6 Hours Sitting May Cause Pressure Sore

SITTING & PRESSURE
By Darren Salinger, M.D., OB/GYN
& Melanie Loomos, Inventor

In modern society, sitting takes up an increasing amount of time, both at home and at work. It has been concluded there is a considerable shift to sedentary work in industrialized countries (3).

1881 Analysis of Contact Stresses

The original analysis of contact stresses which lead to pressure-related problems while sitting was published in 1881 by Heinrich Hertz (5).

6 Hours Sitting May Cause Pressure Sore

A healthy individual can develop a pressure sore in six to twelve hours if left undisturbed in the same position (7). A single pressure sore costs more than $8,000 to heal. The yearly costs of treating pressure sores and related problems have been estimated to be almost $1 billion (9).

One study found that 63 percent of patients who sat for an unlimited period of time developed pressure sores whereas only 7 percent of patients developed pressure sores who sat for maximum periods of two hours (1).

Limiting sitting time is only one starting point in preventing pressure sores. Other possibilities include appropriate posture and pressure-reducing seat cushions (1).

In a test of six pressure-relieving devices, the air doughnut was found to be the least effective in reducing inter-surface pressures. None of the devices tested eliminated the inter-surface pressures generated by sitting in one position (7).

To prevent tissue damage, people must be able to shift their weight or be assisted to alternate pressure points (7).

External Pressure = 1/2 Internal Pressure

Externally measured pressure under the butt bones is only one half of the internal pressure. Given the pressures that are prevalent, Staarink (1995) found it amazing that more people do not get pressure ulcers (1).

Risk Factors for Pressure Sores

Studies have implicated factors such as posture and posture changes, impact loading of tissue, elevated temperature and humidity, age, nutritional status, general health, activity level, body stature and shear stress in the development of pressure sores (4).

Shear Force & Pressure Sores

The interest in shear stems from the observation that shear increases the possibility of causing a pressure sore (6). In 1958, it was Reichel who started to focus attention on shear force, which is defined as a force parallel to a surface (2). It is important to reduce shear force as much as possible (6). Avoidance of shear force is as important as avoidance of direct pressure (8).

Snijders (1984) showed that the inclination and the position of a backrest as well as the angle of the seat surface influence the shear force on the seat (3). The proper combination of backrest and seat inclination can reduce shear forces on the seat and on the sitter.

In tests done on healthy young subjects, it was found that when little shear is accepted, a fixed inclination between seat and backrest should be chosen between 90 degrees and 95 degrees (3). When a person is sitting down, the weight of the body is distributed over the supporting surfaces. The distributed shear and pressure result in forces that act on four major body points:
▪ The Feet
▪ The Butt Bones
▪ The Top of the Hip Bones
▪ The Chest

Shear Stresses Reduced – 90N to 5N

In a study measuring shear stresses on wheelchairs, using healthy young subjects, different seat angles were tested. Previous measurements showed that a total shear force on the seat of a foldable wheelchair could become as high as 90N when the seat is horizontal (2). When the seat slant is 8 degrees forward, the shear force becomes smaller than 5N in healthy subjects (2). The assumption is made that if the unfavorable effect of shear stress can be measured in healthy, young subjects, the effect for the hospitalized geriatric and paraplegic population will be even worse (2).

Enveloping Cushion

The enveloping property of a seat cushion is a measure of its tendency to wrap around the object it supports. When the body adopts a sitting posture, the weight of the body is distributed over the supporting surfaces (3). A good enveloping cushion provides a large contact area and a uniform stress distribution (9).

Medium density foam results in the lowest shear stresses and compressive stresses tested. Soft foam results in the next lowest shear and compressive stresses because soft foam tends to “bottom out” and cause pressure from the surface below the foam.

Caution: Temperature Sensitive Foam

Researchers caution against materials in seat surfaces that react to body temperature because there is a risk of rising temperatures and increased humidity which can lead to pressure sores (1), as well as other pressure-related problems.

Researchers conclude that the use of armrests in the case of healthy persons has a very limited pressure-reducing effect but may help stabilize posture.

  1. Applied Nursing Research, Vol. 12, No. 3, August 1999, pp. 136-142, “Sitting Posture and Prevention of Pressure Ulcers,” written by Tom Defloor, MScN, N.N.; and Maria H.F. Grypdonck, Ph.D., RN, Nursing Sciences, University of Gent, Belgium.
  2.  Scandinavian Journal of Rehabilitation Medicine, 29: 131-136, 1997, “Shear Stress Measured on Beds and Wheelchairs,” written by R.H.M. Goossens, Ph.D.; C.J. Snijders, Ph.D., T.G. Holscher, Mac; W. Chr. Heerens, Ph.D.; and A. E. Holman, MSc.
  3.  Journal of Biomechanics, Vol. 28, No. 2, pp. 225-230, 1995, “Design Criteria for the Reduction of Shear Forces in Beds and Seats,” written by R.H.M. Goossens and C.J. Snijders, Erasmus University, Rotterdam, Faculty of Medicine, Department of Biomedical Physics and Technology, The Netherlands.
  4. Journal of Rehabilitation Research and Development, Vol. 29, No. 4, 1992, pp. 21 – 31, Department of Veterans Affairs, “Comparative Effects of Posture on Pressure and Shear at the Body-Seat Interface,” written by Douglas A. Hobson, Ph.D., School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, P.A. U.S.A.
  5.  Journal of Rehabilitation Research and Development, Vol. 27, No. 2, 1990, pp. 135 – 140, Department of Veterans Affairs, “Reduction of Sitting Pressures with Custom Contoured Cushions,” written by Stephen Sprigle, Ph.D.; Kao-Chi Chung, Ph.D.; Clifford E. Brubaker, Ph.D., University of Virginia, Rehabilitation Engineering Center, U.S.A.
  6.  Journal of Rehabilitation Research and Development, Vol. 27, No. 3, 1990, pp. 239 – 246, Department of Veterans Affairs, “Sitting Forces and Wheelchair Mechanics,” written by Paul Gilsdorf, B.S.; Robert Patterson, Ph.D.; Steven Fisher, M.D.; Nancy Appel, P.T., Department of Physical Medicine and Rehabilitation, University of Minnesota, U.S.A.
  7.  American Journal of Nursing, 1987, “Sitting Easy: How Six Pressure-Relieving Devices Stack up,” written by Robin Charges, RN, M.A., M.S.N.; and Bettie S. Jackson, RN, Ed.D., F.A.A.N., Montefiore Medical Center, N.Y., U.S.A.
  8.  Arch. Phys. Med. Rehabil., Vol. 60, July, 1979, “Shear vs. Pressure as Causative Factors in Skin Blood Flow Occlusion,” written by Leon Bennett, MAE; David Kavner, DEng; Bok K. Lee, M.D.; Frieda A. Trainor, Ph.D., Veterans Administration Prosthetic Center, N.Y., U.S.A.
  9.  J. Biomechanics, Vol. 15, No. 7, 1982, “Model Experiments to Study the Stress Distributions in a Seated Buttock,” Narender P. Reddy, Himanshu Patel, George Van B. Cochran, Biomechanics Research Unit, Helen Hayes Hospital; and John B. Brunski, Center for Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, N.Y., U.S.A.

Too Much Press Made Me A Target / I Am Back & Looking for a Manufacturer

The “featured image” is me with me with Anka in the background when we were on Deco Drive.  They wanted to interview her anyway because she had just been in Playboy.

When I got my second patent, the Ergonomic Seating Cushion, which I called the Buttpillow, the name was so shocking that I ended up on TV and the cover of the Miami Herald Business Section, and several other newspapers.

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The reason I invented the Pillow with Cantilever Supports (also called the Buttpillow) and the Ergonomic Seating Cushion (an improvement on the Pillow with Cantilever Supports) was so that anyone with a sitting-related problem —  whether the individual was suffering with hemorrhoids, low back pain, sciatica, herniated spinal disc, prostatitis, pressure sores, vaginal pain or tailbone pain  — could use the cushion without everyone knowing what it was being used for.  If you bring a doughnut pillow to work, people will make fun of you. . .at least that is what happened to me.

It is also for reduction of risk factors that lead to musculoskeletal disorders or MSDs as well as DVTs.

Scan 2

I found out seven years later that I had gotten several patents my lawyers told me I didn’t get when I received notices from the USPTO that it was time to pay my maintenance fees on the patents I didn’t know I had gotten; or, even worse, that I had lost my patent because I didn’t pay the maintenance fee when I didn’t know I had it in the first place.

I guess the lawyers had to prove they were right:   When I first started trying to patent products, they would say things to me like, “You are just a stupid court reporter; you are not going to be successful.”

I am seeking an open cell foam manufacturer in the United States.  I have until 2023 on this one patent and it has been quoted a lot lately by other inventors to the USPTO, so it is kind of now or the lawyers will be right. . .I will never be successful.

Anka in Inventor’s Digest for Buttpillow (my name is misspelled. . .it should be Loomos):

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Who Do I Write For?

Training people how to sit ergonomically should happen concurrently with training people how to use computers.   Prior to the smart phone, computers were used mostly for work and were found mostly in the workplace.

Since about 1985, companies were audited and fined if it was discovered they did not report a MSD experienced by one (1) employee to OSHA.    In fact, most MSD’s are called Work-related Musculoskeletal Disorders (WMSD’s).   The fines to companies do nothing to help the individuals who are already suffering from a MSD that could have been prevented.

MSD’s may occur before someone enters the workforce because of the change in how computers are used; and waiting until someone enters the workforce to tell them about ergonomics may be setting them up to be disabled before they even begin working as WMSD’s account for between 50 – 80 percent of all disability payments.

Anyone who uses a computer or sits for more than two hours at a time without taking a break can reduce risk factors that lead to musculoskeletal pain and musculoskeletal disorders (MSD’s), such as back pain, by making small changes to their posture.

 

 

 

 

 

ERGOSOFT

 

This is my first post.  My name is Melanie Loomos.  I used to be a court 
reporter (stenographer).  I usually did jury trials because I didn't like 
to fight with the other court reporters for the good jobs. 
Good jobs were usually depositions with a lot of parties (lawyers) because 
we got paid per page; and each copy (lawyer) was an extra $2.50 per page.

When I was in trial, I would just sit in whatever chair the bailiff told me 
to sit in; and I wasn't aware of ergonomics.  

I would write sometimes through lunch (for more 
than 8 hours without breaks); and when I got home, I had to run my hands 
under warm water for a long time before I could get started on my 
transcripts because I was in so much pain.  

I didn't know it but I was developing a upper extremity 
cumulative trauma disorder (carpal tunnel syndrome).  Cumulative trauma 
disorders are musculosketal disorders (MSD's) caused by risk factors 
that include repetition and awkward postures (risk factors I could have 
reduced).  

I also didn't know at the time that there had been a checklist created by
ergonomists ten years prior that could have identified the risk factors I
was exposed to, which would have given me the option of minimizing or 
correcting those risk factors (awkward postures and repetition).

Then came OSHA's Ergonomic Standard which became Federal Law in 2000 
under the Clinton Administration.  The Ergonomic Standard was repealed 
as a Federal Law in March 2001 by the Bush Administration.  

The Ergonomics Standard was not a good law.  It mandated that every 
employer adjust every work station to every employee to reduce ergonomic 
risk factors even if they needed to cut the legs off desks.  

That gave me the idea for what I called "the Carpal Tunnel Chair"; 
I submitted it to the USPTO through an attorney to try to get a patent. 
I also submitted a patent on the Ergonomic Seating Cushion.

After review of the boring Ergonomics Standard, I realized people 
could learn what ergonomic risk factors are and how to reduce or 
correct those risk factors themselves if it were put in a non-boring 
format.  Ergosoft provides the sitting computer user with information 
from the boring repealed Ergonomics Standard either every half hour, 
every hour, or every two hours when the individual sets Ergosoft to 
remind them to take their Ergo-break.  Ergo-woman, Ergo-man, or 
Ergo-doc (in cartoon format) appear with an Ergo-tip.

Why am I telling everyone this?  I didn't realize ergonomics was 
a verypolitical issue, and politics is coming in between people 
and ergonomics.  The checklist that ergonomists worked on for almost 40 
years is not being used in the United States; it is being used in 
other countries. You can't even copy it without permission, and you 
need to pay for it on online.  

The checklist which was used to develop the Ergonomics Standard gives 
an average person the ability to identify ergonomic risk
factors and reduce them before cumulative trauma disorders are developed.  

I intend to give Ergosoft away as a free download to help people identify 
and minimize ergonomic risk factors that can lead to Musculoskeletal 
Disorders (MSD's) or Work-related Musculoskeletal Disorders (WMSD's). 

I am seeking a manufacturer for the OhPillow
and the Ergonomic Seating Cushion.  Today is 2/27/2017.    
 

 
   
      
 
I