Nurse Injuries and Cart Weight Distribution: Research Makes the Case for EVO

Nov 18, 2019 | Blog, EVO

Jaco’s engineers are experts in ergonomics and human factors. They knew exactly what they were doing when they designed EVO with its weight evenly distributed over all four wheels, and how much easier it would be to roll and control EVO as a result – particularly compared to the typically back-heavy straight-post EHR carts predominant in the industry.

Still, it’s always nice to get unsolicited validation from independent research.

A couple of weeks ago we came across a recently published report, The Effects of Direction of Exertion, Path, and Load Placement in Nursing Cart Pushing and Pulling Tasks: An Electromyographical Study. Its authors – a team of scientists motivated by a lack of research on nursing computer carts – collected electromyographical (EMG) data on the activation of arm, back and neck muscles of participants pushing and pulling carts with various load distributions, along different paths simulating hospital hallways.

The muscles monitored in the study are those most directly engaged when pushing, pulling or maneuvering a heavy EHR cart; they’re also some of the muscles that pain nurses most often. In a recent study 75.9% nurses complained of musculoskeletal pain in the upper back, 65.5% in the neck, 62.1% in the shoulders and 51.7% in the wrists and hands. Musculoskeletal injuries account for the largest share of nurse injuries resulting in at least two days off from work – 46 per 10,000 nurses in 2016 – and contribute to the more than $2 billion in workers compensation losses for hospitals every year.

Among the report’s findings, three jumped off the page as we read:

Back-heavy carts require more work to move

The study found that more effort was required – about 9% more on average – to push and steer a cart when the bulk of the weight was positioned in the back of the cart (the side furthest from the operator). The greatest difference in effort was observed in the erector spinae muscles along the back and neck, which exerted up 24% more effort when pushing a backloaded cart vs. a cart with a centered or front-borne load.

A balanced cart is best

The report recommends that ‘the ideal load distribution is to spread the load on the nursing cart equally’ and, when that cannot be achieved, that heavier materials should be mounted closer to the front or center when possible.

Push, don’t pull

You might think well, if a cart is back-loaded, nurses can reduce the strain on their muscles by pulling the instead of pushing it, right? Wrong. The study found that on average, a cart required almost 29% more effort to pull than to push, no matter where the weight was positioned. Pulling is particularly hard on muscles in the fingers and hands – which already get more than their share of stress during data entry and just about every other nursing activity at the point of care.

EVO: Balanced, and 23-60 lbs. lighter, too

EVO’s groundbreaking design, based on our innovative Comfort Glide lift system, distributes the cart’s weight evenly over all four wheels, making the cart noticeably easier to push and steer than traditional straight-post cart designs, which position more weight over the back wheels. The fact that EVO is 23 to 60 pounds lighter than most comparably-equipped straight-post carts makes it that much easier on nurses’ backs, shoulders, necks and hands – up to 45% easier, all other things being equal.

Conduct a stress test of your own – contact Jaco to schedule an EVO demo and evaluation and your hospital.

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