Use of cardiopulmonary exercise testing to assess early ventilatory changes related to occupational particulate matter

Spirometry has been used as the main strategy for assessing ventilatory changes related to occupational exposure to particulate matter (OEPM). However, in some cases, as one of its limitations, it may not be sensitive enough to show abnormalities before extensive damage, as seen in restrictive lung diseases. Therefore, we hypothesized that cardiopulmonary exercise testing (CPET) may be better than spirometry to detect early ventilatory impairment caused by OEPM. We selected 135 male workers with at least one year of exposure. After collection of self-reported socioeconomic status, educational level, and cardiovascular risk data, participants underwent spirometry, CPET, body composition assessment (bioelectrical impedance), and triaxial accelerometry (for level of physical activity in daily life). CPET was performed using a ramp protocol on a treadmill. Metabolic, cardiovascular, ventilatory, and submaximal relationships were measured. We compared 52 exposed to 83 non-exposed workers. Multiple linear regressions were developed using spirometry and CPET variables as outcomes and OEPM as the main predictor, and adjusted by the main covariates. Our results showed that OEPM was associated with significant reductions in peak minute ventilation, peak tidal volume, and breathing reserve index. Exposed participants presented shallower slope of ΔVT/ΔlnV̇E (breathing pattern), i.e., increased tachypneic breathing pattern. The OEPM explained 7.4% of the ΔVT/ΔlnV̇E variability. We found no significant influence of spirometric indices after multiple linear regressions. We conclude that CPET might be a more sensitive feature of assessing early pulmonary impairment related to OEPM. Our cross-sectional results suggested that CPET is a promising tool for the screening of asymptomatic male workers.

A Case of Diffuse Idiopathic Skeletal Hyperostosis Presenting with Dysphagia Secondary to Cervical Osteophyte and Restrictive Ventilatory Impairment / 대한내과학회지

Diffuse idiopathic skeletal hyperostosis (DISH) is a condition characterized by the calcification and ossification of soft tissue, and can lead to severe cervical kyphosis, presenting with a spectrum of physical complaints including dysphagia, hoarseness, stridor, aspiration pneumonia, and dyspnea due to airway compromise. Restrictive ventilatory impairment is very rare. We encountered a 73-year-old man with DISH presenting with progressive dysphagia and dyspnea over a few months. The symptoms were evaluated with a video fluoroscopy swallowing study and pulmonary function tests (PFT). The PFT revealed restrictive ventilatory impairment. A neck magnetic resonance imaging (MRI) study showed anterior cervical osteophytes causing upper airway compromise and compression of the esophagus. Osteophytes were removed surgically and the patient improved clinically. Here, we describe the case with a literature review.

Correlated factors of chronic hypercapnia in patients with obstructive sleep apnea-hypopnea syndrome / 中国实用内科杂志

Objective To identify the correlated factors of chronic hypercapnia in patients with obstructive sleep apnea-hypopnea syndrome(OSAHS).Methods The study cohort consisted 56 patients with OSAHS.They were taken arterial blood gas analysis and pulmonary function tests.They were divided into two groups,hypercapnic(PaCO_2≥45 mm Hg)and normocapnic(PaCO_2

An Evaluation of the Ventilatory Function in Shipyard Welders Using the Lifetime Cumulative Exposure to Welding Fumes / 대한산업의학회지

Objectives:This study was conducted to evaluate the ventilatory function in shipyard welders using the lifetime cumulative exposure to welding fumes. METHODS: Ventilatory function tests were performed on 241 male welders at one large shipyard,exposed to welding fumes for over five years,and was compared to 80 male control subjects. Ventilatory function indices, such as forced vital capacity(FVC), one-second forced expiratory volume(FEV 1), ratio of FEV 1 to FVC(FEV 1%), maximal mid-expiratory flow(MMF), peak expiratory flow rate(PEFR)and maximal expiratory flow at 50 and 75% of expired FVC(FEF50 and FEF75), were obtained by analyzing forced expiratory spirograms and maximal expiratory flow-volume curves that were simultaneously measured by an Impulse ocillometry(IOS)program in the standing position. RESULTS: FEF50 and FEF75 expressed as a percentage of the predicted values were significantly lower in the exposure group than in the controls, and the MMF tended to decrease.The means of all the ventilatory indices,expressed as percentage of the predicted values, were not significantly increased at the current exposure levels. The MMF, FEF50 and FEF75, expressed as a percentage of the predicted values, were significantly decreased with an increase in exposure duration.Only the FEF75 , expressed as a percentage of the predicted value, was significantly decreased with an increase in the cumulativeexposure to welding fumes(C1). The FEF75, expressed as a percentage of the predicted value, was significantly decreased with an increase in the cumulative exposure to welding fumes(C2). The above parameters were calculated to consider the current exposure level, exposure duration, application of the ventilatory system, production rate, personal protection evice, electrode and welding wire. The MMF and FEF50, expressed as a percentage of the predicted value, tended to decrease. The proportion of workers with abnormal MMF, FEF50 and FEF75 were significantly increased with an increase in the cumulative exposure to welding fumes(C2). CONCLUSIONS: These findings suggested that the MMF, FEF50 and FEF75 are sensitive and practical indices for the evaluation of the ventilatory function of workers exposed to welding fumes, when the lifetime cumulative exposure(C2) is considered as a factor affecting exposure.

Obstructive Ventilatory Impairment as a Risk Factor of Lung Cancer / 결핵

BACKGROUND: Cigarette smoking is closely related to both lung cancer and chronic obstructive pulmonary disease. The incidence of lung cancer is higher in patients with obstructive ventilatory impairment than in patients without obstructive ventilatory impairment regardless of smoking. So, obstructive ventilatory impairment is suspected as an independent risk factor of lung cancer. METHODS: For the evaluation of the role of obstructive ventilatory impairment as a risk factor of lung cancer, a total of 73 cases comprising 47 cases of malignant and 26 benign solitary pulmonary nodule were analyzed retrospectively. A comparative study of analysis of forced expiratory volume curves and frequencies of obstructive ventilatory impairment were made between cases with malignant and benign nodules. RESULTS: In comparison of vital capacity and parameters derived from forced expiratory volume curve between two groups, VC, FVC and FEV1 were not significantly different whereas FEV1/FVC% and FEF 25-75 % showed a significant decrease in the cases with malignant nodule. The frequency of obstructive ventilatory impairment determined by pulmonary function test was significantly higher in the cases with malignant nodule (23.4%) than in benign nodule(3.8%). When the risk for lung cancer was examined by the presence or absence of obstructive ventilatory impairment using the logistic regression analysis, the unadjusted relative risk for the lung cancer of obstructive ventilatory impairment was 17.17. When the effect of smoking and age were considered, the relative risk was to 8.13. CONCLUISON: These findings suggest that an obstructive ventilatory impairment is a risk factor of lung cancer.

Differences in Prediction Formulas for the MVV According to the Status of Ventilatory Function / 대한내과학회지

OBJECTIVES: The MVV reflects subjective dyspnea, exercise capacity, postoperative complication. But, the MVV embodies certain disadvantages and is dependent on coordination, endurance and motivation. A timed vital capacity for calculation of an indirect maximal voluntary ventilation is used. We evaluated differences in prediction formulas for the MUV according to the status of ventilatory function. METHODS: Forty-seven normal subjects, 68 patients with obstructive ventilatory impairment, and 23 patients with restrictive ventilatory impairment were studied. The relationships between the MVV and Flow or time parameters in forced expiratory volume and flow volume curves were compared among normal subjects and patients with obstructive or restrictive ventilatory impairment. RESULTS: 1) High correlation coefficients(R>or=0.87) were found between the FEV0.5, 0.75, 1 and the MVV in 47 normal subjects and 91 patients with ventilatory impairment. 2) The MVV can be conveniently estimated from the FEV1 values. The following regression formulas for the prediction of the MVV were obtained. Normal: MVV=44.01 X FEV1-21.09(r(2)=0.771, SEE=11.085) Obstructive ventilatory impairment: MVV=38.34 X FEV1-4.58(r(2)0.812, SEE=4.816) Restrictive ventilatory impairment: MVV=45.20 X FEV1-3.80(r(2)=0.899, SEE=6.929). 3) There were significant differences in prediction formulas for the MVV obtained by FEV1 between each group (P<0.05). CONCLUSION: These results suggest that different prediction formulas for the MVV, by multiplying the FEV1 by a constant, are respectively required in normal subjects and patients with obstructive or restrictive ventilatory impairment.

Effects of Welding Fume on Ventilatory Function / 대한산업의학회지

In order to study the effects of welding fume on ventilatory function, forced expiratory spirogram was performed on 563 male workers exposed to welding fume in motor vehicles industry and 589 male control workers. Ventilatory indices such as forced vital capacity (FVC), forced expiratory volume in one second (FEV(1)), the ratio of one-second forced expiratory volume to forced vital capacity (FEV(1)%= FEV(1)/FVC) and maximal mid-expiratory flow(MMF) were obtained by analyzing forced expiratory spirogram which were measured by Vitalograph in standing position. The results were as follows: 1. Mean values of FVC, FEV(1), FEV(1)%, and MMF expressed as percent of the predicted were significantly lower in exposure group than in control group. 2. No significant differences for mean ventilatory indices were demonstrated between smokers and nonsmokers both in exposure group and control group. However, mean MMF of welders tended to reduce in smokers (77.4 %) than in nonsmokers (82.4 %). 3. In exposure group mean FEV(1) was significantly lower in more than 20 years than those of control group. However, mean MMF, FEV(1)% were significantly reduced with increasing exposure duration compared to control group, indicating 90.8 %; and 62.2 % of the predicted in more than 20 years group. 4. In exposure group workers with obstructive ventilatory impairment (7.5 %) was markedly higher than that with restrictive ventilatory impairment (2.0 %). 5. In exposure group the proportion of workers with low ventilatory indices was' the highest in MMF (26.8 %), and followed by FEV(1)(11.9 %), FEV(1)%(7.6 %) and FVC (2.1 %) in descending order. Workers with low MMF and PEV

Study on the Pulmonary Function in Welding Fume Exposed Workers / 예방의학회지

In order to study the effect of welding fume exposure upon the pulmonary function test, we examined 131 shielded arc welding workers, and 152 CO2 arc welding workers as cases and 172 control workers for their general characteristics, and forced vital capacity (FVC), forced expiratory volume in one second (FEV1.0) forced expiratory volume in one second as a percent of FVC(FEV1.0%), and maximal mid-expiratory flow (MMF) were obtained from in the spirogram. In shielded arc welding group and CO2 arc welding group, FVC, FEV1.0, FEV1.0%, and MMF were significantly decreased than control group, especially marked in the MMF finding. The distribution of workers below normal range was as follows: in the shielded arc welding group, 2 workers(l.5%) for FVC, 17 workers(13.0%) for FEV1.0, 5 workers(3.8%) for FEV1.0%, 28 workers(21.4%) for MMF, and in the CO2 arc welding group, 3 workers(2.0%) for FVC, 25 workers(16.4%) for FEV1.0, 8 workers(5.3%) for FEV1.0% and 37 workers(24.3%) for MMF, and significant increase by exposure duration was found in MMF. The distribution of workers who had ventilation impairment was as follows: 5 workers(3.8%) for obstructive type, 2 workers(l.5%) for restrictive type in the shielded arc welding group and, workers(4.6%) for obstructive type. 2 workers(l.3%) for restriotive type, and 1 worker(0.6%) was combined type of the CO2 arc welding group. In the respect of these results the significant pulmonary function and ventilatory impairment were observed in welding fume exposed workers who had not abnormal finding in chest X-ray, and MMF considered as the most sensitive pulmonary function index by welding fume exposure. Therefore even if it is hard to doing pulmonary function test in the first health examination of workers according to the Industrial Safety Health Act in the welding fume exposure workers. it is desirable to consider doing PFT. Also evaluating the ventilation impairment, it is necessary, to observe the change of MMF that marker of effort-independent portion.