Compression for preventing recurrence of venous ulcers.

BACKGROUND: Up to 1% of adults will have a leg ulcer at some time. Most leg ulcers are venous in origin and are caused by high pressure in the veins due to blockage or damaged valves. Venous ulcer prevention and treatment typically involves the application of compression bandages/stockings to improve venous return and thus reduce pressure in the legs. Other treatment options involve removing or repairing veins. Most venous ulcers heal with compression therapy, but ulcer recurrence is common. For this reason, clinical guidelines recommend that people continue with compression treatment after their ulcer has healed. This is an update of a Cochrane review first published in 2000 and last updated in 2014. OBJECTIVES: To assess the effects of compression (socks, stockings, tights, bandages) for preventing recurrence of venous leg ulcers. SEARCH METHODS: In August 2023, we searched the Cochrane Wounds Specialised Register, CENTRAL, MEDLINE, Embase, three other databases, and two ongoing trials registries. We also scanned the reference lists of included studies and relevant reviews and health technology reports. There were no restrictions on language, date of publication, or study setting. SELECTION CRITERIA: We included randomised controlled trials (RCTs) that evaluated compression bandages or hosiery for preventing the recurrence of venous ulcers. DATA COLLECTION AND ANALYSIS: At least two review authors independently selected studies, assessed risk of bias, and extracted data. Our primary outcome was reulceration (ulcer recurrence anywhere on the treated leg). Our secondary outcomes included duration of reulceration episodes, proportion of follow-up without ulcers, ulceration on the contralateral leg, noncompliance with compression therapy, comfort, and adverse effects. We assessed the certainty of evidence using GRADE methodology. MAIN RESULTS: We included eight studies (1995 participants), which were published between 1995 and 2019. The median study sample size was 249 participants. The studies evaluated different classes of compression (UK class 2 or 3 and European (EU) class 1, 2, or 3). Duration of follow-up ranged from six months to 10 years. We downgraded the certainty of the evidence for risk of bias (lack of blinding), imprecision, and indirectness. EU class 3 compression stockings may reduce reulceration compared with no compression over six months (risk ratio (RR) 0.46, 95% confidence interval (CI) 0.27 to 0.76; 1 study, 153 participants; low-certainty evidence). EU class 1 compression stockings compared with EU class 2 compression stockings may have little or no effect on reulceration over 12 months (RR 1.70, 95% CI 0.67 to 4.32; 1 study, 99 participants; low-certainty evidence). There may be little or no difference in rates of noncompliance over 12 months between people using EU class 1 stockings and people using EU class 2 stockings (RR 1.22, 95% CI 0.40 to 3.75; 1 study, 99 participants; low-certainty evidence). UK class 2 hosiery compared with UK class 3 hosiery may be associated with a higher risk of reulceration over 18 months to 10 years (RR 1.55, 95% CI 1.26 to 1.91; 5 studies, 1314 participants; low-certainty evidence). People who use UK class 2 hosiery may be more compliant with compression treatment than people who use UK class 3 hosiery over 18 months to 10 years (RR for noncompliance 0.69, 95% CI 0.49 to 0.99; 5 studies, 1372 participants; low-certainty evidence). There may be little or no difference between Scholl UK class 2 compression stockings and Medi UK class 2 compression stockings in terms of reulceration (RR 0.77, 95% CI 0.47 to 1.28; 1 study, 166 participants; low-certainty evidence) and noncompliance (RR 0.97, 95% CI 0.84.1 to 12; 1 study, 166 participants; low-certainty evidence) over 18 months. No studies compared different lengths of compression (e.g. below-knee versus above-knee), and no studies measured duration of reulceration episodes, ulceration on the contralateral leg, proportion of follow-up without ulcers, comfort, or adverse effects. AUTHORS' CONCLUSIONS: Compression with EU class 3 compression stockings may reduce reulceration compared with no compression over six months. Use of EU class 1 compression stockings compared with EU class 2 compression stockings may result in little or no difference in reulceration and noncompliance over 12 months. UK class 3 compression hosiery may reduce reulceration compared with UK class 2 compression hosiery; however, higher compression may lead to lower compliance. There may be little to no difference between Scholl and Medi UK class 2 compression stockings in terms of reulceration and noncompliance. There was no information on duration of reulceration episodes, ulceration on the contralateral leg, proportion of follow-up without ulcers, comfort, or adverse effects. More research is needed to investigate acceptable modes of long-term compression therapy for people at risk of recurrent venous ulceration. Future trials should consider interventions to improve compliance with compression treatment, as higher compression may result in lower rates of reulceration.

Support surfaces for treating pressure ulcers.

BACKGROUND: 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. OBJECTIVES: To assess the effects of pressure-relieving support surfaces in the treatment of pressure ulcers. SEARCH METHODS: 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. SELECTION CRITERIA: 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 COLLECTION AND ANALYSIS: 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. MAIN RESULTS: 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 ulcersLow-tech constant pressure support surfacesIt 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 surfacesIt 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 outcomesNo 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. AUTHORS' CONCLUSIONS: 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.

Oral antifungal medication for toenail onychomycosis.

BACKGROUND: Fungal infection of the toenails, also called onychomycosis, is a common problem that causes damage to the nail's structure and physical appearance. For those severely affected, it can interfere with normal daily activities. Treatment is taken orally or applied topically; however, traditionally topical treatments have low success rates due to the nail's physical properties. Oral treatments also appear to have shorter treatment times and better cure rates. Our review will assist those needing to make an evidence-based choice for treatment. OBJECTIVES: To assess the effects of oral antifungal treatments for toenail onychomycosis. SEARCH METHODS: We searched the following databases up to October 2016: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We also searched five trials registers and checked the reference lists of included and excluded studies for further references to relevant randomised controlled trials (RCTs). We sought to identify unpublished and ongoing trials by correspondence with authors and by contacting relevant pharmaceutical companies. SELECTION CRITERIA: RCTs comparing oral antifungal treatment to placebo or another oral antifungal treatment in participants with toenail onychomycosis, confirmed by one or more positive cultures, direct microscopy of fungal elements, or histological examination of the nail. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. MAIN RESULTS: We included 48 studies involving 10,200 participants. Half the studies took place in more than one centre and were conducted in outpatient dermatology settings. The participants mainly had subungual fungal infection of the toenails. Study duration ranged from 4 months to 2 years.We assessed one study as being at low risk of bias in all domains and 18 studies as being at high risk of bias in at least one domain. The most common high-risk domain was 'blinding of personnel and participants'.We found high-quality evidence that terbinafine is more effective than placebo for achieving clinical cure (risk ratio (RR) 6.00, 95% confidence interval (CI) 3.96 to 9.08, 8 studies, 1006 participants) and mycological cure (RR 4.53, 95% CI 2.47 to 8.33, 8 studies, 1006 participants). Adverse events amongst terbinafine-treated participants included gastrointestinal symptoms, infections, and headache, but there was probably no significant difference in their risk between the groups (RR 1.13, 95% CI 0.87 to 1.47, 4 studies, 399 participants, moderate-quality evidence).There was high-quality evidence that azoles were more effective than placebo for achieving clinical cure (RR 22.18, 95% CI 12.63 to 38.95, 9 studies, 3440 participants) and mycological cure (RR 5.86, 95% CI 3.23 to 10.62, 9 studies, 3440 participants). There were slightly more adverse events in the azole group (the most common being headache, flu-like symptoms, and nausea), but the difference was probably not significant (RR 1.04, 95% CI 0.97 to 1.12; 9 studies, 3441 participants, moderate-quality evidence).Terbinafine and azoles may lower the recurrence rate when compared, individually, to placebo (RR 0.05, 95% CI 0.01 to 0.38, 1 study, 35 participants; RR 0.55, 95% CI 0.29 to 1.07, 1 study, 26 participants, respectively; both low-quality evidence).There is moderate-quality evidence that terbinafine was probably more effective than azoles for achieving clinical cure (RR 0.82, 95% CI 0.72 to 0.95, 15 studies, 2168 participants) and mycological cure (RR 0.77, 95% CI 0.68 to 0.88, 17 studies, 2544 participants). There was probably no difference in the risk of adverse events (RR 1.00, 95% CI 0.86 to 1.17; 9 studies, 1762 participants, moderate-quality evidence) between the two groups, and there may be no difference in recurrence rate (RR 1.11, 95% CI 0.68 to 1.79, 5 studies, 282 participants, low-quality evidence). Common adverse events in both groups included headache, viral infection, and nausea.Moderate-quality evidence shows that azoles and griseofulvin probably had similar efficacy for achieving clinical cure (RR 0.94, 95% CI 0.45 to 1.96, 5 studies, 222 participants) and mycological cure (RR 0.87, 95% CI 0.50 to 1.51, 5 studies, 222 participants). However, the risk of adverse events was probably higher in the griseofulvin group (RR 2.41, 95% CI 1.56 to 3.73, 2 studies, 143 participants, moderate-quality evidence), with the most common being gastrointestinal disturbance and allergic reaction (in griseofulvin-treated participants) along with nausea and vomiting (in azole-treated participants). Very low-quality evidence means we are uncertain about this comparison's impact on recurrence rate (RR 4.00, 0.26 to 61.76, 1 study, 7 participants).There is low-quality evidence that terbinafine may be more effective than griseofulvin in terms of clinical cure (RR 0.32, 95% CI 0.14 to 0.72, 4 studies, 270 participants) and mycological cure (RR 0.64, 95% CI 0.46 to 0.90, 5 studies, 465 participants), and griseofulvin was associated with a higher risk of adverse events, although this was based on low-quality evidence (RR 2.09, 95% CI 1.15 to 3.82, 2 studies, 100 participants). Common adverse events included headache and stomach problems (in griseofulvin-treated participants) as well as taste loss and nausea (in terbinafine-treated participants). No studies addressed recurrence rate for this comparison.No study addressed quality of life. AUTHORS' CONCLUSIONS: We found high-quality evidence that compared to placebo, terbinafine and azoles are effective treatments for the mycological and clinical cure of onychomycosis, with moderate-quality evidence of excess harm. However, terbinafine probably leads to better cure rates than azoles with the same risk of adverse events (moderate-quality evidence).Azole and griseofulvin were shown to probably have a similar effect on cure, but more adverse events appeared to occur with the latter (moderate-quality evidence). Terbinafine may improve cure and be associated with fewer adverse effects when compared to griseofulvin (low-quality evidence).Only four comparisons assessed recurrence rate: low-quality evidence found that terbinafine or azoles may lower the recurrence rate when compared to placebo, but there may be no difference between them.Only a limited number of studies reported adverse events, and the severity of the events was not taken into account.Overall, the quality of the evidence varied widely from high to very low depending on the outcome and comparison. The main reasons to downgrade evidence were limitations in study design, such as unclear allocation concealment and randomisation as well as lack of blinding.

Support surfaces for treating pressure ulcers.

BACKGROUND: 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. OBJECTIVES: To assess the effects of pressure-relieving support surfaces in the treatment of pressure ulcers. SEARCH METHODS: We searched: The Cochrane Wounds Group Specialised Register (searched 15 July 2011); The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 3); Ovid MEDLINE (2007 to July Week 1 2011); Ovid MEDLINE (In-Process & Other Non-Indexed Citations, July 14, 2011); Ovid EMBASE (2007 to 2011 Week 27); EBSCO CINAHL (2007 to 14 July 2011). The reference sections of included studies were also searched. SELECTION CRITERIA: We included published or unpublished randomised controlled trials (RCTs), that assessed the effects of support surfaces for treating pressure ulcers, in any patient group or setting, that reported an objective measure of wound healing. DATA COLLECTION AND ANALYSIS: Data extraction and assessment of risk of bias were performed independently by two review authors. Trials with similar patients, comparisons and outcomes were considered for pooled analysis. Where pooling was inappropriate the results of the trials were reported narratively. Where possible, the risk ratio or mean difference was calculated for the results of individual studies. MAIN RESULTS: We identified 18 trials of support surfaces for pressure ulcer treatment, involving 1309 participants with samples sizes that ranged from 14 to 160. Of three trials comparing air-fluidized devices with conventional therapy, two reported significant reductions in pressure ulcer size associated with air-fluidized devices. Due to lack of reported variance data we could not replicate the analyses. In relation to three of the trials that reported significant reductions in pressure ulcer size favouring low air loss devices compared with foam alternatives, we found no significant differences. A small trial found that sheepskin placed under the legs significantly reduced redness and similarly a small subgroup analysis favoured a profiling bed compared with a standard bed in terms of the healing of existing grade 1 pressure ulcers. Poor reporting, clinical heterogeneity, lack of variance data and methodological limitations in the eligible trials meant that no pooled comparisons were undertaken. AUTHORS' CONCLUSIONS: There is no conclusive evidence about the superiority of any support surface for the treatment of existing pressure ulcers. Methodological issues included variations in outcomes measured, sample sizes and comparison groups. Many studies had small sample sizes and often there was inadequate description of the intervention, standard care and co-interventions. Individual study results were often inadequately reported, with failure to report variance data common, thus hindering the calculation of mean differences. Some studies did not report P values when reporting on differences in outcomes. In addition, the age of some trials (some being 20 years old), means that other technologies may have superseded those investigated.Further and rigorous studies are required to address these concerns and to improve the evidence base before firm conclusions can be drawn about the most effective support surfaces to treat pressure ulcers.

Support surfaces for pressure ulcer prevention.

BACKGROUND: Pressure ulcers (i.e. bedsores, pressure sores, decubitus ulcers) are areas of localised damage to the skin and underlying tissue. They are common in the elderly and immobile, and costly in financial and human terms. Pressure-relieving support surfaces (i.e. beds, mattresses, seat cushions etc) are used to help prevent ulcer development. OBJECTIVES: This systematic review seeks to establish: (1) the extent to which pressure-relieving support surfaces reduce the incidence of pressure ulcers compared with standard support surfaces, and, (2) their comparative effectiveness in ulcer prevention. SEARCH STRATEGY: For this third update we searched: the Cochrane Wounds Group Specialised Register (searched 8 December 2010), The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 4); Ovid MEDLINE (1950 to November Week 3 2010); Ovid MEDLINE (In-Process & Other Non-Indexed Citations December 07, 2010); Ovid EMBASE (1980 to 2010 Week 48); EBSCO CINAHL (1982 to 3 December 2010), and the reference sections of included studies. SELECTION CRITERIA: Randomised controlled trials (RCTs) and quasi-randomised studies, published or unpublished, that assessed the effects of any support surface for prevention of pressure ulcers, in any patient group or setting which measured pressure ulcer incidence.Studies reporting only proxy outcomes (e.g. interface pressure) were excluded. Two review authors independently selected studies. DATA COLLECTION AND ANALYSIS: Data were extracted by one author and checked by another. Where appropriate, estimates from similar studies were pooled for meta-analysis. MAIN RESULTS: One new trial was included, bringing the total of included studies to 53.Foam alternatives to standard hospital foam mattresses reduce the incidence of pressure ulcers in people at risk (RR 0.40 95% CI 0.21 to 0.74). The relative merits of alternating- and constant low-pressure devices are unclear. One high-quality trial suggested that alternating-pressure mattresses may be more cost effective than alternating-pressure overlays in a UK context.Pressure-relieving overlays on the operating table reduce postoperative pressure ulcer incidence, although two studies indicated that foam overlays caused adverse skin changes. Meta-analysis of three trials indicated that Australian standard medical sheepskins prevent pressure ulcers (RR 0.56 95% CI 0.32 to 0.97).  AUTHORS' CONCLUSIONS: People at high risk of developing pressure ulcers should use higher-specification foam mattresses rather than standard hospital foam mattresses. The relative merits of higher-specification constant low-pressure and alternating-pressure support surfaces for preventing pressure ulcers are unclear, but alternating-pressure mattresses may be more cost effective than alternating-pressure overlays in a UK context. Medical grade sheepskins are associated with a decrease in pressure ulcer development. Organisations might consider the use of some forms of pressure relief for high risk patients in the operating theatre.

Therapeutic ultrasound for venous leg ulcers.

BACKGROUND: Venous leg ulcers pose a significant burden for patients and healthcare systems. Ultrasound (US) may be a useful treatment for these ulcers. OBJECTIVES: To determine whether US increases the healing of venous leg ulcers. SEARCH STRATEGY: We searched the Cochrane Wounds Group Specialised Register (searched 24 February 2010); The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2010); Ovid MEDLINE (1950 to February Week 2 2010); In-Process & Other Non-Indexed Citations (searched 24 February 2010); Ovid EMBASE 1980 to 2010 Week 07; EBSCO CINAHL 1982 to 24 February 2010. SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing US with no US. DATA COLLECTION AND ANALYSIS: Two authors independently assessed the search results and selected eligible studies. Details from included studies were summarised using a data extraction sheet, and double-checked. We tried to contact trial authors for missing data. MAIN RESULTS: Eight trials were included; all had unclear, or high, risks of bias, with differences in duration of follow-up, and US regimens. Six trials evaluated high frequency US and five of these reported healing at 7 - 8 weeks. Significantly more patients healed with US than without it at 7 - 8 weeks (pooled RR 1.4, 95% CI 1.0 to 1.96), but later assessments at 12 weeks showed the increased risk of healing with US was no longer statistically significant (pooled RR 1.47, 95% CI 0.99 to 2.20). One poor-quality study of high-frequency US found no evidence of an effect on healing after three weeks' treatment.Two trials evaluated low frequency US and reported healing at different time points. Both trials reported no evidence of a difference in the proportion of ulcers healed with US compared with no US: both were significantly underpowered. AUTHORS' CONCLUSIONS: The trials evaluating US for venous leg ulcers are small, poor-quality and heterogeneous. There is no reliable evidence that US hastens healing of venous ulcers. There is a small amount of weak evidence of increased healing with US, but this requires confirmation in larger, high-quality RCTs. There is no evidence of a benefit associated with low frequency US.

Skin preparation with alcohol versus alcohol followed by any antiseptic for preventing bacteraemia or contamination of blood for transfusion.

BACKGROUND: Blood for transfusion may become contaminated at any point between collection and transfusion and may result in bacteraemia (the presence of bacteria in the blood), severe illness or even death for the blood recipient. Donor arm skin is one potential source of blood contamination, so it is usual to cleanse the skin with an antiseptic before blood donation. One-step and two-step alcohol based antiseptic regimens are both commonly advocated but there is uncertainty as to which is most effective. OBJECTIVES: To assess the effects of cleansing the skin of blood donors with alcohol in a one-step compared with alcohol in a two-step procedure to prevent contamination of collected blood or bacteraemia in the recipient. SEARCH STRATEGY: We searched the Cochrane Wounds Group Specialised Register (March 10 2009); The Cochrane Central Register of Controlled Trials (CENTRAL) The Cochrane Library 2009, Issue 1; Ovid MEDLINE - (1950 to February Week 4 2009); Ovid EMBASE - (1980 to 2009 Week 9); and EBSCO CINAHL - (1982 to February Week 4 2009). We also searched the reference lists of key papers. SELECTION CRITERIA: All randomised trials (RCTs) comparing alcohol based donor skin cleansing in a one-step versus a two-step process that includes alcohol and any other antiseptic for pre-venepuncture skin cleansing were considered. Quasi randomised trials were to have been considered in the absence of RCTs. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed studies for inclusion. MAIN RESULTS: No studies (RCTs or quasi RCTs) met the inclusion criteria. AUTHORS' CONCLUSIONS: We did not identify any eligible studies for inclusion in this review. It is therefore unclear whether a two-step, alcohol followed by antiseptic skin cleansing process prior to blood donation confers any reduction in the risk of blood contamination or bacteraemia in blood recipients, or conversely whether a one-step process increases risk above that associated with a two-step process.

Support surfaces for pressure ulcer prevention.

BACKGROUND: Pressure ulcers (also known as bedsores, pressure sores, decubitus ulcers) are areas of localised damage to the skin and underlying tissue due to pressure, shear or friction. They are common in the elderly and immobile and costly in financial and human terms. Pressure-relieving beds, mattresses and seat cushions are widely used as aids to prevention in both institutional and non-institutional settings. OBJECTIVES: This systematic review seeks to answer the following questions:(1) to what extent do pressure-relieving cushions, beds, mattress overlays and mattress replacements reduce the incidence of pressure ulcers compared with standard support surfaces?(2) how effective are different pressure-relieving surfaces in preventing pressure ulcers, compared to one another? SEARCH STRATEGY: For this second update the Cochrane Wounds Group Specialised Register was searched (28/2/08), The Cochrane Central Register of Controlled Trials (CENTRAL)(2008 Issue 1), Ovid MEDLINE (1950 to February Week 3 2008), Ovid EMBASE (1980 to 2008 Week 08) and Ovid CINAHL (1982 to February Week 3 2008). The reference sections of included studies were searched for further trials. SELECTION CRITERIA: Randomised controlled trials (RCTs), published or unpublished, which assessed the effectiveness of beds, mattresses, mattress overlays, and seating cushions for the prevention of pressure ulcers, in any patient group, in any setting. Study selection was undertaken by at least two authors independently with a third author resolving uncertainty. RCTs were eligible for inclusion if they reported an objective, clinical outcome measure such as incidence and severity of new of pressure ulcers developed. Studies which only reported proxy outcome measures such as interface pressure were excluded. DATA COLLECTION AND ANALYSIS: Trial data were extracted by one researcher and checked by a second. The results from each study are presented as relative risk for dichotomous variables. Where deemed appropriate, similar studies were pooled in a meta analysis. MAIN RESULTS: For this second update 11 trials met the inclusion criteria bringing the total number of RCTs included in the review to 52.Foam alternatives to the standard hospital foam mattress can reduce the incidence of pressure ulcers in people at risk. The relative merits of alternating and constant low pressure devices are unclear. There is one high quality trial comparing the different alternating pressure devices for pressure ulcer prevention which suggests that alternating pressure mattresses may be more cost effective than alternating pressure overlays.Pressure-relieving overlays on the operating table have been shown to reduce postoperative pressure ulcer incidence, although two studies indicated that foam overlays resulted in adverse skin changes. Two trials indicated that Australian standard medical sheepskins prevented pressure ulcers. There is insufficient evidence to draw conclusions on the value of seat cushions, limb protectors and various constant low pressure devices as pressure ulcer prevention strategies.A study of Accident & Emergency trolley overlays did not identify a reduction in pressure ulcer incidence. There are tentative indications that foot waffle heel elevators, a particular low air loss hydrotherapy mattress and two types of operating theatre overlays are harmful. AUTHORS' CONCLUSIONS: In people at high risk of pressure ulcer development higher specification foam mattresses rather than standard hospital foam mattresses should be used. The relative merits of higher-tech constant low pressure and alternating pressure for prevention are unclear but alternating pressure mattresses may be more cost effective than alternating pressure overlays. Medical grade sheepskins are associated with a decrease in pressure ulcer development. Organisations might consider the use of some forms of pressure relief for high risk patients in the operating theatre. Seat cushions and overlays designed for use in Accident & Emergency settings have not been adequately evaluated.