Risk assessment of patient handling with ambulance stretcher systems (ramp/(winch), easi-loader, tail-lift) using biomechanical failure criteria

Comparison of physical demanding paramedic work tasks between an Australian and Canadian ambulance service

Ambulance services require candidates to pass physical employment tests (PETs) to be deemed suitable for the paramedic role. Whilst some research has been undertaken to improve to relevance of these tests, they are often arbitrary and not based on research. The first phase in developing PETs is to generate a list of job tasks. To examine the utility of universal physical tasks tests for ambulance work, we conducted a cross-sectional study, utilising the results from previous work in a Canadian ambulance service to create a physical tasks checklist. These lists were then used by paramedics working for an Australian Service to identify physical tasks in their workplace, and the results from the two services were compared. Patient transfer tasks were similar in frequency and description for both services. Stretcher handling and manoeuvring was identified by Canadian paramedics as highly strenuous, (mean rating of perceived exertion (RPE) 7/10) but were rated mean RPE <3/10 by AV paramedics. Although some tasks between these two services were similar, the ambulance services in this study differed sufficiently with regard to equipment, training and policies mean that similarly titled jobs are not comparable, cross-nationally. Service specific job task analysis is required to develop PETs that ensure employees are specifically selected to meet the requirements of that service.

The Effects of Ramp Gradients and Pushing-Pulling Techniques on Lumbar Spinal Load in Healthy Workers

Background

Many tasks in industrial and health care setting are involved with pushing and pulling tasks up or down on a ramp. An efficient method of moving cart which reduces the risk of low back pain should be concerned. This study aimed to investigate the effects of handling types (HTs) and slope on lumbar spinal load during moving a cart on a ramp. We conducted a 2 × 2 × 4 factorial design with three main factors: 2 HTs, 2 handling directions of moving a cart and 4 degrees of ramp slope.

Methods

Thirty healthy male workers performed 14 tasks consist of moving a cart up and down on the ramp of 0°, 10°, 15°, and 20° degrees with pushing and pulling methods. Joint angles from a 3D motion capture system combined with subject height, body weight, and hand forces were used to calculate the spinal load by the 3DSSPP program.

Results

Our results showed significant effect of HT, handling directions and slope on compression and shear force of the lumbar spine (p < 0.001). When the ramp gradient increased, the L4/5 compression forces increased in both pushing and pulling (p < 0.001) Shear forces increased in pulling and decreased in pushing in all tasks. At high slopes, pulling generated more compression and shear forces than that of pushing (p < 0.01).

Conclusion

Using the appropriate technique of moving a cart on the ramp can reduce the risk of high spinal load, and the pushing is therefore recommended for moving a cart up/down on ramp gradients.

Comparing the biomechanical and psychophysical demands imposed on paramedics when using manual and powered stretchers

The aim of this investigation was to compare the effect of three different stretchers (two powered and one manual) on the biomechanical and psychophysical demands experienced by paramedics when performing routine stretcher handling activities. Eight experienced paramedics performed stretcher raising, lowering, unloading and loading tasks. Video data of task performance and static force requirements were recorded and input into a posture matching program with a quasi-static linked segment model (3DMatch) to compute peak and cumulative L4/L5 compression and shear forces and shoulder moments during each activity. Ratings of perceived exertion (RPE) were recorded from paramedics upon the completion of each task. Use of powered stretchers with load assist functionality reduced the demands on paramedics. Peak L4/L5 forces were reduced by 13-62% and 58-93% for compression and shear respectively when using powered stretchers to perform routine stretcher handling activities. Shoulder flexor moments and RPE scores were reduced by 16-95% and 29-60% respectively when using the powered stretchers compared to the manual stretcher. However, cumulative forces showed mixed results. Although powered stretcher use decreased peak forces, loading and unloading a powered stretcher took 1.5 to 3.4 times longer then when using the manual stretcher, which may explain the mixed results regarding cumulative forces. Based on the RPE scores, paramedics preferred power stretchers relative to the manual stretcher. This study demonstrates that powered stretchers can reduce peak biomechanical and psychophysical exposures associated with the development of musculoskeletal disorder (MSD) during routine stretcher handling activities with minimal increases in cumulative exposures.

Perceived exertion using two different EMS stretcher systems, report from a Swedish study

BACKGROUND

Emergency medical services (EMS) facilitate out of hospital care in a wide variety of settings on a daily basis. Stretcher-related adverse events and long term musculoskeletal injuries are commonly reported. Novel stretcher mechanisms may facilitate enhanced movement of patients and reduce workload for EMS personnel.

AIM

To describe EMS personnel's perceived exertion using two different stretcher systems.

METHODS

The methodology of this explorative simulation study included enrolling twenty (n=20) registered nurses and paramedics who worked in ten pairs (n=10) to transport a conscious, 165lb. (75kg) patient using two different EMS stretcher systems: the Pensi stretcher labeled A and the ALLFA stretcher labeled B. The ten pairs (n=10) were randomized to use either an A stretcher or a B stretcher with subsequent crossover. The pairs performed six identical tasks with each stretcher, including conveying stretchers from an ambulance up to the first floor of a building via a staircase, loading a patient on to the stretcher, and using the stretcher to transport the patient back to the ambulance. The subjective Rating of Perceived Exertion (RPE) survey (Borg scale) was used to measure perceived exertion at predefined intervals during transport.

RESULTS

No significant differences in workload were seen between stretcher groups A and B regarding unloading the stretcher (7.4 vs 8.2 p=0.3), transporting up a stairway (13.7 vs 12.5 p=0.06), lateral lift (12.1 vs 11.2 p=0.5), or flat ground transportation (10.4 vs 11.1 p=0.13). Pairs using stretcher A showed significantly less workload with regards to transporting down a stairway (11.0 vs 14.5 p<0.001) and loading into ambulance (11.1 vs 13.0 p<0.001).

CONCLUSION

A structured methodology may be used for testing the exertion levels experienced while using different stretcher systems. The use of supporting stretcher system mechanisms may reduce perceived exertion in EMS personnel mainly during transports down stairs and during loading into ambulance vehicles.

Identifying the critical physical demanding tasks of paramedic work: Towards the development of a physical employment standard

Public safety related occupations including police, fire and military commonly apply physical employment standard (PES) to facilitate job matching, an approach to evaluate if candidates demonstrate acceptable physical capabilities as required to perform the job safely and effectively. In Canada, paramedics remain as one of the few public safety occupations without an evidence-based, validated PES. The purpose of this study was to document and describe the physical demands of paramedic work and to identify the most physically demanding tasks. These outcomes are essential to inform the design and development of an evidence-based PES for the paramedic sector. Physical demands of paramedic work were documented and described using a direct observation-based task analysis technique. Five paramedic's were trained to document the physical demands of their work, then applied their training to observe more than 90 calls over the course of 20 full 12-h work shifts. Physical demands data were then listed in a survey, administered service-wide, where 155 frontline paramedics identified critically demanding tasks and rank-ordered physical demands from not physically demanding to very strongly demanding. Critically important and physically demanding tasks were identified such as: transferring a patient; loading or unloading a stretcher in to or out of the ambulance; performing CPR; and, raising and lowering a stretcher. It is important that a paramedic-based PES evaluate a candidate's physical capabilities to perform the critical and physically demanding tasks identified in this study.

Paramedics' working strategies while loading a stretcher into an ambulance

For paramedics, loading a stretcher into an ambulance is an activity with a high risk of back injury and accidents. The objective of this study was to document strategies paramedics use at work while loading a powered stretcher into an ambulance. A total of 249 stretcher loading operations performed by 58 paramedics, and 51 semistructured post-intervention interviews were analyzed. Almost three quarters of loading operations required additional actions (e.g., raising the shoulders and additional lifting) to insert the stretcher into the cot fastener system in the ambulance. Some strategies that were necessary to complete the stretcher loading operation seemed to have negative impacts on the workers' health, such as repositioning the stretcher. This action wastes time and requires significant physical efforts, as it is usually done alone. This study suggests some potential solutions, related to equipment, training, workers and work organization, to reduce the risk of injury while loading stretchers.

Implementing powered stretcher and load systems was a cost effective intervention to reduce the incidence rates of stretcher related injuries in a paramedic service

Paramedic services are considering moving towards the use of powered stretcher and load systems to reduce stretcher related injuries, but cost is perceived as a barrier. This study compared injury incidence rates, days lost, and compensation costs between Niagara Emergency Medical Service (NEMS) and Hamilton Paramedic Service (HPS) pre- (four years) and post- (one year) implementation of powered stretcher and load systems in NEMS. Prior to the intervention stretcher related musculoskeletal disorder (MSD) incidence rates averaged 20.0 (±6.8) and 17.9 (±6.4) per 100 full time equivalent (FTE), in NEMS and HPS respectively. One-year post intervention rates decreased to 4.3 per 100 FTE in NEMS, a 78% reduction. Rates modestly increased to 24.6 per 100 FTE in HPS in same period. Cost-benefit analysis estimated that the added cost to purchase powered stretcher and load systems would be recovered within their expected 7-year service life due to the reduction in compensation costs.

Patient acuity as a determinant of paramedics' frequency of being exposed to physically demanding work activities

BACKGROUND

The purpose of this investigation was to examine if paramedics' frequency of being exposed to highly physically demanding activities, or their perception of physical, clinical, and emotional demands were altered by patients' acuity level, operationalized using the Canadian Triage and Acuity Scale (CTAS).

METHODS

Physical demands descriptions (PDD) were compiled from thirteen services across Canada. The observation sessions took place during a minimum of two full-shift (12-h) ride-outs at each service. Data were obtained from 53 ride-outs, which included a total of 190 calls.

RESULTS

Higher urgency calls (CTAS level I or II) required significantly more stretcher handling, equipment handling, and intravenous (IV) work, also prompting higher ratings of perceived clinical, physical, and emotional demand. Independent of CTAS level, stretcher loading with patient (15.0%), horizontal patient transfer (13.7%), and pushing/pulling the stretcher with patient (13.1%) were identified as the most physically demanding tasks.

CONCLUSIONS

Patient acuity is an important determinant affecting the frequency for which paramedics are exposed to work tasks with inherent ergonomic hazards (e.g., handling a stretcher with a patient). Patient acuity also affects paramedics' perceived clinical, physical, and emotional demands of a call.

A biomechanical and subjective comparison of two powered ambulance cots

This study investigated biomechanical effects of different leg folding/unfolding mechanisms used for loading/unloading two powered cots (Cots A and B) into and from a simulated ambulance. Sixteen experienced emergency medical service (EMS) workers loaded and unloaded cots with weights of 45, 68 and 91 kg placed on the cots to simulate patients. Peak back and shoulder/arm muscle activity was reduced 52-87% when using Cot A in comparison to Cot B. Peak ground reaction force (PGRF) was reduced by 74% with Cot A. Adding weight resulted in increased muscle activity and PGRF when using Cot B, but had little effect when using Cot A. Task time was longer with Cot A, though was not perceived unfavourably by participants. This study confirmed that it is possible to substantially reduce physical stress imposed on EMS workers when loading and unloading a cot to and from an ambulance through improvements in cot design.

PRACTITIONER SUMMARY

This study compared two powered ambulance cots, one that lifts/lowers the front and rear wheels independently and one that lifts/lowers the four wheels simultaneously during ambulance loading and unloading. Measured muscle activity, ground reaction forces and operator perceptions support using cot designs that lift/lower the front and rear wheels independently.

A biomechanical and subjective assessment and comparison of three ambulance cot design configurations

Effects of ambulance cot design features (handle design and leg folding mechanism) were evaluated. Experienced ambulance workers performed tasks simulating loading and unloading a cot to and from an ambulance, and a cot raising task. Muscle activity, ratings of perceived exertion, and performance style were significantly affected by cot condition (p < 0.05). Erector Spinae activity was significantly less when using Cot-2's stretcher-style handles. Shoulder muscle activity was significantly less when using Cot-2's loop handle. During loading and unloading, operators allowed the cot to support its own weight most often with Cot-2's stretcher-style handles. Preference for Cot-2 (either handles) over Cot-1 (with loop handle) was consistent across tasks. Handle effects were influenced by operator stature; taller participants received more benefit from Cot-2's stretcher-style handles; shoulder muscles' demands were greater for shorter participants due to handle location. Providing handle options and automatic leg folding/unfolding operation can reduce cot operator's effort and physical strain. Practitioner Summary: Paramedics frequently incur musculoskeletal injuries associated with patient-handling tasks. A controlled experiment was conducted to assess effects of ambulance cot design features on physical stress of operators, as seen through muscle activity and operator's perceptions. Differences between cots were found, signalling that intentional design can reduce operator's physical stress.

EMS Stretcher "Misadventures" in a Large, Urban EMS System: A Descriptive Analysis of Contributing Factors and Resultant Injuries

Purpose. There is a paucity of data regarding EMS stretcher-operation-related injuries. This study describes and analyzes characteristics associated with undesirable stretcher operations, with or without resultant injury in a large, urban EMS agency. Methods. In the study agency, all stretcher-related “misadventures” are required to be documented, regardless of whether injury results. All stretcher-related reports between July 1, 2009 and June 30, 2010 were queried in retrospective analysis, avoiding Hawthorne effect in stretcher operations. Results. During the year studied, 129,110 patients were transported. 23 stretcher incidents were reported (0.16 per 1,000 transports). No patient injury occurred. Four EMS providers sustained minor injuries. Among contributing aspects, the most common involved operations surrounding the stretcher-ambulance safety latch, 14/23 (60.9%). From a personnel injury prevention perspective, there exists a significant relationship between combative patients and crew injury related to stretcher operation, Fisher's exact test 0.048. Conclusions. In this large, urban EMS system, the incidence of injury related to stretcher operations in the one-year study period is markedly low, with few personnel injuries and no patient injuries incurred. Safety for EMS personnel and patients could be advanced by educational initiatives that highlight specific events and conditions contributing to stretcher-related adverse events.

Using observation and self-report to predict mean, 90th percentile, and cumulative low back muscle activity in heavy industry workers

Occupational injury research depends on the ability to accurately assess workplace exposures for large numbers of workers. This study used mixed modeling to identify observed and self-reported predictors of mean, 90th percentile, and cumulative low back muscle activity to help researchers efficiently assess physical exposures in epidemiological studies. Full-shift low back electromyography (EMG) was measured for 133 worker-days in heavy industry. Additionally, full-shift, 1-min interval work-sampling observations and post-shift interviews assessed exposure to work tasks, trunk postures, and manual materials handling. Data were also collected on demographic and job variables. Regression models using observed variables predicted 31-47% of the variability in the EMG activity measures, while self-reported variables predicted 21-36%. Observation-based models performed better than self-report-based models and may provide an alternative to direct measurement of back injury risk factors.