Abstract
The growing demand for ultrasound examinations is evident, as is the incidence of work-related musculoskeletal disorders (WRMSDs) incurred by ultrasound practitioners. This paper outlines a simple ergonomic audit that all operators can complete on their ultrasound room and equipment. As a result of this audit, areas of weaknesses in room/equipment design can be highlighted, with recommendations for more ergonomically designed equipment put forward to departmental managers, with the overall aim of reducing WRMSDs among ultrasound practitioners.
An 89% incidence of work-related musculoskeletal disorders (WRMSDs) was found in a study of 300 sonographers. 1 WRMSDs involve conditions affecting the neck, back, shoulders, arms and wrists. 2 Furthermore, prolonged use of visual display units (VDUs) can cause eye strain, although extensive research has shown no evidence that VDUs cause permanent eye damage or disease. 3 These disorders result from an individual's occupation and the environmental conditions in which duties are performed. 4 WRMSDs are debilitating for the sufferer, can lead to sickness absences and eventually early retirement from work. Annually an estimated 5.4 million working days are lost due to employees taking time off work because of WRMSDs, with approximately one month's work lost every year per UK case. 5 Moreover, employers have responsibilities for minimizing WRMSDs in the workplace; recently an ultrasonographer, who lost her job as a result of WRMSDs sustained at work, received from her Trust an out-of-court settlement for £287,500. 6 These issues, coupled with the growing demand for ultrasound services, highlight the importance of trying to reduce the occurrence of WRMSDs within departments.
Ergonomics refers to the ‘fit’ between an employee and their work place, which when optimized can reduce injury. 7 The Society of Radiographers 8 found approximately half of sonographers in their study believed poor equipment design contributed towards WRMSDs. To our knowledge, no previous audit has been published that addresses the ergonomics of an ultrasound room.
The aim of this audit was to objectively evaluate the ergonomics of an ultrasound room within a district general hospital, in relation to the equipment used, and to provide recommendations for further optimization.
Methodology
Setting
Due to reorganization of the ultrasound service within a busy district general hospital, a temporary room was allocated to the ultrasound department for a year. Audit was required to assess the ergonomic design of this room.
Ultrasound room and equipment
The limited size of the room (2.25 m × 3.53 m) restricted its use to ambulant obstetric patients requiring transabdominal scans in the second and third trimesters of pregnancy. A Toshiba Xario™ scanner with cathode-ray tube monitor (Toshiba Medical Systems Ltd, Crawley, UK), Bambach Saddle seat™ (Bambach Saddle Seat (Europe) Ltd, Loughton, UK) and an Akron Streamline™ Merit 2 scan bed (Huntleigh Healthcare, Ipswich, UK) were being used in the room.
Criteria
The gold standard for assessing ergonomic optimization was based on the Sound Ergonomics Website standard. 9 One observer (JWR) did objective measurements and subjective assessments of equipment used in the ultrasound room under the following five subheadings: monitor, keyboard/control panel, transducers, scanner and scan bed/operator's chair (Table 1). The operator's chair was added to the criteria as it offers the user support, if appropriately designed and adjusted. 9 Environmental conditions, which include lighting, room size and temperature, were excluded from the criteria as they were considered to be indirectly linked to WRMSDs, therefore, the audit focused on direct factors relating specifically to equipment design.
Results awarded to each piece of equipment for ergonomic optimization
Questions adapted from Sound Ergonomics Website 9
Added to criteria from Burnage 10
Scoring system and rationale
A question which was answered ‘yes’ scored one point, ‘yes but criteria not fully met’ scored half a point and ‘no’ scored zero points. As four questions were asked in each of the five subsections, a score out of a maximum of four was given for each section and once summated an overall score out of 20 was awarded. We feel that all equipment chosen contributes equally to ergonomic optimization, as poor design features in any one of these pieces of equipment is considered a risk factor that could lead to WRMSDs, 2 therefore, equal weightings were given.
Results
Table 1 summarizes the results of the audit. The overall score for the room was 14.5 out of 20 (72.5%).
Discussion
The results indicate that the ultrasound room is not fully ergonomically optimized, as an overall score of 20 out of 20 was not awarded. Since no piece of equipment scored the maximum, the ergonomic merits and limitations of each piece will be discussed separately and recommendations for future improvements will be provided.
Monitor
The monitor scored 3 out of 4. It did not move independently of the control panel thus restricting height adjustment and angulations. This limitation reduced its usefulness for scanning in a standing position. Consequently uncomfortable head positions may lead to operator neck strain. 14 On the other hand, the monitor height could be adjusted for a seated position, therefore, the operator's sight could be in line with the monitor. 10 Thus with this system, all scans should be performed from a seated position. The operator–screen distance is within the recommended 45.7–76.2 cm range. 14 The monitor's resolution technology gave good image optimization (e.g. enhancing spatial, temporal and contrast resolution), which reduced flicker and monitor brightness/contrast adjustments. These features may reduce eye strain in individuals viewing VDUs. 3
The monitor could swivel to help the operator view the screen from different scan positions, however, it is often inappropriately used to show the client their baby. From clinical experience this often results in the operator/mother twisting their necks to share the monitor. It is recommended that slave monitors be used for client viewing. 2 The system under audit was 18 months old and newer monitors use liquid crystal display flat screen units that are lighter and more manoeuvrable, 11 and may reduce the risk of WRMSDs.
Keyboard
Table 1 shows the keyboard scored well. The keyboard is easily accessed from below the control panel for labelling images and managing patient data. The latter is further optimized as equipment is connected to the ‘CRIS’ Radiology Information System and Picture Archiving and Communication System. However, the operator must look downwards to use the keyboard, which could lead to neck strain and if left out during the examination it increases the operator–screen distance, which may lead to eye strain. It is recommended that practitioners use either keyboards integrated into the control panel or touch-screen predefined labelling to reduce the risk of WRMSDs.
The control panel is height adjustable (although not independent of the monitor, see above), therefore, whether seated or standing the wrist and forearm are in neutral positions. 14 Dials/controls are appropriately labelled, illuminated and designed for their function and are within easy reach of the non-scanning hand. The control panel has a touch-screen, allowing quick access to standard obstetric labels, body markers and pre-sets which reduces the number of steps needed to achieve tasks. Moreover, the Toshiba Xario has a QuickScan button for image optimization, without having to adjust multiple controls, thus examination time is reduced. 15 Baker and Murphy 16 state that repetitive movements can lead to WRMSDs, therefore, the above-mentioned features help to minimize them.
Transducers
The transducer score was good (Table 1). Transducers were lightweight (including cables) and non-bulky with optimized grip in relation to their shape and ridges. These are important factors to: minimize torque on the wrist; adopt a neutral wrist position (non-pinch grip); and assist with a palmer grip. 17 The cable length was adequate to ensure unrestricted transducer movements. Excess cable and additional transducers were safely stored so they did not become an obstacle to the operator or client 14 in the small scan room.
The score for accessory equipment, used for reducing cable weight, was zero. Cable braces are inexpensive, simple and effective for holding/supporting the cable and should be purchased to reduce the strain on the operator's hand/forearm that results from torque. 9 Moreover, placing support cushions under the operator's scan arm to provide additional support helps to prevent prolonged arm abduction which can lead to shoulder and neck injuries. 9
Scanner
The scanner was light-weight, small in size, has handles and is positioned on castors, therefore, it is easily manoeuvrable. Moreover, the scanner had adequate cable storage to prevent trip hazards/cable damage, while in transit and had brakes to provide stability when in use. These features help to reduce the risk of injury sustained by personnel moving the scanner in a small room. 14
The footrest allowed the operator to have a neutral ankle position while scanning, which helps to reduce the risk of WRMSDs, 14 however, this is only possible when the keyboard is not in use. The printer is front-operated for easy operator access, but its location below the control panel meant the user had to stoop down to retrieve the client's obstetric souvenir picture, which could result in neck or back pain. It is recommended that printers be re-positioned to the control panel level. Finally, the Toshiba Xario™ was quiet when in use and has low heat dispersion, therefore, the operator/patient can communicate freely and be in a comfortable working environment.
Scan bed and operator chair
Both the scan bed and operator's chair could be adjusted to accommodate seated/standing positions and ensure the operator's arm was not abducted beyond 30°, 17 as arm abductions beyond 30° could result in shoulder injuries. Moreover, the saddle-type chair is designed to maintain the operator's pelvis in an upright neutral position, which allows the spine to adopt normal alignment 13 and helps to limit back-related problems.
Conversely ergonomic optimization is lost due to the bed design. The bed height can be adjusted to assist the client on/off the bed and is head-end adjustable to help the client into a semi-erect position. The SoR 13 state these features improve client comfort/positioning, which in turn reduces scan times and the need for client movement. 18 However, Trendelenberg and reverse-Trendelenberg positions cannot be achieved and the bed did not have side rails.
Conclusion
Considering the temporary use of the room for second and third trimester ultrasound examinations, the high score for the ergonomic equipment design is helping to reduce operator injury, which could otherwise lead to WRMSDs. Short-term optimization could be achieved by purchasing low-cost accessory equipment (support cushions/cable braces) and installing a slave monitor.
Ultrasound practitioners should perform regular audits on their ultrasound rooms and work with ultrasound manufacturers to design ergonomic equipment that will, when used safely, reduce WRMSDs. Furthermore, equipment reviews and replacement programmes every 4–6 years, as per Royal College of Radiologists’ recommendations 19 may reduce the incidence of WRMSDs among ultrasound practitioners.