONCLUSIONS: Spirometry is very useful at excluding a restrictive defect. When the VC is within the normal range, the probability of a restrictive defect is < 3%, and unless restrictive lung disease is suspected a priori, measurement of lung volumes can be avoided. However, spirometry is not able to accurately predict lung restriction; < 60% of patients with a classical spirometric restrictive pattern had pulmonary restriction confirmed on lung volume measurements. For these patients, measurement of the TLC is needed to confirm a true restrictive defect.     

Predicting inadequate spirometry technique and the use of FEV1/FEV3 as an alternative to FEV1/FVC for patients with mild cognitive impairment

Introduction and Objectives: Some patients cannot perform forced vital capacity (FVC). We conducted a study to answer three questions: Can the ability to perform components of spirometry be predicted by the Mini Mental State Examination (MMSE)? What proportion of subjects can perform forced expiratory volume in 3 s (FEV3) but not FVC? Does the forced expiratory volume in 1 s (FEV1)/FEV3 ratio concord with FEV1/FVC ratio in patients with airflow obstruction? Methods: We conducted a prospective observational study of 267 patients with a mean age of 79 years, including subjects with indicators of frailty. They performed spirometry and the MMSE. Spirometric recordings were compared to the American Thoracic Society 1994 criteria. Results: FVC was achieved by 51% of patients. Inability to perform FVC was predicted by an MMSE < 24 (specificity 94%, sensitivity of 51%). An FEV1/FEV3 ratio < 80% matched a FEV1/FVC ratio < 70% (sensitivity 96%, specificity 97%). Twenty‐five percent of subjects were able to reach FEV3 but not FVC; 14% of that group had an MMSE < 24. Subjects with an MMSE < 20 were unable reliably to perform any spirometry. Conclusion: Patients with an MMSE < 24 are usually unable to reach FVC reliably when tested on a single occasion, but some can reach FEV3. Patients with MMSE < 20 cannot do spirometry. An FEV1/FEV3 ratio < 80% can be used to help identify patients with airflow obstruction if they are unable to perform full spirometry to FVC. Please cite this paper as: Allen S, Yeung P, Janczewski M and Siddique N. Predicting inadequate spirometry technique and the use of FEV1/FEV3 as an alternative to FEV1/FVC for patients with mild cognitive impairment. The Clinical Respiratory Journal 2008; 2: 208–213.     

Effect of tobacco smoking, respiratory symptoms and asthma on spirometry among adults attending a check-up clinic in Mexico City

OBJECTIVE: To evaluate the effect of tobacco smoking, respiratory symptoms, and asthma on lung function among Mexican adults who were evaluated during a medical exam in a private health clinic. MATERIAL AND METHODS: Reference prediction equations were generated for spirometry parameters [forced vital capacity (FVC), forced expired volume in one second (FEV1) and FEV1/FVC] based on multiple linear regression models. The effect of tobacco smoking, respiratory symptoms and asthma on these equations were explored. RESULTS: Spirometry tests were performed on 919 subjects from 14 to 86 years of age.Asthma decreased FVC and FEV1 in men with a R2 change <1%. Respiratory symptoms decreased the FEV1/FVC ratio in both sexes.Tobacco smoking was associated with a significant reduction in FEV in women. CONCLUSIONS: Asthma lightly reduced lung function in males while tobacco smoking decreased FEV, particularly in females.     

Airways obstruction in rheumatoid arthritis.

Owing to the report of an association between rheumatoid arthritis (RA) and obliterative bronchiolitis we have determined the prevalence of airflow obstruction in unselected patients with RA and normal chest radiographs. Spirometry was performed on 100 patients with rheumatoid arthritis and 84 control subjects matched for age, sex, and smoking habits. Patients with rheumatoid arthritis had significantly lower values for FEV1, FVC, FEV1/FVC, and MMEFR when compared with the controls: 39 patients had abnormal spirometry, and at least 32 showed airways obstruction. The prevalence of airflow obstruction is remarkably high, and we suggest that airway disease may be the commonest form of lung involvement in rheumatoid arthritis.     

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.     

Spirometry in early childhood in cystic fibrosis patients

BACKGROUND: Spirometry data in cystic fibrosis (CF) patients in early childhood is scarce, and the ability of spirometry to detect airways obstruction is debatable. OBJECTIVE: To evaluate the ability of spirometry to detect airflow obstruction in CF patients in early childhood. METHODS: CF children (age range, 2.5 to 6.9 years) in stable clinical condition were recruited from five CF centers. The children performed guided spirometry (SpiroGame; patented by Dr. Vilzone, 2003). Spirometry indices were compared to values of a healthy early childhood population, and were analyzed with relation to age, gender, and clinical parameters (genotype, pancreatic status, and presence of Pseudomonas in sputum or oropharyngeal cultures). RESULTS: Seventy-six of 93 children tested performed acceptable spirometry. FVC, FEV1, forced expiratory flow in 0.5 s (FEV0.5), and forced expiratory flow at 50% of vital capacity (FEF50) were significantly lower than healthy (z scores, mean +/- SD: - 0.36 +/- 0.58, - 0.36 +/- 0.72, - 1.20 +/- 0.87; and - 1.80 +/- 1.47, respectively; p < 0.01); z scores for FEV1 and FVC were similar over the age ranges studied. However, z scores for FEV0.5 and forced expiratory flow at 25 to 75% of vital capacity were significantly lower in older children compared to younger children (p < 0.001), and a higher proportion of 6-year-old than 3-year-old children had z scores that were > 2 SDs below the mean (65% vs 5%, p < 0.03). Girls demonstrated lower FEF50 than boys (z scores: - 2.42 +/- 1.91 vs - 1.56 +/- 1.23; p < 0.001). Clinical parameters evaluated were not found to influence spirometric indices. CONCLUSIONS: Spirometry elicited by CF patients in early childhood can serve as an important noninvasive tool for monitoring pulmonary status. FEV0.5 and flow-related volumes might be more sensitive than the traditional FEV1 in detecting and portraying changes in lung function during early childhood.     

Medikro SpiroStar USB便携式肺功能仪临床应用研究

目的 比较在不同肺功能状态人群中用Medikro SpiroStar USB便携式肺功能仪与传统Jaeger MasterScreen IOS肺功能仪测定的一致性。方法 用Jaeger MasterScreen IOS肺功能仪与Medikro SpiroStar USB肺功能仪分别对100例正常肺功能者,阻塞性、限...     

Peak expiratory flow is not a quality indicator for spirometry: peak expiratory flow variability and FEV1 are poorly correlated in an elderly population

BACKGROUND: Peak forced expiratory flow (PEF) and FEV(1) are spirometry measures used in diagnosing and monitoring lung diseases. We tested the premise that within-test variability in PEF is associated with corresponding variability in FEV(1) during a single test session. METHODS: A total of 2,464 healthy adults from the Health, Aging, and Body Composition Study whose spirometry results met American Thoracic Society acceptability criteria were screened and analyzed. The three "best" test results (highest sum of FVC and FEV(1)) were selected for each subject. For those with acceptable spirometry results, two groups were created: group 1, normal FEV(1)/FVC ratio; group 2, reduced FEV(1)/FVC ratio. For each subject, the difference between the highest and lowest PEF (DeltaPEF) and the associated difference between the highest and lowest FEV(1) (DeltaFEV(1)) were calculated. Regression analysis was performed using the largest PEF and best FEV(1), and the percentage of DeltaPEF (%DeltaPEF) and percentage of DeltaFEV(1) (%DeltaFEV(1)) were calculated in both groups. RESULTS: Regression analysis for group 1 and group 2 showed an insignificant association between %DeltaPEF and %DeltaFEV(1) (r(2) = 0.0001, p = 0.59, and r(2) = 0.040, p = 0.15, respectively). For both groups, a 29% DeltaPEF was associated with a 1% DeltaFEV(1). CONCLUSION: Within a single spirometry test session, %DeltaPEF and %DeltaFEV(1) contain independent information. PEF has a higher degree of intrinsic variability than FEV(1). Changes in PEF do not have a significant effect on FEV(1). Spirometry maneuvers should not be excluded based on peak flow variability.     

Validity of the American Thoracic Society and other spirometric algorithms using FVC and forced expiratory volume at 6 s for predicting a reduced total lung capacity

OBJECTIVES: (1) To compare the performance of three spirometric algorithms developed to predict whether the total lung capacity (TLC) is reduced vs normal or increased, (2) to determine if forced expiratory volume at 6 s (FEV(6)) can be substituted for FVC in these algorithms, and (3) to determine if ascertainment bias was present in patients referred for the measurement of spirometry and TLC compared to patients referred for spirometry only. METHODS: We analyzed the results of 219 consenting consecutive patients referred to a New Zealand tertiary hospital respiratory laboratory for spirometry and TLC measurements. Spirometry results from 370 patients referred for spirometry but not lung volumes were used to test for potential ascertainment bias. Spirometry results were analyzed using the lower limit of normal (LLN) values from the third National Health and Nutrition Examination Study reference equations. The equations of Goldman and Becklake, and Crapo were used to classify TLC as normal or abnormal. Receiver operator characteristic curves were used to produce an algorithm using the LLN for FVC and FEV(6). The performances of previous algorithms and our own algorithms were analyzed for predicting a reduced lung volume against the "gold standard," plethysmographic TLC. RESULTS: All three algorithms predicted a reduced TLC with an accuracy of approximately 50%. In contrast, all algorithms predicted TLC was either normal or increased with an accuracy of > or = 99% regardless of the reference set used. The algorithms based on FEV(6) performed equally as well as the FVC algorithms. No ascertainment bias was found. CONCLUSIONS: This study provides evidence that spirometry-based algorithms can accurately predict when TLC is either normal or increased, and can also increase the a priori probability that TLC is reduced to approximately 50%. FEV(6) is equivalent to FVC in these predictions.     

Clinical data discriminating between adults with positive and negative results on bronchodilator testing.

OBJECTIVE: To evaluate how spirometry, symptoms and smoking discriminate between subjects who are responsive to bronchodilator testing and those who are non-responsive, and to examine how cut-off points of positive tests are related to symptoms of chronic obstructive pulmonary disease (COPD) and asthma. METHODS: Subjects aged 47-48 and 71-73 years living in Bergen, Norway, were recruited. The 3506 participants (69%) filled in questionnaires and performed a bronchodilator test using salbutamol. RESULTS: Tests were positive (forced expiratory volume in 1 s [Delta FEV1] >or=200 ml and >or=12%) in 107 subjects (3%). In logistic regression, spirometry (FEV1 < 80%, OR 6.0, 95%CI 3.6-10.2, and FEV1/FVC < 0.70, OR 3.1, 95%CI 1.9-5.2) and pack-years >or= 20 (OR 0.3, 95%CI 0.2-0.7), but not symptoms, predicted the test outcome. FEV1% and FEV1/forced volume capacity (FVC) discriminated equally well between positive and negative tests (area under the receiver operating characteristic [ROC] curve 0.81, 95%CI 0.77-0.85 vs. 0.77, 95%CI 0.72-0.82). The largest likelihood ratio for positive tests was 5.4 (95%CI 3.8-7.8) using FEV1 < 80% and FEV1/FVC < 0.70. CONCLUSIONS: Spirometry and to a lesser extent smoking, but not symptoms, are useful in discriminating between middle-aged and elderly patients with positive and negative bronchodilator tests. Acute responses to salbutamol, expressed by commonly used Delta FEV1 cut-off points, are poorly related to COPD- and asthma-like symptoms.     

Spirometric values in Gypsy (Roma) children

Values of spirometry indices vary among subjects of similar age, gender and somatometrics but of different ethnic origins. Low socioeconomic status in childhood is inversely related to lung growth. The aim of this investigation was to assess spirometry values in Gypsy children and compare them to reported values for Caucasians. Gypsy students attending primary schools in Central Greece were recruited. Spirometry indices were measured using a portable spirometer. Regression analysis was applied to construct prediction equations for forced vital capacity (FVC) and other spirometric indices (FEV(1), FEF(50), FEF(25), FEF(25-75)) based on standing height. Predicted spirometric values were compared to values for Caucasians from published studies. In 152 children (ages 5-14 years; 57 girls) lung function increased linearly with height: spirometry index=intercept+[slopexheight], (r(2)=0.68 for FVC and FEV(1) in girls; r(2)=0.78 for FVC and r(2)=0.74 for FEV(1) in boys). Excluding boys-but not girls-in puberty increased fit for FVC (r(2)=0.83) and FEV(1) (r(2)=0.79). Mean predicted values were 5-10% lower than values for Caucasians. In Gypsy children, FVC and expiratory flow function increase linearly with standing height and predicted values are lower than those for Caucasians of similar height.     

Six-second spirometry for detection of airway obstruction: a population-based study in Austria

RATIONALE: The presence of airway obstruction is currently defined by Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines on the basis of the post-bronchodilator (BD) FEV(1)/FVC. It has been proposed that the traditional FVC can be replaced with the shorter and less demanding FEV(6) for detecting airway obstruction. OBJECTIVES: A comparison of FEV(1)/FVC and FEV(1)/FEV(6) for the detection of airway obstruction in population-based post-bronchodilator spirometry data. METHODS: A population-based sample of 1,349 adults participated in the Burden of Obstructive Lung Disease study in Austria. Specially trained and certified technicians conducted pre-BD and post-BD spirometry according to American Thoracic Society guidelines and administered standardized questionnaires. A total of 93% of the post-BD test sessions were acceptable, and were included in this analysis. The Third National Health and Nutrition Examination Survey reference equations were used to calculate predicted values and lower limits of normal (LLN) for FEV(1), FEV(6), FVC, FEV(1)/FVC, and FEV(1)/FEV(6). MEASUREMENTS AND MAIN RESULTS: The post-BD FEV(1)/FVC was below the LLN in 199 (15.8%) subjects. The sensitivity of the FEV(1)/FEV(6) for airway obstruction depended greatly on the threshold of percent predicted FEV(1) also used in the definition. The overall sensitivity of FEV(1)/FEV(6) for a diagnosis of airway obstruction, as defined by FEV(1)/FVC (including participants with an FEV(1) above the LLN), was 72.9%, with 98.8% specificity. The sensitivity increased to 98.0% when a low FEV(1) was also required to diagnose post-BD airway obstruction. The discordant cases had long forced expiratory times, often showed a flow-volume curve pattern consistent with two-compartment emptying, and were more often never-smokers. CONCLUSIONS: Six-second spirometry maneuvers (which measure FEV(6)) are as sensitive and specific for post-BD airway obstruction as traditional (prolonged exhalation time) FVC maneuvers only when the definition of airway obstruction includes a low FEV(1).     

脉冲振荡法在阻塞性通气功能障碍评定中的价值

目的 探讨脉冲振荡法评定阻塞性通气功能障碍的应用价值及其与常规肺通气功能测定的关系.方法 2007年11月至2008年5月,采用德国耶格公司的肺功能仪及产品说明书给出的预计值公式,测定100例(男72例,女28例)门诊和住院患者的FEV1、FVC、5 Hz时气道阻力(R5)、20 Hz时气道阻力(R20)、结构参数图中的中心阻力(Rc)和周边阻力(Rp)的实测值,FEV1、R5和R20占预计值%,以及FEV1/FVC等指标.并对常规和脉冲振荡法测定肺通气功能的指标进行相关分析.结果 所有受试者均获得满意的脉冲振荡测定结果.当FEV1/FVC低于正常时(＜70%),R5和Rp明显升高至(5.3±2.1)和(6.2±2.9)cm H2O·L-1·S-1(1 cm H2O=0.098 kPa),FEV1与R5、Rp呈显著负相关(r值分别为-0.38和-0.47,均P＜0.01),FVC与R5、Rp也呈显著负相关(r值分别为-0.28和-0.37,均P＜0.01).FEV1占预计值%、FVC占预计值%、FEV1/FVC与R5占预计值%均呈显著负相关(r值分别为-0.49、-0.39和-0.43,均P＜0.01).结论 脉冲振荡法的测定指标可用于评估阻塞性通气功能障碍,尤其是R5的诊断价值最大,并且与常规肺通气功能指标之间有良好的相关性.     

Spirometry in 3- to 6-year-old children with cystic fibrosis

Spirometry is routinely used to assess pulmonary function of older children and adults with cystic fibrosis (CF); however, few data exist concerning the preschool age group. We have reported normative spirometric data for 3- to 6-year-old children. The current study was designed to assess a similarly aged group of clinically stable patients with CF. Thirty-three of 38 children with CF were able to perform 2 or 3 technically acceptable maneuvers. These patients had significantly decreased FVC, FEV(1), FEV(1)/FVC, and FEF(25-75) when expressed as z scores (number of SD from predicted): -0.75 +/- 1.63, -1.23 +/- 1.97, -0.87 +/- 1.33, and -0.74 +/- 1.63, respectively. There were significant positive correlations of the Brasfield radiological score with FVC and FEV(1) z scores (r(2) = 0.26, p < 0.01 and r(2) = 0.24, p < 0.01). In addition, homozygous patients for the DeltaF508 mutation had lower z scores for FVC (-1.21 versus 0.47, p < 0.01) and FEV(1) (-1.38 versus 0.21, p < 0.05) than heterozygous patients. Of the 14 patients who had full flow-volume spirometric measurements during infancy, 10 had FEF(25-75) z scores greater than -2 at both evaluations. Our findings suggest that spirometry can successfully be used to assess lung function in preschool children with CF and has the potential for longitudinal assessment from infancy through adulthood.     

The Prevalence of COPD in Individuals with Acute Coronary Syndrome: A Spirometry-Based Screening Study

Background: The prevalence of COPD among individuals with acute coronary syndrome (ACS) is estimated at 5% to 18%, and COPD appears to be a predictor of poor outcome. Diagnosis of COPD has mostly been based on medical records without spirometry. As COPD is largely undiagnosed and misdiagnosed, the prevalence and clinical significance of COPD in the ACS population has not been reliably assessed. The present study aimed to estimate the prevalence of COPD in patients with ACS and evaluate the accuracy of medical record-based COPD diagnoses. Methods: This was a single-centre spirometry screening study for COPD in patients admitted for ACS in the county of Jämtland, Sweden. Patient medical records were reviewed to register previous medical history. Spirometry was performed prior to discharge or at the first follow-up outpatient visit after discharge. COPD was defined as a post-bronchodilator FEV1/FVC of <0.7 or below lower limit of normal. Results: Of 743 eligible patients, 407 performed spirometry. Five percent had COPD according to medical records; 11% and 5% fulfilled spirometric criteria of COPD according to FEV1/FVC of < 0.7 (p = 0.002) and below lower limit of normal definitions, respectively. “COPD according to medical history” had a sensitivity of 23%, specificity of 98%, positive predictive value of 53%, and negative predictive value of 91% compared with spirometric COPD FEV1/FVC of < 0.7 Conclusions: In patients with ACS, COPD is underdiagnosed and misdiagnosed. We raise concerns regarding the validity of medical record-based COPD in evaluating the biological and clinical association between COPD and coronary disease. ­Clinical Trial Registration: ISRCTN number 05697808 (www. controlled-trials.com)