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Development of an Ergonomic Syringe Adaptor
RS2010-IG14
Final Report Date: October 2011
| Principal Investigator: | Rick Hall |
| Co-Investigators:: | Dennis Schweers (Children’s & Women’s Hospital), Nigel Halsted (BCIT), Yvette Jones (BCIT), Patrick Rebstein (BC Cancer Agency) |
For more information about this project, please contact Rick Hall.
Issue
Many cancer patients cannot receive chemotherapy drugs via syringe pump. As a result, nurses must administer the medication manually, using large volume syringes. An ergonomic assessment conducted by a Provincial Health Services Authority (PHSA) ergonomist revealed that there is a moderate to high risk of injury to the hand, wrist, forearm, and elbow of British Columbia Cancer Agency (BCCA) nurses who administer chemotherapy drugs via large volume syringes (20 cc and greater) as a result of prolonged awkward and static hand and wrist postures, combined with high hand-grip force. The researchers set out to design and develop an ergonomic syringe adapter to help eliminate awkward hand and wrist postures, and to reduce hand-grip force so that risk of injury for users could be prevented or reduced.
Key findings
- The ergonomic syringe adapter, developed for intravenous chemotherapy drug administration, was shown to significantly reduce risk of injury to the hand, wrist, and elbow by:
- Significantly reducing hand-grip force by a factor of 2.2:1 (p<0.01)
- Distributing hand-grip force over the entire hand and fingers, rather than two finger tips and thumb tip
- Eliminating awkward hand and wrist postures
- All of the ten BCCA chemotherapy nurses who evaluated the adapter stated that they would use the adapter if it was available to them
- Eight of the ten nurses who participated in the study indicated that they would use the adapter instead of a standard syringe
- On average, the nurses in the evaluation study who had pain in the thumb, hand, wrist, or forearm (eight of ten) stated that they experienced less pain when using the adapter as compared to only using a syringe
- On average, the nurses in the evaluation study found the adapter to be more comfortable than a traditional syringe
Objectives
The central objectives of this project were to design and develop an ergonomic syringe adapter to help eliminate awkward hand and wrist postures in nurses who administer intravenous chemotherapy drugs, and to reduce hand-grip force so that risk of injury would be reduced or prevented. An evaluation of the syringe adaptor was carried out to determine the success of the solution based on a study of joint postures, hand-grip force, user acceptance, ease-of-use, functionality, performance, safety (to caregiver and patient), and hygiene.
The adapter was designed to be:
- Quick and easy to set up and use
- Used with either hand
- Safe for patients and nurses
- Easy to clean (with some disposable components)
- Low cost
- Universal – able to fit a variety of larger syringe sizes from the three main syringe manufacturers (Monojet, BD, and Terumo)
Method
The results of an earlier ergonomic assessment and injury statistics for BCCA chemotherapy nurses were reviewed to examine levels of pain and parts of the body affected, along with potential causative factors for the injuries. Out of 19 injury reports, 16 nurses reported that the causative factor was administration of drugs using traditional intravenous chemotherapy syringes. In all 19 cases, pain and discomfort was localized to the hand, wrist, and forearm. In response, a PHSA ergonomist and a biomedical engineer at the British Columbia Children’s and Women’s Health Centre teamed up to design a proof-of-concept syringe adapter that could be evaluated for its potential in minimizing risk of injury by reducing hand-grip force and eliminating awkward hand and wrist postures. With the assistance of BCIT’s Products and Process Applied Research Team (PART) and funding through WorkSafeBC’s Focus on Tomorrow program, further development of the prototype was undertaken.
Ten female chemotherapy nurses were recruited to participate in the study, and were evaluated using a syringe with and without the adapter. Potential participants were excluded from the study if they were on leave or had limited duties due to an injury at the time of the research.
Development of the adapter was undertaken in five phases:
- Development of design requirements based on feedback from the potential users of the device and videotaping of four subjects during a mock procedure. A hazard analysis was conducted to determine safety and regulatory requirements, which were incorporated into the overall design requirements.
- Concept development to identify the best design options. Two versions of the adapter were constructed and evaluated by ten female chemotherapy nurses on usability, functionality, ergonomics, and safety. Based on that feedback, a final version of the adapter was chosen that best met the design requirements.
- Detailed design to create drawings suitable for the fabrication of one proof-of-concept prototype.
- Device fabrication to build a “proof of principle” system designed to meet the requirements and that could be used in the verification and validation process.
- Device verification and validation to ensure the adapter met the design requirements. Ten chemotherapy nurses were studied using a syringe with and without the adapter to determine its effectiveness in reducing hand-grip force and minimizing awkward hand and wrist postures. Force sensors and angle sensors were used to determine hand-grip force and joint angles, respectively. A questionnaire was also administered to the study participants to obtain feedback on usability, functionality, ergonomics, safety, hygiene, and aesthetics.
Results
- Maximum hand-grip forces were found to be significantly lower when using the syringe adapter as compared to a standard syringe by a factor of 2.2:1.
- Subjective hand-grip force measurements showed that the subjects, on the average, found a standard syringe to be “moderate to somewhat hard” in comparison to the syringe adapter, which they found “very light to fairly light.“
- Hand-grip forces were distributed over the entire hand and fingers when using the adapter, rather than two finger tips and the thumb tip as when using a standard syringe, which further reduced stress across joints of the hand and wrist of the user.
- Use of the adapter minimized awkward wrist flexion, resulting in near-optimal wrist posture.
- Use of the adapter resulted in a significantly greater amount of shoulder extension as compared to a standard syringe, due to the pulling motion required for operation of the adapter. While the maximum amount of shoulder extension is not considered excessive, this may provide important information for training nurses on the use of the adapter, as a slight of amount of shoulder flexion at the beginning of the procedure could help them to avoid extended shoulder postures.
- There was no difference in shoulder abduction between the syringe adapter and a standard syringe, with the amount of shoulder abduction being within a neutral range.
The research team determined that use of the ergonomic syringe adapter for intravenous chemotherapy drug administration could result in a significant reduction in risk of injury to the hand, wrist, forearm and elbow. The research also showed that nurses who are working through existing pain would likely be able to work in more comfort and to recover more quickly from injury if using the adapter. As this type of chemotherapy treatment is conducted in clinics around the world, the adapter could be introduced broadly. There are approximately 2.5 million visits annually across North America for cancer therapy treatment requiring intravenous drug administration.
The high percentage of acceptance of the syringe adapter as an alternative to using a standard syringe indicates that there would be minimal resistance from nurses if the adapter were to be made commercially available.
Future directions
A modified version of the ergonomic syringe adapter may be of benefit to pharmacy technicians who are responsible for manually pre-filling syringes, and therefore at risk for musculoskeletal injury. Initial trials of a prototype of this device have been very successful.
The researchers suggest that the methods used in this project could be used in the development and evaluation of other ergonomic products in the healthcare field.