What is the aim of this review?
The aim of this review was to find out whether different support surfaces such as specially-designed beds, mattresses or cushions can help to treat pressure ulcers. Researchers from Cochrane collected and analysed all relevant studies (randomised controlled trials) to answer this question, and found 19 relevant studies.
Key messages
We cannot be certain which support surfaces are most effective for pressure ulcer treatment as the studies comparing them did not involve enough people and were not well designed.
What was studied in the review?
Pressure ulcers (also called pressure sores, decubitus ulcers and bed sores) are wounds to the skin and underlying tissue caused by pressure or rubbing. They typically form at points on the body which are bony or which bear weight or pressure, such as the hips, buttocks, heels and elbows. People who have mobility problems or who lie in bed for long periods are at risk of developing pressure ulcers. A range of treatments, including wound dressings and support surfaces like special mattresses and cushions, are used to treat pressure ulcers.
Support surfaces for pressure ulcer treatment can include specially-designed beds, mattresses, mattress overlays and cushions that are used to protect vulnerable parts of the body and distribute the surface pressure more evenly. Low-tech support surfaces include mattresses filled with foam, fluid, beads or air; and alternative foam mattresses and overlays. High-tech support surfaces include mattresses and overlays that are electrically powered to alternate the pressure within the surface, beds that are powered to have air mechanically circulated within them and low-air-loss beds that contain warm air moving within pockets inside the bed. Other support surfaces include sheepskins, cushions and operating table overlays.
We wanted to find out which support surfaces were most effective in helping pressure ulcers to heal. We also wanted to compare different support surfaces in terms of cost, reliability, durability, and the benefits or harms for patients using them.
What are the main results of the review?
In September 2017, we searched for trials looking at support surfaces for treating pressure ulcers and which reported their effects on wound healing. We found 19 trials involving 3241 participants, all adults, the majority of whom were older people and bed-bound in hospitals or nursing homes. In studies where participants' sex was reported, the majority were women. Not all studies reported their funding sources, but two of those who did were funded by device manufacturers.
Five studies involving 318 participants compared low-tech constant low-pressure (CLP) support surfaces such as foam mattresses. We cannot be certain how these different support surfaces affect pressure ulcer healing as the evidence is mainly of low certainty. Fourteen studies involving 2923 participants compared different high-tech support surfaces such as air-fluidised beds. Again, we cannot be certain how these different support surfaces affect ulcer healing rates as the certainty of the evidence is mainly low.
We are not able to draw firm conclusions about the effects of different support surfaces for treating pressure ulcers because the overall quality of the evidence is low to very low. Many of the studies included only small numbers of people, did not provide adequate information on their results, or were not well designed. Further, better conducted trials are necessary to determine which support surfaces are most effective in treating pressure ulcers.
How up to date is this review?
We searched for studies that had been published up to September 2017.
Based on the current evidence, it is unclear whether any particular type of low- or high-tech support surface is more effective at healing pressure ulcers than standard support surfaces.
Pressure ulcers are treated by reducing pressure on the areas of damaged skin. Special support surfaces (including beds, mattresses and cushions) designed to redistribute pressure, are widely used as treatments. The relative effects of different support surfaces are unclear. This is an update of an existing review.
To assess the effects of pressure-relieving support surfaces in the treatment of pressure ulcers.
In September 2017 we searched the Cochrane Wounds Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL); Ovid MEDLINE (including In-Process & Other Non-Indexed Citations); Ovid Embase and EBSCO CINAHL Plus. We also searched clinical trials registries for ongoing and unpublished studies, and scanned reference lists of relevant included studies as well as reviews, meta-analyses and health technology reports to identify additional studies. There were no restrictions with respect to language, date of publication or study setting.
We included published or unpublished randomised controlled trials (RCTs), that assessed the effects of support surfaces for treating pressure ulcers, in any participant group or setting.
Data extraction, assessment of 'Risk of bias' and GRADE assessments were performed independently by two review authors. Trials with similar participants, comparisons and outcomes were considered for meta-analysis. Where meta-analysis was inappropriate, we reported the results of the trials narratively. Where possible, we planned to report data as either risk ratio or mean difference as appropriate.
For this update we identified one new trial of support surfaces for pressure ulcer treatment, bringing the total to 19 trials involving 3241 participants. Most trials were small, with sample sizes ranging from 20 to 1971, and were generally at high or unclear risk of bias.
Primary outcome: healing of existing pressure ulcers
Low-tech constant pressure support surfaces
It is uncertain whether profiling beds increase the proportion of pressure ulcer which heal compared with standard hospital beds as the evidence is of very low certainty: (RR 3.96, 95% CI 1.28 to 12.24), downgraded for serious risk of bias, serious imprecision and indirectness (1 study; 70 participants).
There is currently no clear difference in ulcer healing between water-filled support surfaces and foam replacement mattresses: (RR 0.93, 95% CI 0.63 to 1.37); low-certainty evidence downgraded for serious risk of bias and serious imprecision (1 study; 120 participants).
Further analysis could not be performed for polyester overlays versus gel overlays (1 study; 72 participants), non-powered mattresses versus low-air-loss mattresses (1 study; 20 participants) or standard hospital mattresses with sheepskin overlays versus standard hospital mattresses (1 study; 36 participants).
High-tech pressure support surfaces
It is currently unclear whether high-tech pressure support surfaces (such as low-air-loss beds, air suspension beds, and alternating pressure surfaces) improve the healing of pressure ulcers (14 studies; 2923 participants) or which intervention may be more effective. The certainty of the evidence is generally low, downgraded mostly for risk of bias, indirectness and imprecision.
Secondary outcomes
No analyses were undertaken with respect to secondary outcomes including participant comfort and surface reliability and acceptability as reporting of these within the included trials was very limited.
Overall, the evidence is of low to very low certainty and was primarily downgraded due to risk of bias and imprecision with some indirectness.