Due to a lack of robust evidence, the benefits and risks of most types of beds, mattresses and mattress toppers for treating pressure ulcers are unclear.
Beds with an air-filled surface that apply constant pressure to the skin may be better than mattresses and toppers made of foam for ulcer healing if the evidence on the time needed to completely heal an ulcer is looked at, but may cost more.
Future research in this area should focus on options and effects that are important to decision-makers, such as:
- foam or air-filled surfaces that redistribute pressure under the body; and
- unwanted effects and costs.
What are pressure ulcers?
Pressure ulcers are also known as pressure sores or bed sores. They are wounds to the skin and underlying tissue caused by prolonged pressure or rubbing. They often occur on bony parts of the body, such as heels, elbows, hips and the bottom of the spine. People who have mobility problems or who lie in bed for long periods are at risk of developing pressure ulcers.
What did we want to find out?
There are beds, mattresses and mattress toppers specifically designed for people with pressure ulcers. These can be made from a range of materials (such as foam, air cells or water bags) and are divided into two groups:
- reactive (static) surfaces that apply a constant pressure to the skin, unless a person moves or is repositioned; and
- active (alternating pressure) surfaces that regularly redistribute the pressure under the body.
We wanted to find out if reactive and active surfaces:
- help ulcers to heal;
- are comfortable and improve people’s quality of life;
- have health benefits that outweigh their costs; and
- have any unwanted effects.
What did we do?
We searched the medical literature for studies that evaluated the effects of beds, mattresses and mattress toppers. We compared and summarised their results, and rated our confidence in the evidence, based on factors such as study methods and sizes.
What did we find?
We found 13 studies (972 people, average age: 83 years) that lasted between seven days and 18 months (average: 37.5 days).
In general, the studies did not provide sufficiently robust evidence for us to determine the effects of active and reactive surfaces.
Evidence from two studies suggests that, when compared with mattresses and mattress toppers made of foam, beds with a reactive air-filled surface may:
- improve chances of pressure ulcers healing if the data on the time needed to completely heal an ulcer is looked at (1 study, 84 people);
- cost an extra 26 US dollars per person for every ulcer-free day in the first year of use (1 study, 87 people).
The other benefits and risks of these and other surfaces are unclear.
What limited our confidence in the evidence?
Most studies were small (72 people on average) and nearly half of them (six studies) used methods likely to introduce errors in their results.
How up-to-date is this review?
The evidence in this Cochrane Review is current to November 2019.
We are uncertain about the relative effects of most different pressure-redistributing surfaces for pressure ulcer healing (types directly compared are alternating pressure air surfaces versus foam surfaces, reactive air surfaces versus foam surfaces, reactive water surfaces versus foam surfaces, and Nimbus versus Pegasus alternating pressure (active) air surfaces). There is also uncertainty regarding the effects of these different surfaces on the outcomes of comfort and adverse events. However, people using reactive air surfaces may be more likely to have pressure ulcers completely healed than those using foam surfaces over 37.5 days' follow-up, and reactive air surfaces may cost more for each ulcer-free day than foam surfaces.
Future research in this area could consider the evaluation of alternating pressure air surfaces versus foam surfaces as a high priority. Time-to-event outcomes, careful assessment of adverse events and trial-level cost-effectiveness evaluation should be considered in future studies. Further review using network meta-analysis adds to the findings reported here.
Pressure ulcers (also known as pressure injuries, pressure sores, decubitus ulcers and bed sores) are localised injuries to the skin or underlying soft tissue, or both, caused by unrelieved pressure, shear or friction. Beds, overlays or mattresses are widely used with the aim of treating pressure ulcers.
To assess the effects of beds, overlays and mattresses on pressure ulcer healing in people with pressure ulcers of any stage, in any setting.
In November 2019, 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 randomised controlled trials that allocated participants of any age to pressure-redistributing beds, overlays or mattresses. Comparators were any beds, overlays or mattresses that were applied for treating pressure ulcers.
At least two review authors independently assessed studies using predetermined inclusion criteria. We carried out data extraction, 'Risk of bias' assessment using the Cochrane 'Risk of bias' tool, and the certainty of the evidence assessment according to Grading of Recommendations, Assessment, Development and Evaluations methodology.
We included 13 studies (972 participants) in the review. Most studies were small (median study sample size: 72 participants). The average age of participants ranged from 64.0 to 86.5 years (median: 82.7 years) and all studies recruited people with existing pressure ulcers (the baseline ulcer area size ranging from 4.2 to 18.6 cm2,median 6.6 cm2). Participants were recruited from acute care settings (six studies) and community and long-term care settings (seven studies). Of the 13 studies, three (224 participants) involved surfaces that were not well described and therefore could not be classified. Additionally, six (46.2%) of the 13 studies presented findings which were considered at high overall risk of bias. We synthesised data for four comparisons in the review: alternating pressure (active) air surfaces versus foam surfaces; reactive air surfaces versus foam surfaces; reactive water surfaces versus foam surfaces, and a comparison between two types of alternating pressure (active) air surfaces. We summarise key findings for these four comparisons below.
(1) Alternating pressure (active) air surfaces versus foam surfaces: we are uncertain if there is a difference between alternating pressure (active) air surfaces and foam surfaces in the proportion of participants whose pressure ulcers completely healed (two studies with 132 participants; the reported risk ratio (RR) in one study was 0.97, 95% confidence interval (CI) 0.26 to 3.58). There is also uncertainty for the outcomes of patient comfort (one study with 83 participants) and adverse events (one study with 49 participants). These outcomes have very low-certainty evidence. Included studies did not report time to complete ulcer healing, health-related quality of life, or cost effectiveness.
(2) Reactive air surfaces versus foam surfaces: it is uncertain if there is a difference in the proportion of participants with completely healed pressure ulcers between reactive air surfaces and foam surfaces (RR 1.32, 95% CI 0.96 to 1.80; I2 = 0%; 2 studies, 156 participants; low-certainty evidence). When time to complete pressure ulcer healing is considered using a hazard ratio, data from one small study (84 participants) suggests a greater hazard for complete ulcer healing on reactive air surfaces (hazard ratio 2.66, 95% CI 1.34 to 5.17; low-certainty evidence). These results are sensitive to the choice of outcome measure so should be interpreted as uncertain. We are also uncertain whether there is any difference between these surfaces in patient comfort responses (1 study, 72 participants; very low-certainty evidence) and in adverse events (2 studies, 156 participants; low-certainty evidence). There is low-certainty evidence that reactive air surfaces may cost an extra 26 US dollars for every ulcer-free day in the first year of use (1 study, 87 participants). Included studies did not report health-related quality of life.
(3) Reactive water surfaces versus foam surfaces: it is uncertain if there is a difference between reactive water surfaces and foam surfaces in the proportion of participants with healed pressure ulcers (RR 1.07, 95% CI 0.70 to 1.63; 1 study, 101 participants) and in adverse events (1 study, 120 participants). All these have very low-certainty evidence. Included studies did not report time to complete ulcer healing, patient comfort, health-related quality of life, or cost effectiveness.
(4) Comparison between two types of alternating pressure (active) air surfaces: it is uncertain if there is a difference between Nimbus and Pegasus alternating pressure (active) air surfaces in the proportion of participants with healed pressure ulcers, in patient comfort responses and in adverse events: each of these outcomes had four studies (256 participants) but very low-certainty evidence. Included studies did not report time to complete ulcer healing, health-related quality of life, or cost effectiveness.