A biomechanical assessment of floor and overhead lifts using one or two caregivers for patient transfers

Effectiveness of Safe Patient Handling Equipment and Techniques: A Review of Biomechanical Studies

OBJECTIVE

This review aimed to evaluate all studies that have evaluated the biomechanical effects when using assistive devices.

INTRODUCTION

The physical demands of patient handling activities are well known. One safety strategy for the reduction of the physical risks is use of assistive devices.

METHOD

The search process identified articles published in English-speaking journals through Google Scholar, Medline, and ISI Web of Science. The included 56 studies contained a biomechanical assessment of a patient handling activity with assistive devices.

RESULTS

The biomechanical effects included four groups: changes in body posture (spinal, other joints), subjective assessment (force, effort, discomfort), measured force (hand force, ground reaction force, spine force, joint torque), and physiological measures. The evidence showed caregivers benefited from using lift hoists, air-assisted devices, and to a lesser extent friction reducing devices for lateral transfers and repositioning, while floor and ceiling lifts were most effective for patient transfers. Some gaps were noted in the evidence and other handling tasks such as sit-to-stand, turning patient in bed, limb lifting, and repositioning and some more high hazard activities like supporting people with limited balance and those that fall need to be investigated with respect to biomechanical outcomes.

CONCLUSION

There is a growing level of biomechanical evidence to support the use of assistive devices for many patient-handling tasks, but the benefits of equipment use in some transfers remain uninvestigated.

PRACTICAL APPLICATION

Evidence indicates the best way to lift patients safely is with floor or ceiling lifts, and air-assisted devices for lateral and repositioning tasks.

Participatory Action Design and Engineering of Powered Personal Transfer System for Wheelchair Users: Initial Design and Assessment

Caregivers that assist with wheelchair transfers are susceptible to back pain and occupational injuries. The study describes a prototype of the powered personal transfer system (PPTS) consisting of a novel powered hospital bed and a customized Medicare Group 2 electric powered wheelchair (EPW) working together to provide a no-lift solution for transfers. The study follows a participatory action design and engineering (PADE) process and describes the design, kinematics, and control system of the PPTS and end-users' perception to provide qualitative guidance and feedback about the PPTS. Thirty-six participants (wheelchair users (n = 18) and caregivers (n = 18)) included in the focus groups reported an overall positive impression of the system. Caregivers reported that the PPTS would reduce the risk of injuries and make transfers easier. Feedback revealed limitations and unmet needs of mobility device users, including a lack of power seat functions in the Group-2 wheelchair, a need for no-caregiver assistance/capability for independent transfers, and a need for a more ergonomic touchscreen. These limitations may be mitigated with design modifications in future prototypes. The PPTS is a promising robotic transfer system that may aid in the higher independence of powered wheelchair users and provide a safer solution for transfers.

The influence of bed height as a percentage of participant height on low back forces when boosting a patient up in bed

BACKGROUND

Repositioning patients is a frequent task for healthcare workers causing substantial stress to the low back. Patient handling methodologies that reduce low back load should be used. Some studies have observed the effect of bed height on back forces using a limited range of heights. This study details a wider range.

OBJECTIVE

The aim of this study was to discover an optimal bed height for reducing low back force when boosting a patient.

METHODS

11 university students and local residents participated by completing a series of boosts with a 91.6 kg research assistant acting as dependent. The bed was adjusted 3% of participant height and 3 boosts were completed at each height which resulted in 8-10 different bed heights depending on the height of the participant. Motion and force data were collected to estimate low back forces via 3DSSPP. Pearson's R was performed to observe the correlation between caregiver height and low back forces.

RESULTS

There were significant negative correlations between bed height and low back compression force at L4-L5 (r = -0.676, p = <0.001) and L5-S1 (r = -0.704, p = <0.001). There were no significant correlations with any shear forces.

CONCLUSION

The highest bed height led to decreased low back compression forces regardless of participant height, but there was not a significant difference in shear forces. Thus, healthcare workers may experience less low back stress with the bed at a higher height. There may be a force tradeoff between the low back and other parts of the body that needs further exploration. Healthcare workers need to be made aware of the implications of adjusting the environment when performing patient handling tasks.

Inertial Motion Capture-Based Estimation of L5/S1 Moments during Manual Materials Handling

Inertial motion capture (IMC) has gained popularity in conducting ergonomic studies in the workplace. Because of the need to measure contact forces, most of these in situ studies are limited to a kinematic analysis, such as posture or working technique analysis. This paper aims to develop and evaluate an IMC-based approach to estimate back loading during manual material handling (MMH) tasks. During various representative workplace MMH tasks performed by nine participants, this approach was evaluated by comparing the results with the ones computed from optical motion capture and a large force platform. Root mean square errors of 21 Nm and 15 Nm were obtained for flexion and asymmetric L5/S1 moments, respectively. Excellent correlations were found between both computations on indicators based on L5/S1 peak and cumulative flexion moments, while lower correlations were found on indicators based on asymmetric moments. Since no force measurement or load kinematics measurement is needed, this study shows the potential of using only the handler's kinematics measured by IMC to estimate kinetics variables. The assessment of workplace physical exposure, including L5/S1 moments, will allow more complete ergonomics evaluation and will improve the ecological validity compared to laboratory studies, where the situations are often simplified and standardized.

Lauren M, Cooper R, Bendixen R, Koontz AM, Cooper RA. Clinical and Ergonomic Comparison Between a Robotic Assisted Transfer Device and a Mobile Floor Lift During Caregiver-Assisted Wheelchair Transfers

BACKGROUND

The robotic assisted transfer device was developed as an updated lift technology to reduce adjustments in posture while increasing capabilities offered by transfer devices. The purpose of this study was to compare the trunk biomechanics of a robotic assisted transfer device and a mechanical floor lift in the transfer of a care recipient by a caregiver during essential transfer tasks.

METHODS

Investigators enrolled 28 caregiver/care recipient dyads to complete 36 transferring tasks. Surface electromyography for the back muscles and motion data for trunk range of motion were collected for selected surfaces, phase, and direction tasks using a robotic assisted transfer device and a mechanical floor lift.

RESULTS

Robotic assisted transfer device transfers required significantly smaller range of trunk flexion (P < 0.001), lateral bend (P < 0.001), and axial rotation (P = 0.01), in addition to smaller distance covered (P < 0.001), average instantaneous velocity (P = 0.01), and acceleration (P < 0.001) compared with a mobile floor lift. The robotic assisted transfer device transfers required significantly smaller peak erector spinae (left: P = 0.001; right: P < 0.001) and latissimus dorsi (right: P < 0.001) and integrated erector spinae left (P = 0.001) and latissimus dorsi right (P = 0.01) electromyography signals compared with the floor lift.

CONCLUSIONS

The robotic assisted transfer device provides additional benefits to mobile floor lifts which, coupled with statistically lower flexion, extension, and rotation, may make them an appealing alternative intervention.

The effects of patient transfer devices on the risk of work-related musculoskeletal disorders (WMSDs): a systematic review

Objectives. This study aimed to evaluate the efficacy of patient transfer assistive devices in reducing the risk of work-related musculoskeletal disorders (WMSDs) among nurses. Methods. PubMed, Scopus, Google Scholar and the Cochrane Database of Systematic Reviews were searched to identify studies with a quantitative assessment of the efficacy of patient transfer assistive devices on the incidence and injury claims of WMSDs as compared to the manual lifting of patients. A health impact analysis of the pre-post intervention of assistive device implementation was performed. The percentage of the reduction of forces, incidence of WMSDs, number of missed workdays and injury compensation claims were calculated, pooled and presented as boxplots. Results. A total of 25 studies met the inclusion criteria. The best post-intervention outcomes of assistive devices deployment in the healthcare setting included a reduction in WMSD incidence by 59.8%, missed workdays by 90.0% and workers' compensation claims by 95.0%. Additionally, hand force declined by 71% (p < 0.05) and 70% (p < 0.05) with the use of air-assisted devices and ceiling lifts respectively. Conclusions. Overall, the evidence suggests that patient transfer assistive devices, notably ceiling lifts and air-assisted devices, are effective in reducing the risk of WMSDs among nurses.

Evaluating a wearable biofeedback device for reducing end-range sagittal lumbar spine flexion among home caregivers

Caregivers who work in the home environment are at risk of back injury due to the awkward postures they have to adopt while providing care. Real-time biofeedback provided by a recently developed wearable device (PostureCoach) may be able to reduce this risk. The effectiveness of a two-day training intervention (including PostureCoach and an educational video) was evaluated for its ability to decrease the amount of time spent in end-range spine flexion. Twenty novice caregivers repeated a series of simulated care tasks. Real-time auditory biofeedback was provided to the intervention group (n = 10) when participants' sagittal lumbar spine flexion exceeded a preset threshold during training trials. Participants in the control group (n = 10) received no feedback. Participants repeated the tasks again two weeks and two months post-intervention. The intervention group maintained decreased end-range (80th and 95th percentile) spine flexion compared to controls at both post-intervention time points.

People Lifting Patterns-A Reference Dataset for Practitioners

Many health professionals do not use correct person transfer techniques in their daily practice. This results in damage to the paraspinal musculature over time, resulting in lower back pain and injuries. In this work, we propose an approach for the accurate multimodal measurement of people lifting and related motion patterns for ergonomic education regarding the application of correct patient transfer techniques. Several examples of person lifting were recorded and processed through accurate instrumentation and the well-defined measurements of kinematics, kinetics, surface electromyography of muscles as well as multicamera video. This resulted in a complete measurement protocol and unique reference datasets of correct and incorrect lifting schemes for caregivers and patients. This understanding of multimodal motion patterns provides insights for further independent investigations.

Biomechanical comparison between manual and motorless device assisted patient handling: sitting to and from standing position

Although lots of assistive devices have been studied to fight against caregivers' work-related musculoskeletal disorders, stand-and-turn devices effects on biomechanical constraints are still unknown. The aim of this study is to provide and compare quantitative data on loads in the low back area resulting from the use of a motorless stand-and-turn device and from manual patient handling. Nine caregivers participated to motion capture and ground reaction forces measurement sessions of three cases of handling: manual handling with one caregiver, manual handling with two caregivers, motorless device assisted handling. Forces and torques at the L5/S1 joint were computed through Inverse Dynamics process. Motorless device assisted handling required the smallest loads whereas manual handling with one caregiver required the biggest loads, the latter being in some cases twice as big as the former. Caregivers should use a stand-and-turn device when handling a patient from sitting/standing to standing/sitting position whenever it is possible.

Comparison of lift use, perceptions, and musculoskeletal symptoms between ceiling lifts and floor-based lifts in patient handling

Lifting equipment can reduce the risk of injury from patient handling, but limited availability and adoption have been a persistent problem. Data from statewide surveys of California nurses (N = 389) in 2013 and 2016 were analyzed to evaluate lift use, perceptions about lifts and injury risk, and musculoskeletal symptoms by type of available lifts. Nurses with ceiling lifts (23%) were significantly more likely to use lifts and had more positive perceptions about lifts, regarding worker safety, patient safety and comfort, ease of use, access, and storing, than nurses with only floor lifts (77%). Nurses with ceiling lifts reported less low back pain and shoulder pain. Our study findings suggest that providing ceiling lifts can result in superior outcomes to floor-based lifts in multiple aspects, including better acceptance and use by nurses for patient handling, as well as being associated with reduced work-related musculoskeletal symptoms in the low back and shoulders.

The biomechanical evaluation of patient transfer tasks by female nursing students: With and without a transfer belt

This study was to examine the kinematics, muscle activities, and perceived physical exertion in different regions of the spine during patient transfers by nursing students between a bed and a wheelchair, with or without a transfer belt in a laboratory setting. Results showed that with the effect of the belt, the % maximum voluntary contraction of the lumbar erector spinae was reduced significantly by nearly 10%. Muscle activity was significantly increased in thoracic erector and multifidus spinae during wheelchair-to-bed transfer, compared to bed-to-wheelchair transfers. There was no significant effect of belt or task on the spinal angular displacement in different spinal regions. Using the transfer belt was associated with a significantly decreased score for perceived exertion. In conclusion, this study supports the use of a transfer belt contributing to lower muscle activity and lower perceived physical exertion in the low back.

Person transfer assist systems: a literature review

OBJECTIVE

Novel developments in the robotics field have produced systems that can support person wheelchair transfers, maximize safety and reduce caregiver burden. The purpose of this study was to identify and describe these systems, their usability (or satisfaction), the context for which they have been or can be used and how they have been evaluated to determine evidence for their effectiveness.

METHOD

Available research on Person Transfer Assist Systems (PTAS) was systematically gathered using similar standards to the PRISMA guidelines. The search terms were derived from common terms and via exploring similar review articles. Initial search terms displayed 1330 articles and by using the inclusion/exclusion criteria 96 articles were selected for abstract review. After full- text reviewing 48 articles were included.

RESULTS

29 articles concerned research in robotic transfer systems, 10 articles used both ceiling and floor-mounted lifts and 9 articles used only floor-mounted lifts as an intervention/control group. The results of this analysis identified a few usability evaluations for robotic transfer prototypes, especially ones comparing prototypes to existing marketed devices.

CONCLUSION

Robotic device research is a recent development within assistive technology. Whilst usability evaluations provided evidence that a robotic device will provide better service to the user, the sample number of subjects used are minimal in comparison to any of the intervention/control group articles. Experimental studies between PTASs are required to support technological advancements. Caregiver injury risk has been the focus for most of the comparison articles; however, few articles focus on the implications to the person.IMPLICATIONS FOR REHABILITATIONCeiling mounted lifts are preferred over floor-based lifts due to lower injury rates.Many robotic transfer systems have been developed; however, there is a paucity of quantitative and qualitative studies.Based on the results of this review, rehabilitation settings are recommended to use ceiling over floor assist systems, and it is recommended to provide training on using devices to assist with patient transfers to lower the risk of injuries.

Further Development of a Robotic-Assisted Transfer Device

Background: The task of performing transfers, such as from a wheelchair to a bed, has a high risk of injury to both the caregiver and the person being transferred. Although mechanical transfer devices can reduce these risks, these devices are not meant for use in the community and they still place strain on the caregiver when used. Purpose: The aim of this study is to describe feedback gathered from focus groups of potential users of the Robotic-Assisted Transfer Device (RATD) and describe design changes aimed at preparing the device for the next step in the development process. Method: The RATD was transferred to a newer electric-powered wheelchair (EPW), key components were redesigned, and the control program was updated to increase the safety of the device. Two focus groups, one consisting of people with disabilities and the other consisting of clinicians and caregivers, were conducted to gather feedback from potential users. Results: Error checking, safety zones, a motor brake, and a new track helped increase the safety of the device. Sixty-three percent of the people with disabilities and 83% of caregivers surveyed said they would use the device. Conclusions: The results from the focus groups were positive and the design changes were successful, but more development is needed before the RATD can be marketed.

Experimental evaluation of a novel robotic hospital bed mover with omni-directional mobility

Bed pushing during patient transfer is one of the most physically demanding and yet common tasks in the hospital setting. Powered bed movers have been increasingly introduced to hospitals to reduce physiological strains on the users. This study introduces and quantifies the manpower efficiency and health benefits of a novel robotic-assisted omni-directional hospital bed transporter (SESTO Bed Mover) in comparison with a conventional manual transport stretcher (Stryker Trauma Stretcher 1037) and a powered transport stretcher (HOSPIMEK HMPT 740), which has a fifth powered wheel providing power assistance only in the forward direction. A total of 14 subjects were recruited (7 porters and 7 students) and were tasked to complete a course within a controlled lab environment. It is concluded that the robotic bed mover is able to halve the required manpower to push hospital beds as compared to conventional bed pushing without any additional physiological strain, potentially improving efficiency by two-fold. Electromyography (EMG) patterns showed that users relied on the shoulder and back muscles in a fashion similar to conventional pushing, further confirming the intuitive drive of the robotic bed mover. Overall, the robotic bed mover shows reduced physical demands, less manpower required for patient transport and reduced back muscle activities, which strongly suggest health benefits for workers in the hospital.

Can experience modulate handler responses to boxes designed to decrease musculoskeletal load?

Biomechanical load during the handling of commercial (cardboard box with and without cut out) and non-commercial boxes (cardboard box with a retreat on the bottom edges), on experienced compared to inexperienced subjects was evaluated. Thirty-seven inexperienced and 21 experienced workers handled all boxes at shoulder and ground levels. Biomechanical load on upper limb was investigated through posture and electromyography (EMG) recordings. Comfort and effort were assessed immediately after each handling. In general, experienced workers had low range of motion. On the other hand, EMG was similar between both groups, except when non-commercial boxes were handled in non-favourable heights. Comfort was higher when a non-commercial box was handled versus a commercial one, regardless of the group. Both groups had a lower biomechanical load when handling the non-commercial boxes compared to the commercial ones. However, experienced workers did not have the same advantage as inexperienced subjects when handling those new boxes. Practitioner Summary: Box designs favouring intuitive hand coupling and more efficient postures have potential to reduce the risk of upper-limb musculoskeletal disorders in inexperienced subjects. However, ergonomist has to deal with workers on different levels of experience. Results of this study can support the development of effective recommendations for the working context.

Spine loading during the application and removal of lifting slings: the effects of patient weight, bed height and work method

The biomechanical loading on the lumbar spine was assessed as 12 female nurses applied and removed slings under two patients of differing weights (54 and 100 kg), using two work methods, and while working at three bed heights (56, 71, 93 cm). Three-dimensional spine loads at the L2/L3, L3/L4, L4/L5 and L5/S1 disc levels were measured using a validated EMG-assisted biomechanical model. Anterior/posterior (A/P) shear loading at the L5/S1 level consistently exceeded the tolerance threshold limit for disc failure. The peak compression values exceeded the 3400 N tolerance threshold for several participants when placing the sling under the 100-kg patient. In general, working from both sides of the bed generated slightly higher A/P shear loading than the one-sided method. Raising the bed significantly decreased compression and A/P shear forces. Therefore, raising the bed to at least the nurse's knuckle height is recommended when applying and removing patient slings. Practitioners Summary: We investigated the spine loading associated with placing and removing slings used for the mechanised lifting of patients. Peak compression and anterior shear forces exceeded recognised thresholds when placing slings underneath heavier patients. Raising the bed to at least knuckle level helps mitigate these spinal loads.

External Hand Forces Exerted by Long-Term Care Staff to Push Floor-Based Lifts: Effects of Flooring System and Resident Weight

OBJECTIVE

The aim of this study was to investigate the effects of flooring type and resident weight on external hand forces required to push floor-based lifts in long-term care (LTC).

BACKGROUND

Novel compliant flooring is designed to reduce fall-related injuries among LTC residents but may increase forces required for staff to perform pushing tasks. A motorized lift may offset the effect of flooring on push forces.

METHOD

Fourteen female LTC staff performed straight-line pushes with two floor-based lifts (conventional, motor driven) loaded with passengers of average and 90th-percentile resident weights over four flooring systems (concrete+vinyl, compliant+vinyl, concrete+carpet, compliant+carpet). Initial and sustained push forces were measured by a handlebar-mounted triaxial load cell and compared to participant-specific tolerance limits. Participants rated pushing difficulty.

RESULTS

Novel compliant flooring increased initial and sustained push forces and subjective ratings compared to concrete flooring. Compared to the conventional lift, the motor-driven lift substantially reduced initial and sustained push forces and perceived difficulty of pushing for all four floors and both resident weights. Participants exerted forces above published tolerance limits only when using the conventional lift on the carpet conditions (concrete+carpet, compliant+carpet). With the motor-driven lift only, resident weight did not affect push forces.

CONCLUSION

Novel compliant flooring increased linear push forces generated by LTC staff using floor-based lifts, but forces did not exceed tolerance limits when pushing over compliant+vinyl. The motor-driven lift substantially reduced push forces compared to the conventional lift.

APPLICATION

Results may help to address risk of work-related musculoskeletal injury, especially in locations with novel compliant flooring.