Advances in pressure relief and reduction.

Choosing a bed surface for a low- or no-mobility resident who is experiencing or at-risk of pressure ulcers has become complicated -- and that's good news. The past two decades have seen the development of a variety of beds, overlays, and systems designed to do everything from increasing patient comfort to healing pressure ulcers.

In choosing among these options, there is first the need for clinicians to determine whether the goal is pressure reduction (preventing ulcers) or pressure relief (healing them). Then other variables have to be taken into account: age (how thick and strong is the skin?), weight (can the unit cope with a resident weighing 300 pounds?), makeup of body tissue (does the resident have a "cushioning" layer of fat?), and level of mobility (is the resident totally bedridden, unable even to roll over?).

The least sophisticated -- and least expensive -- of today's pressure management devices are foam mattresses and foam overlay pads. They also have the shortest life. Many of the pads are thought of as "throwaways," to be sent home with the patient for use in short-term recuperation. While this works for the more acute patients of the hospital setting, it falls short as a long-term care strategy.

Foam mattresses have been developed to address this problem. Their optimum expected therapeutic life, depending on amount of use, patient weight, and other variables, is from three to five years. However, foam loses its resiliency with use and time. Old pads and mattresses can begin to "dish" visibly, with resulting dramatic drop in effectiveness. Nevertheless, they have a cost advantage: Foam mattresses are comparable in price to the standard inner spring mattresses they are intended to replace.

Foam pads and mattresses are most effectively used as pressure reduction devices to prevent the development of decubitus ulcers rather than for pressure relief for already existing ulcers. They come in a variety of designs and shapes. A common preference is for an uneven or "egg-crate" surface. Some mattresses are contoured to the body. Others have variable, removable sections. Even as a pressure reducer, foam is best used for patients with at least some degree of mobility. Other static mattresses and pads that work primarily as pressure reducers include those filled with air, water, and gel.

Recent years have seen the development of what are called dynamic air surfaces. These mattresses "float" the patient in an effort to eliminate the tissue displacement that results from compression against a support surface. The first of these dynamic air systems began to enter the market a decade and a half ago, and did so as full bed systems. Today the trend is toward portability by developing mattresses and mechanical and control units which can be fitted to existing bed flames. Dynamic air beds include air fluidization systems and low air loss therapy systems.

Air fluidized systems are really a tank filled to a depth of 10 to 12 inches with tiny silicone coated glass beads approximately 100 microns in diameter. A filter sheet is placed over the top of the beads and attached to the sides of the tank. A blower or compressor below the tank forces heated ambient air up through its bottom and into the beads, floating each on its own cushion of air. The result is a dense, fluid-like medium upon which the patient is "floated."

Air fluidized beds do an excellent job of reducing pressure and shear, and therefore function as pressure relievers. There are some cautions, however -- for example, the constant flow of a large amount of warm air creates a risk of dehydration. In addition, staff access for physically maneuvering the resident can be inconvenient and repositioning difficult. Other questions about their use involve sensory deprivation (i.e. a loss of body sense"), insufficient support for residents experiencing paroxysmal coughing, and odor from incontinence and urinary drainage that has passed through the filter sheet into the beads. Finally, these beds are heavy, in many instances weighing nearly a ton.

Low air loss systems are generally a conglomeration of air sacks or tubes which are inflated by an air blower system. They get their name from intentional air loss, designed to take place through the covering fabric, stitching, seams or tiny holes. This air flow is delivered to the resident's skin to prevent maceration. Often the different sacks will have different pressures, the thinking being that the areas of the body which contain the most padding and the fewest bony prominences should be able to bear more weight.

Low air loss systems usually provide excellent pressure reduction and relief. Their main disadvantage may be a problem with particularly passive residents being able to maintain proper positioning.

Low air loss systems "with enhanced therapy" are advanced versions which incorporate some sort of automated patient movement. These include turning beds, with their lateral raising and lowering, or mattresses with alternately pulsating horizontal cells; the latter are assumed to provide therapeutic massage to the skin. (Turning beds, which some believe to be the future of pressure relief and reduction as their prices come down, were discussed in the "Nursing Home Technology" section of the June 1994 Nursing Homes.) Low air loss systems are manufactured as complete beds, as mattresses and control units only, and as thin overlay pads.

A recent development in this overall field has been the combining of low air loss technology with foam coverings. Some low air loss systems can create uneven lying surfaces. To combat the potential discomfort caused by this, manufacturers have begun to develop low air loss mattresses wrapped in a foam shell two to three inches thick.

Experts and designers in the field of pressure management systems see the future holding refinements in all the system types available today. All agree that the greatest reduction in pressure ulcers over the next few years will be realized by clinicians learning how to choose among the alternatives in order to effectively individualize resident care. Effort spent on picking the fight system for the right residents can be expected to yield dramatic results, both clinically and financially.