Since the functionality and usability of the prototype had not been evaluated, it was necessary to conduct thorough evaluation in both fields and laboratories and to come up with redesign goals and strategies. Therefore, this study aimed to evaluate the functionality and usability of the prototype using various ergonomic evaluation approaches and to redesign the prototype based on the results of the evaluation. Then, using the findings of the evaluation, redesign ideas were made and the prototype was upgraded to reflect the ideas.
Research Background
- Fall Accidents at Healthcare Facilities
- Patient Transfer and Work-Related Musculoskeletal Disorders of Nurse
- Assist Devices for WMSD Prevention
- New Patient Transfer Device
Likewise, the wheelchair is the most used assistive device in the hospital because it is light in weight and easy to use and store. In a real hospital environment in Korea, the number of transitions between bed and wheelchair is over 40 times, and it included most of the harmful factors of work-related musculoskeletal disorders (WMSD), such as high repetition, awkward posture, and use of strong force. This means that two or more caregivers are required to transfer a patient using the lift.
Problem of New Patient Transfer
Research Objectives
Full Flow Chart of Research
Background Research
Guideline Research About Assist Devices in The Hospital
The wheelchair robot showed significantly less muscle activity when the robot was used (p<0.05). When transferring from bed, participants used both muscles significantly more when using the robot. Conversely, when transferring to bed, the participant used the same muscles significantly less when using the robot (p<0.05).
Similarly, transferring from the robot to bed took an average of 11.4 seconds, and transferring from the wheelchair took 1.6 seconds longer. In contrast, when the robot was used, muscle activity was higher during disembarkation than in the wheelchair. This procedure involved usability research for ergonomic benefits and a usability evaluation of the robot to come up with design improvement ideas using the prototype.
The robot was provided to each hospital and participating nursing staff used the robot for their routine patient movements for two weeks. Since the user is a patient and not a healthy person, the materials and shape of the robot should be determined accordingly. If so, most of the robot's problems can be avoided by this process.
So the robot was too big to use in patient room and the field test was hardly performed.
Expert Focus Group Interview
User Manual Development
Experiment for Effectiveness Verification of Piggyback Mechanism
Objectives
Methods
The patient was assumed to be elderly who are at risk of falling due to lack of strength and balance. The nurse stood close to the patient with feet shoulder-width apart, then the left hand gripped the patient under the axilla around the upper arm and the other hand held tightly to their shirts and pants at the same time. On the count of three, the nurse pushed the patient against the bed in a zigzag motion until they sat comfortably on the bed.
There is a slight difference in the grip: one hand grabbed the patient under the armpits around the upper arm and the other hand supported the patient's clothing around the lower back. The nurse stood facing the patient, with one food pointed toward the patient and the other foot in the direction of movement. Then the nurse came closer and stood as close to the patient as possible.
Synchronously, they pulled the patient toward them with a gentle rocking motion, shifted their weight to the foot in the direction of the movement, and rotated to prevent twisting. Finally, the nurse should put them down slightly and push them, maintaining the grip until the patient leans back enough in the wheelchair. The maximum EMG means the peak value at the moment when the patient's weight shifts to the nurse.
The left column shows the task score from bed to CarryBot/wheelchair and the right column shows that from CarryBot/wheelchair to bed (* p<0.05).
Conclusion
When transferring from bed to CarryBot, participants spent 9.9 seconds, while transferring to a wheelchair vehicle averaged 3.6 seconds longer.
Field Evaluation
- Objectives and Field Training Session
- Methods
- Results
- Direction of Design Improvement
- Conclusion
Six nursing staff, two porters, two nursing assistants, and two nurses were recruited from two general hospitals and one nursing home in Korea. During the period, they recorded their own and the patient's opinions in a diary and were interviewed individually twice a week about the advantages and disadvantages of the robot. In addition, they were shadowed by researchers to observe how they use the robot for their routine patient transfers and to discover potential problems and needs.
There are similar feedback and opinions on the general hospital and nursing home prototype (Table 4). In particular, the seat, seat belt and other parts can cause painful pressure on the patient due to incorrect dimensions. The patient's body size must therefore be taken into account. Therefore, all dimensions of components must be determined by considering anthropometric data such as hip width, chest width, etc.
In addition, appropriate accessories should be added to induce a stable and comfortable neutral position during transfer. Transferring with the CarryBot took twice as long as the wheelchair, and this can cause reluctance to use it. Although the difference in size between the robot and the wheelchair, the CarryBot, which must be operated with a joystick, is too difficult to use in tight room sizes.
Although the above design improvement directions are proposed, the specific design should be taken into consideration as a result of quantitative experiments and data, as well as these results.
Design Improvement
- Direction Determination of Design Improvement
- Design Requirements
- Design Specification
- Prototyping
- Field Evaluation
- Conclusion
Going back to the first stage of development of this device, it is highly recommended that we develop the product for a nursing home first. Therefore, it is more appropriate to first develop a device specialized for nursing home patients because it has many chronic rather than acute patients and has a relatively monotonous system. In other words, it has an environment where user research can be conducted more smoothly than a general hospital.
It is especially necessary to reflect the characteristics of patients who are sensitive to friction or pressure and have extreme physical conditions compared to the general public. Likewise, there are government regulations, but because they are enacted without considering reality, it is difficult to find a hospital that fully complies with the requirements. So the patients waited their turn and it is difficult to require other transfer except for schedule.
Although the field test is necessary, it is very difficult for a researcher who is not a medical professional to examine and directly observe patients. Nevertheless, it is not a good idea to review a product only by a healthy person, as this can lead to troublesome results. If possible, the researchers draw up a list of questions in advance for the nursing staff and involve them directly as co-researchers in the user research.
In addition, hospitals have very different environments and systems, so direct user research is needed. Traditional user research and market analysis for consumer product design do not work well for healthcare product development, especially for patient care equipment. It is critical to perform quantitative ergonomic evaluation as well as qualitative usability evaluation to validate the functions and benefits of the product.
Issues by The Absence of User Study
Problems Form Inappropriate Context Research
Essential Considerations
A small stimulus such as a little pressure and friction is not a problem for the public, while patients can feel pain and be injured by it. Therefore, when developing patient-related products, every detail must be taken into account and keep in mind that the threshold of patients is low. In this research, when observing patients in the hospital, many patients were reluctant to be interviewed and acted unnaturally.
In this situation, the best solution is for nursing staff who are always present and familiar with a patient to conduct a user study themselves. In addition, the product must provide a lot of trust to users, patients and nursing staff, so that a lot of feedback can be collected. Patients generally have much more anxiety than the public and the nursing staff always pays attention to them.
If they experienced a small defect in the product while riding, they would think the product was dangerous, feel the fear of guard events and not want to use it again. Therefore, the product should be fully verified through experiment and adjustment before field test. At the very least, if an ergonomist familiar with the human-centered design process had participated in the development process at the beginning, he would have shown better results.
Therefore, it is important to prepare from the beginning for the approval of the Korean Food and Drug Administration, to use the approved material and to follow the regulations during the process.
Proposed Product Design Process
Research Contribution
In the latest field test, the redesigned prototype proved to be more usable and safer than the original prototype. The main causes of the problem were the development of the product without understanding the actual user and the lack of adequate consideration of the real hospital environment. Therefore, in this study, based on our experience, we proposed a new product design/development process to avoid such problems in the future development of health products.
Users of healthcare products are diverse in their physical and cognitive abilities, and such aspects can be a serious limiting issue when using the products due to safety and cost. In addition, it must be studied where the products are used, how the products interact with the environment and whether the interaction will comply with existing regulations and codes. Healthcare products that do not comply with the regulation will fail even without any field evaluation.
We hope that our proposed design process will help future healthcare product developers and guide them how to use ergonomic user and product evaluation methods throughout the process. Use of targeted risk factor reduction to prevent falls in elderly inpatients: a randomized controlled trial. Analysis of muscle activities in the upper body of caregivers according to the driving speed of the shower carrier.
FASE Project Team, Exposure assessment of risk factors for musculoskeletal disorders in hospital work: Interrater reliability of PATH observations.
