Printer Friendly

A Simple Measure to Assess Hyperinflation and Air Trapping: 1-Forced Expiratory Volume in Three Second / Forced Vital Capacity.

Background: Several recent studies have suggested that 1 minus-forced expiratory volume expired in 3 seconds / forced vital capacity (1-[FEV.sub.3]/FVC) may be an indicator of distal airway obstruction and a promising measure to evaluate small airways dysfunction.

Aims: To investigate the associations of 1-[FEV.sub.3]/FVC with the spirometric measures and lung volumes that assess small airways dysfunction and reflects hyperinflation and air trapping.

Study Design: Retrospective cross-sectional study.

Methods: Retrospective assessment of a total of 1110 cases who underwent body plethysmographic lung volume estimations between a time span from 2005 to 2012. Patients were assigned into two groups: firstly by [FEV.sub.1]/FVC ([FEV.sub.1]/FVC <70% vs.[FEV.sub.1]/FVC [greater than or equal to]70%); secondly by [FEV.sub.3]/FVC < lower limits of normal (LLN) ([FEV.sub.3]/FVC < LLN vs. [FEV.sub.3]/FVC [greater than or equal to] LLN). Spirometric indices and lung volumes measured by whole-body plethysmography were compared in groups. Also the correlation of spirometric indices with measured lung volumes were assessed in the whole-study population and in subgroups stratified according to [FEV.sub.1]/FVC and [FEV.sub.3]/FVC.

Results: Six hundred seven (54.7%) were male and 503 (45.3%) were female, with a mean age of 52.5[+ or -]15.6 years. Mean [FEV.sub.3]/FVC and 1-[FEV.sub.3]/FVC were 87.05%, 12.95%, respectively. The mean 1-[FEV.sub.3]/FVC was 4.9% in the [FEV.sub.1]/FVC [greater than or equal to]70% group (n=644) vs. 24.1% in the [FEV.sub.1]/FVC <70% group (n=466). A positive correlation was found between 1-[FEV.sub.3]/FVC and residual volume (r=0.70; p<0.0001), functional residual capacity-pleth (r=0.61; p<0.0001), and total lung capacity (r=0.47; p<0.0001). 1-[FEV.sub.3]/FVC was negatively correlated with forced expiratory [flow.sub.25-75] (r=-0.84; p<0.0001). The upper limit of 95% confidence interval for 1-[FEV.sub.3]/FVC was 13.7%. 1-[FEV.sub.3]/FVC showed significant correlations with parameters of air trapping and hyperinflation measured by whole-body plethysmography. Importantly, these correlations were higher in study participants with [FEV.sub.1]/FVC <70% or [FEV.sub.3]/FVC < LLN compared to those with [FEV.sub.1]/FVC [greater than or equal to]70% or [FEV.sub.3]/FVC [greater than or equal to] LLN, respectively.

Conclusion: 1-[FEV.sub.3]/FVC can be easily calculated from routine spirometric measurements. 1-[FEV.sub.3]/FVC is a promising marker of air trapping and hyperinflation. We suggest that 1-[FEV.sub.3]/FVC is complementary to [FEV.sub.1]/FVC and recommend clinicians to routinely report and evaluate together with [FEV.sub.1]/FVC during spirometry.

Keywords: 1-[FEV.sub.3]/FVC, hyperinflation, spirometry

The ratio of the forced vital capacity (FVC) that is not yet expired within the first 3 seconds of a forced exhalation is expressed with the following formula: 1 minus-forced expiratory volume in third seconds (1-[FEV.sub.3]) / FVC (1,2). Originally, Hansen et al. (3) showed that 1-[FEV.sub.3]/FVC may be used for the evaluation of small airways, may be an indicator of the distal expiratory obstruction and was more sensitive than forced expiratory flow [(FEF).sup.25-75] % in evaluating small airways (3).

In chronic obstructive pulmonary diseases (COPD), although small airways are mainly involved, larger airways are also affected due to a number of factors, including the loss of ciliated epithelial cells, squamous metaplasia, thickening of the basement membrane, mucous gland hypertrophy and hyperplasia (4). All these factors contribute to irreversible obstruction mainly caused by progressive air trapping, which is a prominent feature of COPD. Both the peripheral and proximal airways are also affected not only in COPD but also in asthma. The forced expiratory volume in the first second ([FEV.sub.1]) mainly reflects large airways obstruction, and for [FEV.sub.1] to become abnormal a significant amount of small airways must be affected (5). Later fractions of forced exhalation those occur after [FEV.sub.1], such as [FEV.sub.3] was proposed to be more sensitive to reductions in terminal expiratory flow (1,3). For that reason, [FEV.sub.3], [FEV.sub.3]/FVC ratio and 1-[FEV.sub.3]/FVC were suggested to better assess small airways disease (3,6-8). Therefore, both in asthma and COPD, 1-[FEV.sub.3]/FVC may be an indicator of small airways dysfunction and air trapping.

In order to detect the presence of air trapping in the lungs, lung volumes should be measured to determine the total lung capacity and the residual volume. However, since these methods are associated with increased medical costs and require sophisticated equipment, they are not widely utilized. However, 1-[FEV.sub.3]/FVC value can be readily calculated by the widely available standard spirometric examination, and thus may help to detect air trapping in patients with obstructive pulmonary disease. In order to test this hypothesis, the present study aimed to investigate the associations of 1-[FEV.sub.3]/FVC in obstructive lung diseases and its relationship with the spirometric measures and lung volumes that assess small airways dysfunction, which reflects hyperinflation and air trapping.

MATERIALS AND METHODS

A retrospective assessment of a total of 1110 participants with at least three acceptable spirometric manoeuvres who underwent body plethysmographic lung volume estimations (ZAN 500 Plethysmography, nSpire, Germany) between 2005 and 2012 at the Pulmonary Function Test Laboratory was carried out. Repeated tests of same person were excluded (according to duplicated name, surnames and identity card numbers). None of the authors have reported a conflict of interest prior to the study. The pulmonologists reviewed all of the pulmonary function tests on a daily basis. The technicians were trained in whole-body plethysmography techniques, and the laboratory supervisor also checked all the steps involved in the test procedures in terms of adherence to the American Thoracic Society and American Thoracic Society/European Respiratory Society guidelines (9-12). The whole-body plethysmography device was calibrated daily according to manufacturer's guidelines and biological quality control was performed on a monthly basis.

Patients younger than 18 years of age were excluded, and only pre-bronchodilator test results were utilized. 1-[FEV.sub.3]/FVC was calculated electronically by whole-body plethysmography for each patient; this can also be calculated by spirometers.

1-[FEV.sub.3]/FVC estimation: After [FEV.sub.3] and [FEV.sub.3]/FVC measurements were obtained from records of the patients, 1-[FEV.sub.3]/FVC was calculated to show the remaining unexhaled vital capacity ratio in the lung at the end of the 3 (rd) second [(FVC-[FEV.sub.3])/FVC=1-[FEV.sub.3]/FVC].

There is controversy regarding appropriate criteria to define airflow obstruction by using the fixed threshold of 70% or the lower limits of normal (LLN) for the [FEV.sub.1]/FVC ratio (13). In the present study, firstly, we defined airflow obstruction by using the fixed threshold of 70% for the [FEV.sub.1]/FVC ratio by using pre-bronchodilator spirometry (14,15). Patients were assigned into either the group with [FEV.sub.1]/FVC <70% or the group with [FEV.sub.1]/FVC [greater than or equal to]70%. The two groups were compared in terms of FVC, [FEV.sub.1], [FEV.sub.1]/FVC, [FEF.sub.25-75], inspiratory capacity (IC), total lung capacity (TLC), residual volume (RV), RV/TLC, thoracic gas volume at functional residual capacity (FRC-pleth), [FEV.sub.3], [FEV.sub.3]/FVC, and 1-[FEV.sub.3]/FVC.

Secondly, in order to assess whether [FEV.sub.3]/FVC (accordingly, 1-[FEV.sub.3]/FVC) provides additional information on air trapping and hyperinflation to that of [FEV.sub.1]/FVC, we analysed correlations of [FEV.sub.3]/FVC abnormality. We defined [FEV.sub.3]/FVC abnormality by using the redefined LLN criteria for [FEV.sub.3]/FVC (16). Analyses were performed separately, for the whole study population, and the subgroups, including individuals with [FEV.sub.3]/FVC < LLN and [FEV.sub.3]/FVC [greater than or equal to] LLN.

Statistical analyses

Statistical analyses were performed using Statistical Package for Social Sciences (SPSS) software version 21.0 (IBM SPSS Statistics for Windows, Armonk, NY: IBM Corp.) Continuous variables were expressed as mean [+ or -] standard deviation, whereas categorical variables were shown as the number and percentage of cases. Means and medians were compared using Student's t-test or Mann-Whitney U-test, depending on the normality distribution of data. A p value <0.05 was considered an indication of statistical significance. In addition, the correlations between variables were tested using Spearman's correlation analysis. The study protocol was approved by the Ethics Board (Approval No: 83045809/604.01/02-346067).

RESULTS

Of the overall study population, 607 (54.7%) were male, and 503 (45.3%) were female, with a mean age of 52.5[+ or -]15.6 years, mean [FEV.sub.3]/FVC of 87.05% and 1-[FEV.sub.3]/FVC of 12% (Table 1).

Of the total study population, 644 had a [FEV.sub.1]/FVC ratio [greater than or equal to]70%, and 466 had [FEV.sub.1]/FVC <70%. Mean [FEV.sub.3]/FVC was 95.1% in the group with [FEV.sub.1]/FVC [greater than or equal to]70% and 75.9% in the group with [FEV.sub.1]/FVC <70%, while the corresponding 1-[FEV.sub.3]/FVC values in these two groups were 4.9% and 24.1%, respectively (Table 2). The upper 95% confidence limit for 1-[FEV.sub.3]/FVC was 13.7%.

Individuals with [FEV.sub.1]/FVC <70% had a significantly higher TLC, RV, FRCpleth, RV/TLC, and a significantly more reduced IC than those with [FEV.sub.1]/FVC [greater than or equal to]70% (Table 2). 1-[FEV.sub.3]/FVC had moderate to strong and significant correlations with RV (r=0.70; p<0.0001), [FEF.sub.25-75] (r=-0.84; p<0.0001), RV/TLC (r=0.59; p<0.0001), TLC (r=0.47; p<0.0001) and FRCpleth (r=0.61; p<0.0001) in the total study population (Table 3). When analysed separately in the [FEV.sub.1]/FVC [greater than or equal to]70% and [FEV.sub.1]/FVC <70% groups, we observed that 1-[FEV.sub.3]/FVC had significant correlations with RV, RV/TLC, TLC, FRC pleth and [FEF.sub.25-75] (Table 3). Importantly, 1-[FEV.sub.3]/FVC displayed stronger correlations with RV, RV/LC, TLC, FRCpleth and [FEF.sub.25-75] in those with [FEV.sub.1]/FVC <70% compared to those with [FEV.sub.1]/FVC [greater than or equal to]70% (Table 3). On the other hand, correlation of 1-[FEV.sub.3]/FVC with IC was weak in the total study population and both [FEV.sub.1]/FVC [greater than or equal to]70% and [FEV.sub.1]/FVC <70% groups (Table 3).

In a further analysis, we assessed [FEV.sub.3]/FVC normality by the newly defined [FEV.sub.3]/FVC LLN criteria. A total of 379 (34.1%) of the whole study population were below the LLN for [FEV.sub.3]/FVC. Individuals with [FEV.sub.3]/FVC < LLN had a significantly higher TLC, RV and RV/TLC, and a significantly more reduced IC than those in the group with [FEV.sub.3]/FVC [greater than or equal to] LLN (Table 4).

1-[FEV.sub.3]/FVC had significant correlations with RV, RV/TLC, TLC, FRCpleth and [FEF.sub.25-75] in both [FEV.sub.3]/FVC [greater than or equal to] LLN and [FEV.sub.3]/FVC < LLN groups. 1-[FEV.sub.3]/FVC displayed stronger correlations with RV, RV/TLC, TLC, FRCpleth and [FEF.sub.25-75] in those with [FEV.sub.3]/FVC < LLN compared to those with [FEV.sub.3]/FVC [greater than or equal to] LLN (Table 4). More importantly, we observed somewhat higher correlation coefficients for [FEV.sub.3]/FVC with IC, [FEF.sub.25-75] and the air trapping measures - RV and RV/TLC - in [FEV.sub.3]/FVC < LLN subgroup than the correlations observed in [FEV.sub.1]/FVC <70% subgroup (Table 5).

We also observed that [FEV.sub.1]/FVC has a similar or slightly higher level of correlation with TLC, RV, FRCpleth, RV/TLC and [FEF.sub.25-75] in the total study population and subgroup analyses (Table 3). But when airflow obstruction is defined by [FEV.sub.3]/FVC LLN criterion instead of [FEV.sub.1]/FVC, we observed that 1-[FEV.sub.3]/FVC displays a stronger correlation with TLC (r=0.66, p<0.0001), RV (r=0.67, p<0.0001), RV/TLC (r=0.55, p<0.0001), FRCpleth (r=0.66, p<0.0001), [FEF.sub.25-75] (r=-0.82, p<0.0001) and even with IC (r=0.30, p<0.0001) (Table 4).

DISCUSSION

In the present study, we report that the fraction of FVC that has not been expired at the end of the first three seconds of the FVC (1-[FEV.sub.3]/FVC), is significantly increased in patients with a [FEV.sub.1]/FVC below 70%. Both groups, including [FEV.sub.1]/FVC <70% and [FEV.sub.3]/FVC < LLN subjects, had significantly increased hyperinflation and air trapping with regard to RV, RV/TLC, TLC compared to [FEV.sub.1]/FVC [greater than or equal to]70% and [FEV.sub.3]/FVC [greater than or equal to] LLN groups, respectively. We also showed that 1-[FEV.sub.3]/FVC significantly correlates with measures of hyperinflation and air trapping in the whole study population as well as in subgroup analyses, including [FEV.sub.1]/FVC <70% and [FEV.sub.3]/FVC < LLN subjects.

Small airways are major contributors to airflow limitation in asthma and COPD (17). Air trapping and premature airway closing are accepted as useful surrogates to assess and quantify small airways obstruction. RV and RV/TLC ratios are useful and widely accepted measures of hyperinflation and air trapping (18).

The earliest change associated with airflow obstruction is a reduction in the terminal portion of the spirogram, even though the initial part of the spirogram is barely affected (9). In this context, later fractions of forced exhalation, i.e. those that occur after the first second of exhalation, such as [FEV.sub.3], were proposed to define reductions in terminal expiratory flow (1,3). [FEV.sub.3] and [FEV.sub.3]/FVC were introduced in the last three decades, first by Crapo et al. (19) in 1981, followed by Miller et al. (20,21) in 1985. Later on, Hansen et al. (16) introduced the concept of 1-[FEV.sub.3]/FVC to identify the increased fraction of the long-time-constant lung units as a measure of late expiratory fraction in their study utilizing data from a smokers and never-smokers population of the Third National Health and Nutrition Examination Survey (22). Our study shows that 1-[FEV.sub.3]/FVC is a promising spirometric parameter that correlates with markers of air trapping and hyperinflation. 1-[FEV.sub.3]/FVC can be easily calculated by using standard spirometry through the measurement of [FEV.sub.3] at the 3rd second of the forced expiratory manoeuvre. We suggest that 1-[FEV.sub.3]/FVC may be used to assess the presence of hyperinflation and air trapping, especially in settings where the lung volumes cannot be measured. Furthermore, [FEV.sub.3]/FVC LLN criteria define a group with significantly worse spirometric indices ([FEV.sub.1], [FEV.sub.3], [FEV.sub.1]/FVC, [FEF.sub.25-75]), and increased RV, RV/TLC, TLC compared to [FEV.sub.3]/FVC [greater than or equal to] LLN subjects.

Previously, [FEV.sub.3]/FVC and 1-[FEV.sub.3]/FVC were reported to be superior to [FEF.sub.25-75] in the assessment of expiratory airflow limitation, since [FEF.sub.25-75] can be misleading, with a high rate of false-negative and false-positive results (3,22). We observed that [FEF.sub.25-75] had a high correlation with 1-[FEV.sub.3]/FVC in the total study population as well as in subgroup analyses. Interestingly, we found that [FEF.sub.25-75] had a higher correlation with RV/TLC and IC than that of 1-[FEV.sub.3]/FVC, whereas 1-[FEV.sub.3]/FVC had a higher correlation with RV, TLC and FRCpleth than that of [FEF.sub.25-75]. But as we did not define normality vs. abnormality according to LLN for [FEF.sub.25-75], our analysis did not allow a comparison of our results with previous findings.

In addition to these results, we also observed that not only [FEV.sub.3]/FVC but also [FEV.sub.1]/FVC was negatively correlated with RV (r=-0.75; p<0.001), RV/TLC (r=-0.63; p<0.001) and TLC (r=0.49; p<0.001). We think this finding is consistent with Hansen's suggestion that [FEV.sub.1]/FVC and [FEV.sub.3]/FVC are complementary and both ratios are beneficial in the characterization of expiratory airflow obstruction (3). Current studies and our own are still unable to answer the question of which ratio is better, 1-[FEV.sub.3]/FVC or the [FEV.sub.1]/FVC, in diagnosing expiratory airflow obstruction.

The potential strengths of this study include the fact that the pulmonary function test laboratory where all of the tests were performed is the most comprehensive and qualified laboratory in the country, accepting referrals for whole-body plethysmography from more than 40 hospitals. For that reason, we believe our analysis reflects a wide range of a patient profile based on reliable measurements. However, its retrospective design with a lack of detailed history of smoking and other exposures, limited us in investigating the effect of smoking on spirometric measures effects of smoking on spirometric measures. In addition, our database does not include the necessary information regarding the medication history of the study participants. This was another limitation of our study. Nevertheless, whether the [FEV.sub.3]/FVC ratio translates into clinically meaningful disease-centred outcomes needs to be evaluated in further observations, together with clinical and radiologic features.

CONCLUSION

1-[FEV.sub.3]/FVC can be easily calculated from routine daily spirometric measurements. 1-[FEV.sub.3]/FVC is a promising marker of air trapping and hyperinflation. We suggest that 1-[FEV.sub.3]/FVC is complementary to [FEV.sub.1]/FVC and recommend clinicians routinely report this measurement and evaluate it together with [FEV.sub.1]/FVC during spirometry..

Conflict of Interest: No conflict of interest was declared by the authors.

REFERENCES

(1.) Hansen, JE. Clinical Function Testing [delta] Interpretation. Clinical Focus Series, 1st ed. London, Jaypee Brothers Medical Publishers, 2011.

(2.) Burgel PR, Bourdin A, Chanez P, Chabot F, Chaouat A, Chinet T, at al. Update on the roles of distal airways in COPD. Eur Respir Rev 2011;20:7-22.

(3.) Hansen JE, Sun XG, Wasserman K. Discriminating measures and normal values for expiratory obstruction. Chest 2006;129:369-77.

(4.) Hogg JC, McDonough JE, Sanchez PG, Cooper JD, Coxson HO, Elliott WM, et al. Micro-Computed Tomography Measurements of Peripheral Lung Pathology in Chronic Obstructive Pulmonary Disease. Proc Am Thorac Soc 2009;6:546-9.

(5.) McNulty W, Usmani OS. Techniques of assessing small airways. Eur Clin Respir J 2014;1.

(6.) Morris ZQ, Coz A, Starosta D. An isolated reduction of the [FEV.sub.3]/FVC ratio is an indicator of mild lung injury. Chest 2013;144:1117-23.

(7.) Zelter M. The return of [FEV.sub.3]. Chest 2013;144:1089-91.

(8.) Lam DC, Fong DY, Yu WC, Ko FW, Lau AC, Chan JW, et al. [FEV.sub.3], FEV6 and their derivatives for detecting airflow obstruction in adult Chinese. Int J Tuberc Lung Dis 2012;16:681-6.

(9.) Pellegrino R, Viegi G, Brusasco V, Crapo RO, Burgos F, Casaburi R, et al. ATS/ERS Task Force: Standardisation of lung function testing. Interpretative strategies for lung function tests. Eur Respir J 2005;26:948-68.

(10.) Miller MR, Crapo R, Hankinson J, Brusasco V, Burgos F, Casaburi R, et al. ATS/ERS Task Force: Standardisation of lung function testing. General considerations for lung function testing. Eur Respir J 2005;26:153-61.

(11.) Miller MR, Hankinson J, Brusasco V, Burgos F, Casaburi R, Coates A, et al. ATS/ERS Task Force: Standardisation of lung function testing. Standardisation of spirometry. Eur Respir J 2005;26:319-38.

(12.) Wanger J, Clausen JL, Coates A, Pedersen OF, Brusasco V, Burgos F, et al. ATS/ERS Task Force: Standardisation of lung function testing. Standardisation of the measurement of lung volumes. Eur Respir J 2005;26:511-22.

(13.) Mohamed Hoesein FA, Zanen P, Lammers JW. Lower limit of normal or [FEV.sub.1]/FVC <0.70 in diagnosing COPD: an evidence-based review. Respir Med 2011;105:907-15.

(14.) BTS guidelines for the management of chronic obstructive pulmonary disease. The COPD Guidelines Group of the Standards of Care Committee of the BTS. Thorax 1997;52(Suppl 5):S1-28.

(15.) Kohansal R, Martinez-Camblor P, Agusti A, Buist AS, Mannino DM, Soriano JB. The natural history of chronic airflow obstruction revisited: an analysis of the Framingham offspring cohort. Am J Respir Crit Care Med 2009;180:3-10.

(16.) Hansen JE, Porszasz J, Casaburi R, Stringer WW. Re-defining lower limit of normal for [FEV.sub.1]/FEV6, [FEV.sub.1]/FVC, [FEV.sub.3]/FEV6 and [FEV.sub.3]/FVC to improve detection of airway obstruction. J COPD F 2015;2:94-102.

(17.) Burgel PR. The role of small airways in obstructive airway diseases. Eur Respir Rev 2011;119:23-33.

(18.) van Veen IH, Sterk PJ, Schot R, Gauw SA, Rabe KF, Bel EH. Alveolar nitric oxide versus measures of peripheral airway dysfunction in severe asthma. Eur Respir J 2006;27:951-6.

(19.) Crapo RO, Morris AH, Gardner RM. Reference spirometric values using techniques and equipment that meet ATS recommendations. Am Rev Respir Dis 1981;123:659-64.

(20.) Miller MR, Grove DM, Pincock AC. Time domain spirogram indices: their variability and reference values in nonsmokers. Am Rev Respir Dis 1985;132:1041-8.

(21.) Miller MR, Pincock AC, Grove DM. Patterns of spirometric abnormality in individual smokers. Am Rev Respir Dis 1985;132:1034-40.

(22.) US Department of Health and Human Services (DHHS) National Center for Health Statistics. Third National Health and Nutrition Examination Survey, 1988 - 1994: NHANES III Raw Spirometry Data File. Hyattsville, MD: Centers for Disease Control and Prevention; 2001.

Sermin Borekci (1), Tuncalp Demir (1), Asli Gorek Dilektasli (2), Melahat Uygun (1), Nurhayat Yildirim (1)

(1) Department of Pulmonology, Istanbul University Cerrahpasa School of Medicine, Istanbul, Turkey

(2) Department of Pulmonology, Uludag University School of Medicine, Bursa, Turkey

Address for Correspondence: Dr. Sermin Borekci, Department of Pulmonology, Istanbul University Cerrahpasa School of Medicine, Istanbul, Turkey

Phone: +90 212 414 32 06

Received: 1 July 2015

e-mail: serminborekci@yahoo.com.tr

Accepted: 18 August 2016

Available at www.balkanmedicaljournal.org

Cite this article as:

Borekci S, Demir T, Gorek Dilektasli A, Uygun M, Yildirim N. A Simple Measure to Assess Hyperinflation and Air Trapping: 1-Forced Expiratory Volume in Three Second / Forced Vital Capacity. Balkan Med J 2017;34:113-8

[c]Copyright 2017 by Trakya University Faculty of Medicine / The Balkan Medical Journal published by Galenos Publishing House.
TABLE 1. Characteristic features of the study participants

Characteristics       Total               [FEV.sub.1]/FVC
                                          [greater than or equal to]70%

Total patient         1110                644
number (n)
Age (mean[+ or -]SD)    52.5[+ or -]15.6   58.8[+ or -]14.2
Gender (n; %)
Female                 503; 45.3          373; 33.6
Male                   607; 54.7          271; 24.4

Characteristics
                      <70%

Total patient         466
number (n)
Age (mean[+ or -]SD)  48.0[+ or -]15.1
Gender (n; %)
Female                130; 11.7
Male                  336; 30.3

Characteristics                         [FEV.sub.3]/FVC
                      [greater than or equal to] LLN  < LLN

Total patient         731                             379
number (n)
Age (mean[+ or -]SD)   57.2[+ or -]15.4                50.2[+ or -]15.2
Gender (n; %)
Female                399; 35.9                       104; 9.4
Male                  332; 29.9                       275; 24.8

SD: standard deviation; n: number of patients; [FEV.sub.1]: forced
expiratory volume in the first second; FVC: forced vital capacity;
[FEV.sub.3]: forced expiratory volume expired in third seconds

TABLE 2. Comparison of spirometric measures and lung volumes between
groups with [FEV.sub.1]/FVC <70% (n=466) vs. [FEV.sub.1]/FVC
[greater than or equal to]70 (n=644) and [FEV.sub.3]/FVC < LLN (n=379)
vs. [FEV.sub.3]/FVC [greater than or equal to] LLN (n=731)

                                  [FEV.sub.1]/FVC
                  [greater than or equal to]  <70% (n=466)         p
                  70% (n=644)

FVC (mL)          3024[+ or -]1170            2719[+ or -]969     <0.001
[FEV.sub.1] (mL)  2430[+ or -]940             1425[+ or -]660     <0.001
[FEV.sub.1]/        80.6[+ or -]6.1             52.2[+ or -]12.4  <0.001
FVC (%)
[FEF.sub.25-75]      2.45[+ or -]1.2             0.63[+ or -]0.4  <0.001
(L/s)
[FEV.sub.3] (mL)  2875[+ or -]1121            2061[+ or -]832     <0.001
[FEV.sub.3]/        95.1[+ or -]3.3             75.9[+ or -]11.7  <0.001
FVC (%)
1-[FEV.sub.3]/       4.9[+ or -]3.3             24.1[+ or -]11.7  <0.001
FVC (%)
IC (mL)           1976[+ or -]830             1744[+ or -]671     <0.001
TLC (mL)          4786[+ or -]1405            6211[+ or -]1640    <0.001
RV (mL)           1748[+ or -]603             3411[+ or -]1299    <0.001
RV/TLC (%)          37.5[+ or -]10.9            54.3[+ or -]12.2  <0.001
FRCpleth (mL)     3664[+ or -]1037            5044[+ or -]1427    <0.001

                                  [FEV.sub.3]/FVC
                  [greater than or equal to]  < LLN (n=379)
                  LLN (n=731)

FVC (mL)          2940[+ or -]1175            2811[+ or -]943
[FEV.sub.1] (mL)  2317[+ or -]940             1413[+ or -]671
[FEV.sub.1]/        78.60[+ or -]7. 9           49.6[+ or -]12.2
FVC (%)
[FEF.sub.25-75]      2.3[+ or -]1.2              0.60[+ or -]0.,4
(L/s)
[FEV.sub.3] (mL)  2776[+ or -]1128            2066[+ or -]821
[FEV.sub.3]/        94.3[+ or -]4.1             73.1[+ or -]11.2
FVC (%)
1-[FEV.sub.3]/       5.7[+ or -]4.1             26.9[+ or -]11.2
FVC (%)
IC (mL)           1940[+ or -]826             1755[+ or -]654
TLC (mL)          4859[+ or -]1439            6397[+ or -]1601
RV (mL)           1893[+ or -]753             3510[+ or -]1363
RV/TLC (%)         39.7[+ or -]12.3             54.0[+ or -]12.7
FRCpleth (mL)     2893[+ or -]947             4617[+ or -]1458


                   p


FVC (mL)           0.22
[FEV.sub.1] (mL)  <0.001
[FEV.sub.1]/      <0.001
FVC (%)
[FEF.sub.25-75]   <0.001
(L/s)
[FEV.sub.3] (mL)  <0.001
[FEV.sub.3]/      <0.001
FVC (%)
1-[FEV.sub.3]/    <0.001
FVC (%)
IC (mL)            0.002
TLC (mL)          <0.001
RV (mL)           <0.001
RV/TLC (%)        <0.001
FRCpleth (mL)     <0.001

FVC: forced vital capacity; [FEV.sub.1]: forced expiratory volume in
the first second; [FEF.sub.25-75]: forced expiratory flow over the
middle half of the FVC; [FEV.sub.3]: forced expiratory volume expired
in third seconds; IC: inspiratory capacity; TLC: total lung capacity;
RV: residual volume; FRCpleth: thoracic gas volume at functional
residual capacity

TABLE 3. Correlation matrix of 1-[FEV.sub.3]/FVC, [FEV.sub.1] and
[FEV.sub.1]/FVC with RV, FRCpleth, TLC and [FEF.sub.25-75] in the whole
study population, and subgroups with [FEV.sub.1]/FVC [greater than or
equal to]70% and [FEV.sub.1]/FVC <70%

                            1-[FEV.sub.3]/FVC  [FEV.sub.3]

Total study
population
(n=1110)
RV                             0.70 (*)        -0.23 (*)
RV/TLC                         0.59 (*)        -0.75 (*)
FRCpleth                       0.61 (*)         0.09 (*)
TLC                            0.47 (*)         0.41 (*)
IC                            -0.09 ([phi])     0.79 (*)
[FEF.sub.25-75]               -0.84 (*)         0.75 (*)
Participants with
[FEV.sub.1]/FVC
[greater than or equal to]
70% (n=644)
RV                             0.29 (*)         0.19 (*)
RV/TLC                         0.17 (*)        -0.67 (*)
FRCpleth                       0.15 (*)         0.64 (*)
TLC                            0.15 (*)         0.88 (*)
IC                             0.12 (*)         0.81 (*)
[FEF.sub.25-75]               -0.48 (*)         0.75 (*)
Participants with
[FEV.sub.1]/FVC
<70% (n=466)
RV                             0.59 (*)        -0.20 (*)
RV/TLC                         0.39 (*)        -0.77 (*)
FRCpleth                       0.61 (*)         0.05
TLC                            0.47 (*)         0.36 (*)
IC                            -0.16 (*)         0.81 (*)
[FEF.sub.25-75]               -0.77 (*)         0.84 (*)

                            [FEV.sub.1]    [FEV.sub.1]/FVC

Total study
population
(n=1110)
RV                          -0.38 (*)      -0.75 (*)
RV/TLC                      -0.82 (*)      -0.63 (*)
FRCpleth                    -0.08 ([phi])  -0.66 (*)
TLC                          0.24 (*)      -0.49 (*)
IC                           0.73 (*)       0.12 (*)
[FEF.sub.25-75]              0.87 (*)       0.88 (*)
Participants with
[FEV.sub.1]/FVC
[greater than or equal to]
70% (n=644)
RV                           0.16 (*)      -0.38 (*)
RV/TLC                      -0.69 (*)      -0.21 (*)
FRCpleth                     0.60 (*)      -0.27 (*)
TLC                          0.85 (*)      -0.22 (*)
IC                           0.79 (*)      -0.09 ([phi])
[FEF.sub.25-75]              0.81 (*)       0.60 (*)
Participants with
[FEV.sub.1]/FVC
<70% (n=466)
RV                          -0.31 (*)      -0.63 (*)
RV/TLC                      -0.80v         -0.46 (*)
FRCpleth                    -0.09 ([phi])  -0.63 (*)
TLC                          0.22 (*)      -0.47 (*)
IC                           0.79 (*)       0.23 (*)
[FEF.sub.25-75]              0.91 (*)       0.79 (*)

                            [FEF.sub.25-75]

Total study
population
(n=1110)
RV                          -0.63 (*)
RV/TLC                      -0.81 (*)
FRCpleth                    -0.41 (*)
TLC                         -0.13 (*)
IC                           0.47 (*)
[FEF.sub.25-75]              -
Participants with
[FEV.sub.1]/FVC
[greater than or equal to]
70% (n=644)
RV                          -0.10 ([phi])
RV/TLC                      -0.66 (*)
FRCpleth                     0.29 (*)
TLC                          0.52 (*)
IC                           0.57 (*)
[FEF.sub.25-75]              -
Participants with
[FEV.sub.1]/FVC
<70% (n=466)
RV                          -0.45 (*)
RV/TLC                      -0.72 (*)
FRCpleth                    -0.31 (*)
TLC                         -0.03
IC                           0.63 (*)
[FEF.sub.25-75]              -

RV: residual volume; TLC: total lung capacity; FRCpleth: thoracic gas
volume at functional residual capacity; [FEF.sub.25-75]: forced
expiratory flow over the middle half of the FVC; IC: inspiratory
capacity; [FEV.sub.3]: forced expiratory volume in the third seconds;
FVC: forced vital capacity; LLN: lower limit of normal; [FEV.sub.1]
forced expiratory volume in the first second; Spearman correlation
coefficients (r) are presented; (*) corresponds to p<0.0001; ([phi])
corresponds to p<0.05

TABLE 4. Correlation matrix of 1-[FEV.sub.3]/FVC, [FEV.sub.1] and
[FEV.sub.1]/FVC with RV, FRCpleth, TLC and [FEF.sub.25-75] in
[FEV.sub.3]/FVC [greater than or equal to] LLN (n=731) and
[FEV.sub.3]/FVC < LLN (n=379) subgroups

                            1-[FEV.sub.3]/FVC  [FEV.sub.3]  [FEV.sub.1]

[FEV.sub.3]/FVC
[greater than or equal to]
LLN (n=731)
RV                               0.29 (*)       0.19 (*)     0.16 (*)
RV/TLC                           0.17 (*)      -0.67 (*)    -0.69 (*)
FRCpleth                         0.15 (*)       0.64 (*)     0.60 (*)
TLC                              0.15 (*)       0.88 (*)     0.85 (*)
IC                               0.12 (*)       0.81 (*)     0.80 (*)
[FEF.sub.25-75]                 -0.48 (*)       0.75 (*)     0.81 (*)
[FEV.sub.3]/FVC
< LLN (n=379)
RV                               0.67 (*)      -0.34 (*)    -0.44 (*)
RV/TLC                           0.55 (*)      -0.80 (*)    -0.83 (*)
FRCpleth                         0.66v         -0.10 (*)    -0.23 (*)
TLC                              0.48 (*)       0.23 (*)     0.09 (*)
IC                              -0.30 (*)       0.82 (*)     0.82 (*)
[FEF.sub.25-75]                 -0.82 (*)       0.89 (*)     0.93 (*)

                            [FEV.sub.1]/FVC  [FEF.sub.25-75]

[FEV.sub.3]/FVC
[greater than or equal to]
LLN (n=731)
RV                          -0.38 (*)        -0.10 ([phi])
RV/TLC                      -0.21 (*)        -0.66 (*)
FRCpleth                    -0.27 (*)         0.29 (*)
TLC                         -0.22 (*)         0.52 (*)
IC                          -0.09 ([phi])     0.57 (*)
[FEF.sub.25-75]              0.60 (*)         -
[FEV.sub.3]/FVC
< LLN (n=379)
RV                          -0.68 (*)        -0.53 (*)
RV/TLC                      -0.59 (*)        -0.78 (*)
FRCpleth                     0.66 (*)        -0.38 (*)
TLC                         -0.47 (*)        -0.09 (*)
IC                           0.35 (*)         0.67 (*)
[FEF.sub.25-75]              0.82 (*)         -

[FEV.sub.3]: forced expiratory volume in the third seconds; FVC: forced
vital capacity; LLN: lower limit of normal; [FEV.sub.1]: forced
expiratory volume in the first second; [FEF.sub.25-75]: forced
expiratory flow over the middle half of the FVC; RV: residual volume;
TLC: total lung capacity; FRCpleth: thoracic gas volume at functional
residual capacity; IC: inspiratory capacity, Spearman correlation
coefficients (r) are presented, (*) corresponds to p<0.0001; ([phi])
corresponds to p<0.05

TABLE 5. Comparison of correlation coefficients of 1-[FEV.sub.3]/FVC
with RV, TLC and [FEF.sub.25-75] in [FEV.sub.3]/FVC < LLN (n=379) and
[FEV.sub.1]/FVC <0.70 (n=466) subgroups

                       RV        RV/TLC    FRCpleth  TLC

[FEV.sub.3]/FVC < LLN
(n=379)
1-[FEV.sub.3]/FVC      0.67      0.55 (*)  0.66 (*)  0.48 (*)
Participants with
[FEV.sub.1]/FVC
<70% (n=466)
1-[FEV.sub.3]/FVC      0.59 (*)  0.39 (*)  0.61 (*)  0.47 (*)

                       IC         [FEF.sub.25-75]
[FEV.sub.3]/FVC < LLN
(n=379)
1-[FEV.sub.3]/FVC      -0.30 (*)    -0.82 (*)
Participants with
[FEV.sub.1]/FVC
<70% (n=466)
1-[FEV.sub.3]/FVC      -0.16 (*)    -0.77 (*)

RV: residual volume; TLC: total lung capacity; FRCpleth: thoracic gas
volume at functional residual capacity; IC: inspiratory capacity;
[FEF.sub.25-75]: forced expiratory flow over the middle half of the
FVC; [FEV.sub.3]: forced expiratory volume in the third seconds; FVC:
forced vital capacity; LLN: lower limit of normal, spearman correlation
coefficients (r) are presented, (*) corresponds to p<0.0001
COPYRIGHT 2017 Galenos Yayinevi Tic. Ltd.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2017 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Original Article
Author:Borekci, Sermin; Demir, Tuncalp; Dilektasli, Asli Gorek; Uygun, Melahat; Yildirim, Nurhayat
Publication:Balkan Medical Journal
Article Type:Report
Date:Mar 1, 2017
Words:5539
Previous Article:Intracranial Lesions in Children and Adolescents with Morbid Obesity.
Next Article:Diagnosis of Nipple Discharge: Value of Magnetic Resonance Imaging and Ultrasonography in Comparison with Ductoscopy.
Topics:

Terms of use | Privacy policy | Copyright © 2020 Farlex, Inc. | Feedback | For webmasters