• Tuberculosis and Respiratory Diseases
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• v.50 no.3
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• pp.310-319
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• 2001

Background : The peak flowmeter is very useful in monitoring of out-patients as well as those in emergency departments because of its convenience and simplicity with low cost. There have been many studies aimed at determining the accuracy and reproducibility of the peak flow meter in normal population. However, there is a paucity of reports regarding its accuracy in patients with chronic obstructive pulmonary disease(COPD) or asthma. The accuracy of the peak expiratory flow(PEF) measured with a mini-Wright peak flowmeter was assessed by a comparison with the results of a mass flow sensor. Methods : The PEF measurements were performed in 108 patients aged 19-82 years presenting with either a chronic obstructive lung disease or asthma before and after inhaling salbutamol. The PEF measurements from the mini-Wright flowmeter were compared with those obtained by the calibrated mass flow sensor. Results : The average of the readings taken by the mini-Wright meter were 37-39 l/min higher than those taken by the mass flow sensor. The average percentage error of the mini-Wright meter were higher, ranging less than 300 l/min. The mean of the differences between the values obtained using both instruments (the bias)$\pm$limits of agreement(${\pm}2$ SD) were $37.1{\pm}90\;l/min$ for the PEF(p<0.001). Conclusions : The mini-Wright peak flowmeter overestimated the flows in patients with COPD or asthma. It was also found that the accuracy of the mini-Wright peak flowmeter decreased in its mid to low range. The limits of agreement are wide and the difference between the two instruments is significant. Therefore, the measurements made between the two types of machines in patients with asthma or COPD cannot be used interchangeably.

• Tuberculosis and Respiratory Diseases
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• v.50 no.3
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• pp.320-333
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• 2001

Background : Peak expiratory flow (PEF) provides a simple, quantitative, and reproducible measure of the existence and severity of airflow obstructions. Peak flow meters are designed to monitor the condition asthma patients. There are many reports showing the normal predicted value of PEF in other countries. Studies on healthy Korean adults have been performed in a relatively small sample number and a lower limit for the normal value was not reported. Therefore, an attempt to provide normal predictive PEF value with a lower limit was made. Method : The PEF(Mini-Wright Peak Flow Meter) measurements and spirometry were done in 233 men and 631 women without history of respiratory disease. All subjects were non-smokers with no respiratory symptoms. The normal predictive value and its lower limit were developed by multiple regression analysis. The result was compared with regression equations in other reports. Results : The regression equation for the normal PEF predictive value(L/min) is $25.117+4.587{\times}$Age(year)-$0.064{\times}Age^2+2.931{\times}$Height(cm) in men($R^2=025$), and 146.942-$0.011{\times}Age^2+1.795{\times}$Height(cm)+$0.836{\times}$Weight(kg) in women($R^2=0.21$). The regression equation for the lower limit of this value (L/min) is $25.117+4.587{\times}$Age(year)-$0.064{\times}Age^2+1.936{\times}$Height(cm) in men, and $146.942-0.011{\times}Age^2+1.232{\times}$Height(cm)+$0.481{\times}$Weight(kg) in women. The residuals were normally distributed. The PEF in Korean males was sililar to those reported in British and Japanese subjects. The PEF in Korean females was similar to that in British subjects, but higher than the PEF in Japanese subjects. The lower limit of normal value was 71% of normal predictive PEF value in men and 76% in women. Conclusion : The normal predictive PEF value and its lower limit was measured from 233 male and 631 female asymptomatic, lifelong non-smoking participants. The normal predictive value was different from those of other studies on Korean subjects. Therefore, further studies are required.

• Tuberculosis and Respiratory Diseases
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• v.45 no.5
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• pp.1000-1011
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• 1998

Background: For the diagnosis or evaluation of airway obstruction in bronchial asthma and chronic obstructive lung disorders, various parameters derived from the forced expiratory volume curve and maximal expiratory flow volume curve have been used. Recently the peak expiratory flow(PEF) measured by the peak flow meter is widely used because of its simplicity and convenience. But there were still no data of the predicted normal values measured by the peak flow meter in Korea. This study was to obtain the predicted normal value of PEF and to know the accuracy of this value to predict $FEV_1$. Method: The measurements of PEF by the MiniWright peak flow meter and several parameters derived from the forced expiratory volume and maximal expiratory flow volume curves by the Microspiro HI 501(Chest Co.) were done in 129 men and 125 women without previous history of the respiratory diseases. The predicted normal values of parameters according to the age and the height were obtained, and the regression equation of $FEV_1$ by PEF was calculated. Results: The predicted normal values of PEF(L/min) were -2.45$\times$Age(year) +1.36 $\times$ Height(cm)+427 in men, and -0.96 $\times$ Age (year) + 2.01 $\times$ Height (cm) + 129 in women. FEFmax derived from the maximal expiratory flow volume curve was less than by 125 L/min in men and 118 L/min in women respectively compared to PEF. $FEV_1$(ml) predicted by PEF was 5.98 $\times$ PEF(L/min) + 303 in men, and 4.61 $\times$ PEF(L/min) + 291 in women respectively. Conclusion : The predicted normal value of PEF measured by the peak flow meter was calculated and it could be used as a standard value of PEF while taking care of patients with airway obstruction. $FEV_1$, the gold standard of ventilatory function, could be predicted by PEF to a certain extent.

• Tuberculosis and Respiratory Diseases
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• v.44 no.2
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• pp.298-308
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• 1997

Background : Portable devices for measuring peak expiratory flow(PEF) are now of proved value in the diagnosis and management of asthma and many lightweight PEF meters have become available. However, it is necessary to determine whether peak expiratory flow rate(PEFR) measurements measured with peak flowmeters is accurate and reproducible for clinical application. The aim of the present study is to define accuracy, agreement, and precision of mini-Wright peak flow meter(MPFM) against standard pneumotachygraph. Methods : The lung function tests by standard pneumotachygraph and PEFR measurement by MPFM were performed in a random order for 2 hours in 22 normal and 17 asthmatic subjects and also were performed for 3 successive days in 22 normals. Results : The PEFR measured with MPFM was significantly related to the PEFR and $FEV_1$ measured with standard pneumotachygraph in normal and asthmatics(for PEFR, r = 0.92 ; p < 0.001 ; for $FEV_1$, r = 0.78 ; p < 0.001). The accuracy of MPFM was within 100(limits of accuracy recommeded by NAEP) in all the subjects or 22 normal, mean difference from standard pneumotachygraph being 16.5L/min(percentage of difference being 2.90%) or 10.6L/min(percentage of difference being 1.75%), respectively. According to the method proposed by Bland and Altman, the 95% limits of the distribution of differences between MPFM and standard pneumotachygraph after correction of PEFR using our regression equation were +38.2 and -71.5L/min in all the subjects or 20.49~+9.49L/min in 22 normal and was similar to the intraindividual agreements for 3 successive days in normal. There was no statistically significant difference of PEFR measured with MPFM and standard pneumotachygraph among three days(p > 0.05) and the coefficient of variation($2.4{\pm}1.2%$) of PEFR measured with MPFM was significantly lower than that($5.2{\pm}3.5%$) with standard pneumotachygraph in normal (p < 0.05). Conclusion : This results suggest that the MPFM was as accurate and reproducible as standard pneumotachygraph for monitoring of PEFR in the asthmatic subjects.

• Tuberculosis and Respiratory Diseases
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• v.56 no.2
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• pp.144-150
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• 2004

Background : An assessment of the presence and the degree of reversibility of airflow obstruction is clinically important in patients with asthma or chronic obstructive pulmonary disease. However, the time responses of spirometric parameters in response to bronchodilator have not been well investigated. Methods: We studied 15 patients with asthma. Spirometric and mini-Wright peak expiratory flow measurements were performed at 15, 30, 45, and 60 minutes after using single dose($200{\mu}g$) of inhaled bronchodilator, salbutamol. Results : The mean values of forced expiratory volume in one second($FEV_1$) and forced vital capicaty(FVC) were significantly increased at 60 minutes after using bronchodilator in comparison to 15 minutes. And peak expiratory flow rate measured by either mass flow sensor or mini-Wright peak flow meter were significantly increased at 45 minutes after using bronchodilator in comparison to 15 minutes. Conclusions : To appropriate evaluation of the bronchodilator response in patients with reversible airflow limitation, it would be useful measuring either $FEV_1$ or PEF at the later time point 60 or 45 minutes in comparison to 15 minutes after using bronchodilator.

• Environmental Analysis Health and Toxicology
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• v.14 no.1_2
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• pp.21-33
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• 1999

A large number of studies have indicated associations between the impairment of respiratory health and exposure to ambient air pollutants such as ozone (O$_3$) , nitrogen dioxide (NO$_2$) , sulfur dioxide(SO$_2$) , particulate matters (PM$\_$10/). To evaluate this associations, we used the pulmonary function tests (peak expiratory flow rate : PEFR) by mini-wright peak flow meter and counting neutrophils in the nasal lavage (NL) as biomarker. From 15 June to 16 July 1998, for the workers in the highway tollgates, PEFR and NL were measured three times daily and twice per week. and association between the level of air pollutants and PEFR and NL were analyzed using the multiple regression model and the poisson regression model respectively. The results indicated that the effects of all measured air pollutants (SO$_2$, NO$_2$, O$_3$, PM$\_$10/) were not significantly associated with the value of PEFR. On the other side, SO$_2$, NO$_2$, PM$\_$10/ were significantly associated with the number of neutrophils in NL. The increase in SO$_2$, NO$_2$of 10ppb and in PM$\_$10/ of 10$\mu\textrm{g}$/m$^3$was associated with 24%, 21%, 35% increases in neutrophil counts. But the ozone exposure was not associated with NL.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.06a
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• pp.311-314
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• 2005

To evaluate the acute effects of fine particles on pulmonary function, a longitudinal study was conducted. This study was carried out for the schoolchildren(3rd and 4th grades) living in Inner-Mongolia, China. 113 Chinese children were asked to record their daily levels of peak expiratory flow rate(PEPR) using portable peak flow meter(mini-Wright) for 40 days and 3 time everyday(12 April 2004 to 21 May 2004). The atmospheric concentration of fine particles in study area was also determined everyday during same period. The relationship between dailypeak expiratory flow rate(PEFR) and fine particle levels was analyzed using a mixed linear regression models including gender, age, height, the presence of respiratory symptoms, and daily average relative humidity as extraneous variables. The analysis showed that the increase of fine particle concentrations was negatively associated with the variability in PEPR. The IQR(inter-quartile range) increments of $PM_{10}$ or $PM_{2.5}(66.0{\mu}g/m^3$ and $118.9{\mu}g/m^3$, respectively) were also shown to be related with 1.422L/min(95% Confidence intervals: 0.270 ${\sim}$ 2.574) and 1.214L1min(95% Cl: 0.010 ${\sim}$ 2.418) decline in PEFR.

• Tuberculosis and Respiratory Diseases
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• v.51 no.3
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• pp.248-259
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• 2001

Background : In diagnosis or monitor of the airway obstruction in bronchial asthma, the measurement of $FEV_1$ in the standard method because of its reproducibility and accuracy. But the measurement of peak expiratory flow(PEF) by peak flow meter is much simpler and easier than that of $FEV_1$ especially in children. Yet there have been still no data of the predicted normal values of PEF measured by peak flow meter in Korean children. This study was conducted to provide equations to predict the normal value of PEF and correlation between PEF and $FEV_1$ in healthy children. Method : PEF was measured by MiniWright peak flow meter, and the forced expiratory volume and the maximum expiratory flow volume curves were measured by Microspiro HI 501(Chest Co.) in 346 healthy children(age:5-16 years, 194 boys and 152 girls) without any respiratory symptoms during 2 weeks before the study. The regression equations for various ventilatory parameters according to age and/or height, and the regression equations of $FEV_1$ by PEF were derived. Results : 1. The regression equation for PEF(L/min) was: $12.6{\times}$age(year)+$3.4{\times}$height(cm)-263($R^2=0.85$) in boys, and $6{\times}$age(year)+$3.9{\times}$height(cm)-293($R^2=0.82$) in girls. 2. The value of FEFmax(L/sec) derived from the maximum expiratory flow volume curves was multiplied by 60 to compare with PEF(L/min), and PEF was faster by 125 L/min in boys and 118 L/min in girls, respectively. 3. The regression equation for $FEV_1$(ml) by PEF(L/min) was:$7{\times}$PEF-550($R^2=0.82$) in boys, and $5.8{\times}$PEF-146 ($R^2=0.81$) in girls, respectively. Conclusion : This study provides regression equations predicting the normal values of PEF by age and/or height in children. And the equations for $FEV_1$, a gold standard of ventilatory function, was predicted by PEF. So, in taking care of children with airway obstruction, PEF measured by the peak flow meter can provide useful information.

• Proceedings of the Korean Environmental Health Society Conference
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• 2004.06a
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• pp.193-196
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• 2004

To evaluate the acute effects of fine particles on pulmonary function, a longitudinal study was conducted. This study was carried out for the schoolchildren (3rd and 6th grades) living in Beijing, China. Children were asked to record their daily levels of peak expiratory flow rate using portable peak flow meter (mini-Wright) for 40 days. The relationship between daily PEFR and fine particle levels was analyzed using a mixed linear regression models including gender, height, the presence of respiratory symptoms, and daily average temperature and relative humidity as extraneous variables. The total number of students participating in this longitudinal study was 87. Daily measured PEFR was in the range of $253{\sim}501L/min$. On the daily basis, a PEFR measured in the morning was shown to be lower than that measured in the evening (or afternoon). The daily mean concentrations of $PM_{10}$ and $PM_{2.5}$ over the study period were $180.2\;{\mu}g/m^3$ and $103.2\;{\mu}g/m^3$, respectively. The IQR (inter-quartile range) of $PM_{10}$ and $PM_{2.5}$ were $91.8\;{\mu}g/m^3$ and $58.0\;{\mu}g/m^3$. Daily mean PEFR was regressed with the 24-hour average $PM_{10}$ (or $PM_{2.5}$) levels, weather information such as air temperature and relative humidity, and individual characteristics including gender, height, and respiratory symptoms. The analysis showed that the increase of fine particle concentrations was negatively associated with the variability in PEFR. The IQR increments of $PM_{10}$ or $PM_{2.5}$ (at 1-day time lag) were also shown to be related with 1.54L/min (95% Confidence intervals -2.14, -0.94) and 1.56L/min (95% CI -2.16, -0.95) decline in PEFR.

• Proceedings of the Korean Environmental Health Society Conference
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• 2003.06a
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• pp.183-186
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• 2003

To evaluate the effect of air pollution on respiratory health in children, we conducted a longitudinal study in which children were asked to record their daily levels of peak expiratory flow rate using potable peak flow meter (mini-Wright) far 4 weeks. The relationship between daily PEFR and ambient air particle levels was analyzed using a mixed linear regression models including gender, age in you, weight, the presence of respiratory symptoms, and relative humidity as an extraneous variable. The daily mean concentrations of PM$\_$10/ and PM$\_$2.5/ over the study period were 64.9$\mu\textrm{g}$/㎥ and 46. l$\mu\textrm{g}$/㎥, respectively. The range of daily measured PEFR in this study was 170-481 l/min. Daily mean PEFR was regressed with the 24-hour. average PM$\_$10/ (or PM$\_$2.5/) levels, weather information such as air temperature and relative humidity, and individual characteristics including sex, weight, and respiratory symptoms. The analysis showed that the increase of air particle concentrations was negatively associated with the variability in PEFR. We estimated that the IQR increment of PM$\_$10/ or PM$\_$2.5/ were associated with 1.5 l/min (95% Confidence intervals -3.1, 0.1) and 0.8 l/min (95% Cl -1.8, 0.1) decline in PEFR. Even though this study shows negative findings on the relationship between respiratory function and air particles, it is worth noting that the findings must be interpreted cautiously because exposure measurement based on monitoring of ambient air likely results in misclassification of true exposure levels and this is the first Korean study that PM$\_$2.5/ measurement is applied as an index of air particle quality.