Scanner/Sonographer Interface

1. GOALS

Sonography has opened the door to many positive advances in diagnostic imaging for patients, and provided a stimulating career for sonologists (physicians) and sonographers (technologists and nurses). Unfortunately, the modality presents a health threat to the operators because of equipment ergonomics and the manner in which examinations are performed. Surveys in North America and Australia have documented health risks such as repetitive strain injury (RSI) or musculoskeletal injury (MSI), and there has been gradual recognition of the prevalence of MSI in the diagnostic ultrasound workplace. This discussion will review current concerns with ultrasound equipment design and suggest priorities for future ergonomic research and development to prevent workplace-related sonographer injuries.

Further research into causes of sonographer MSI will be valuable, as measurement of variables is difficult. For example, there is variation among sonographers with regard to body fitness, approach to scanning technique, workstation configuration, examination duration and mix, and specialties practised.

2. DESCRIPTION

The nature of the examination and configuration of the technology (i.e. monitors, instrumentation panels and handheld transducers), including ancillary equipment (i.e. VCR, hard copy printer and camera, and electronic image file systems) will be discussed. Nontechnical equipment (such as stretchers and chairs) and the workplace environment (characterized by, for example, ambient lighting, workloads and frequency of breaks) will also be touched on.

3. IMPORTANCE

The Canadian Society of Diagnostic Medical Sonographers (Work, Health & Ergonomics Survey, Nov. 1999) reports a high prevalence of work-related musculoskeletal symptoms among respondents:

87 percent had pain and discomfort at some time during their career, for an average period of four years;

majority of symptoms involved the shoulder (54 percent), neck (37 percent), wrist (25 percent) and upper back (25 percent);

14 percent of survey respondents with pain submitted a workers compensation claim; 61 percent of these claims were accepted; and

10 percent of respondents reported absence from work with an average of 25 consecutive work days missed due to MSI.

Data from a pilot study in Washington and Oregon in 1996 found that “18% of respondents suffered no symptoms, 66% suffered symptoms without RSI, and 15% have been diagnosed with RSI.” The analysis revealed that a positive correlation exists between certain ergonomically unsound work habits and increased symptomatology. The proportion of sonographers diagnosed with RSI tended to increase as the number of years in the profession increased. The reporting rate of musculoskeletal symptomatology and RSI also appeared to be influenced by other variables, such as gender, workload, and stress in the workplace.”

In Sydney, Australia, a survey (McFarlane 1997) of sonographers at the Royal Prince Alfred Hospital working in general, obstetrics/gynecology, and vascular and cardiac ultrasound sections revealed that 78 percent of sonographers suffered symptoms of work-related MSI.

A review of several surveys conducted in various parts of the world confirms a high incidence of MSI in the sonographer workforce. Performance of any one (or more) diagnostic ultrasound examination (i.e. echo, obstetrics, vascular, abdomen, small parts or neonatal) can lead to symptoms of MSI. Musculoskeletal symptoms are aggravated by sustained pinch grasp of small transducers, repetitive minute transducer manipulation, sustained pressure of the transducer against the patient’s body, sustained shoulder abduction, sustained and repetitive twisting of the neck, trunk or both, awkward sustained postures and insufficient recovery time (breaks). Awkward posture (as with portable examinations or poor layout of an exam room), high daily workload, and years of service all play a role.

Musculoskeletal injury in the sonographer workforce with the resultant lost work days has a significant negative impact on the delivery of health care in an environment of high demand and limited resources for ultrasound services. There is a severe shortage of trained sonographers, coupled with expanding ultrasound demand due to technology advances (i.e. cardiac, vascular, musculoskeletal and interventional) in addition to increased requests for established examinations. Diagnostic ultrasound is an investigative tool used early in the diagnostic process by physicians. Lack of timely access to ultrasound resources causes treatment delays and added expense in patient diagnosis (i.e. duplication of testing, longer hospital stay and prolonged patient discomfort). To an already limited sonographer workforce and high demand, there is added the risk and impact of MSI among sonographers.

In Canada, data on workers’ compensation MSI-related claims made by sonographers is not available due to the methods of data collection. However from sonographer surveys in North America, anecdotal information suggests claims do occur and are likely to increase as sonographers, employers and physicians increase their knowledge of MSI.

Aside from the issues mentioned, there is a difficult personal course of recovery and real possibility of career loss for individual sonographers suffering from MSI. Many affected sonographers continue working in pain and have a decreased ability to perform regular work duties. The pain and discomfort extend to situations outside the workplace, limiting activities at home and during recreation.

Ultrasound is an expanding technology and the need for sonographers is increasing. Ultrasound examinations are highly subjective and must be performed by trained personnel who have met a standard of practice. Managers, sonographers, and manufacturers involved in the health care industry must guard against losing sonographers to MSI.

4. CLINICAL REQUIREMENTS AND RECOMMENDATIONS

The prevention of MSI is a responsibility jointly shared by sonographers and managers. Both groups need an educated approach to MSI and to adopt preventive measures with regard to equipment placement and set up, workload and rest periods, and personal factors such as physical conditioning. Manufacturers need to be aware of MSI problems and provide user-friendly design when possible. It is recognized that perhaps there are no perfect ergonomic design solutions due to the nature of ultrasound examinations.

Given that surveys and research indicate the body regions most susceptible to MSI are the shoulders, fingers, neck and back, perhaps special attention should be given to the design of monitors, front-panel controls, and transducers and cables. Suggested design parameters are listed below by device or use.

Device Need Monitors Adjustable for operator-screen distance, angle, swivel and height (sit and stand); resolution technology optimized for the human eye to discern detail without eye strain Keyboard Easily accessible controls; adjustable control panel positions; knobs, dials and buttons appropriate for function; minimal steps to achieve task Transducers Light weight cables and transducers; comfortable transducer shape for operator’s grip and patient comfort; optimal cable and transducer storage Scanner Light weight; small size; easily maneuverable (with castors and handles); on-board storage of ancillary equipment with front-panel operation; cable management; quiet operation; low heat dispersion; footrest Scan Bed Bed height adjustable (21" to 32"); Trendelenburg and reverse T.; head end upright adjustable; scan beds with side rails that move under the bed, thereby facilitating patient positioning at the edge of the mattress; removable echo window cushion

5. MATURITY AND RISK

Ultrasound scanners are a product with a high degree of maturity in terms of purpose and functionality. Equipment purchase is always a compromise of features, with image quality usually the first consideration and ergonomics ranking second. The necessary technology and knowledge exist to enhance the user-friendliness of scanners. However, it can be said that the ergonomics of sonography has not advanced significantly since the early years of real-time sonography. Purchasers need to demand that the user interface improve, and this will occur as managers become more aware of the costs of MSI.

6. AVAILABILITY

Ultrasound scanners are available from many vendors, who offer products to meet many needs. Some products offer greater ergonomic comfort than others.

7. BREADTH OF APPLICATION

The technology is applied in diagnostic medical imaging. Many medical specialties rely on diagnostic ultrasound, with examinations frequently performed by departments other than the traditional radiology department (e.g. vascular, cardiac, obstetrics and surgery).

8. COST-BENEFIT ANALYSIS

It is in the best interest of a manufacturer to design equipment to be user friendly, as it increases desirability of the product.

9. IMPACT OF STANDARDS AND REGULATIONS

Currently, regulations for ultrasound scanners apply to power output of scanners, ensuring that patients are kept safe from possible biological damage from high-frequency ultrasound (United States, Food and Drug Administration).

Regarding operator and scanner ergonomics, it is desirable that sonographer associations, vendors, and perhaps government stakeholders collaborate to develop and constantly review ergonomic guidelines for the manufacture of ultrasound scanners.

10. REFERENCES

Canadian Society of Diagnostic Medical Sonographers: http://www.csdms.com.

Canadian Society of Diagnostic Medical Sonographers and Healthcare Benefit Trust. November 1999. Work, Health & Ergonomics Survey. Vancouver.

Necas M. 1996. “Musculoskeletal symptomatology and repetitive strain injuries in diagnostic medical sonographers: A pilot study in Washington and Oregon,” Journal of Diagnostic Medical Sonography, 12: 266–273.

Ogram D. May 1995. Ergonomic Evaluation of Work Performed By Sonographers While Conducting Ultrasound Examinations (Saskatchewan: Occupational Health & Safety Division, Saskatchewan Labour).

Pike I, Russo A, Berkowitz J, Baker J, Lessoway VA. September/October 1997. “The Prevalence of Musculoskeletal Disorders Among Diagnostic Medical Sonographers,” Journal of Diagnostic Medical Sonography, 13: 219–227.

Society of Diagnostic Medical Sonographers: http://www.sdms.org/msi.

Stevens D. April 11, 1994. Repetitive Strain Injuries and Cardiac Sonographers. Calgary: Foothills Hospital.

11. FURTHER READING

Gregory V. September 1998. “Musculoskeletal Injuries: Occupational Health and Safety Issues in Sonography,” Sound Effects 30.

Habes DJ, Barton S. 1999. Health Hazard Evaluation Report. 99-0093-2749.

Magnavita N, Bevilacqua L, Mirk P, Fileni A, Castellino N. 1999. “Work-related musculoskeletal complaints in sonologists,” Journal of Occupational and Environmental Medicine, 41: 981–988.

Melzack R. 1975. “The McGill Pain Questionnaire: major properties and scoring methods,” Pain, 1: 277–299.

Mirk P, Magnavita N, Masini L, Bazzocchi M, Fileni A. October 1998. “Frequency of Musculoskeletal Symptoms in Diagnostic Medical Sonographers. Results of a Pilot Survey,” Radiol Med, 4: 236–241.

NIOSH Technical Report, HETA 99-0093-2749

Pransky G, Feuerstein M, Himmelstein J, Katz JN. 1997. “Development and validation of the Upper Extremity Function Scale,” Journal of Occupational and Environmental Medicine, 39: 1195–1202.

Schoenfeld A, Goverman J, Weiss DM, Meizner I. 1999. “Transducer user syndrome: an occupational hazard of the ultrasonographer,” European Journal of Ultrasound, 10: 41–45.

Sjøgarrd G, Søgaard K. 1998. “Muscle injury in repetitive motion disorders,” Clinical Orthopaedics and Related Research, 351: 21–31.

Smith and Sainfort (1989) in Kuorinka et al. (eds). 1995. Work-Related Musculoskeletal Disorders: a Reference for Prevention. Philadelphia: Taylor & Francis.Smith AC, Wolf JG, Xie GY, Smith MD. 1997. “Musculoskeletal pain in cardiac ultrasonographers: results of a random survey,” American Society of Echocardiography, 10: 357–362.

Vanderpool HE, Friis EA, Smith BS, Harms KL. 1993. “Prevalence of carpal tunnel syndrome and other work-related musculoskeletal problems in cardiac sonographers,” Journal of Occupational Medicine, 35: 604–610.