Background: Although friction-reducing devices reduce the amount of force to complete a lateral transfer, the total force is significantly higher than the recommended pushing and pulling limits. Caregivers complete lateral transfers without knowing the amount of force required to laterally transfer patients, which subjects them to injury. Methods: This study was designed to identify the force to laterally transfer patients of any weight, in conditions similar to those found within the hospital of this study. There were 16 participants in this study. The participants were moved from a hospital bed to a hospital cart using two force gauges pulling two gait belts secured around the participant. Each participant was moved three times, resulting in 48 data points. A regression analysis was used to evaluate trends between two variables. A general linear model was applied and the coefficient of determination was calculated to show the percent fit to the trend line. Results: This study found a strong correlation between force of lateral transfer and the weight of the patient. Using this correlation, this study was able to predict the total force of a lateral transfer for any patient weight. The results from this study allowed for the creation of a guide to determine how many caregivers are required during a lateral transfer to maintain a safe amount of force per caregiver. Conclusion: Caregivers need to be given information regarding the forces required to complete physical movements so they can protect themselves from overexertion and injury. This study provides a guideline for caregivers to know how many people are needed to safely complete a lateral transfer.
Hospitals and nursing homes have become dangerous industries in the United States. According to the Bureau of Labor Statistics, hospitals have injury rates that are nearly double than that of the average of all private industries. Private industry represents all nongovernmental businesses. In 2016, hospitals had an incidence rate of 5.9 nonfatal occupational injuries and illnesses per 100 full-time workers compared with 2.9 nonfatal occupational injuries per 100 full-time workers in all industries of United States combined [Figure 1]. When considering injuries that required time off work, hospitals have a higher rate than construction and manufacturing industries.
According to the Bureau of Labor Statistics, the incidence of musculoskeletal disorders in hospitals in 2016 was 60.5 per 10,000 full-time workers compared with 29.4 per 10,000 full-time workers in all private industries of United States. One of the most common sources of musculoskeletal disorders in hospitals involves moving the patients.
The introduction of safe patient handling programs has aided in the reduction of musculoskeletal injuries in hospitals. There are several hospitals and hospital systems that have seen significant reductions in patient handling injuries because of these programs. The hospital of this study has seen a 73% reduction in patient handling injuries since implementing a safe patient handling program in 2012.
Even with safe patient handling programs, patient lifts, and friction-reducing devices, one of the most significant challenges has been reducing each task to be less than 35 lbs lifting and reducing the pushing and pulling force of each task to a safe level. In other industries, lifting, pushing, and pulling inanimate objects is very predictable. Solutions can be developed to move fixed sized items with machines. In contrast, the movement of patients is much less predictable; patients can be of any size or shape, they may have different medical conditions that affect the way they can be moved (such as a fracture of a limb), they may have different levels of physical abilities, or they may have different levels of cognitive abilities. These issues make developing solutions for moving patients incredibly difficult.
One of the most common tasks related to patient handling is the lateral transfer. A lateral transfer is moving a patient from surface to surface, such as bed to bed or bed to hospital cart. This movement has been completed historically with very few staff members and typically, the majority of the force resides on the caregivers pulling across the surface that the patient is being transferred to. This creates a risk of injury, most likely to the caregiver's shoulders and lower back.
Multiple options are available to reduce the force of the lateral transfer. There are friction-reducing sheets, roller boards, repositioning sheets with use of a ceiling lift, and air transfer devices. The purpose of this study is not to evaluate the different products on the market but to establish a guideline to understand how many caregivers are needed to safely complete a lateral transfer within the hospital of this study.
MaterIals and Methods
The participants of this study included 16 healthy adults. The participants were employees of the hospital where the study was conducted and they volunteered to participate in this study during their regularly scheduled work shifts. The weight of the participants ranged from 67.49 to 148.69 kg. The height of the participants ranged from 59” to 74”.
Chatillon DFX II and a Chatillon Force Gauge manufactured by AMETEK Measurement and Calibration Technologies, Largo, Florida, were the devices used in this study. The attachment point for each force gauge was a carabiner-style clip that was connected with a threaded rod. The devices were set in tension and the data were measured in pounds-force. Each carabiner-style clip was connected to a gait belt. One gait belt was secured around the participant's chest and the other gait belt was secured around the participant's upper leg. A tubular slide sheet was used under the patient as the friction-reducing device.
The procedure for this study included abutting the hospital bed with the hospital cart. A fitted sheet with a tubular slide sheet was placed underneath. The tubular slide sheet was placed from the participant's shoulders to approximately midleg. A tubular slide sheet was also placed under the participant's feet. The hospital bed was positioned slightly higher than the hospital cart to prevent any resistance from the hospital bed mattress being compressed under the weight of the participant. The gait belts were placed around the participant's chest and upper legs. The force gauge was attached to the gait belt. The two researchers counted to three and pulled uniformly across the bed until the participant was on the hospital cart. Each participant was transferred three times. This procedure is shown in Figure 2.
A statistical analysis was completed on the resulting data from the study. A regression analysis was used to evaluate any trends between two variables. The following variables were analyzed: total force versus body mass index (BMI), total force versus height, total force versus weight, average force versus BMI, average force versus height, and average force versus weight [Figures 3 and 4]. A general linear model was applied and the coefficient of determination was calculated to show the percent fit to the trend line.
The results from the statistical analysis showed that the coefficient of determination for average force versus weight was found to be the highest of any comparison at 94.4%. This showed a trend line that is very consistent with the data found in this study. Because of the high reliability of this trend line, it was used to predict the force of transferring patients of any weight, assuming the same physical circumstances. Using the predicted forces from the trend line, the forces were divided by the number of caregivers (2–8). These forces per caregiver were used to define a safe number of caregivers to complete a lateral transfer for each patient's weight [Table 1].
This study found extremely high forces when laterally transferring patients even with the use of a friction-reducing device. Total forces were found to be 286.8– 556.9 N for participants that weighed 67.49–148.69 kg. A study by Knapik and Marras analyzing safe pushing and pulling limits in any industry states that it is safe to push 20% of your body weight and pull 30% of your body weight. For a 68-kg caregiver, this would be 133 N of pushing force and for a 113-kg caregiver, this would be 222 N of pushing force. Knowing that patients in a hospital setting have weights that are considerably larger than the weight of the upper weight tested in this study, it is absolutely critical to reduce the force of lateral transfers and use a safe amount of staff members.
This study was completed in a simulated environment using participants that were healthy and fully clothed. There could be differences in force if moisture was present or skin was contacting the bed rather than clothing or a sheet. There could be differences in force with different mattresses or mattresses in poor condition. In reality, a patient could assist in the transfer if they were physically able. The facility that this study was conducted in performs lateral transfers by primarily using pushing force rather than pulling. Theoretically, these forces should be the same; however, in practice, these may have a slight difference in force to the caregivers.
During the study, it was found that the two researchers were not able to pull the exact amount of force in each trial. This shows that one caregiver might have higher or lower forces. This could be due to a number of factors such as physical capabilities, height, and experience performing lateral transfers.
The Chatillon force gauges are able to document the peak force required during the trial. Using two independent Chatillon force gauges, it is not known whether the totaled peak forces would equal the total force at any given time during the transfer. This would represent the highest amount of force possible during the lateral transfer.
A literature review was completed related to lateral transfers. The majority of the studies were evaluating the benefit of or the reduction of force by using friction-reducing sheets or air transfer devices when compared to the use of the drawsheet. The reduction of force by use of these devices has been well established in literature. One study by Bacharach et al. concluded that there are multiple factors to reducing back injuries during lateral transfers, including the use of friction-reducing devices, the type of friction-reducing device, proper body position, and training. It further states that the ease of use, convenience, time required to transfer a patient, and cleanliness of the device were factors that contributed to the use by caregivers. This study was limited by the fact that only three subjects were included for each device.
This prevents a clear analysis of the number of caregivers required to complete each lateral transfer.
The primary purpose of the study by Baptiste et al. was to test different lateral transfer devices. This study had a different approach by using a wide variation of caregivers to trial the products. It also used a five-question survey to glean the caregiver's subjective assessment of each device. This study concluded that the air-assisted devices performed the best and the drawsheet performed poorly. It did not include actual forces of lateral transfers and only used subjective reports from caregivers. It did not allow for establishing a safe working limit with a specific device or method.
A study by Waters et al. was designed to analyze the effects of lateral transfers to and from the operating room (OR) table as well as some other movements in the OR. It presented a guideline for a number of caregivers to safely complete a lateral transfer; however, the forces used for this guideline were based on a 72.6% force-to-patient weight ratio using a drawsheet, which the study cites from another study conducted by Baptiste et al. This study's findings did not find a standard force-to-patient weight ratio but rather the force-to-patient weight ratio reduced as the patient's weight increased.
A study by Bohannon analyzed the forces to complete a lateral transfer using drawsheets and friction-reducing slide sheets. This study completed a similar method to the one shown in the previous study. The force data in the previous study were only used to compare the different products. They were not used to establish a guideline for safe number of caregivers required for patients of different weights.
Lateral transfers of patients are one of the most frequently completed tasks in a hospital setting. The forces required to complete lateral transfers are extremely high and pose a significant risk for musculoskeletal injury to the caregivers completing them. The use of friction-reducing devices decrease the amount of force to complete a lateral transfer; however, without knowing the actual forces during the transfer, the caregivers have no way of knowing how many caregivers are needed to complete a lateral transfer with a safe amount of force per caregiver. A guideline was created from the results of this study to define how many caregivers are needed during a lateral transfer to maintain a safe amount of force per caregiver. This guideline will allow caregivers to understand the number of people required to complete a lateral transfer safely to reduce overexertion and injury to the caregivers. This guideline is shown in Table 1.
Financial support and sponsorship
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Conflicts of interest
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