No abstract available.
Spirometry*

Pneumotachometer is the most widely used respiratory air flow sensor. But the measurement error hard to be ignored exists, since the empirical calibration carve in a closed form cannot provide accurate flow values at all measured pressure data. Any possible distortion of the calibration curve further increases measurement error, which cannot he corrected by the conventional calibration method. The present study suggests a new error correction algorithm applicable to any type of pneumotachometer equipped with computer-based data processing device. This algorithm evaluates conductance error correction coefficients at each digitized pressure level based on the cumulative pressure data obtained by manual volume syrange stroke operation at different speeds. Experiment demonstrated error minimization down to below 1/10 in mean stroke volume measurement compared to the conventional calibration curve method. The standard deviation of the stroke volume also decreased down to below 1/2 of the conventional method. The present technique can be introduced with no difficulty to the calibration procedure the American Thoracic Society, and expected to guarantee the accuracy and reliability of the respiratory air flow measurement during spirometric tests.
Calibration ; Spirometry ; Stroke ; Stroke Volume

User package program run on PC was developed for clinical spirometric test, which enabled to perform popular FVC, SVC, and MVV test items in a very convenient manner. In addition, a program module for research was implemented to study breathing pattern of a patient. The program written in C language was designed to run on Windows OS, and consisted of patient information management, test procedure control, results print out, and accumulation of parameter values in a customized data base which made possible future clinical research and quality assurance. When engaged with the previously developed respiratory air flow measurement unit, the system resulted in an accurate enough performance in that FVC data showed a high correlation coefficient of higher than 0.98 with an imported system. The technician tried the present system under clinical environment and judged the convenient utility to be satisfactory. Therefore, industrialization effort is being currently made and expected to be successful.
Humans ; Information Management ; Respiration ; Spirometry ; Industrial Development

No abstract available.
Lung Neoplasms* ; Lung* ; Risk Factors* ; Spirometry*

No abstract available.
Asthma ; Diagnosis, Differential* ; Respiratory Sounds* ; Spirometry

No abstract available.
Nebulizers and Vaporizers ; Pulmonary Disease, Chronic Obstructive ; Spirometry

BACKGROUND: Blunted perception of dyspnea, which may be related to the increased mortality, has been demonstrated in patients with a history of near-fatal asthma and in the elderly. OBJECTIVE: The purpose of this study was to evaluate the relationship between the perception of dyspnea and the severity of asthma. METHOD: Baseline spirometry and Borg score change(A Borg score) during breathing through an inspiratory muscle trainer were measured in 27 consecutive asthma patients and 11 normal subjects. RESULTS: The baseline Borg score was negatively related to FEV1 A Borg score was significantly lower in asthmatics than in controls at high level of loads. A Borg score was lower in severe asthma than in mild asthma. A Borg score was positively related to the baseline FEV1. Seventy-five percent of severe asthma, 62.5% of moderate one, and 9.1% of mild one showed impaired dyspnea perception. Dyspnea perception was related to age(r, = -0.49, p<0.001). CONCLUSION: Three quarters of patients with severe asthma showed impaired dyspnea perception to inspiratory resistive load. Dyspnea perception was related to asthma severity and age.
Aged ; Asthma ; Dyspnea* ; Humans ; Mortality ; Respiration ; Spirometry

BACKGROUND: Long-term management of bronchial asthma based on the fractional exhaled nitric oxide (FeNO) value alone is not conclusive yet. Therefore, we combined FeNO testing and spirometry, a commonly used test in routine practice, to evaluate acute exacerbation and respiratory function in children with bronchial asthma. OBJECTIVE: We combined FeNO testing and spirometry, commonly used in routine practice, to evaluate acute exacerbations and respiratory function in children with bronchial asthma. METHODS: Subjects were school aged children 7 years and older with bronchial asthma who underwent FeNO testing in January 2015 to May 2016. We evaluated the changes in the frequency of acute exacerbations and respiratory function in the 30 subsequent months. Subjects were divided into 2 groups: those with initial FeNO levels ≥ 21 parts per billion (ppb) (high FeNO) and < 20 ppb (normal FeNO) groups. RESULTS: There were 48 children (33 boys) in the high FeNO group and 68 children (46 boys) in the normal FeNO group. Spirometry was conducted on 83 children (72%) prior to the initial FeNO test, revealing no difference in the ratio of detecting lung dysfunction between the 2 groups. The observation period was 25.8 ± 0.7 and 24.7 ± 0.6 months for the high and normal FeNO groups, respectively. The children in the high FeNO group with lung dysfunction in the initial FeNO test continued to exhibit lung dysfunction at the test at 30 months. In the normal FeNO group, even if lung dysfunction was observed at the initial FeNO, it improved within the 20-month point, and the improvement was maintained thereafter. CONCLUSION: Children with bronchial asthma with high FeNO levels and lung dysfunction are at a higher risk of prolonged lung dysfunction.
Asthma ; Child ; Humans ; Lung ; Nitric Oxide ; Spirometry

BACKGROUND: A spirometric reference equation was recently developed for the general population in Korea. The applicability of the new Korean equation to clinical practice was examined by comparing it with the Morris equation, which is one of the most popular reference equations used for interpreting the spirometric patterns and for grading the disease severity in Korea. METHODS: Spirometry was performed on 926 men and 694 women, aged 20 years or older, in November 2004 at the Asan Medical Center, Seoul, Korea. The subjects' age, gender, height, weight, and spirometric values (FEV1 [forced expiratory volume in one second], FVC [forced vital capacity], and FEV1/FVC) were obtained. The spirometric patterns and disease severity were evaluated using both equations, and the results of the Korean equation were compared with the Morris equation. The spirometric patterns were defined as normal, restrictive, obstructive, and undetermined according to the level of FEV1/FVC and FVC. The disease severity was defined according to the level of FEV1 level for subjects with an airflow limitation, and according to the FVC level for those subjects without an airflow limitation. RESULTS: Spirometric patterns were differently interpreted in 22.5% (208/926) of the men and 24.8% (172/694) of the women after the application of the Korean equation compared with the Morris equation. Of the subjects with airflow limitation, disease severity was differently graded in 30.2% (114/378) of the men and 39.4% (37/94) of the women after the application of the Korean equation. Of the subjects without airflow limitation, disease severity was differently graded in 27.9% (153/548) of the men and 30.2% (181/600) of the women after the application of the Korean equation. CONCLUSION: Achange in the reference equation for spirometry could have an effect on the interpretation of spirometric patterns and on the grading of disease severity.
Chungcheongnam-do ; Female ; Humans ; Korea ; Male ; Seoul ; Spirometry

BACKGROUND: When patients with chronic respiratory symptoms have a normal spirometry result, it is not always easy to consider bronchial asthma as the preferential diagnosis. Forced expiratory flow between 25% and 75% of vital capacity (FEF(25~75%)) is known as a useful diagnostic value of small airway diseases. However, it is not commonly used, because of its high individual variability. We evaluated the pattern of bronchodilator responsiveness (BDR) and the correlation between FEF25~75% and BDR in patients with suspicious asthma and normal spirometry. METHODS: Among patients with suspicious bronchial asthma, 440 adult patients with a normal spirometry result (forced expiratory volume in one second [FEV1]/forced vital capacity [FVC] > or =70% & FEV1% predicted > or =80%) were enrolled. We divided this group into a positive BDR group (n=43) and negative BDR group (n=397), based on the result of BDR. A comparison was carried out of spirometric parameters with % change of FEV1 after bronchodilator (DeltaFEV1%). RESULTS: Among the 440 patients with normal spirometry, FEF(25~75%)% predicted were negatively correlated with DeltaFEV1% (r=-0.22, p<0.01), and BDR was positive in 43 patients (9.78%). The means of FEF(25~75%)% predicted were 64.0+/-14.5% in the BDR (+) group and 72.9+/-20.8% in the BDR (-) group (p<0.01). The negative correlation between FEF(25~75%)% predicted and DeltaFEV1% was stronger in the BDR (+) group (r=-0.38, p=0.01) than in the BDR (-) group (r=-0.17, p<0.01). In the ROC curve analysis, FEF(25~75%) at 75% of predicted value had 88.3% sensitivity and 40.3% specificity for detecting a positive BDR. CONCLUSION: BDR (+) was not rare in patients with suspicious asthma and normal spirometry. In these patients, FEF(25~75%)% predicted was well correlated with BDR.
Adult ; Asthma ; Bronchodilator Agents ; Humans ; ROC Curve ; Spirometry ; Vital Capacity