Medical Surveillance for Hearing Loss

Transcription

1 Medical Surveillance for Hearing Loss Kenneth Corbet MD FRCPC Consultant, Occupational Medicine Clinical Associate Professor University of Calgary September 30,

2 Objectives Describe the objectives of a medical surveillance program for hearing loss Compare regulatory and risk-based eligibility criteria: who is noise-exposed? Describe the essential elements of the audiometric history and testing Determine when medical or audiology referral is indicated. 2

3 Medical Surveillance Medical surveillance is periodic screening for defined clinical criteria in groups of employees who are: exposed to a workplace hazard at risk of an occupational disease At risk cohort Case Referral 3

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5 Objectives of Medical Surveillance Employee education: effects of noise, effects of hearing loss Baseline medical history and audiogram Early identification of new or progressive hearing loss Referral to IH to review noise exposure and controls Medical or audiometric referrals Case and program reporting (OHS, WCB/WSIB, corporate) 5

6 Components of Medical Surveillance Audiometry Standards Audiometric Technician Standards Identification of employees/seg at risk for hearing loss Baseline, Periodic, and Confirmatory Audiograms Interpretation of Audiograms Medical or audiometric referrals Case and program reporting (OHS, WCB/WSIB, corporate) 6

7 Who is noise exposed? 7

8 Regulations - Ontario 8-hour OEL 85 dba Intensity of exposure criteria Every employer shall ensure that no worker is exposed to a sound level greater than 85 db Lex,8hr (Ontario Reg. 565/06, s. 2. Frequency of exposure criteria Frequency of noise exposure not specified Content of hearing conservation program No regulatory requirement for audiometric testing. 8

9 Regulations - Alberta 8-hour OEL 85 dba Intensity of exposure criteria If a worker's exposure to noise exceeds 85 db Lex the employer must implement a noise management program that includes requirements for audiometric testing. (Alberta OHS Code Part 16) Frequency of exposure criteria Frequency of noise exposure not specified Content of hearing conservation program Alberta OHS Code Part 16 Section 223 9

10 Occupational Exposure Limit (OEL) 1. the target (or allowable) daily exposure to a hazard achieved through exposure controls (including personal protective equipment) used by occupational hygienists 2. a level of continuous, daily, occupational exposure that should not lead to serious adverse effects over a working lifetime more relevant for medical surveillance 10

11 Issues and Challenges Many employees currently in medical surveillance programs for hearing loss are not at risk for hearing loss from the workplace. resources expended on monitoring these employees offer little preventive value medical surveillance implies risk of hearing loss to the employee 11

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13 Useful Tools for Intermittent Exposure to Noise Weekly dose equivalent: 16 hours (2 days) per week when hearing protection is required Energy-average The energy-average ( effective or rms) sound level is: Lrms =10 log10 {1/n [10L1/ L2/ L3/ Ln/10]}

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15 HOW DO WE DEFINE NOISE EXPOSED? age ISO/ANSI 1999: Noise-induced hearing loss at 2,3,4 KHz in susceptible workers (5th percentile) exposed continuously to noise at work 80 db years exposed average 2,3,4 KHz age db years exposed average 2,3,4 KHz age db years exposed average 2,3,4 KHz

16 Interpretation of Audiograms 16

17 Audiogram Interpretation Criteria: Medical Referral 17

18 Audiogram Interpretation Criteria: Early shifts 18

19 Audiogram Interpretation Criteria: Hearing Loss Case 19

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21 Key References Occupational Noise Induced Hearing Loss Kirchner et al ACOEM Guidance Statement 2012 The Role of the Professional Supervisor in the Audiometric Testing Component of Hearing Conservation Programs ACOEM Position Statement

22 Sample Audiograms 22

23 52 year-old Refinery Technician - LEFT 52 year-old Refinery Technician - RIGHT Dec-77 3-Jan Dec-77 3-Jan Jan Jan

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25 48 year-old Machinist - LEFT 48 year-old Machinist - RIGHT Sep Sep Jan-02 9-Jun Sep Sep Jan-02 9-Jun

26 61 year-old Welder- LEFT 61 year-old Welder - RIGHT Dec-78 5-Jul-89 1-Nov Jul Dec-78 5-Jul-89 1-Nov Jul

27 Discussion & Questions 27