The NPUAP defines support surfaces as, "A specialized device for pressure redistribution designed for management of tissue loads, micro-climate, and/or other therapeutic functions (i.e., any mattresses, integrated bed system, mattress replacement, mattress overlay or seat cushion, or seat cushion overlay)." Powered, non-powered, mattress replacements, mattress overlays, reactive and active all describe support surfaces for beds. Many bed support surfaces are designed to not only redistribute pressure and reduce shear, but also seek to address the micro-climate (humidity and temperature), friction and maceration and patient/user comfort, and even pulmonary function. Support surfaces for seats or wheelchairs are even more varied and plentiful, and seek to address not only skin protection but positioning needs.

An effective support surface works in practice, or in "real life", while an efficacious support surface works in clinical trials or laboratory studies, but not in a practical setting. Some of the most efficacious support surfaces are too expensive or use too much energy/power, are too cumbersome for the user’s environment or caregiver, or are simply not tolerated well by the patient. Effective support surfaces need to be tested first to make sure they actually do what they were designed to do, namely, get more blood flow to the skin and underlying structures by lessening or redistributing pressure and shear away from bony prominences. Drive Medical's entire suite of Pressure Prevention offerings are both effective and efficacious and promise to get more blood flow to the skin, a vital component of preventing and treating pressure ulcers, while promoting comfort and ease of use for both patient and caregiver without breaking the bank.

Selecting the right support surface gets complicated when marketing and sales and manufacturer-specific terms like: foam density, indentation load deflection, alternating pressure, low air loss, lateral rotation, pulsation, self-adjusting, static,  auto-firm, fowler, auto return to alternating, pressure readjustment, moisture vapor permeable, liters per minute flow, mmHg air pressure, cycle times, digital vs. analog pumps and blowers, zoned, cell on cell, 2 way vs. 4 way stretch, are used to describe the support surface. A dictionary definition of all these terms (available at will help you become an expert in support surface terminology, but an understanding of the most relevant terms and how they relate to selecting the best support surface for your specific needs, or the needs of your patient, is more useful. The remainder of this article will focus on "real life" practical definitions and guidelines for selecting an effective and efficacious support surface for you and/or your patient.

Mitigating Pain while using Support Surfaces

Let's address pain and comfort first and foremost. Pain for both patients and caregivers can be reduced with proper support surface selection and use. Patients in pain do not want to be moved much, and when they are moved it hurts them. Yet virtually all clinical guidelines recommend at least every 2 hour turning and repositioning while in bed, and every 15 minute positioning weight shifts while in a wheelchair or chair. If pain is related to interface pressure between the skin and support surface (and not the underlying disease process), the support surface may help, simply because pressure is redistributed away from the body parts experiencing the most pressure and pain, such as coccyx or tail bone, sacrum or lower back and ischial tuberosities or sitting bones. If the pain is not strictly due to pressure, support surfaces can still help. The feature to look for to help is auto firm.

Auto firm is a feature on some powered mattresses and overlays that rapidly hyper-inflates the air cells or baffles so they perform like rollers, making it easier to turn and position patients, and may require less force than traditional draw sheets and pillows. This feature may also decrease the nursing time required for turning and repositioning patients, may reduce risk of injury to caregivers' backs, shoulders and wrists and may improve patient and caregiver compliance to turning/ repositioning protocol. When a support surface is set in auto firm the pressure redistribution, or ability to help get blood flow to the skin, is hampered. That is why panel lock out and return to alternating and/or therapy are also important features.

Alternation and therapeutic pressure redistribution are interrupted with auto firm. Caregivers are often very busy and may be called upon to leave the patient's room without returning the system to alternating or therapy mode. Auto firm should automatically disengage within 30 minutes of being triggered to insure that therapeutic pressure redistribution is being provided. The return to alternating and/or therapy feature assures that therapeutic function will begin if the system is left on static mode, and should return within 2 hours. Panel lock out is important to protect the pressure and comfort settings from ill-advised or inadvertent tampering.

Understanding the "WHY" behind the Technology

Alternating pressure, defined as pressure redistribution via cyclic changes in loading and unloading is a strongly recommended bed support surface feature. When at-risk or ulcerated patients cannot be repositioned manually, active support surfaces (alternating pressure) are needed, as they can change their load-distribution properties and help make sure blood is getting to the skin. Generally, the less time between cycles the better for load-distribution and blood flow, so it is best to alternate more, as tolerated.

Some bed support surfaces offer pulsation instead of or in addition to alternating pressure. Pulsation differs from alternation in that the duration of peak inflation is shorter and the cycling time is more frequent. For example, Drive's LS9000's pulsation mode reduces air flow every 30 seconds to 50% of the comfort setting. Pulsation is theorized to increase lymphatic drainage (may decrease swelling) and blood flow by having a "massaging" benefit. It may also enhance patient comfort and relieve pain.

Pain due to lying down or sitting with or without limited ability to reposition can be lessened by using support surfaces for beds and wheelchairs that provide immersion and envelopment. Immersion is the depth of penetration or "sinking" into the support surface. Envelopment is the ability of the support surface to conform to the body parts sinking into it. Sitting tolerance can also be increased and pain decreased by making sure a proper back cushion is used in a wheelchair, not just a pressure redistributing seat cushion. The sling fabric on any wheelchair is there so the wheelchair folds; not to support a human trunk or back of pelvis.

Many bed support surfaces are described as Low Air Loss (LAL) or True Low Air Loss (TLAL). Low Air Loss is a feature of a support surface that provides a flow of air to assist in managing the heat and humidity (microclimate) of the skin. If you or your patient are very diaphoretic (perspiring profusely) or always hot or cold, Low Air Loss may help. Low Air Loss can be achieved with compressors pumping as little as 4 liters per minute (LPM) of air or with blowers producing over 1000 LPM of air. While there is no consensus on the definition of true low air loss, it is generally used to describe blower based, rather than compressor or pump based systems.

A blower is capable of transferring or wicking more moisture vapor away from the patient than a pump, helping to maintain the microclimate or proper skin temperature and humidity.

The use of a plastic, rubber or other air blocking product on LAL virtually eliminates the LAL's ability to control the microclimate. Pressure redistribution and shear and friction reduction capabilities remain.

Transferring from support surface to wheelchair or other surface and back again should be easy and safe and should not create shear. If a patient lift is used, the aforementioned auto firm feature will make getting the sling properly positioned, with less shear, easier for both patient and caregiver. If a transfer board or sit-to-stand transfer is the preferred egress/ingress method, a bed support surface should have a firm border and the wheelchair cushion should not be greatly contoured. Sit-to-stand transfers further require that the patient is able to put feet flat on the floor. Thus, mattress replacements, rather than overlays, which increase distance from floor to top of mattress, are often preferred.

Some powered bed support surfaces boast cell on cell or cell in cell technology. Cell on cell and cell in cell mattress designs prevents "bottoming out" (which can increase pressure and stop blood flow to the skin) and stay inflated during power outages or patient transit. Foam bases (at least 2" thick is recommended) to support patients are an alternate way to protect patients in the event of a power outage or during transport. A third option is to use a non-powered support surface. These can be simple gel.foam or static air overlays, specially designed foam mattress replacements, or more advanced self-adjusting support surfaces that adjust without outside or additional power.

A zoned or multi-zoned mattress or cushion is important because human bodies are heavy in some places and lighter in others. Zoned mattresses and cushions take this into account and redistribute pressure accordingly. Zones with precisely patterned die cuts help reduce shear and heel zones with slopes and/or special materials or designs help assure the heels are being well perfused (supplied with adequate blood flow).

Some bed support surfaces provide Lateral Rotation along a longitudinal axis as characterized by degree of patient turn, duration and frequency. Lateral rotation certainly redistributes pressure, but its efficacy is based on addressing respiratory concerns, not pressure ulcers. Lateral rotation has been associated with decreased incidence of pneumonia, respiratory complications, atelectasis and pulmonary congestion of the lungs.

Educated and critical thinking is required when selecting the right support surface for ourselves and our patients for pressure redistribution, microclimate control and comfort. Look for clinical examples and referrals, learn the products yourself, and remember that support surfaces help get blood flow to the skin, a critical component of pressure ulcer prevention and treatment. The case studies below provide helpful guidelines to becoming an educated support surface provider or consumer.

Case Study

Mr. Tom Smith, 55 years old, 5'10" 175 pounds, is a well-nourished, non-smoker, diagnosed with Multiple Sclerosis five years ago. He can no longer walk more than a few steps with a walker and has been confined to bed or wheelchair for the past two months. He cherishes any remaining independence he has and refuses to sleep in a hospital bed, preferring to sleep in his queen sized bed with his wife. Mr. Smith can still stand for an assisted stand and pivot transfer. He does not want to use a patient lift. His medical history is significant for re-occurring stage one pressure ulcers on his sacrum and coccyx, and chronic pain. How can support surfaces help Mr. Smith?

A single or twin sized gel/foam overlay can be safely placed on a queen sized bed (queen sized gel.foam overlays are also available from Drive Medical) and provide some pressure redistribution for Mr. Smith while enabling him to remain in his marital bed. The 15 gel-containing bladders of the Drive Premium Guard Gel Overlay will allow Mr. Smith's pelvis to immerse and be enveloped, enhancing comfort and blood flow to his stage one pressure ulcers. Because the gel overlay is heavy, it will not shift while Mr. Smith sits on the side of the bed to stand and pivot to his wheelchair, which should have an adjustable skin protection cushion, like Drive's Balanced Air Cushion, and a memory foam with Masonite board back cushion, like Drive's General Use Back, to provide support and a tactile curve to help Mr. Smith maintain correct posture. A pivot disc and transfer or gait belt, as well as free standing trapeze or transfer pole, will help Mr. Smith re-position, stay independent and safe at home.

Case Study

Ms. Laura Perez is 71 years old, has Alzheimer's disease, and had her right hip replaced one week ago. She left the acute care hospital after two days and is now "rehabbing" in a local sub-acute or skilled nursing facility. It hurts to move, she is agitated and in pain even when lying still, she has urinary incontinence, her nutrition is poor and both of Ms. Perez's legs exhibit swelling or edema. Ms. Perez has a stage four pressure ulcer on her left hip, a stage two on her sacrum, and an un-stageable (eschar covered) wound on her right ischial tuberosity. Her physician ordered complete bed rest until the pressure ulcers are healed. What support surface is best for Ms. Perez?

A blower based "true" low air loss mattress replacement, like Drive's LS9000 10" True Low Air Loss Mattress System with Puslation, is highly recommended for optimal pressure redistribution, shear and friction reduction and control of the microclimate, all needed because Ms. Perez does not have two intact integument (skin) surfaces on which to lie. Raised perimeters are needed for safety (restraints not allowed in sub-acute facilities) and easy bed articulation as Ms. Perez will be encouraged to eat and needs the head of the bed elevated while doing so. Thus, a breathable cover with raised rails, like Drive's 14333 Universal Mattress Cover with Defined Perimeters, is also suggested. It may also be helpful to engage the pulsation therapy feature of Drive's LS9000. Pulsation mimics the body’s natural movements to help improve blood flow for increased oxygenation to Ms. Perez's skin and to reduce edema. This increase in capillary blood flow will increase oxygenation to the wound and skin, which will promote wound healing and the prevention and treatment of pressure ulcers. Ultimately, this improves healing time. When engaged, Pulsating air suspension therapy uses small pockets of air, individually inflated and deflated to cause a pulsation. The Pulsation therapy will cause the blower system to reduce the air flow in the mattress system every 30 seconds to 50% of the comfort setting pressure. The internal control sensor continuously monitors interface pressure for optimal redistribution.

Pulsation can also increase lymph flow and reduce edema.  The lymphatic system relies on body movement to facilitate flow.  Pulsation Therapy will mimic the body’s intermittent movements which will stimulate lymphatic flow to help reduce Ms. Perez's lower extremity edema, which increases circulation and reduces her pain.

The Low Air Loss should also have seat inflate to insure that there is no bottoming out while the head of the bed is elevated. Auto firm with automatic return to therapeutic levels (if caregiver inadvertently forgets to disengage the auto firm) will enable caregivers to turn and reposition Ms. Perez easily without causing them or her pain. Panel Lock Out is needed as there are often many caregivers in sub-acute facilities and the therapeutic pressure redistribution settings should not be tampered with. Complete bed rest is rarely needed nowadays, as controlled seating is possible, like Drive's patient lift with u shaped sling to Geri-chair with Drive's 3" gel/foam Geri Chair overlay to protect skin.

Case Study

Mr. Spike Yee is 25 years old, and has a spinal cord injury, C6 level with a stage two pressure ulcer on his right medial buttock, possibly caused by shear and friction. While hospitalized and recovering from his injury he was required to lie on an air mattress. He hated it because he felt the alternation under the pillow at his head and could not sleep. Although he has little ability to move or reposition, he wants to be able to use his transfer board when he egresses/ingresses from his hospital bed to his power wheelchair, and the air mattress was too soft to permit an independent transfer board transfer. Mr. Yee lives alone. He has caregiving during the day but is alone at night. What would be best for Mr. Yee to sleep on?

Mr. Yee should sleep on a non-powered, with self-adjusting technology mattress such as Drive's Balanced Air Non-Powered Self-Adjusting Convertible Mattress. As a general rule, self-adjusting mattresses are more firm than low air loss and/or alternating pressure mattresses and do not obtain the same level of immersion or envelopment, permitting easier user movement in bed. The self-adjusting mattress should have a firm foam border for transfer board use and a non-shear, non-friction, moisture vapor permeable, stretch cover. Mr. Yee would not be compromised in the event of a power failure, as Drive's self-adjusting mattress is non-powered. Drive's alternating pressure mattresses have a Pillow Function, and do not alternate at the head of the bed.

Case Study

Ms. Bridget Jones is a 63 year CVA, 5'0" tall, 200 pounds, who developed a stage four pressure ulcer on her right trochanter (hip bone). She has had many hospitalizations and multiple setbacks, but the stage four recently epithelized (closed). Ms. Jones can move all four limbs, walk a few steps with a walker, and she is continent of urine and stool. She has a wheelchair and hospital bed at home. Ms. Jones is obese with edematous lower extremities, limited mobility and limited funds. She cannot afford any medical equipment that is not covered by Medicare. Ms. Jones is scheduled for discharge to home and the hospital cannot afford for her to come back again. What support surfaces will Medicare cover?

Ms. Jones qualifies for a Group 1 bed support surface because she has limited mobility and a compromised circulatory status (edematous legs). She qualifies for a skin protection cushion because she has a history of a pelvic pressure ulcer, and she qualifies for a wheelchair. Because Ms. Jones is only 5' tall, a mattress overlay may make it difficult for her feet to reach the floor when getting in and out of bed. Ms. Jones would benefit from a Group 1 foam mattress replacement. Drive’s Therapeutic 5 Zone Support Mattress is 6" thick so Ms. Jones' feet will be securely on the floor when getting in and out of bed. The 5 Zone provides comfort and pressure redistribution over five different pressure zones and has a 275 pound weight limit. Ms. Jones should sit on a gel-foam skin protection cushion, such as Drive’s 3" Gel Seat Cushion(her wheelchair can be put into a hemi position if needed) to help prevent further pelvic ulcers but to allow easy sit-to-stand. The dual gel chamber will redistribute pressure and make her very comfortable. Ms. Jones has weak trunk support secondary to her CVA. Without a wheelchair back, such as Drive's General Use Back Cushion with lumbar support. Ms. Jones would, with prolonged seating against upholstery, develop a curved, kyphotic shaped back. 

Therapeutic Support Surfaces

Matching the Right Product to the Right Client

We need support surfaces to help get blood to our skin, especially when we are sitting or lying down and cannot move much. Skin, the largest organ of the human body, with an average weight of 8-10 pounds and an average area of 22 square feet, dies without adequate blood flow to supply needed oxygen and nutrients. Support surfaces come in hundreds of shapes, sizes, makes and models, with dozens of different "bells and whistles". They are all designed, however, to help get more blood to the skin so the skin does not die – or develop a pressure ulcer.

Our National Pressure Ulcer Advisory Panel (NPUAP) defines a pressure ulcer as “localized injury to the skin and/or underlying tissue usually over a bony prominence, as a result of pressure, or pressure in combination with shear. A number of contributing or confounding factors are also associated with pressure ulcers; the significance of these factors is yet to be elucidated." Thus, if support surfaces, both for lying in bed and while seated, help lessen or redistribute pressure and reduce shear, blood flow to the skin is less impeded and the support surface will help prevent and/or treat pressure ulcers. 

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