Evaluation of alveolar clearance by Tc-99m DTPA radioaerosol inhalation scintigraphy in welders

Welding Fumes, a Risk Factor for Lung Diseases

(1) Background: Welding fumes (WFs) are composed of fine and ultrafine particles, which may reach the distal airways and represent a risk factor for respiratory diseases. (2) Methods: In vitro and in vivo studies to understand WFs pathogenesis were selected. Epidemiological studies, original articles, review, and meta-analysis to examine solely respiratory disease in welders were included. A systematic literature search, using PubMed, National Institute for Occupational Safety and Health Technical Information Center (NIOSHTIC), and Web of Science databases, was performed. (3) Results: Dose, time of exposure, and composition of WFs affect lung injury. Inflammation, lung defense suppression, oxidative stress, DNA damage, and genotoxic effects were observed after exposure both to mild and stainless steel WFs. (4) Conclusions: The detection of lung diseases associated with specific occupational exposure is crucial as complete avoidance or reduction of the exposure is difficult to achieve. Further studies in the area of particle research may aid the understanding of mechanisms involved in welding-related lung disease and to expand knowledge in welding-related cardiovascular diseases.

The role of Tc-99m DTPA aerosol scintigraphy in the differential diagnosis of COPD and asthma

OBJECTIVE

Chronic obstructive lung disease (COPD) and asthma are characterized as similar to each other in causing airway obstruction and being an inflammatory process. The purpose of this study was to investigate whether technetium-99m diethylenetriaminepentaacetic acid ((99m) Tc-DTPA) aerosol scintigraphy could be used in the differential diagnosis of asthma and COPD.

METHODS

Eighty-four patients (male/female: 32/52; mean age 50.2 ± 12.7 years) with obstructive lung disease and 30 healthy volunteers as the control group were enrolled in the study. The patients were divided into two groups as COPD and asthma and also smoking subgroups. Alveolar clearance study was performed using a radiolabeled aerosol of (99m) Tc-DTPA. Mucociliary clearance was evaluated with T½ , cap value and penetration index parameters. All patient underwent pulmonary function tests and Forced expiratory volume (FEV1 ), forced vital capacity (FVC) and FEV1 /FVC parameters were obtained.

RESULTS

The mean of T½ values of (99m) Tc-DTPA aerosol and FEV1 /FVC value among spirometric tests of the nonsmoking COPD patients were significantly lower than nonsmoking asthma patients (46.1 ± 14.3, 62.3 ± 18.7, P = 0.02; 65.2 ± 10.8, 81.4 ± 16.5, P = 0.04, respectively). The cap value was significantly higher in nonsmoking COPD patients (1.21 ± 0.49, 0.76 ± 0.22, P = 0.03). While there were no statistically and significantly different between control and asthmatic groups at the scintigraphic parameters and spirometric parameters, the mean of T½ values, cap value and spirometric parameters were statistically different between control and COPD groups (P < 0.05).

CONCLUSION

We showed that assessment of mucociliary permeability with (99m) Tc-DTPA aerosol scintigraphy was a useful, easy to apply and a noninvasive technique to use in the differential diagnosis of nonsmoker COPD and asthma.

Lung epithelial permeability and inhaled furosemide: added dimensions in asthmatics

OBJECTIVE

Lung clearance rates of inhaled (99m)Tc-DTPA aerosols constitute a sensitive index to evaluate the permeability changes characteristic of airway epithelial damage. It was thought that edema of the airway wall which is reported in asthma could be relieved with a diuretic like furosemide, helping to relieve the symptoms. We intended to study the effect of inhaled furosemide on lung epithelial permeability in asthmatics and smokers with the help of (99m)Tc-DTPA lung clearance test (LCT).

METHODS

The study included three groups (n = 15), viz. normal healthy controls, asymptomatic chronic smokers, and chronic persistent asthmatics. Each subject underwent the LCT twice, baseline and post-furosemide (Lasix) study, within a week's interval. The post-furosemide study was carried out 15 min after inhalation of 10 mg of lasix. Lung epithelial permeability was determined in terms of clearance half-life (T (1/2)).

RESULTS

The baseline mean T (1/2) values for controls, smokers, and asthmatics were 50.95 +/- 16.58, 20.81 +/- 5.47, 24.06 +/- 6.19 min, respectively. Post-lasix T (1/2) values were 50.83 +/- 15.84, 20.70 +/- 5.65, 41.27 +/- 15.07 min, respectively. There was a significant difference (P < 0.001) in baseline and post-lasix clearance values in asthmatics only.

CONCLUSION

Baseline lung epithelial permeability was altered in smokers and asthmatics compared to the controls. Furosemide was effective only in asthmatics in reverting the permeability almost back to the normal range. Inhaled furosemide was effective even in moderate and severe asthmatics. Furosemide has multiple mechanisms of action. It possibly acts at bronchial level in view of the pathology in asthmatics lying in the airways.