functional evaluation of occupational lung diseases
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Functional evaluation of occupational lung diseases. Prof. Dr. Arif Çımrın Dokuz Eylül Univ Medical School Pulmonary Dept. İZMİR [email protected]. Acute / subacute disorders Airway diseases Asthma - RADS, Asthma-like syndrome- Byssinosis Inhalational injury Toxic pneumonitis - PowerPoint PPT PresentationTRANSCRIPT
Functional evaluation of occupational lung diseases
Prof. Dr. Arif ÇımrınDokuz Eylül Univ Medical SchoolPulmonary Dept. İZMİR
Occupational lung diseases
Acute / subacute disordersAirway diseases
Asthma - RADS, Asthma-like syndrome- Byssinosis
Inhalational injury Toxic pneumonitis
Hypersensitivity pneumonitis
Chronic disorders
Interstititial fibrotic disorders Pneumoconiosis
Chronic bronchitis, COPD
MalignancyLung cancer, mesotelioma
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
Indications of evaluation of pulmonary function at the workplace
Work fitness(?) Dangerous exposure risk,
Physical stress, respirator use
Spirometry
Exercise test
Surveillance and screening
Dangerous exposure (allergen, silica, asbestos)
Spirometry NSBHR
Diagnosis and Management
Obstructive defectRestrictive defect
Spirometry NSBHR
Lung volumes
DLco
Evaluation of Impairment and Disability
Medico-legal evaluation Spirometry DLco
Exercise test
Research Pulmonary effects of working conditions,Evaluation of new asthmagenic agent
Spirometry
SIC
Sood A., Pulmonary function tests at work. Clin Chest Med. 2001 Dec;22(4):783-93.
Spirometry
Key diagnostic element
- Not specific for causative diagnosis
- Not patognomonic for disease
Spirometry Indications in Occupational Health Primary prevention
Pe-employment evaluationJobs contain physical stressRespirator use
Screening of exposed workers about pulmonary problems Secondary prevention
Surveillance programsFrequency not clearEvaluation standarts not clearLower sensitivity for diagnosis of asthma and early interstitial lung disease
Tertiary preventionClinical evaluation of symptomatic cases
Obstructive – FEV1/FVC ↓ (FVC= N)Restrictive – FVC ↓ (FEV1/FVC= ↑ / N)
Grading of functional lossSeverity 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
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
Flow-volume relationshipIndications
Variable/fixed airway obstruction Vocal kord disfunction , FEF50 / FIF50 >1
Diagnosis and management of occupational asthmaLong term PEF measurement
Burge P. Thorax. 1979; 34: 308-16Chan-Yeung M. Chest. 1995; 108: 1084-1117
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
Diagnosis Specific 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 periodsFrequent treatment changesContradictory 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
PEF follow upVisual evaluation
PEF follow upVisual evaluation
Occupational asthma>%20 daily variationThis type of variation is more frequent during working days
OtherVariation 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
PEF follow upQuantitative evaluation
PEF follow upImportant points
n: 17 PEF follow up 6 times/day, 2wk work, >10days holiday, manuel and automatic record
Result; Lack of data % 22.0Reliable data % 55.3Insufficient record % 23.3
Conclusion: Training and motivation are important
Quirce S. Am J Respir Crit Care Med 1995; 152: 1100-2
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: 308-16Gannon PFG, Burge PS. Eur Respir J. 1997; 10(suppl 24): 57sSood A. Clin Chest Med. 2001 Dec;22(4):783-93
PEF follow upImportant points
PEF record evaluation;7 readerssoftware (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
ConclusionAs 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
PEF follow upObjective, standard evaluation
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
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
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
Nonspecific bronchial hyperreactivity Indications
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):783-93Sastre J, et al.: Need for monitoring nonspecific bronchial hyperresponsiveness before and after isocyanate inhalation challenge. Chest 2003, 123:1276–1279
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: 950-51ATS. Guidelines for the evaluation of impairment/disability in patients with asthma. Am J Respir Crit Care Med. 1993; 147: 1056-61
Asthma severity
n PC20
mg/ml
FEV1
% pred.
0
1
2
3
4
42
16
12
11
6
11.6 ± 13.5
4.9 ± 9.0
1.4 ± 2.1
1.2 ± 2.0
0.4 ± 0.5
100 ± 15
93 ± 23
86 ± 27
86 ± 20
70 ± 21
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
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
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
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; 44:325–328Campo P. Advances in methods used in evaluation of occupational asthma. Curr Opin Pulm Med. 2004; 10:142–146
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
Cardio-pulmonary exercise test
Exercise induced asthma Evaluation of comorbidities with dyspnea Disability- impairment evaluation Pre-employment evaluations
Surveillance
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
Effect of occupational exposure on pulmonary functions
Chronic effect of exposure-Pre-employment-Periodical evaluation
-difference between case and controls
Medicolegal conditions
-Impairment -Disability
Evaluation of impairment have to be multifactorial
ATS, exercise capacity graded with FEV1, FVC ve DLco ≤ %80, %FEV1 ≤%75 pred.
Disability criteria equal each parameterATS, 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
Permanent impairment grading
Parameter
Group 1 Group 2 Group 3 Group 4
İmpairment level (%)
0-9 10-25 26-50 51-100
FVC (%pred)
FEV1 (%pred)
DLco (%pred)
VO2max(ml/kg/min)
≥ below normal
“ “ “ “ “
“ “ “ “ “
≥25
60-79
“ “
“ “
≥20 and <25
51-59
“ “
“ “
≥15 and <20
≤ %50
≤ %40
≤ %40
<15
FVC, FEV1, DLco, Vo2max= %pred
AMA. Guide to the evaluation of permenent impairment. 2000
Examples of clinical applications
Occupational asthma
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: 280-305Campo P. Advances in methods used in evaluation of occupational asthma. Curr Opin Pulm Med. 2004; 10:142–146
Diagnostic critera of OASurveillance 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 DefinitionOccupational 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
Diagnostic approach in OA
Chan-Yeung M. Assessment of asthma in the workplace. Chest 1995;108;1084-1117
Functional evaluation of pneumoconiosis
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.
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.
Research
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
Surveillance
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
Surveillance for Occupational Asthma
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
Fishwick D., Standards of care for occupational asthma. Thorax 2008;63;240-250
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
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
-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
Effect of surveillance on OAResults
Conclusion
Functional evaluation is a key element of occupational lung disorders
Aim of the evaluation determine method
Thank you