Evaluation of the quality of screening audiometry in a sample of occupational settings in East Rand, Gauteng

Transcription

1 PEER REVIEWED ORIGINAL RESEARCH Evaluation of the quality of screening audiometry in a sample of occupational settings in East Rand, Gauteng ABSTRACT Pure tone air conduction audiometry (PTACA) is a non-invasive screening tool that if carried out correctly is an important component of a hearing conservation programme. An earlier pilot study identified poor testing standards. Compliance with recognised South African standards and legislation by audiometrists conducting PTACA at fixed-site clinics in East Rand, Gauteng, using the PTACA Audit Tool was evaluated. A secondary objective was to compare the results with those of the earlier study to ascertain if they differed. A non-experimental descriptive study was conducted, in which 40 audiometrists were interviewed and observed preparing the client and performing a PTACA test. The level of compliance was low and similar to those of the earlier study. The total mean score as a percentage of the maximum possible score was 66.8%. It is recommended that corrective action be implemented to improve compliance to recognised standards with regard to audiometry testing in the occupational setting. K. Michell, Occupational Health Nursing Practitioner, SASOHN National Education Representative Keywords: evaluation, audit tool, quality, audiometry, occupational setting INTRODUCTION Noise-induced hearing loss Pure tone air conduction audiometry (PTACA) testing is used as a component of hearing conservation programmes (HCP) in the occupational setting to screen workers exposed to excessive levels of noise ( 85 db) to prevent noise-induced hearing loss (NIHL). 1 It allows for the determination of an employee s baseline hearing threshold, the identifi cation of early shifts in workers hearing thresholds, monitoring the effect of working in a noise zone over a period of time and assessment of success of the HCP. 1,2,3 Consequently, workers can be counselled, educated and monitored to reduce further deterioration. NIHL is easily preventable if the correct management controls are implemented. Despite knowledge about NIHL, its incidence has not decreased and it remains the greatest compensated occupational disease in South Africa. 4 Screening audiometry test methodology The screening PTACA test procedure to be followed by an audiometrist is stipulated in SANS to ensure correct client testing and results that are an accurate refl ection of client hearing at that point in time (see Box 1). South African legislation requires that testing is performed by a registered audiometrist in the occupational setting. 3,5 Quality of audiometric testing Section 8 (2) (d) of the NIHL Regulations requires that PTACA is performed by a competent person i.e. a registered audiometrist. 3 The Department of Labour (DoL) introduced registration to improve the quality of testing by ensuring that persons performing PTACA in the occupational setting are competent. The administration and maintenance of the audiometry registration database was assigned to the South African Society of Occupational Health Nursing Practitioners (SASOHN). 5 Audiometrists are not audited by SASOHN or the DoL. So apart from the need to register as a practicing audiometrist there is no further evaluation of their practice. A literature search found no published studies evaluating the performance of PTACA. Mets in 1987 studied the reliability of the PTACA in determining hearing loss but not the quality of the testing procedure. 6 NIOSH have a Box 1. Performance criteria that should be met when conducting PTACA testing 1 Conducting an otoscopic examination to rule out otopathology; ensuring the client has been noise free for the required period so there is no temporary threshold shift; conducting calibrations to ensure reliable test results; history taking and client preparation to ensure factors which contribute to hearing loss are identified; and setting of recording and reporting standards to ensure corrective action is applied where necessary and that the information can be transferred from one test to the next creating serial measurements. OCCUPATIONAL HEALTH SOUTHERN AFRICA JULY/AUGUST

2 HCP checklist which includes checking PTACA but this tool also does not assess the quality with which the test is implemented. 7 The PTACA Audit Tool for automatic testing in an occupational setting was developed and pilot tested 8 to review the quality of PTACA testing and incorporates the steps and procedures of SANS It contains fi ve areas of evaluation: legal requirements, equipment and environment controls, client controls, test procedure and recording. For each area, performance indicators and their associated criteria are provided. The criteria must be met in order to demonstrate compliance with standards. The 2003 pilot test in KwaZulu-Natal with 10 participants found that the quality of audiometry testing in the occupational setting was of concern as the mean audit score obtained was 70.8%. 8 It was recommended that the research be expanded to a larger group to determine if this poor quality was an isolated fi nding. Research in action Many South African audiometrists are nurses and the scopes of practice determined by the South African Nursing Council 9 require that nurses undertake and participate in research. 10 Therefore, they should be using research findings to improve their service delivery. However, this depends upon research results being disseminated to the relevant stakeholders. To this end, the 2003 Audit Tool was published in this journal, which is circulated to all SASOHN members, so that they could use it for self assessment to identify strengths and weaknesses, and ultimately improve service delivery in their HCPs. In addition, all registered audiometrists are sent an annual audiometry newsletter covering aspects of the audiometry programme to assist continuing professional development (CPD) and so improve quality of service. With this in mind, the compliance with recognised South African standards and legislation by audiometrists conducting PTACA at fixed-site clinics in East Rand, Gauteng, using the PTACA Audit Tool was evaluated. The initial pilot study had been conducted in KwaZulu-Natal and this study was conducted in a different region using a larger sample. A secondary objective was to compare the results with those of the 2003 study to ascertain if they differed. METHODOLOGY Research design A non-experimental descriptive design, involving observation and interviews, was used. Population and sampling strategy Accessible population Audiometrists practicing in fi xed-site clinics on the East Rand formed the target population. The area was chosen as the researcher and data collection assistants resided in this area. Audiometrists practicing from mobile settings were excluded as they also work outside the area and there were time constraints. In June 2008 the SASOHN audiometry database for the entire country listed 1664 registered audiometrists. 9 It was assumed persons performing PTACA in the occupational setting would be registered to achieve legal compliance, and that this list would represent a complete list of all audiometrists practicing in the area. The database has limited contact information (name, company, postal address, date of registration and registration number and no Table 1. Comparison of the mean scores and the means as percentages of maximum possible scores for the 2003 and 2008 audits. Element Maximum possible score N = 10 N = Mean score Mean as % of maximum possible score Mean score Mean as % of maximum possible score Legislated requirements Registered audiometrist Relevant legislation available Hearing conservation programme Equipment and testing environment Type 4 audiometer Electro-acoustic calibration Biological calibration Daily listening checks Suitable testing site Client controls Comprehensive audiometric history Pre-test preparation Test procedure 11 7* Correct testing procedure Baseline methodology followed 4 * * * Recording of results Results are recorded Results are reviewed Baseline and exit results given to client Total score 72 60* *No baseline tests were performed as part of the 2008 study. The maximum total score for 2008 was adjusted to refl ect this. 20 JULY/AUGUST 2010 OCCUPATIONAL HEALTH SOUTHERN AFRICA

3 telephone numbers). Thus the postal area codes were used to locate eligible audiometrists. An accessible population of 291 was identifi ed. Sample selection A convenience sample of 40 audiometrists was recruited. The researcher and assistants contacted them by searching the telephone directory for the company and then telephonically requesting participation. Many declined to participate thereby possibly introducing a self selection bias. The process was very time-consuming. In some clinics there was more than one practicing audiometrist. Ten (25%) participants were not registered on the database, indicating that it is not a complete list of those conducting audiometry. However, they were included in the study as they are conducting audiometry tests in the occupational setting. Due to time constraints recruitment efforts ceased after a four month period. The 30 registered audiometrists constituted 10.3% of the accessible population were placed on this study. This poor participation rate is similar to the previous study by Michell in which 80% of those approached refused to participate in the study. 8 The most frequent reasons given for declining were that two of the researchers were associated with a business competitor and insuffi cient time to participate. Data collection Instruments The PTACA audit tool 8 was used to assess the quality of audiometry by determining the level of compliance of testing to legislated requirements and South African standards. It was refi ned by the addition of the following criteria: procedures for baseline PTACA, copy of the Occupational Health and Safety (OHS) Act 11 or the Mine Health and Safety (MHS) Act 12 on-site, and all the criteria for a type 4 audiometer. The MHS Act was included so the tool could be used in the mining sector that operates under this Act as opposed to the OSH Act. Recording and reporting criteria were refi ned to include the handing of results to the client and giving appropriate feedback to the client. This was motivated by the researchers experience of employees frequently being unable to provide past tests to new employers. This is a legal requirement in terms of the NIHL Regulations. 3 The refi ned tool was then pretested by the researcher and two data collection assistants at a fi xed-site clinic on the East Rand. No need for further refi nement was indicated (see Figure 1 on pages 22 and 23). Inter-rater reliability was confi rmed by all three auditing a test and obtaining the same scores. A structured interview and response sheet was used to collect data regarding the registration of the audiometrist, SASOHN membership, receipt of the audiometry newsletter and journal, and previous use of the audit tool. experience in auditing and research. They interviewed the participant and observed and documented the client preparation and the procedure for one audiometry test. If the participant was busy conducting tests when the data collector arrived on site, the next complete test was the one selected for auditing. Otherwise, the participant selected the test to be audited. A record review was performed to determine what recording and reporting practices were followed and participants were asked to show the researchers copies of relevant standards and legislation. Data collection was conducted from July to October Ethical considerations SASOHN granted permission for the use of the audiometry database. All participants gave written informed consent, having been assured that confi dentiality would be maintained. No names were recorded on the audit tool or questionnaire. Verbal feedback on performance was given directly after the audit, and written feedback for management where requested by the participant. RESULTS Audit results The mean scores for each of the performance criteria for both the 2008 and 2003 audits have been depicted in Table 1. The total mean score as a percentage of the maximum possible score (MS%) for the audit in 2008 was Continued on page 24 Implementation of the data collection strategy All three data collectors were registered audiometrists with OCCUPATIONAL HEALTH SOUTHERN AFRICA JULY/AUGUST

4 Figure 1. Refined PTACA audit tool SCREENING PURE TONE AIR CONDUCTION AUDIOMETRY AUDITING TOOL KEY TO SCORING TOTAL SCORE ACHIEVED = / 0 = Standard not met 1 = Standard met PERCENTAGE = % PLH = Percentage Loss of Hearing No. PERFORMANCE INDICATORS SOURCE CRITERIA FOR INDICATORS 0 1 COMMENTS 1.0 LEGISLATED REQUIREMENTS 1.1 A competent person (NIHL Regs) performs the audiometric examination. Records The audiometrist is currently registered with the Audiometry Registrar as a practising audiometrist. Score = (max 1) 1.2 Legislation applicable to audiometric testing is available on site. Records Copies of the following legislation are available in the testing environment. - SANS COID Instruction COID Instruction 171 Supplement - Noise-induced hearing loss regulations - OHS Act or MHS Act Score = (max 5) 1.3 The company has a hearing conservation programme. Records A copy of the company s hearing conservation programme is available at the testing site. Score = (max 1) TOTAL = (max 7) 2.0 EQUIPMENT AND TESTING ENVIRONMENT 2.1 The audiometer used meets all Type 4 audiometer requirements. Records Measures frequencies 0.5, 1, 2, 3, 4, 6, 8 KHz Dual fi xed headphones Tone Interrupt switch Patient Response Button Measures decibels 0 to 90 Score = (max 5) 2.2 The audiometer is correctly calibrated Electro acoustic calibration is performed and recorded according to Records A certifi cate of calibration from an approved technician is available. recognised standards. Calibration was performed within the past year. Score = (max 2) Biological calibration (BC) is performed correctly and is recorded. Records A valid biological calibration was performed within the past week. Biological calibration subject has a hearing threshold below 25 db. Biological calibration subject has not been exposed to noise in excess of 80 db. Biological calibration subject is free of otopathology. Score = (max 4) Daily listening checks (DLC) are performed when the audiometer is in use. Records/ Audiometrist performs DLC when the audiometer is in use. Observe Daily listening checks are recorded. Daily listening checks include: o Cable o Decibel o Frequency o Tone interrupt button o Patient response button Score = (max 7) 2.3 The test environment has been assessed as a suitable testing site as per Records/ The testing environment has been certifi ed as suitable for screening audiometry by a certifi ed technician. Score = (max 1) SANS Section Observe TOTAL = (max 19) 3.0 CLIENT CONTROLS 3.1 A comprehensive audiometric history is obtained from the client. Records/ Data is collected from and recorded for the client. Observe Past exposures to noise are documented. Current occupational exposure levels are recorded. Medical data is collected relevant to events since the past audiogram. Current exposure to non-occupational noise is recorded. Score = (max 5) 22 JULY/AUGUST 2010 OCCUPATIONAL HEALTH SOUTHERN AFRICA

5 No. PERFORMANCE INDICATORS SOURCE CRITERIA FOR INDICATORS 0 1 COMMENTS 3.2 Subject is prepared according to pre-test criteria. Records/ Client has not been exposed to noise in excess of 80 db for the past 16 hrs. (For baseline or exit Observe without the use of HPD and periodic HPD may be used.) Test procedure has been explained to the client. An otoscopic examination is conducted prior to testing to rule out otopathology. The better ear is established. Client preparation is recorded. Action taken by the audiometrist is appropriate to the fi ndings of the client preparation. Score = (max 6) TOTAL = (max 11) 4.0 TEST PROCEDURE 4.1 The correct testing procedure is followed for baseline, periodic and exit audiograms. Records/ The headphones are wiped clean prior to use. Observe The audiometrist fi ts the headphones. Objects that impede the headphone seal have been removed. Headphones are correctly placed (Red right and blue left) Client is given the patient response button. Hearing acuity tested at frequencies 0,5, 1, 2, 3, 4, 6, 8 KHz. Testing equipment not visible to client during test process. Score = (max 7) 4.2 Applicable to baseline audiograms only. Records Two audiograms are performed. Baseline methodology is correctly followed. The audiograms are performed on the same day at different sittings. The audiograms do not differ by more than 10 db at any of the frequencies 0.5, 1, 2, 3 or 4 KHz. Has there been previous exposure to occupational noise? Score = (max 4) TOTAL = (max 11) 5.0 RECORDING OF RESULTS 5.1 Audiometric results are recorded correctly. Records/ The recorded test information includes: Observe o Date of test. o Time of test. o Name of audiometrist. o Client s name. o Client s identifi cation number. o Client s date of birth/age. o Client s signature. o Audiometrist signature. o The percentage loss of hearing is calculated. Score = (max 9) 5.2 Results are reviewed in accordance with good practice. Records/ The PLH is compared to the previous audiogram. Observe The PLH is compared to the baseline audiogram. Action is taken by the audiometrist that is appropriate to the results. Feedback given to the client on outcome of results Feedback to client is recorded. Score = (max 5) 5.3 Copy of exit and baseline audiogram is given to client after testing. Client is given a copy of the baseline and exit audiograms. Recorded in records that baseline and exit audiograms are given to client. Score = (max 2) TOTAL = (max 16) AUDIT RESULTS SECTION SCORE TOTAL Percentage MAX % ACTUAL Feedback given to candidate Feedback given by Feedback given on Feedback format OCCUPATIONAL HEALTH SOUTHERN AFRICA JULY/AUGUST

6 Figure 2. Percentage of participants (N=40) who had copies of required legislation and standards on-site Continued from page % compared to 70.8% in The MS%s were lower than in the 2003 study in all areas assessed except for the criteria of having a HCP on-site, biological calibration and daily listening checks, as well as the area or element of test procedure. Despite these higher criteria scores, the overall scores for the performance indicators were still poor with each being below 80% except for test procedure (87.1%). One (2.5%) participant did not have a valid calibration certificate and 12 (30%) of the calibration certificates did not address the suitability of the testing environment for audiometry testing. Figures 2 and 3 provide the results for the availability of legislated standards and documents and noise exposure and history taking respectively. Only 19 (48%) of the audiometrists were checking that workers were not exposed to noise ( 85 db) for the 16 hours preceding the test. Client preparation was recorded by 3 (8%). Interview Only 39 of the 40 participants were interviewed as one was called away. Of these, 30 (77%) were registered audiometrists and the remaining 9 (23%) were performing audiometry without the required proof of registration which is in contravention of the NIHL Regulations. 5 However, the database indicated that 10 (25%) of the sample were not registered. Reasons given were lack of time to complete the registration process. Only 13 (43%) of the 30 registered audiometrists received the audiometry newsletter. Twenty-six (66%) of the participants were SASOHN members and acknowledged receiving the journal but only 12 of these (46%) recalled seeing the audit tool and only 3 (87%) of the sample had used the tool. DISCUSSION Non-registration of audiometrists It is concerning that 25% were not registered, therefore contravening the NIHL Regulations and not deemed competent. 3 The training required for registration provides the practitioner with knowledge and skills necessary to correctly perform the test and all participants had completed a training course. Non-auditing of audiometry testing Only 3 (87%) participants had used the tool to audit the quality of their PTACA testing which is signifi cant as programme weaknesses will not be identifi ed without 24 JULY/AUGUST 2010 OCCUPATIONAL HEALTH SOUTHERN AFRICA

7 Figure 3. Percentage of participants who took a noise exposure history (N=40) some form of evaluation, resulting in perpetuation of errors and poor quality. Evaluation is important for improving quality. 7 Legislated requirements The relevant standards and legislation explain how to implement the PTACA programme (see Figure 2). A lack of access to these documents could be a reason for the poor quality seen as practitioners are working from their knowledge and memory which may not allow for recall of all the required activities. ability to affect test accuracy and should be recorded for future reference. The Compensation Commissioner requires that medical opinion submitted with a claim for compensation indicate that the hearing loss is commensurate with past exposures. 2 This cannot be stated if the historical data has not been collected. Uncontrolled exposure to noise ( 85 db) in the 16 hours preceding the PTACA test may cause a temporary Equipment and testing environment Compliance regarding calibration was good, although 30% of calibration certifi cates did not address the testing environment s suitability for audiometry testing. It cannot be assumed that the test site meets SANS criteria, this must be verifi ed and certifi ed through a calibration certifi cate. The MS%s for biological calibration and daily listening checks were only 30% and 40% respectively. Despite this being better than in 2003 (see Table 1) it was still inadequately covered. Calibration is a requirement for test validity and its absence compromises overall programme results as it leads to false positive or negative NIHL results, which can incur inappropriate expense and loss of hearing respectively. A practitioner must demonstrate through record keeping that equipment was calibrated at the time of testing. Practitioners should take more care over record keeping as these are legal documents. Client controls These address correct client preparation and data collection, through history taking, 14 that may account for hearing loss. Weaknesses were that history of exposure to both occupational and non-occupational noise was poorly collected (see Figure 3). All of these have the OCCUPATIONAL HEALTH SOUTHERN AFRICA JULY/AUGUST

8 threshold shift (TTS) 15 so workers must not be exposed to such noise 1 for 16 hours preceding the test. Yet only 48% were checking this, which could result in an erroneously poorer hearing threshold being recorded due to a TTS. As with the 2003 study, record keeping that any of this preparation had been completed was poor. similar to the 2003 study (see Table 1), which was on another group in a different geographical area. Other possible limitations are that being observed whilst doing the test might have impaired performance because of nervousness or that participants improved their scores due to prior notice. Test procedure No baseline audiograms were performed as part of the 2008 study reducing the possible score for this indicator to seven. The score for this criterion (87.1%) was relatively good in comparison to other criterion audit scores. The weakness was the failure of the audiometrist to remove objects that impeded the headphone placement. Recording of results The recording of results was one of the highest scoring areas (86.7%). Points were lost due to absence of the responsible person s name and not using client s national identity document (ID) number as the identifying number. All compensation claims require the claimant s ID number and when recorded on the audiogram facilitates record retrieval for comparison with future tests as company numbers change as clients change employers. Study limitations Although the sample size was small, the results are very CONCLUSIONS AND RECOMMENDATIONS The value of PTACA testing to prevent NIHL lies in the correct measurement of hearing acuity and early intervention where deviations from the norm are identified. This study found poor test quality, which could be one reason for NIHL being the most reported occupational disease. 4 Audiometrist registration was intended to improve the quality of testing but would appear to not be the case in this study. Despite the small sample, the poor level of compliance found in this study appears to be no different from that found in the 2003 study in KwaZulu-Natal, which is a concern. Corrective actions to improve compliance with recognised standards based on the study findings follow. 1. The audiometry database should include a contact telephone number, name and physical address of employer and an address, to facilitate contact for CPD, auditing and further research. 2. Audits need to be conducted in workplaces, where excessive noise is a hazard, to identify non-registered audiometrists and to assess and improve the quality of the programmes. The DoL should conduct these audits as it has the authority to enforce corrective action. 3. Professional development articles, by the relevant stakeholders who include DoL, audiologists, researchers and peers on all aspects of the audiometry programme need to be made more accessible to audiometrists. These contribute to a CPD programme which would allow audiometrists to retain their registration provided sufficient points are collected. 4. Audiometrists should be encouraged to audit their own PTACA programmes to enable them to identify strengths and weaknesses and take action. 5. A questionnaire to prompt data collection on history taking and client preparation should be introduced. Correct completion will facilitate follow-up in terms of possible confounders of hearing loss compliance with relevant standards. This document could be developed by SASOHN in association with other stakeholders. ACKNOWLEDGEMENTS The author would like to acknowledge the assistance provided by AD Butkovic and A Kruger who collected data. They are both OHNPs and SASOHN members. 26 JULY/AUGUST 2010 OCCUPATIONAL HEALTH SOUTHERN AFRICA

9 LESSONS LEARNED Audiometry screening that is not conducted according to accepted standards and legislation will not yield accurate results, which will impede appropriate actions being taken to prevent noiseinduced hearing loss in exposed employees. Audiometry screening programmes need to be externally audited to address the level of quality with which they are implemented. Practitioners should conduct self audits on their audiometry screening programmes to determine compliance with accepted standards and legislation. The audiometry database must include additional contact information to facilitate continuing professional development, auditing and further research. REFERENCES 1. Standards South Africa. The measurement and assessment of occupational noise for hearing conservation purposes. South Africa. SANS 10083: Louw J and du Randt Louw A. Noise induced hearing loss in industry - a legal and medical guide. South Africa: Lexis Nexis, Butterworths; South Africa. Noise Induced Hearing Loss Regulations. Occupational Health and Safety Act, No 85 of Government Gazette March Department of Labour. Compensation Fund Annual Report Accessed 22 April Available at: 5. Michell K. Registration process for audiometrists as of 17 March Occupational Health Southern Africa. 2003;9(3): Mets J. Reliability of industrial audiometry as a screening method for incipient noise-induced hearing loss. South African Medical Journal. 1987; (71): NIOSH. NIOSH safety and health topic: noise and hearing loss prevention. USA: NIOSH. Accessed 20 July Available at: html 8. Michell K. Auditing occupational audiometric testing a pilot study. Occupational Health Southern Africa. 2007;13(3): SASOHN Audiometry Database. Johannesburg: SASOHN National Offi ce. Accessed 14 February Not published. 10. South African Nursing Council. Charter of nursing practice. Draft 1. Pretoria: SANC;, South African Nursing Council; 29 September Accessed on 29 September Available from sanc.co.za/pdf/charter%20draft.pdf 11. Department of Labour, South Africa. Occupational Health and Safety Act, No. 85 of 1993, as amended by the Occupational Health and Safety Amendment Act, No. 181 of Accessed on 18 January Available at legislation/acts/occupational-health-and-safety/ 12. South Africa. Mine Health and Safety Act, No 29 of Government Gazette No June Accessed on 17 January Available at DownloadFileAction?id= Standards South Africa. The measurement and assessment of acoustic environments for audiometric tests. SANS 10182:2006. South Africa; SSA; Rogers B, Meter D, Summey C, Scheessele D, Atwell T, Ostendorf J, et al. What makes a successful hearing conservation program? AAOHN. 2009;57(8): National Institute on Deafness and Other Communication Disorders, NIH. Noise induced hearing loss. Maryland, USA: NIDCD. Accessed 20 July Available at: health/hearing/noise.asp OCCUPATIONAL HEALTH SOUTHERN AFRICA JULY/AUGUST