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Pulmonary Function Testing in Inorganic Dust Diseases. Dr Peri Arbak Duzce University , School of Medicine Department of Chest Diseases. Presentation plan. Pulmonary function tests in inorganic dust diseases Correlation between pulmonary functions and progression of disease
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PulmonaryFunctionTesting in InorganicDustDiseases Dr Peri Arbak DuzceUniversity, School of Medicine Department of ChestDiseases
Presentation plan • Pulmonaryfunctiontests in inorganicdustdiseases • Correlationbetweenpulmonaryfunctionsandprogression of disease • Algorithm in longtermpulmonaryfunctionfollow-up • What is thelower limit of normal? • Why is longtermpulmonaryfunctionfollow-upnecessary? • Thepinpointsin longtermpulmonaryfunctionfollow-up • Thesignificantchangein longtermfollow-up
PulmonaryFunctionTestsin InorganicDustDiseases • Pulmonaryfunctiondisordersseen in pneumoconiosismay be restrictive, obstructiveorcombined • Testsarelistedbelow; 1- Forcedexpiratoryflowsincluded FVC, FEV1, FEV1/FVC, MMFR can be measuredeither in workplaceorpulmonaryfunctionlaboratory, 2- Diffusioncapacityand total lungcapacity can be measured in sophisticatedlaboratoryfacilities, 3- 6 minutewalking test, 4- Arterialbloodgases, measurement of pulmonaryarterialpressure, 5- Cardiopulmonaryexercisetesting.
Correlationbetweenpulmonaryfunctionsandprogression of disease(Baum GL, Textbook of PulmonaryDiseases. Vol 1. Philadelphia, Pa: Lippincott-Raven; 1998:683-92.). • Simple pneumoconiosis • Lowercategories (1) • Categories 2-3 • Focalemphysema • B and C opasities • Conglomeratedmass • No functionimpairment, normal capacity • Diffusioncapacity ↓ • Mildhypoxemia (duetoshunt) • Lungcomplianceand RV ↑ • Lungcapacitiesanddiffusion↓ • Pulmonaryhypertension
EVE BOURGKARD. AM J RESPIR CRIT CARE MED 1998;158:504–509.A Longitudinal Study
LU-ANN F. Am J RespirCrit Care Med Vol 163. pp 633–639, 2001
Meral SAYGUN, Tüberküloz ve Toraks Dergisi 2001; 49(3): 359-372
What is thelower limit of normal? • Thepointbelow which 5% of nonexposedasymptomaticsubjects (similarage, race, height, gender)are expected to fall is definedas thelower limit of the reference range (LLN) • Lower limit of normal foreachsubject can be measuredusingstatisticalprograms • http://www.spirxpert.com/GOLD.html
ACOEM 2004 (MC Townsend) 1- OSHA- and industry-mandated medicalsurveillanceprograms require health professionals to assess respiratory health using previous and current examination results. 2- Traditionalevaluationof pulmonary function determines whether test results are in the normal range, which is based on asymptomatic non-smokers.
ACOEM 2004 (MC Townsend) • 3- Unlike clinic patients, many workers have aboveaveragelungfunction, i.e., >100% Pred. Such lung function can deteriorate dramatically, falling from the top to the bottom of the normal range, without dropping below the normal range. This loss of function will not be detected by simply determining whether each year's test results fall within the traditional normal range. • 4- Health professionals must determine whether monitoring change over time is an effective screening test for the outcome disease of interest.
Thepinpoints in longtermpulmonaryfunctionfollow-up 1- Standardize andDocument the Testing Protocol, Equipment Used, and All Changes in Protocol or Equipment. 2- Technician Training and Periodic QA Audits of Spirograms
3- Equipment • Minimize unnecessaryequipmentchanges, • Minimize changes in spirometerconfiguration, • Insurespirometeraccuracy; • Laboratorytestingof spirometer submitted by manufacturer, • Calibration or calibrationchecks at least daily when in use, • On-going scrutiny of spirogramsand patterns of test results • Retaincalibrationrecordsindefinitely
4- BiologicalVariability • Standardize time of day and season of testing to evaluate long-term change, • Postponetesting; • For 3 days if subject feels ill, • For 3 weeks after severe respiratory or ear infection, • For 1 hr after smoking, use of bronchodilator, or a heavy meal, • Untilmedically approved after surgery.
Baselines >100 % Pred • Follow-up FEV1% Pred or FVC % Pred falls below Longitudinal Lower Limit of Normal (LNL) • [Baseline % Pred x 0.85] • A 66-inch tall Caucasian woman was tested periodically from age 30 - 50 years. Is her FVC loss "significant" at age 50? %109X0.85= %93
ForBaselines <= 100 % Pred-1 • Follow-up Measured FEV1 or FVC falls below Longitudinal Lower Limit of Normal (LNL) • [0.85 x Baseline Measured Value - (Baseline Pred - Follow-up Pred)] • Slope Steeper than 90-100 ml/yr over 4-6 or More Years
ForBaselines <= 100 % Pred-2 • A 65-inch tall 67- year old Caucasian woman with Baseline FEV <= 100% Pred was tested annually; biennial results are shown below. Has her FEV1 declined "significantly" by age 69? • 2.42 LtX0.85= 2.06Lt • Calculateexpectedagingeffect; • 2.49-2.43=0.06 [BaselinePred FEV1- Pred FEV1at Age 69] • 2.06-0.06= LNL withclearedageeffect=2.00 [0.85 x Baseline FEV1- Expected Aging Effect]
References 1- Spirometry in the Occupational Health Setting—2011 Update. Mary C. Townsend. ACOEM GUIDANCE STATEMENT 2-http://www.acoem.org/EvaluatingPulmonaryFunctionChange.aspx