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NSW workers compensation guidelines for the evaluation of permanent impairment

These guidelines explain permanent impairment assessment in the NSW workers compensation system. This is the fourth edition of these guidelines, published in April 2016.

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The State Insurance Regulatory Authority (SIRA) has issued the 4th edition of the NSW workers compensation guidelines for the evaluation of permanent impairment (Guidelines) for assessing the degree of permanent impairment arising from an injury or disease within the context of workers’ compensation. When a person sustains a permanent impairment, trained medical assessors must use the Guidelines to ensure an objective, fair and consistent method of evaluating the degree of permanent impairment.

The Guidelines are based on a template that was developed through a national process facilitated by Safe Work Australia. They were initially developed for use in the NSW system and incorporate numerous improvements identified by the then WorkCover NSW Whole Person Impairment Coordinating Committee over 13 years of continuous use. Members of this committee and of the South Australia Permanent Impairment Committee (see list in Appendix 2) dedicated many hours to thoughtfully reviewing and improving the Guidelines. This work is acknowledged and greatly appreciated.

The methodology in the Guidelines is largely based on the American Medical Association’s Guides to the Evaluation of Permanent Impairment, 5th Edition (AMA5). The AMA guides are the most authoritative and widely used in evaluating permanent impairment around the world. Australian medical specialists representing Australian medical associations and colleges have extensively reviewed AMA5 to ensure it aligns with clinical practice in Australia.

The Guidelines consist of an introductory chapter followed by chapters dedicated to each body system.

The Introduction is divided into three parts. The first outlines the background and development of the Guidelines, including reference to the relevant legislative instrument that gives effect to the Guidelines. The second covers general assessment principles for medical practitioners applying the Guidelines in assessing permanent impairment resulting from work-related injury or disease. The third addresses administrative issues relating to the use of the Guidelines.

As the template national guideline has been progressively adapted from the NSW Guideline and is to be adopted by other jurisdictions, some aspects have been necessarily modified and generalised. Some provisions may differ between different jurisdictions. For further information, please see the Comparison of Workers’ Compensation Arrangements in Australia and New Zealand report, which is available on Safe Work Australia’s website.

Publications such as this only remain useful to the extent that they meet the needs of users and those who sustain a permanent impairment. It is, therefore, important that the protocols set out in the Guidelines are applied consistently and methodically. Any difficulties or anomalies need to be addressed through modification of the publication and not by idiosyncratic reinterpretation of any part. All queries on the Guidelines or suggestions for improvement should be addressed to SIRA at contact@sira.nsw.gov.au.

7. Respiratory system

AMA5 Chapter 5 (p 87) applies to the assessment of permanent impairment of the respiratory system, subject to the modifications set out below. Before undertaking an impairment assessment, users of the Guidelines must be familiar with:

  • the Introduction in the Guidelines
  • chapters 1 and 2 of AMA5
  • the appropriate chapter(s) of the Guidelines for the body system they are assessing
  • the appropriate chapter(s) of AMA5 for the body system they are assessing.

The Guidelines take precedence over AMA5.

Introduction

8.1 AMA5 Chapter 5 provides a useful summary of the methods for assessing permanent impairment arising from respiratory disorders.

8.2 The level of impairment arising from conditions that are not work-related needs to be assessed by the medical assessor and taken into consideration in determining the level of permanent impairment. The level at which pre-existing conditions and lifestyle activities, such as smoking, contribute to the level of permanent impairment requires judgement on the part of the clinician undertaking the impairment assessment. The manner in which any deduction for these is applied needs to be recorded in the assessing specialist’s report.

Examinations, clinical studies and other tests for evaluating respiratory disease (AMA5 Section 5.4)

8.3 AMA5 tables 5-2b, 5-3b, 5-4b, 5-5b, 5-6b and 5-7b (pp 95–100) give the lower limits of normal values for pulmonary function tests. These are used in AMA5 Table 5-12 (p 107) to determine the impairment classification for respiratory disorders.

8.4 Classes 2, 3 and 4 in Table 5-12 list ranges of whole person impairment (WPI). The assessor should nominate the nearest whole percentage based on the complete clinical circumstances when selecting within the range.

Asthma (AMA5 Section 5.5)

8.5 In assessing permanent impairment arising from occupational asthma, the assessor will require evidence from the treating physician that:

  • at least three lung function tests have been performed over a six-month period and that the results were consistent and repeatable over that period
  • the worker has received maximal treatment and is compliant with his or her medication regimen.

8.6 Bronchial challenge testing should not be performed as part of the impairment assessment. Therefore, in AMA5 Table 5-9 (p 104), ignore column 4 (PC20 mg/mol or equivalent, etc.).

8.7 Permanent impairment due to asthma is rated by the score for the best post-bronchodilator forced expiratory volume in one second (FEV1) (score in column 2, AMA5 Table 5-9) plus per cent of FEV1 (score in column 3) plus minimum medication required (score in column 5). The total score derived is then used to assess the per cent impairment in AMA5 Table 5-10 (p 104).

Obstructive sleep apnoea (AMA Section 5.6)

8.8 This section needs to be read in conjunction with AMA5 sections 11.4 (p 259) and 13.3c (p 317).

8.9 Before permanent impairment can be assessed, the person must have appropriate assessment and treatment by an ear, nose and throat surgeon and a respiratory physician who specialises in sleep disorders.

8.10 The degree of permanent impairment due to sleep apnoea should be calculated with reference to AMA5 Table 13-4 (p 317).

Hypersensitivity pneumonitis (AMA5 Section 5.7)

8.11 Permanent impairment arising from disorders included in this section are assessed according to the impairment classification in AMA5 Table 5-12 (p 107).

Pneumoconiosis (AMA5 Section 5.8)

8.12 This section is excluded from the Guidelines, as these are the subject of the Dust Diseases Legislation.

Lung cancer (AMA5 Section 5.9)

8.13 Permanent impairment due to lung cancer should be assessed at least six months after surgery. AMA5 Table 5-12 (p 107), not Table 5-11, should be used for assessment of permanent impairment.

8.14 Persons with residual lung cancer after treatment are classified in respiratory impairment class 4 (AMA5 Table 5-12).

Permanent impairment due to respiratory disorders (AMA5 Section 5.10)

8.15 AMA5 Table 5-12 should be used to assess permanent impairment for respiratory disorders. The pulmonary function tests listed in Table 5-12 must be performed under standard conditions. Exercise testing is not required on a routine basis.

8.16 An isolated abnormal diffusing capacity for carbon monoxide (DCO) in the presence of otherwise normal results of lung function testing should be interpreted with caution and its aetiology should be clarified.