Dataset Information

Early Diagnosis of Respiratory Abnormalities in Asbestos-Exposed Workers by the Forced Oscillation Technique.

ABSTRACT:

Background

The current reference test for the detection of respiratory abnormalities in asbestos-exposed workers is spirometry. However, spirometry has several shortcomings that greatly affect the efficacy of current asbestos control programs. The forced oscillation technique (FOT) represents the current state-of-the-art technique in the assessment of lung function. This method provides a detailed analysis of respiratory resistance and reactance at different oscillatory frequencies during tidal breathing. Here, we evaluate the FOT as an alternative method to standard spirometry for the early detection and quantification of respiratory abnormalities in asbestos-exposed workers.

Methodology/principal findings

Seventy-two subjects were analyzed. The control group was composed of 33 subjects with a normal spirometric exam who had no history of smoking or pulmonary disease. Thirty-nine subjects exposed to asbestos were also studied, including 32 volunteers in radiological category 0/0 and 7 volunteers with radiological categories of 0/1 or 1/1. FOT data were interpreted using classical parameters as well as integer (InOr) and fractional-order (FrOr) modeling. The diagnostic accuracy was evaluated by investigating the area under the receiver operating characteristic curve (AUC). Exposed workers presented increased obstruction (resistance p<0.001) and a reduced compliance (p<0.001), with a predominance of obstructive changes. The FOT parameter changes were correlated with the standard pulmonary function analysis methods (R = -0.52, p<0.001). Early respiratory abnormalities were identified with a high diagnostic accuracy (AUC = 0.987) using parameters obtained from the FrOr modeling. This accuracy was significantly better than those obtained with classical (p<0.001) and InOr (p<0.001) model parameters.

Conclusions

The FOT improved our knowledge about the biomechanical abnormalities in workers exposed to asbestos. Additionally, a high diagnostic accuracy in the diagnosis of early respiratory abnormalities in asbestos-exposed workers was obtained. This makes the FOT particularly useful as a screening tool in the context of asbestos control and elimination. Moreover, it can facilitate epidemiological research and the longitudinal follow-up of asbestos exposure and asbestos-related diseases.

SUBMITTER: de Sa PM

PROVIDER: S-EPMC5017649 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Publications

Early Diagnosis of Respiratory Abnormalities in Asbestos-Exposed Workers by the Forced Oscillation Technique.

de Sá Paula Morisco PM Castro Hermano Albuquerque HA Lopes Agnaldo José AJ Melo Pedro Lopes de PL

PloS one 20160909 9

<h4>Background</h4>The current reference test for the detection of respiratory abnormalities in asbestos-exposed workers is spirometry. However, spirometry has several shortcomings that greatly affect the efficacy of current asbestos control programs. The forced oscillation technique (FOT) represents the current state-of-the-art technique in the assessment of lung function. This method provides a detailed analysis of respiratory resistance and reactance at different oscillatory frequencies durin ...[more]

PMID: 27612198

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Project description:Intravascular fluid shifts, mechanical ventilation and inhalational anesthetic drugs may contribute to intraoperative lung injury. This prospective observational study measured the changes in respiratory impedance resulting from inhalational anesthesia and mechanical ventilation in adults undergoing transurethral resection of bladder tumors. The components of respiratory impedance (resistance and reactance) were measured using the forced oscillation technique (FOT).Respiratory resistance at 5 Hz (R5) and 20 Hz (R20), respiratory reactance at 5 Hz (X5), resonant frequency (Fres) and area of low reactance (ALX) were measured before and immediately after surgery in 30 adults. In addition, preoperative vital capacity (VC), forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1.0) were evaluated using spirometry. All patients were intubated with an endotracheal tube and were mechanically ventilated, with anesthesia maintained with sevoflurane. Pre- and postoperative FOT measurements were compared using Wilcoxon paired rank tests, and the relationships between FOT measurements and preoperative spirometry findings were determined by Spearman's rank correlation analysis.Twenty-six patients were included in the final analysis: postoperative FOT could not be performed in four because of postoperative restlessness or nausea. The mean duration of surgery was 47 min. All components of respiratory resistance deteriorated significantly over the course of surgery, with median increases in R5, R20, and R5-R20 of 1.67 cmH2O/L/s (p < 0.0001), 1.28 cmH2O/L/s (p < 0.0001) and 0.46 cmH2O/L/s (p = 0.0004), respectively. The components of respiratory reactance also deteriorated significantly, with X5 decreasing 1.7 cmH2O/L/s (p < 0.0001), Fres increasing 5.57 Hz (p < 0.0001) and ALX increasing 10.51 cmH2O/L/s (p < 0.0001). There were statistically significant and directly proportional relationships between pre- and postoperative X5 and %VC, %FEV1.0 and %FVC, with inverse relationships between pre- and postoperative Fres and ALX.All components measured by FOT deteriorated significantly after a relatively short period of general anesthesia and mechanical ventilation. All components of resistance increased. Of the reactance components, X5 decreased and Fres and ALX increased. Pre- and postoperative respiratory reactance correlated with parameters measured by spirometry.JMA-IIA00136 .

Project description:IntroductionPerforming lung function test in geriatric patients has never been an easy task. With well-established evidence indicating impaired small airway function and air trapping in patients with geriatric COPD, utilizing forced oscillation technique (FOT) as a supplementary tool may aid in the assessment of lung function in this population.AimsTo study the use of FOT in the assessment of airflow limitation and air trapping in geriatric COPD patients.Study designA cross-sectional study in a public hospital in Hong Kong. ClinicalTrials.gov ID: NCT01553812.MethodsGeriatric patients who had spirometry-diagnosed COPD were recruited, with both FOT and plethysmography performed. "Resistance" and "reactance" FOT parameters were compared to plethysmography for the assessment of air trapping and airflow limitation.ResultsIn total, 158 COPD subjects with a mean age of 71.9±0.7 years and percentage of forced expiratory volume in 1 second of 53.4±1.7 L were recruited. FOT values had a good correlation (r=0.4-0.7) to spirometric data. In general, X values (reactance) were better than R values (resistance), showing a higher correlation with spirometric data in airflow limitation (r=0.07-0.49 vs 0.61-0.67), small airway (r=0.05-0.48 vs 0.56-0.65), and lung volume (r=0.12-0.29 vs 0.43-0.49). In addition, resonance frequency (Fres) and frequency dependence (FDep) could well identify the severe type (percentage of forced expiratory volume in 1 second <50%) of COPD with high sensitivity (0.76, 0.71) and specificity (0.72, 0.64) (area under the curve: 0.8 and 0.77, respectively). Moreover, X values could stratify different severities of air trapping, while R values could not.ConclusionFOT may act as a simple and accurate tool in the assessment of severity of airflow limitation, small and central airway function, and air trapping in patients with geriatric COPD who have difficulties performing conventional lung function test. Moreover, reactance parameters were better than resistance parameters in correlation with air trapping.

Project description:Background: The bronchial provocation test (BPT) performed by using the forced oscillation technique (FOT) is cooperated without forced expiratory effort. However, a comparison of the application value and safety of BPTs measured by using the FOT and the standardized dosimeter method is lacking, which limits its clinical practice. Objective: We aimed to analyze the diagnostic value and safety of the BPT as measured by the FOT in patients with asthma and in healthy subjects. Methods: This was a randomized cross-over clinical study. Airway responsiveness was measured by using the FOT and the aerosol provocation system (APS) dosimeter method in all the participants. The between-test interval was 24 hours. The diagnostic value and safety of the two tests were analyzed. Results: Asthma control status was assessed based on ACT scores, and patients with asthma (including 27 uncontrolled, 34 partially controlled, and 32 controlled) were collected, and 69 healthy subjects were recruited. Receiver operating characteristic curves revealed slightly superior screening capability of cumulative dose of methacholine causing a 20% decrease (PD20)-forced expiratory volume in the first second of expiration when measured by using the APS-dosimeter method (area under the curve [AUC] 0.981 [95% confidence interval {CI}, 0.952-1.000]) over that of cumulative dose of inhaled methacholine at the inflection point when respiratory resistance began to increase continuously (Dmin) by using the FOT (AUC 0.959 [95% CI, 0.924-0.994]). The sensitivity and specificity were 98.9% and 98.6%, respectively, with the APS-dosimeter method, and 100% and 87.0%, respectively, with the FOT. It took an average of 9.0 minutes (range, 6.0-11.0 minutes) when using the FOT and an average of 17.0 minutes (range, 14.0-25.0 minutes) when using APS-dosimeter method (p < 0.01) in all the participants. The measurement time for the FOT was reduced by 47.1% than the APS-dosimeter. The incidence rate of the adverse events with the FOT was slightly higher than that with the APS-dosimeter method (p < 0.05). Both tests were well tolerated. No serious adverse event was found. Conclusion: The FOT, characterized as being simple, safe, and time saving, could be used to assess airway hyperresponsiveness in patients with asthma and worthy of clinical application.

Project description:ObjectiveDescribe respiratory health and quality of life in persons exposed to Libby amphibole asbestos (LAA) contaminated vermiculite.DesignCross-sectional descriptive.SettingAsbestos-related disease clinic in Libby, Montana USA.Participants329 individuals exposed to LAA; mostly men, married, between 50 and 69 years; two-thirds lived in the surrounding county; one-third lived elsewhere in the state and USA.Primary outcome measuresChest radiograph (CXR), pulmonary function data and the St George Respiratory Questionnaire (SGRQ).ResultsExposure categories included vermiculite workers=7.6%; family/household contact of vermiculite worker=32%; and environmental exposure only=60%. Of the participants, 55% had only pleural abnormalities; 5.4% had only interstitial abnormalities; nearly 21% had both abnormalities and 18% had no lung abnormality on chest x-ray. Mean forced vital capacity (FVC) 95.3% (SD=18.7); forced expiratory volume (FEV(1)) mean 87% (SD=20.2); ratio of FEV1(1)/FVC 95.5% (SD=12.0); and diffusing capacity (DLCO) of 83% (SD=21.7) of the percent predicted. The mean total SGRQ (38.5; SD=22.1) indicated a lower quality of life than healthy persons and persons with other chronic conditions. SGRQ subscale means were Symptoms 52.1 (SD=24.9), activity 49.4 (SD=26.9) and impacts 27.5 (SD=21.9). Participants with normal CXR differed significantly from those with both interstitial and pleural abnormalities on total, activity and impacts scores. For activity alone, subjects with normal CXR differed significantly from those with pleural disease; no differences were found for those with interstitial disease. Significant findings were found for smoking history across all pulmonary measures, and for exposure status, radiographic findings, age and gender for select pulmonary parameters. Subjects with any smoking history had significantly worse average total and subscale scores on the SGRQ.ConclusionsOf 329 persons exposed to LAA, the majority (182) had pleural abnormalities identified on CXR. SGRQ scores for persons with abnormalities (pleural, interstitial or both) (269) differed significantly from those with a normal CXR.

Dataset Information

Early Diagnosis of Respiratory Abnormalities in Asbestos-Exposed Workers by the Forced Oscillation Technique.

Background

Methodology/principal findings

Conclusions

Publications

Early Diagnosis of Respiratory Abnormalities in Asbestos-Exposed Workers by the Forced Oscillation Technique.

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