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Functional evaluation of occupational lung diseases

Functional evaluation of occupational lung diseases. Prof. Dr. Arif Çımrın Dokuz Eylül Univ Medical School Pulmonary Dept. İZMİR acimrin@deu.edu.tr. Acute / subacute disorders Airway diseases Asthma - RADS, Asthma-like syndrome- Byssinosis Inhalational injury Toxic pneumonitis

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Functional evaluation of occupational lung diseases

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  1. Functional evaluation of occupational lung diseases Prof. Dr. Arif Çımrın Dokuz Eylül Univ Medical School Pulmonary Dept. İZMİR acimrin@deu.edu.tr

  2. Acute / subacute disorders Airway diseases Asthma - RADS, Asthma-like syndrome- Byssinosis Inhalational injury Toxic pneumonitis Hypersensitivity pneumonitis Chronic disorders Interstititial fibrotic disorders Pneumoconiosis Chronic bronchitis, COPD Malignancy Lung cancer, mesotelioma Occupational lung diseases

  3. Tools for functional evaluation of respiratory system • Spirometry • Peak expiratory flow rate • Flow-volume curve • Lung volumes and DLco • Nonspecific bronchial challenge • Specific inhalation challenge • Cardio-pulmonary exercise test

  4. Indications of evaluation of pulmonary function at the workplace Sood A., Pulmonary function tests at work. Clin Chest Med. 2001 Dec;22(4):783-93.

  5. Spirometry Key diagnostic element - Not specific for causative diagnosis - Not patognomonic for disease

  6. Spirometry Indications in Occupational Health • Primary prevention Pe-employment evaluation Jobs contain physical stress Respirator use Screening of exposed workers about pulmonary problems • Secondary prevention Surveillance programs Frequency not clear Evaluation standarts not clear Lower sensitivity for diagnosis of asthma and early interstitial lung disease • Tertiary prevention Clinical evaluation of symptomatic cases Obstructive – FEV1/FVC ↓ (FVC= N) Restrictive – FVC ↓ (FEV1/FVC= ↑ / N) Grading of functional loss Severity of pulmonary functional defect (impairment) Disability evaluation Townsend, MC., et al. Spirometry in the Occupational Setting. JOEM 2000; 42(3), 228-245 Sood A., Pulmonary function tests at work. Clin Chest Med. 2001 Dec;22(4):783-93. Burge PS, et al. Peak flow records in the diagnosis of occupational asthma due to isocyanates. Thorax 1979; 34: 317-23

  7. SpirometryNecessities • FEV1, FVC, FEV1/FVC, flow-volume curve • Accuracy, standardization, Equipment, technician, patient • Normative values, race effect • Criteria for longitudinal follow up evaluation and acute effect

  8. Flow-volume relationshipIndications • Variable/fixed airway obstruction • Vocal kord disfunction , FEF50 / FIF50 >1 • Diagnosis and management of occupational asthma Long term PEF measurement Burge P. Thorax. 1979; 34: 308-16 Chan-Yeung M. Chest. 1995; 108: 1084-1117

  9. Diagnosis of occupational asthmaPEF vs FEV1 • 20 consecutive cases (occup asthma suspected) • (+) SIC: 11 cases • Un-inspected PEF and FEV1 record • 3 readers Sensitivity Specifity PEF 73-82 89-100 FEV1 45-55 56-100 Leroyer C. Am J Respir Crit Care Med. 1998; 158: 827-832

  10. PEF follow upVisual evaluation DiagnosisSpecific periods in a working week(impairment/improvement) • Work-related asthma ≥3/4 working week • Not work-related asthma 4/4 week • Bipolar record %25-75/week • Insufficient record: Shortness of holiday periods Frequent treatment changes Contradictory data No exposure during record Burge SP. Peak flow rate records in the diagnosis of occupational asthma due to colophony Thorax. 1979; 34: 308-16

  11. PEF follow upVisual evaluation

  12. PEF follow upQuantitative evaluation • Occupational asthma >%20 daily variation This type of variation is more frequent during working days • Other Variation only one time or irregular during days • Diagnostic value Sensitivity %93, Specifity %90 -Diurnal variation: Max-Min/Max x100 Liss GM. Peak expiratory flow rates in possible occupational asthma.Chest 1991; 100: 63-9

  13. PEF follow upImportant points n: 17 PEF follow up 6 times/day, 2wk work, >10days holiday, manuel and automatic record Result; Lack of data % 22.0 Reliable data % 55.3 Insufficient record % 23.3 • Conclusion: Training and motivation are important Quirce S. Am J Respir Crit Care Med 1995; 152: 1100-2

  14. PEF follow upImportant points • Difference of consecutive measurements <20L/dmin • Frequency of measurements= 2 hrs/day (4 measure/day) • Same measurement times • Same equipment • Follow up period • >2wk work , >2 weekend • Start work after minimum 1 week off work period • No change in treatment • No change for working conditions Burge PS. Thorax. 1979; 34: 308-16 Gannon PFG, Burge PS. Eur Respir J. 1997; 10(suppl 24): 57s Sood A. Clin Chest Med. 2001 Dec;22(4):783-93

  15. PEF follow upObjective, standard evaluation • PEF record evaluation; 7 readers software (OASYS-2) • Result; • Good agreement between readers • High variation between readers to establish asthma cases (low kappa levels). - Poor agreement between readers about comment and OASYS-2 results • Conclusion As a diagnostic tool, validity of OASYS-2 has to be confirm Baldwin DR, et al. Interpretation of occupational peak flow records: level of agreement between expert clinicians and Oasys-2. Thorax 2002, 57:860–864

  16. Static lung volumes and DLcoIndications • Definite diagnosis of restrictive functional defect - Total lung capacity , pneumoconiosis • Screening and early diagnosis - DLco, beryliosis • Impairment and disability evaluation • Evaluation of exposure – effect relationship Sood A. Clin Chest Med. Pulmonary function tests at work. 2001;22(4):783-93

  17. Nonspecific bronchial hyperreactivity Metacholine • Sensitivity ↑ = superficial inspiration • Specificity ↑ = deep inspiration • Cut off level; PC20 8-16mg/ml • sensitivity high, specificity medium • NPV high, PPV medium • COPD, allergic rhinitis, smoking ATS. Guidelines for metacholine and exercise challenge testing. Am J Respir Crit Care Med. 2000; 161: 309-329

  18. Nonspecific bronchial hyperreactivity Indications • Diagnosis of occupational asthma • Evaluation of NSBHR in exposed, symptomatic, spirometry normal cases • Characterization of natural history • Evaluation of response to intervention • Evaluation of changing in NSBHR before and after SIC Campo P. Advances in methods used in evaluation of occupational asthma. Curr Opin Pulm Med. 2004; 10:142–146 Sood A. Clin Chest Med. Pulmonary function tests at work. 2001;22(4):783-93 Sastre J, et al.: Need for monitoring nonspecific bronchial hyperresponsiveness before and after isocyanate inhalation challenge. Chest 2003, 123:1276–1279

  19. Nonspecific bronchial hyperreactivity Indications • Evaluation of asthma severity Chan-Yeung M. Evluation of impairment/disability in patients with occupational asthma. Am Rev Respir Dis. 1987; 135: 950-51 ATS. Guidelines for the evaluation of impairment/disability in patients with asthma. Am J Respir Crit Care Med. 1993; 147: 1056-61

  20. Nonspecific bronchial hyperreactivity Important points • OA has no NSBHR • ≥2 working-week enough for NSBHR test • After 2 week working, (-) NSBHR rule out OA - Maybe SIC (+) • Longer off work period, less NSBHR • NSBHR follow up; -PEF follow up = higher specifity and sensitivity *Mapp CE., et al. TDI-induced asthma without airwayhyperresponsiveness. Eur Respir J. 1986; 68: 89-95 #Vandenplas O. Increase in NSBHR as an early marker of bronchial response to occupational agents during specific inhalation challenges. Thorax 1996; 51: 472-478 $Baur X, Relation between occupational asthma case history, bronchial metcholine challenge and specific challenge test in patients with suspected occupational asthma. Am J İndust Med 1998; 33: 114-122 Sood A. Clin Chest Med. Pulmonary function tests at work. 2001;22(4):783-93

  21. Specific inhalation challengeIndications • Evaluation of airway response to responsible agent -GOLD STANDARD- • After prevention of exposure at the workplace; • Specific hyperreeactivity to allergen can continue • NSBHR can be normalized Lemiere C.Persistent specific bronchial reactivity to occupational agents in workers with normal nonspecific bronchial reactivity. Am J Respir Crit Care Med. 2000 Sep;162(3 Pt 1):976-80

  22. Specific inhalation challengeIndications • Diagnosis of Occupational Asthma • To define a new agent • To evaluate a responsible agent in a complicated working environment • Definitive diagnosis, if there is a nontypical history or no objective evidence about relation with the job • Diagnosis of Hypersensitivity Pneumonitis

  23. Specific inhalation challenge limitations • Difficult to realize • Time consumer • Expensive • Dangerous • Trained staff, physician observer • False negative and positive results often • Difficult to differentiate acute reactions from irritant effect Perfetti L. OA with sensitization to diphenylmethane diisocyanate (MDI) presenting at the onset like a RADS. Am J Ind Med 2003; 44:325–328 Campo P. Advances in methods used in evaluation of occupational asthma. Curr Opin Pulm Med. 2004; 10:142–146

  24. Specific inhalation challenge Important points • MDI exposed, symptomatic patient. • After diagnosis of RADS, he went back to job • Work related asthma revealed • SIC test to MDI (+) • Definite diagnosis : Occupational asthma • Conclusion; History and NSBHR results are not reliable for OA diagnosis Perfetti L. OA with sensitization to diphenylmethane diisocyanate (MDI) presenting at the onset like a RADS. Am J Ind Med 2003; 44:325–328

  25. Cardio-pulmonary exercise test • Exercise induced asthma • Evaluation of comorbidities with dyspnea • Disability- impairment evaluation • Pre-employment evaluations

  26. Surveillance

  27. Effect of occupational exposure on pulmonary functions • Acute effects of exposure -Pre-employment evaluation -Daily variations • Conclusion; • Comparing with basal value • Longitudinal change • Response to SABA • Response to provocative agent

  28. Effect of occupational exposure on pulmonary functions • Chronic effect of exposure -Pre-employment -Periodical evaluation -difference between case and controls

  29. Medicolegal conditions -Impairment -Disability

  30. Evaluation of impairment have to be multifactorial • ATS, exercise capacity graded with FEV1, FVC ve DLco ≤ %80, %FEV1 ≤%75 pred. • Disability criteria equal each parameter ATS, Evalıuation of impairment/disability secondary to respiratory disorders. Am Rev Respir Dis. 1986; 133: 1205-09 • n: 157 ♂, occupational related respiratory disorders suspected • ECG normal, VO2max (≤2SD, mean FEV1) • Comment; • “FEV1, FVC, DLco, %FEV1 pred.” levels do not estimate disability • Submaximal exercise test results increase accuracy Cotes JE, Lung function impairment as a guide to exercise limitation in work-related lung disorders. Am Rev Respir Dis 1988; 137: 1089-93

  31. Permanent impairment grading FVC, FEV1, DLco, Vo2max= %pred AMA. Guide to the evaluation of permenent impairment. 2000

  32. Examples of clinical applications

  33. Occupational asthma

  34. Diagnostic approach • History • Immunolojik tests • In vivo test s(Skin prick test) • In vitro tests • NSBHR • Airway inflammation • Induced sputum • Ekshaled NO • PEF follow up • SIC at the workplace • SIC at the lab Mapp CE, et al. Occupational asthma. Am J Respir Crit Care Med. 2005; 172: 280-305 Campo P. Advances in methods used in evaluation of occupational asthma. Curr Opin Pulm Med. 2004; 10:142–146

  35. Diagnostic critera of OA Surveillance Case Definition (A) Diagnosis of asthma; (B) onset of asthma after entering the workplace; (C) association between symptoms of asthma and work; (D) one or more of the following criteria: (1) workplace exposure to an agent known to give rise to occupational asthma; (2) work-related changes in FEVi or PEF rate; (3) work-related changes in bronchial responsiveness; (4) positive response to specific inhalation challenge tests; (5) onset of asthma with a clear association with a symptomatic exposure to an irritant agent in the workplace Medical Case Definition Occupational asthma : A+B+C+D2 or D3 or D4 or D5 Likely Occupational asthma: A+B+C+ DI Work-aggravated asthma : A+C+ symptoms with exposure or medication need Chan-Yeung M. Assessment of asthma in the workplace. Chest 1995;108;1084-1117

  36. Diagnostic approach in OA Chan-Yeung M. Assessment of asthma in the workplace. Chest 1995;108;1084-1117

  37. Functional evaluation of pneumoconiosis

  38. IPF, functional changes • Pulmonary function tests • Restrictive= VC, TLC ve RV ↓ • İsovolüme flow rates protected • DLCO ↓ • ABGs= normal or hipoksemia and respiratory alcalosis • Airway mechanics • FEV1 and FVC ↓, FEV1/FVC protected • Elastic recoil↑, Airflow / lung volume↑ • Gas exchange during resting and exercise • A-aPO2 with exercise ↑(%20-30), PaO2 ve SaO2 ↓ • Pulmonary hemodynamics • Early,resting Pulmonary hypertension not common • VC <%50 pred or DLco %45 pred (Pulm. HT usual) ATS guidelines: Idiopathic pulmonary fibrosis: Diagnosis and treatment Am J Respir Crit Care Med 2000; 161:646.

  39. Silica exposure and functional effects Silica exposure with not silicosis; • Chronic obstructive defect • Hypersecretion • Pathology; emphysema Moderate to severe silicosis; • Small and medium size airways narrowing and distortion • Large airways; BALT hypertrophia Very severe silicosis; • İrreversible obstructive defect • + interstital lung disease The official statement of the ATS. ATS guidelines: Adverse effects of crystalline silica exposure. Am J Respir Crit Care Med 1997; 155:761.

  40. Research

  41. Silicosis, correlation between HRCT findings and functional variations • n: 41, stone carver, HRCT and functional evaluation • Decreasing in lung volumes related to severity of silicosis dos Santos Antao VC, et al. High-Resolution CT in Silicosis. Correlation With Radiographic Findings and Functional Impairment. J Comput Assist Tomogr 2005;29:350–356

  42. Surveillance

  43. Surveillance for prevention of silicosis • Inclusion criteria= high level silica exposed person (≥0.05 mg/m3 crystalline silica) • Evaluation items 1. History (Occupational and medical) 2. Physical examination 3. Tuberculin test 4. Chest X-ray 5. Spirometry • Calendar 1. Pre-employment 2. Follow-up (<12 ay) - <0.05mg/m3 dust exposed, <10 yrs working, 1 time/3 yrs, - >10 yrs working, 1 time/2 yrs - High level exposure, close observation 3. Leaving work evaluation • Managing with experienced physician Raymond LW, Wintermeyer S. Medical Surveillance of Workers Exposed to Crystalline Silica. JOEM. 2006; 48(1): 95-101

  44. Lower level: - Probabl respiratory threat - If there are preventive measures: A)Pre-employment evaluation + FEV1 ve FVC B)Inform workers(exposure and symptoms) C)Report symptoms to manager D)Annual questionnaire High level: - Strong respiratory thread A) Pre-employment evaluation + FEV1 ve FVC B) Inform workers(exposure and symptoms) C) Report symptoms to manager D)Questionnaire (6 and 12. wk) E) Annual questionnaire F) Spirometry G)Immunological tests Surveillance for Occupational Asthma Fishwick D., Standards of care for occupational asthma. Thorax 2008;63;240-250

  45. Surveillance, Diisocyanate workplaces • 1983, Ontario,Canada, • Diisocyanate measurement in working areas; <5 ppb / mean 8h ve 20 ppb / short term exposure • Surveillance programme -Pre-employment evaluation respiratory questionnaire + spirometry - Respiratory questionnaire (6. month at work) -Annual spirometry -Workers who have respiratory symptoms and spirometric variations goes next step Tarlo SM, Liss GM. Diisocyanate-Induced Asthma: Diagnosis, Prognosis, and Effects of Medical Surveillance Measures. Appl Occup Envir l Hyg. 2002; 17(12): 902–908

  46. Effect of surveillance on OA Tarlo SM, Liss GM. Diisocyanate-Induced Asthma: Diagnosis, Prognosis, and Effects of Medical Surveillance Measures. Appl Occup Envir l Hyg. 2002; 17(12): 902–908

  47. Effect of surveillance on OA Results -Early diagnosis -Better prevention of pulmonary functions -Better prognosis Tarlo SM, Liss GM. Diisocyanate-Induced Asthma: Diagnosis, Prognosis, and Effects of Medical Surveillance Measures. Appl Occup Envir l Hyg. 2002; 17(12): 902–908

  48. Conclusion • Functional evaluation is a key element of occupational lung disorders • Aim of the evaluation determine method

  49. Thank you acimrin@deu.edu.tr

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