General Knowledge

Support Surfaces for Treating Bed Sores (Pressure Ulcers) and How They Work


If you care for someone confined to a bed or chair, every day is a battle against bed sores.

You may have heard that preventing and treating bed sores (also called pressure sores or pressure ulcers) requires support surfaces. You may also be overwhelmed by the variety of support surfaces, and just how much there is to know about this condition and how to treat it. You’re not alone — unless you’re a professional caregiver, most people only find themselves faced with caring for an incapacitated person once or twice in their lifetime.

That’s why it’s so important to educate yourself. Armed with knowledge, you can give the patient the best care possible, the care they deserve.

The Danger of Bed Sores

The skin is a vulnerable organ.

Like any organ, it needs to be taken care of. Specifically, the skin needs blood and oxygen to stay healthy. So when the skin is deprived of these things by sustained pressure, bed sores — also known as pressure ulcers — start to form. In that case, only the right tools and treatments can help. That’s where support surfaces come in.

Generally, support surfaces accomplish one thing: they decrease pressure on the skin, allowing blood and oxygen to return and refresh the dying tissue. In fact, you could say that support surfaces don’t really “heal” bed sores; they simply allow the skin to heal itself.

We can’t overstate the danger posed by bedsores. They are not minor irritations or cosmetic blemishes. They are serious, potentially life-endangering threats to human health. We’ll spare you the gruesome pictures, but bedsores need to taken seriously, and support surfaces need to be applied as soon as possible.

If someone you care for is convalescent or otherwise confined to a bed or chair, it’s time to take action.

What is a Support Surface?

The National Pressure Ulcer Advisory Panel (NPUAP) defines a support surface as “A specialized device for pressure redistribution designed for management of tissue loads, micro-climate, and/or therapeutic functions.”

In layman’s terms, a support surface is any medical device designed to take the pressure, heat, and moisture off the areas of  skin prone to bedsores, like bony prominences. They usually accomplish this by redistributing the pressure to other parts of the body, so the vulnerable area can “breathe.”

Most clinical guidelines recommend relieving pressure by repositioning the body every 2 hours while in bed, and every 15 minutes while seated. Support surfaces use a variety of methods to achieve or simulate this repositioning.  

Support surfaces come in many shapes and forms, designed to address different needs and bedsore-causing conditions. They include:

Each of these support surfaces come in many different variations. They range from the wildly expensive to the affordable. They also range widely in effectiveness and comfort, depending on the patient’s condition and preferences. Choosing the right support surface is key to maximizing patient comfort and reducing or eliminating bedsores.

Support Surface Terminology

As you encounter different support surface products, it’s important to understand the medical terminology involved in order to find the right device for your needs.

  • Alternating pressure
    Simply refers to any mattress that shifts pressure from one part of the body to another, using air cells that inflate and deflate. By alternating the areas of firmness and softness, different areas of the skin are relieved in turn.
  • Zoned or Multi-zoned
    These mattresses have areas (zones) designed to accommodate the heavier and lighter parts of the body. The air pressure distribution reflects where body weight puts the most pressure on the skin.
  • Lateral Rotation
    This feature is primarily for treating respiratory complications, but also redistributes pressure. The mattress literally turns the patient by folding lengthwise.
  • Shear
    Shear is a specific kind of pressure, generated when two surfaces shift against each other in opposite directions. Shear injuries may not be visible, and are often deep in the tissue. For example, a patient with their head elevated may slide downwards. While the bones and interior tissue move down, the top layer of skin remains in place against the mattress, causing opposing lateral pressure.
  • Cell-on-cell
    These mattresses have an extra “backup” layer of air cells that remain inflated, even during a power outage. Typically the top layer of cells does the alternating, while the bottom maintains a consistent air pressure.
  • Low air loss
    These systems allow a stream of air, generally from a blower, through tiny perforations in the air cells. This steady airflow helps regulate the “microclimate” of the skin, reducing heat and moisture that can exacerbate bedsores.
  • Auto firm
    This feature rapidly hyper-inflates the air cells, making it easy to turn or reposition patients. It’s also important to use this feature when the patient gets in or out of bed, to protect the air cells and prevent breakage.
  • Pulsation
    Pulsation is essentially a more rapid version of alternating pressure, in which the pressure is alternated much more quickly and frequently, having a massage-like effect.
  • Immersion
    Immersion is the depth into which the patient’s body can sink into the support surface. More or less immersion may be required to maintain patient comfort.
  • Envelopment
    Envelopment refers to the support surface’s ability to conform to the shape of the patient.
  • Blower vs Compressor/Pump
    A blower allows air to escape the support surface, better managing the skin’s “microclimate,” and is the defining feature of a Low Air Loss mattress. A compressor or pump is the standard air source, and is less effective in managing heat and moisture on the skin.
  • Mattress Overlay
    Made of gel or foam, these more simple support surfaces can be placed on top of a standard mattress for added support.
  • Panel Lock
    This feature, often used in hospitals or other settings with frequent visitors, locks the settings on an alternating pressure mattress to prevent tampering.

As you research the hundreds of products on the market, make sure that whatever you choose fits the needs of the patient. Get to know the product and its features before buying, so that you can form an appropriate care plan. With some basic knowledge, you can make informed decisions that result in relief for the patient, and peace of mind for you.


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