Superficies de apoyo para el tratamiento de las úlceras de decúbito
Resumen
Antecedentes
Las úlceras de decúbito son tratadas mediante la reducción de la presión sobre las áreas de la piel lesionada. Las superficies de apoyo especiales (incluidas las camas, colchones y almohadones) diseñadas para redistribuir la presión, son ampliamente utilizadas como tratamiento. Los efectos relativos de las diferentes superficies de apoyo no están claros. Esta es una actualización de una revisión existente.
Objetivos
Evaluar los efectos de las superficies de apoyo para aliviar la presión en el tratamiento de las úlceras de decúbito.
Métodos de búsqueda
En septiembre 2017, se hicieron búsquedas en el registro especializado del Grupo Cochrane de Heridas (Cochrane Wounds Specialised Register), en el Registro Cochrane Central de Ensayos Controlados (CENTRAL); Ovid MEDLINE (incluido In‐Process & Other Non‐Indexed Citations); Ovid Embase y EBSCO CINAHL Plus. Para identificar estudios adicionales, también se buscaron estudios en curso y no publicados en los registros de ensayos clínicos y se revisaron las listas de referencias de los estudios relevantes incluidos, así como de las revisiones, los metanálisis y los informes de tecnología de la salud. No hubo restricciones en cuanto al idioma, la fecha de publicación ni el contexto de los estudios.
Criterios de selección
Se incluyeron ensayos controlados aleatorizados (ECA) publicados o no publicados, que evaluaron los efectos de las superficies de apoyo para el tratamiento de las úlceras de decúbito, en cualquier grupo o entorno de participantes.
Obtención y análisis de los datos
La extracción de datos, la evaluación del "riesgo de sesgo" y las evaluaciones de GRADE fueron realizadas independientemente por dos autores de la revisión. Se consideraron para el metanálisis los ensayos con participantes, comparaciones y resultados similares. En los casos en que el metanálisis fue inapropiado, se informaron los resultados de los ensayos de forma narrativa. Cuando fue posible, se planeó informar los datos como riesgos relativos o diferencia de medias, según era apropiado.
Resultados principales
Para esta actualización, se ha identificado un nuevo ensayo de superficies de apoyo para el tratamiento de las úlceras de decúbito, lo que hace un total de 19 ensayos con 3241 participantes. La mayoría de los ensayos fueron pequeños, con tamaños de muestra que oscilaban entre 20 y 1971, y en general, presentaban un riesgo de sesgo alto o poco claro.
Resultado primario: curación de las úlceras de presión existentes
Superficies de soporte de presión constante de baja tecnología
No es seguro que las camas articuladas aumenten la proporción de úlceras de decúbito que se curan en comparación con las camas de hospital estándar, ya que la evidencia es de muy poca certeza: (RR 3,96; IC del 95%: 1,28 a 12,24), disminuida por riesgo grave de sesgo, imprecisión grave y falta de direccionalidad (un estudio; 70 participantes).
Actualmente, no hay una clara diferencia en la curación de las úlceras entre las superficies de apoyo rellenas de agua y los colchones de espuma de reemplazo: (RR 0,93; IC del 95%: 0,63 a 1,37); la evidencia de baja certeza se disminuyó por el grave riesgo de sesgo y la grave imprecisión (un estudio; 120 participantes).
No se pudieron realizar análisis adicionales para las superposiciones de poliéster frente a las superposiciones de gel (un estudio; 72 participantes), los colchones sin motor frente a los colchones con baja pérdida de aire (un estudio; 20 participantes) o los colchones estándar de hospital con superposiciones de piel de oveja frente a los colchones estándar de hospital (un estudio; 36 participantes).
Superficies de soporte de presión de alta tecnología
Actualmente, no está claro si las superficies de apoyo de alta tecnología para la presión (como las camas de baja pérdida de aire, las camas de suspensión neumática y las superficies de presión alterna) mejoran la curación de las úlceras de decúbito (14 estudios; 2923 participantes) o qué intervención puede ser más efectiva. La certeza de la evidencia es generalmente baja, disminuida sobre todo por el riesgo de sesgo, falta de direccionalidad e imprecisión.
Resultados secundarios
No se realizaron análisis con respecto a los resultados secundarios, como la comodidad de los participantes y la fiabilidad y aceptabilidad de la superficie, ya que la información al respecto en los ensayos incluidos fue muy limitada.
En general, la evidencia es de certeza baja a muy baja y se disminuyó principalmente debido al riesgo de sesgo e imprecisión con cierta falta de direccionalidad.
Conclusiones de los autores
Según la evidencia actual, no está claro si algún tipo particular de superficie de apoyo de baja o alta tecnología es más efectiva para la curación de las úlceras por presión que las superficies de apoyo estándar.
PICO
Resumen en términos sencillos
Superficies de apoyo para el tratamiento de las úlceras de decúbito
¿Cuál era el objetivo de esta revisión?
El objetivo de esta revisión fue averiguar si las diferentes superficies de apoyo, como camas, colchones o cojines especialmente diseñados, pueden ayudar a tratar las úlceras de decúbito. Los investigadores Cochrane recopilaron y analizaron todos los estudios pertinentes (ensayos controlados aleatorizados) para responder esta pregunta y encontraron 19 estudios relevantes.
Mensajes clave
No se sabe con seguridad cuáles son las superficies de apoyo más efectivas para el tratamiento de las úlceras de decúbito, ya que los estudios que las comparan no contaron con la participación de suficientes pacientes y no estaban bien diseñados.
¿Qué se estudió en la revisión?
Las úlceras de decúbito (también llamadas úlceras por presión, úlceras por decúbito y úlceras de cama) son heridas en la piel y el tejido subyacente causadas por la presión o el roce. Típicamente se forman en puntos del cuerpo que son huesudos o que soportan peso o presión, como las caderas, las nalgas, los talones y los codos. Los pacientes que tienen problemas de movilidad o que permanecen en cama durante largos períodos corren el riesgo de desarrollar úlceras de decúbito. Para el tratamiento de las úlceras de decúbito, se utilizan diversos tratamientos, como apósitos para las heridas y superficies de apoyo como colchones y cojines especiales.
Las superficies de apoyo para el tratamiento de las úlceras de decúbito pueden incluir camas, colchones, capas de colchón y cojines especialmente diseñados que se utilizan para proteger las partes vulnerables del cuerpo y distribuir la presión de la superficie de manera más uniforme. Las superficies de apoyo de baja tecnología incluyen colchones llenos de espuma, líquido, perlas o aire; y colchones de espuma alternativos y superposiciones. Las superficies de apoyo de alta tecnología incluyeron los colchones y cubiertas que se accionan eléctricamente para alternar la presión de la superficie, las camas que se accionan mecánicamente para que circule el aire dentro de ellas y las camas de baja pérdida de aire, que contienen aire caliente que se mueve dentro de bolsas que se encuentran en el interior de la cama. Otras superficies de apoyo fueron las pieles de oveja, los almohadones y las cubiertas de mesa de operaciones.
Se quería saber qué superficies de apoyo eran más efectivas para ayudar a curar las úlceras de decúbito. También se querían comparar las diferentes superficies de apoyo en términos de costo, confiabilidad, durabilidad, y los beneficios o daños para los pacientes que las usan.
¿Cuáles son los principales resultados de la revisión?
En septiembre de 2017, se buscaron ensayos que analizaban las superficies de apoyo para el tratamiento de las úlceras de decúbito y que informaban de sus efectos en la cicatrización de las heridas. Se encontraron 19 ensayos con 3241 participantes, todos adultos, la mayoría de los cuales eran pacientes mayores y estaban confinados a la cama en hospitales o asilos. En los estudios en los que se informó el sexo de los participantes, la mayoría eran mujeres. No todos los estudios informaron sobre sus fuentes de financiación, pero dos de los que lo hicieron fueron financiados por los fabricantes de dispositivos.
Cinco estudios con 318 participantes compararon superficies de soporte de baja tecnología de baja presión constante (BPC) como los colchones de espuma. No se sabe con seguridad cómo estas diferentes superficies de apoyo afectan a la curación de las úlceras de decúbito, ya que la evidencia es principalmente de baja certeza. Catorce estudios con 2923 participantes compararon diferentes superficies de apoyo de alta tecnología como las camas fluidificadas. Una vez más, no se sabe con seguridad cómo estas diferentes superficies de apoyo afectan a las tasas de curación de las úlceras, ya que la certeza de la evidencia es principalmente baja.
No se pueden extraer conclusiones firmes sobre los efectos de las diferentes superficies de apoyo para el tratamiento de las úlceras de decúbito porque la calidad general de la evidencia es baja o muy baja. Muchos de los estudios incluyeron sólo un pequeño número de pacientes, no proporcionaron información adecuada sobre sus resultados o no estaban bien diseñados. Además, se necesitan ensayos mejor realizados para determinar qué superficies de apoyo son más efectivas para el tratamiento de las úlceras de decúbito.
¿Cómo de actualizada está esta revisión?
Se hicieron búsquedas de estudios que se habían publicado hasta septiembre 2017.
Authors' conclusions
Summary of findings
| Profiling bed with foam mattress compared with hospital bed with foam mattress | ||||||
| Patient or population: patients from two surgical and two medical wards | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of Participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Foam mattress | Profiling bed | |||||
| Pressure ulcer healing | Study population | RR 3.96 | 70 | ⊕⊝⊝⊝ | ||
| 200 per 1000 | 792 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded twice for multiple high risks of bias, twice for imprecision (low numbers of participants resulting in wide fragile confidence intervals) and once for indirectness as only a minority of participants had pressure ulcers at enrolment | ||||||
| Water mattress overlay compared withlow‐tech mattress | ||||||
| Patient or population: nursing home patients, > 59 years old | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of Participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Foam replacement mattress | Water mattress support | |||||
| Pressure ulcer healing | Study population | RR 0.93 | 120 | ⊕⊕⊝⊝ | ||
| 483 per 1000 | 450 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded once for risks of bias including Incomplete outcome data and once for imprecision resulting in wide confidence intervals | ||||||
| Low‐air‐loss bed compared with low‐tech mattress overlay | ||||||
| Patient or population: elderly nursing home residents with multiple medical problems | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of Participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Low‐tech mattress overlay | Low‐air‐loss bed | |||||
| Pressure ulcers completely healed | Study population | RR 1.30 | 84 | ⊕⊕⊝⊝ | ||
| 463 per 1000 | 602 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded once for risks of bias including incomplete outcome data and once for imprecision resulting in wide confidence intervals | ||||||
| Alternating pressure mattresses | ||||||
| Patient or population: varied | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of Participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Control | Alternating pressure mattress | |||||
| Ulcers completely healed | Study population | RR 0.57 | 30 | ⊕⊕⊝⊝ | ||
| 625 per 1000 | 356 per 1000 | |||||
| Decrease in pressure ulcer size | Study population | RR 0.58 | 30 | ⊕⊕⊝⊝ | ||
| 429 per 1000 | 249 per 1000 | |||||
| Ulcers completely healed | Study population | RR 0.99 | 141 | ⊕⊕⊝⊝ | ||
| 929 per 1000 | 919 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded once for risk of bias including high rates of withdrawal and once for imprecision resulting in wide confidence intervals 3 Downgraded once for selection bias and once for imprecision resulting in wide confidence intervals which include the possibility of both benefit and harm. | ||||||
| Alternating‐pressure mattress compared with alternating‐pressure mattress overlay | ||||||
| Patient or population: varied | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of Participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Alternating‐pressure mattress overlay | Alternating‐pressure mattress | |||||
| Pressure ulcer improvement | Study population | RR 0.97 | 158 | ⊕⊕⊝⊝ | ||
| 747 per 1000 | 724 per 1000 | |||||
| Pressure ulcer healing | Study population | RR 0.96 | 113 | ⊕⊕⊝⊝ | ||
| 352 per 1000 | 338 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded once for risk of attrition bias and once for imprecision resulting in wide confidence intervals | ||||||
| Alternating‐pressure mattress compared with air‐filled devices | ||||||
| Patient or population: patients with pressure ulcers | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of Participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Air‐filled devices | Alternating‐pressure mattress | |||||
| Proportion of patients with healed pressure ulcer | Study population | RR 5.50 (0.73, 41.44) | 50 | ⊕⊕⊝⊝ | ||
| 38 per 1000 | 206 per 1000 | |||||
| Moderate | ||||||
| 39 per 1000 | 209 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded once for possible selection bias and attrition bias due to limited details provided and once due to imprecision resulting in wide confidence intervals | ||||||
| Alternating‐pressure cushion compared with dry flotation cushion | ||||||
| Patient or population: patients with pressure ulcers | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of Participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Dry flotation cushion | Alternating‐pressure cushion | |||||
| Pressure ulcers completely healed | Study population | RR 0.47 | 25 | ⊕⊕⊝⊝ | ||
| 455 per 1000 | 214 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded once for risk of bias due to lack of an ITT analysis and once for imprecision resulting in wide confidence intervals | ||||||
Background
Description of the condition
Pressure ulcers (also known as pressure sores, decubitus ulcers and bed sores) are areas of localised damage to the skin and underlying tissue, believed to be caused either by pressure, or by a combination of pressure and shear (Alderden 2011; Coleman 2013; Coleman 2014; NPUAP‐EPUAP‐PPPIA 2014). Pressure ulcers are more likely to occur in those who are seriously ill or who are neurologically compromised, e.g. individuals with spinal cord injuries, who have impaired mobility (Cooper 2015; Gefen 2014; Van de Wielen 2016), or are immobilised (including by a prostheses, body brace or plaster cast). People with impaired nutrition are also at risk of developing pressure ulcers (Banks 2013; Casey 2003; Delmore 2015; Ferguson 2000; Langer 2014; Posthauer 2015; Roberts 2014). Other risk factors include obesity (Mathison 2003; Pokorny 2014; Wilson 2004); poor posture, or use of equipment such as beds or seating that do not provide appropriate pressure relief; increased age (Bosanquet 2016; Brienza 2010; Hanonu 2016; Horn 2004; Khor 2014; Russo 2008; Stockton 2009; Wipke‐Tevis 2004); and being pregnant (Bick 2011; Cheesman 2010). Serious consequences of pressure ulcers include an increased incidence of infection, including osteomyelitis (Bodavula 2015; Rennert 2009).
Description of the intervention
Strategies for treating pressure ulcers usually comprise a combination of pressure‐relieving devices such as mattresses and cushions, wound care and repositioning. Wound management strategies, such as wound dressings, debridement techniques, physical therapies and nutritional interventions, are the focus of other recent systematic reviews (Chen 2014; Cullum 2017; Dumville 2015a; Dumville 2015b; Dumville 2015c; Gillespie 2014; Langer 2014; McGinnis 2015; Moore 2013; Moore 2015a; Smith 2013; Zhang 2015).
The aim of pressure‐relieving devices is to reduce the magnitude or duration of pressure, or both (including shear and friction) between patients and their support surface (this is called the "interface pressure"). Such devices include cushions, mattress overlays, replacement mattresses, or whole bed‐replacements. The cost of these interventions varies widely, from over GBP 30,000 (UK) for some bed replacements to less than GBP 100 for some foam overlays. Information on the relative cost‐effectiveness of this equipment is needed to aid rational use.
How the intervention might work
Pressure‐relieving support surfaces either mould around the shape of the person to distribute his/her weight over a larger area (constant low‐pressure devices) (CLP), or vary the pressure beneath the person mechanically, thus reducing the duration of the pressure applied (alternating‐pressure devices) (AP) (Nixon 2006b; Vanderwee 2008). CLP devices (either overlays, mattresses or replacement beds) can be grouped according to their construction (foam, foam and air, foam and gel, profiled foam, hammocks, air suspension, water suspension and air‐particulate suspension/air‐fluidised). These devices envelop the body so that pressure is dispersed over a large area. AP devices generate alternating high‐ and low‐interface pressures between the body and the support, usually by sequential inflation and deflation of air‐filled cells. Such devices are available as cushions, mattress overlays, and single or multi‐layer mattress replacements. Other pressure relieving surfaces move the person. These can include turning beds, such as turning frames, net beds, and turning/tilting beds. These devices, either manually or automatically, assist people who are unable to turn themselves to rotate laterally.
Why it is important to do this review
Research indicates that pressure ulcers represent a major burden of sickness and reduced quality of life for those with a pressure ulcer, their carers and their families (Gorecki 2010; Gorecki 2012; Gorecki 2014; Lourenco 2014; McGinnis 2014; McGinnis 2015; Spilsbury 2007). Often those affected by pressure ulcers require prolonged and frequent contact with the healthcare system, and experience high levels of pain, discomfort and inconvenience (Briggs 2013; Pieper 2009).
The development of pressure ulcers is relatively common. Estimates of pressure ulcer incidence and prevalence from hospital‐based studies vary widely according to the definition and grade of ulcer, the patient population and care setting. A review of epidemiological studies in Europe, Canada and the USA describes reported pressure ulcer prevalence in European hospitals as ranging from 8.3% to 23% (Kaltenhalter 2001). In the UK, an estimate of the overall prevalence of pressure ulcers within care settings was 10.2%, with 59% of these being hospital‐acquired (Phillips 2009). In US healthcare facilities, reports of prevalence have been estimated at 12.3% (VanGilder 2009), while in Canadian healthcare settings incidence has been reported as 26% (Woodbury 2004).
In Australia, the prevalence of pressure ulcers estimated for the period of 1983 to 2002, ranged from 3% to 37%. This wide variation has been attributed to different healthcare settings and their prevention practices as well as to data collection methods. For example, pressure ulcer prevalence ranged from 9.5% to 17.6% in acute care hospitals and in nursing homes was estimated as 8.9% (Ngyuen 2015).
The presence of pressure ulcers has been associated with a two‐to‐four‐fold increase in risk of death in older people in intensive care units (Bo 2003; Clough 1994; Thomas 1996). Based on the data available, between one‐in‐four and one‐in‐five patients within an acute hospital will experience a pressure ulcer (Posnett 2009). The community incidence rate within the UK ranges from 4.4% to 6.8%, and is as high as 16.5% in the USA and Canada (Kaltenhalter 2001).
The annual cost of treating pressure ulcers in Australia was estimated to be AUD 983 million (95% CI 815 to 1151 million) at 2012/13 prices, with opportunity costs valued at a further AUD 819 million (95% CI 572 to 1067 million) (Ngyuen 2015). The cost of treating a pressure ulcer in the UK has been estimated to range from GBP 1214 (category 1 ulcer) to GBP 14,108 for a category 4 ulcer; these are conservative estimates which exclude the impact of more costly negative pressure wound therapy (Dealey 2012). A 2015 systematic review identified treatment costs associated with pressure ulcers, per patient, per day of between EUR 1.71 and 470.49, based on 14 studies across a wide range of settings in Europe and North America between 2001 and 2013 (Demarré 2015). A Canadian study used data from the period 2002‐2006 in a single province to estimate treatment costs of pressure ulcers identified as being hospital‐acquired as ranging from CAD 44,000 (category 2) to CAD 90,000 (category 4); in each case these costs were higher than estimates for the cost of treatment of pressure ulcers present on admission to hospital (Chan 2013).
The presence of a pressure ulcer creates a number of difficulties (psychologically, physically and clinically) for those affected, carers and their families. Clinicians, working in a variety of clinical and non‐clinical settings (including primary care and acute trusts) also face challenges when providing holistic, person‐centred services for the assessment and treatment of pressure ulcers. These challenges include clinical decisions regarding methods of assessment, and treatments that should be used for individuals with an existing pressure ulcer.
Regardless of the strategies employed to identify people at high risk for developing pressure ulcers, and the numerous interventions deployed to prevent them, pressure ulcers still occur. Treatment should use initiatives based on the best available evidence of clinical‐ and cost‐effectiveness. Hence, we have undertaken a systematic review of the evidence for the effects of pressure‐relieving support surfaces, such as beds, mattresses and cushions, in the treatment of pressure ulcers.
Healthcare professionals attempt to prevent the incidence of pressure ulcers using various pressure‐relieving devices including, but not limited to, mattresses, beds, overlays, cushions and chairs. A summary of the available devices for pressure ulcer prevention is the subject of another Cochrane Review (McInnes 2015).
Objectives
To assess the effects of pressure‐relieving support surfaces in the treatment of pressure ulcers.
Methods
Criteria for considering studies for this review
Types of studies
Randomised controlled trials (RCTs) of support surfaces that measured the healing of pressure ulcers. No restrictions were imposed on the basis of language of publication of the reports. Studies that also included the incidence of new pressure ulcers were referred for consideration for inclusion in another Cochrane Review, Support surfaces for pressure ulcer prevention (McInnes 2015).
Types of participants
People with existing pressure ulcers (of any grade) in any setting. A range of pressure ulcer grading systems are used in pressure ulcer trials. An example of a commonly used grading system which is adapted from an EPUAP classification system (www.epuap.org.uk) is presented below (EPUAP‐NPUAP 2009).
Grade 1: persistent discolouration of the skin including non‐blanchable erythema; blue, purple, or black discolouration.
Grade 2: partial‐thickness skin loss involving epidermis and dermis.
Grade 3: full‐thickness skin loss involving damage or necrosis of subcutaneous tissues, but not through the underlying fascia, and not extending to the underlying bone, tendon or joint capsule.
Grade 4: full‐thickness skin loss with extensive destruction and tissue necrosis extending to the underlying bone, tendon or joint capsule.
Types of interventions
Trials that evaluated the following interventions for pressure ulcer treatment were eligible for inclusion.
Low‐tech (non‐powered) constant low‐pressure (CLP) support surfaces
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Standard foam mattresses.
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Alternative foam mattresses/overlays (e.g. convoluted foam, cubed foam): these are conformable and aim to redistribute pressure over a larger contact area.
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Gel‐filled mattresses/overlays: mode of action as above.
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Fibre‐filled mattresses/overlays: mode of action as above.
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Air‐filled mattresses/overlays: mode of action as above.
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Water‐filled mattresses/overlays: mode of action as above.
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Bead‐filled mattresses/overlays: mode of action as above.
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Sheepskins.
High‐tech support surfaces
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Alternating‐pressure (AP) mattresses/overlays: person lies on air‐filled sacs which sequentially inflate and deflate and relieve pressure at different anatomical sites for short periods; may incorporate a pressure sensor.
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Air‐fluidised beds: warmed air circulated through fine ceramic beads covered by a permeable sheet; allows support over a larger contact area (CLP).
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Low‐air‐loss beds: patients are supported on a series of air sacs through which warmed air passes (CLP).
Other support surfaces
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Turning beds/frames: these devices work by either aiding manual repositioning of the individual, or by automatic motor‐driven turning and tilting. They may have a static or an alternating support surface in conjunction with the frame.
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Operating table overlays: mode of action as above.
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Wheelchair cushions: may be conforming and reduce contact pressures by increasing the surface area in contact with the individual, or mechanical e.g. alternating‐pressure mattresses/overlays.
We included trials that compared the interventions listed above, and those where the intervention was compared with "usual" or "standard" care.
The classifications of the support surfaces included in this review are in line with classifications used previously. It is acknowledged that these categories have since been updated by the National Pressure Ulcer Advisory Panel (EPUAP‐NPUAP 2009), and this will be considered in future updates of this review.
Types of outcome measures
Trials that measured only surrogate outcome measures, such as interface pressure, were excluded on the basis that interface pressure measurements have not been demonstrated to predict the clinical performance of support surfaces reliably.
Primary outcomes
Healing rates of existing pressure ulcers was the primary outcome examined. Currently, there is no consensus regarding the most valid and reliable means of measuring healing rates of pressure ulcers. Therefore, trials were included if they measured healing by some objective method, such as time to complete healing, rate of change in the area/volume of the ulcer(s), or number of ulcers healed.
Secondary outcomes
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Costs of the devices
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Participant comfort
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Durability of the devices
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Reliability of the devices
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Acceptability of the devices
Search methods for identification of studies
Electronic searches
For this review we searched the following databases to identify reports of relevant clinical trials:
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Cochrane Wounds Specialised Register (searched 13 September 2017);
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Cochrane Central Register of Controlled Trials (CENTRAL; 2017, Issue 8) in the Cochrane Library (searched 13 September 2017);
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Ovid MEDLINE including In‐Process & Other Non‐Indexed Citations (1946 to 13 September 2017);
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Ovid Embase (1974 to 13 September 2017);
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EBSCO CINAHL Plus (1937 to 13 September 2017).
The search strategies for the Cochrane Wounds Specialised Register, CENTRAL, Ovid MEDLINE, Ovid Embase and EBSCO CINAHL Plus can be found in Appendix 1. We combined the Ovid MEDLINE search with the Cochrane Highly Sensitive Search Strategy for identifying randomised trials in MEDLINE: sensitivity‐ and precision‐maximizing version (2008 revision) (Lefebvre 2011). We combined the Embase search with the Ovid Embase filter developed by the UK Cochrane Centre (Lefebvre 2011). We combined the EBSCO CINAHL Plus with the trial filters developed by the Scottish Intercollegiate Guidelines Network (SIGN) (SIGN 2018). There were no restrictions on the basis of date, or language, of publication.
We also searched the clinical trial registries using the keywords 'pressure ulcer*' or 'pressure injur*':
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ClinicalTrials.gov (www.clinicaltrials.gov);
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World Health Organization International Clinical Trials Registry Platform (ICTRP) (www.who.int/trialsearch).
Details of the search strategies used for the previous version of the review are given in (McInnes 2011).
Studies were added to awaiting classification and ongoing studies as detailed below.
Searching other resources
Originally, we contacted experts in the field of wound care to enquire about ongoing and recently published trials in this field. In addition, we also contacted manufacturers of wound care materials for details of any trials they were conducting. We did not repeat this process for this version of the review, since previously it was unproductive.
We aimed to identify other potentially eligible trials or ancillary publications by searching the reference lists of retrieved included trials, as well as relevant systematic reviews, meta‐analyses and health technology assessment reports.
Data collection and analysis
We carried out data collection and analysis according to methods based on the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011).
Selection of studies
The titles and abstracts of the papers identified by the search were independently assessed for relevance by at least two review authors (VL, AJ‐B), and full copies of all potentially‐relevant studies were obtained. Decisions on final inclusion were then made by one review author (VL) and checked by a second review author (AJ‐B); disagreements were resolved by discussion with a third review author (EMcI). A third review author (EMcL) checked any rejected studies.
Data extraction and management
Two review authors independently extracted details of eligible studies and summarised the information using a data extraction sheet.
The following data were extracted for each study:
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inclusion/exclusion criteria;
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care setting;
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key baseline variables by group e.g. age, sex, baseline risk, baseline area of existing ulcers;
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description of the interventions and numbers of those randomised to each intervention;
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description of any co‐interventions/standard care;
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follow‐up period;
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outcomes;
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acceptability and reliability of equipment, if reported.
Individual study details are presented in structured tables (see Characteristics of included studies).
Assessment of risk of bias in included studies
For this version of the review, two review authors (AJB and VL) independently assessed each included study using the Cochrane tool for assessing risk of bias (Higgins 2011). This tool addresses six specific domains, namely sequence generation, allocation concealment, blinding, incomplete outcome data, selective outcome reporting and other issues (e.g. extreme baseline imbalance, timing of outcome assessment) (see Appendix 2) for details of criteria on which the judgement was based). Blinding and completeness of outcome data were assessed for each outcome separately. We completed a 'Risk of bias' table for each eligible study and discussed any disagreement amongst all review authors to achieve a consensus.
We presented assessment of risk of bias using a 'Risk of bias' summary figure, which presents all of the judgements in a cross‐tabulation of study by entry. This display of internal validity indicates the weight the reader may give the results of each study.
Measures of treatment effect
Results of dichotomous variables are presented as risk ratio (RR) with 95% confidence intervals (CIs). Risk ratio has been used rather than odds ratios, as event rates are high in these trials, and odds ratios would give an inflated impression of the magnitude of effect (Deeks 1998). Risk ratio is the rate of the event of interest (e.g. pressure ulcers healed in the experimental group divided by the rate of this event in the control group), and indicates the chances of pressure ulcer healing in the experimental treatment compared with the control treatment. As, by definition, the risk of an event occurring in the control group is 1, then the relative risk reduction associated with using an experimental treatment is 1‐RR. The risk ratio indicates the relative benefit of a therapy, but not the actual benefit; i.e. it does not take into account the number of people whose pressure ulcer would have healed naturally without treatment.
Continuous outcome variables such as change in wound volume were summarised using the difference in means (MD). All calculations were made using RevMan 5 software. Where insufficient detail was reported in the included studies to permit calculation of the RR or MD, the results reported by study authors have been presented. Data on secondary outcomes such as comfort, durability, reliability and acceptability are presented, where reported, in Characteristics of included studies.
Unit of analysis issues
Studies presented multiple units of analysis including individual pressure ulcer numbers or participant level data (i.e. number of those with one or more pressure ulcers). In rare instances there were study participants with multiple pressure ulcers. We reported results of the studies as they were presented in the original studies.
Dealing with missing data
When a paper provided insufficient information for full data extraction, or if conflicting data were found, we approached study authors for additional information. Where there were losses to follow‐up and a treatment effect existed, we undertook a complete case analysis. We included studies published in duplicate only once; we nominated a primary data source, although we reviewed secondary publications for additional data. We have noted the instances when we were unable to obtain the necessary information from the authors of potentially‐eligible trials in time for the update in Characteristics of studies awaiting classification (Mastrangelo 2010; Mayer 2004).
Assessment of heterogeneity
Where there was more than one trial comparing similar devices and using the same outcome measure (though possibly differing lengths of follow‐up), statistical heterogeneity was assessed using I2 (Higgins 2003) and tested for using Chi2 (with P < 0.10 being regarded as statistically significant). In the event we undertook a meta‐analysis, we assumed that the RR remained constant for different lengths of follow‐up.
Assessment of reporting biases
We assessed publication bias by checking trials registries and contacting the authors of identified studies to ask if they had other publications or were aware of any other unpublished studies we had missed.
Data synthesis
While we planned to pool trials with similar participants, comparisons and outcomes using the statistical measures described above, the results of the trials were reported narratively because pooling was inappropriate.
Subgroup analysis and investigation of heterogeneity
We were unable to carry out any subgroup analyses due to the paucity of data and the fact that we had not pre‐specified any effect modifiers which we planned to investigate.
Sensitivity analysis
Due to clinical heterogeneity observed among the studies, it was decided that no studies would be pooled therefore there was no need for a sensitivity analysis.
GRADE and 'Summary of findings' tables
We created seven ‘Summary of findings’ tables for different comparisons of support surfaces using healing outcomes as described by study authors. For other comparisons, we presented GRADE assessment without a 'Summary of findings' table. We used the five GRADE considerations (study limitations, consistency of effect, imprecision, indirectness and publication bias) to assess the quality of evidence as it relates to the studies which contributed data for the prespecified outcomes. We used methods and recommendations described in Section 8.5 and Chapter 12 of the Cochrane Handbook for Systematic Reviews of Interventions using GRADEpro GDT software.
The GRADE levels of evidence include (Schünemann 2011):
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high quality: further research is very unlikely to change our confidence in the estimate of effect.
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moderate quality: further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
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low quality: further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
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very low quality: we are very uncertain about the estimate.
When evaluating the 'Risk of bias' domain, we downgraded the GRADE assessment when we classified a study as being at high risk of bias for one or more domains. We downgraded the GRADE assessment when the 'Risk of bias' assessment for blinding was high. We did not downgrade for unclear 'Risk of bias' assessments in other domains. We also followed GRADE guidance and downgraded twice for imprecision when there were very few events and CIs around effects included both appreciable benefit and appreciable harm.
Results
Description of studies
The results of the searches are shown in a PRISMA diagram (Figure 1).
Study flow diagram.
Nineteen eligible RCTs were identified and included. Fourteen of these involved only those with pressure ulcers, and assessed the treatment efficacy of pressure‐relieving support surfaces (Allman 1987; Branom 2001; Caley 1994 [pers comm]; Clark 1998; Day 1993; Devine 1995; Evans 2000; Ferrell 1993; Groen 1999; Mulder 1994; Munro 1989; Russell 2000; Russell 2003; Strauss 1991). A further four trials evaluated surface effects for both prevention and treatment of pressure ulcers in the same trial (Ewing 1964; Keogh 2001; Nixon 2006a; Osterbrink 2005). For this version of the review, one study has been added (Cassino 2013).
The studies included a variety of participants and settings, for example, those in nursing homes and care of the elderly, medical or surgical wards. Most of the included trials were small, and, although nine reported an a priori sample size calculation, 15 of the 19 trials involved 100, or fewer, people. The larger trials (over 100 participants) were: Groen 1999 (120 participants); Russell 2000 (141 participants); Russell 2003 (158 patients); and Nixon 2006a (1971 participants).
Outcomes were measured in various ways and there was little standardisation across studies. Outcome measures included: proportion of pressure ulcers healed; time to healing; rate of healing; size of wound area healed (often not reported clearly); number of pressure ulcers healed; number of participants with healed pressure ulcers and the direction of the effect measured (that is, specifying an increase or decrease in epithelialisation). Measuring the size of wounds was done in a variety of ways including the use of mathematical formulae and computerised photoplanimetry. Some studies presented an absolute change in size by deducting the final size of the wound from the initial size, and some presented the change in size as a percentage change. Some studies used pre‐ and post‐treatment photographs of pressure ulcers to assess whether there had been any improvement in healing. Some studies reported secondary outcomes, such as healthcare resource utilisation or interface pressure, comprehensively, while the healing outcomes were summarised in a form that meant the data could not be entered into RevMan and recalculated (Caley 1994 [pers comm]; Cassino 2013; Munro 1989; Strauss 1991).
Two trials evaluated the use of a cushion as a pressure‐relieving device; Clark 1998 compared a dry flotation cushion with an alternating‐pressure (AP) cushion, and Osterbrink 2005 evaluated cushions as part of the REPOSE system. One trial assessed the use of sheepskins (Ewing 1964), and the remaining studies evaluated different mattresses, mattress overlays and beds.
Excluded studies
Sixteen studies were excluded (of which three were newly identified for this update), mainly because they did not report healing data, or were not RCTs (Bennett 1998; De Roche 2004; Finnegan 2008; Gardner 2008; Hardin 2000; Lazzara 1991; Malbrain 2010; Manzano 2013; Marchand 1993; McGinnis 2017; Meyers 2008; Prebio 2005; Rosenthal 1996; Rosenthal 2003; Stoneberg 1986; Timmons 2008) (see Characteristics of excluded studies).
Ongoing studies
We identified the published protocol for one large ongoing trial in this update (Brown 2016).
Studies awaiting classification
We identified five studies (three in this update), which are awaiting classification for various reasons (Mastrangelo 2010; Mayer 2004; Ozyurek 2015; Park 2017; Sauvage 2017).
Risk of bias in included studies
The methodological quality of the trials was generally poor. Details of the risk of bias of each individual study are included in Characteristics of included studies and summarised in Figure 2 and Figure 3.
'Risk of bias' graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.
'Risk of bias' summary: review authors' judgements about each risk of bias item for each included study.
Allocation
Adequate sequence generation using a random component was evident in 6/19 (32%) of the trials (Allman 1987; Cassino 2013; Devine 1995; Nixon 2006a; Russell 2003; Strauss 1991). Methods of randomisation used included random‐number tables, automated phone systems and computerised random‐number generators. In 12/19 (63%) of the studies, the method of randomisation was unclear and in one it was considered to have a high risk of bias Branom 2001).
Adequate allocation concealment was evident in 10/19 (53%) of the trials (Allman 1987; Cassino 2013; Clark 1998; Devine 1995; Evans 2000; Ferrell 1993; Groen 1999; Keogh 2001; Nixon 2006a; Russell 2003). Adequate allocation concealment can be defined as the use of central allocation or the use of sequentially‐numbered, opaque, sealed envelopes. The method of allocation concealment was unclear in the remainder of the trials.
Blinding
Unfortunately blinded outcome assessment is rarely used in wound care studies, and this was certainly the case in these evaluations of pressure‐relieving surfaces. Furthermore, it can be difficult or impossible to disguise from a patient, or outcome assessor, the surface that a participant is on. Nevertheless, some studies minimise bias in outcome assessment by having a second assessor and presenting inter‐rater reliability data, or by presenting photographic evidence of pressure area status, which can then be assessed by an assessor blinded to treatment. We could be confident that some form of blinded outcome assessment had been used in only 4/19 (21%) of the trials included in this review (Allman 1987; Evans 2000; Russell 2000; Strauss 1991).
Incomplete outcome data
Assessment of whether incomplete outcome data had been addressed adequately in each study involved examining whether the reasons for attrition or exclusion were reported, whether there was re‐inclusion of participants, and whether the completeness of data for each main outcome was described. Of the studies reviewed, 7/19 (37%) addressed incomplete outcome data adequately (Allman 1987;Clark 1998;Devine 1995;Evans 2000;Mulder 1994;Nixon 2006aRussell 2000), while two studies (Cassino 2013; Keogh 2001) were at high risk of bias; it was unclear, or unstated, whether they had been addressed adequately in the remaining 10 studies (Branom 2001; Caley 1994 [pers comm]; Day 1993; Ewing 1964; Ferrell 1993; Groen 1999; Munro 1989; Osterbrink 2005; Russell 2003; Strauss 1991). An intention‐to‐treat (ITT) analysis was performed in 6/19 (32%) of the studies (Allman 1987; Ferrell 1993; Mulder 1994; Nixon 2006a; Osterbrink 2005; Strauss 1991). Nine of the remaining studies did not perform this analysis, and it was unclear whether such analyses took place for four studies (Caley 1994 [pers comm]; Evans 2000; Ewing 1964; Munro 1989).
Selective reporting
For a study to have demonstrated it was free of selective outcome reporting, there would need to have been access to a study protocol with all pre‐specified outcomes stated, or, if the study protocol was not available, the report clearly included all expected outcomes (including pre‐specified outcomes). Thirteen (68%) of the studies were free of selective outcome reporting (Allman 1987;Caley 1994 [pers comm]Cassino 2013; Clark 1998;Devine 1995;Evans 2000;Ewing 1964;Ferrell 1993;Groen 1999; Nixon 2006a; Osterbrink 2005;Russell 2000;Russell 2003). Four studies were not free from selective outcome reporting as they did not report pre‐specified outcomes completely, or reported outcomes that were not pre‐specified (Day 1993; Keogh 2001; Mulder 1994; Munro 1989). For two studies, there was insufficient information to classify whether there was or was not selective outcome reporting (Branom 2001; Strauss 1991).
Other potential sources of bias
Other potential sources of bias were explored by assessing whether the timing of outcomes under investigation was similar in both groups, and whether the groups under investigation were similar at baseline for the most important prognostic indicators. Quality was not used to weight the studies in the analysis using any statistical technique, however, methodological quality is discussed in relation to the interpretation of the results. Methodological flaws for each study are presented in Characteristics of included studies (see also Figure 2; Figure 3).
Baseline comparability
In pressure ulcer treatment trials it is essential to ensure baseline comparability for initial area of ulcers. A change in wound area is often expressed as the percentage change, which, unlike the absolute change in area, takes into account the initial size of the wound. For two wounds healing at the same linear rate (as measured by diameter reduction), percentage area calculations will show a larger change for a small wound than a big wound. The converse is true when the absolute change in area is measured, since, for any unit reduction in wound radius, a bigger area reduction will occur for a large wound. This has important consequences for the validity of trial results where there is poor comparability in initial wound size at baseline between the treatment groups. For large trials, randomised allocation should ensure that the mean wound size and variance in each group is similar, however, in small trials, random allocation is unlikely to result in an even distribution of wound sizes. In a trial where there is poor comparability between groups for wound size at baseline, and the outcome is based on the change in area, the result can only be considered valid if it is obtained either: against the anticipated direction of the bias for wound size; or where percentage area change and absolute area change are in the same direction. If baseline data are not given, then it is not possible to determine the direction of bias and the validity of the result cannot be determined.
The risk of bias assessed in each study regarding baseline comparability refers to important prognostic factors such as age, sex, continence, reasons for immobility etc. These results are presented in Figure 3. In addition to this, Cochrane review authors have calculated the number of studies that presented data for baseline pressure ulcer area and the number of studies that reported comparability of pressure ulcers between participant groups at the start of the study. This review included 19 trials of beds, mattresses and cushions for treating pressure ulcers, and only nine of these presented data for baseline ulcer area (Caley 1994 [pers comm]; Cassino 2013; Clark 1998; Evans 2000; Ferrell 1993; Groen 1999; Nixon 2006a; Russell 2000; Russell 2003). The remaining 10 studies did not present baseline ulcer area (Allman 1987; Branom 2001; Day 1993; Devine 1995; Ewing 1964; Keogh 2001; Mulder 1994; Munro 1989; Osterbrink 2005; Strauss 1991). Five trials did not report comparability of pressure ulcer size or grade at baseline (Branom 2001; Cassino 2013; Ewing 1964; Mulder 1994; Strauss 1991), and one trial reported more severe ulcers in the air‐suspension group (Day 1993). The remaining 13 studies reported comparability of pressure ulcer size and/or grade at baseline (Allman 1987; Caley 1994 [pers comm]; Clark 1998; Devine 1995; Evans 2000; Ferrell 1993; Groen 1999; Keogh 2001; Munro 1989; Nixon 2006a; Osterbrink 2005; Russell 2000; Russell 2003). Fourteen of the 19 studies (74%) reported that participants were comparable at baseline regarding other prognostic factors e.g. age, sex, continence, reasons for immobility etc (Branom 2001; Caley 1994 [pers comm]; Cassino 2013; Clark 1998; Day 1993; Devine 1995; Evans 2000; Ferrell 1993; Groen 1999; Nixon 2006a; Osterbrink 2005; Russell 2000; Russell 2003; Strauss 1991). Of the remaining five studies, three had insufficient information (Ewing 1964; Mulder 1994; Munro 1989) and two did not have comparable groups (Allman 1987; Keogh 2001) (Figure 3).
Timing of outcome assessment
Overall, the included studies followed up participants for varying lengths of time, from four days to 18 months. Sixteen (84%) of the studies reported similar timing of outcomes in both groups (Allman 1987; Branom 2001; Caley 1994 [pers comm]; Cassino 2013; Clark 1998; Day 1993; Devine 1995; Evans 2000; Ferrell 1993; Groen 1999; Mulder 1994; Munro 1989; Nixon 2006a; Osterbrink 2005; Russell 2000; Russell 2003).
Effects of interventions
See: Summary of findings for the main comparison Profiling bed with foam mattress compared with hospital bed with foam mattress; Summary of findings 2 Water mattress overlay compared with low‐tech mattress; Summary of findings 3 Low‐air‐loss bed compared with low‐tech mattress overlay; Summary of findings 4 Alternating pressure mattresses; Summary of findings 5 Alternating‐pressure mattress compared with alternating‐pressure mattress overlay; Summary of findings 6 Alternating‐pressure mattress compared with air‐filled devices; Summary of findings 7 Alternating‐pressure cushion compared with dry flotation cushion
Low‐tech constant pressure support surfaces
This section considers comparisons of low specification (low‐tech), constant low‐pressure (CLP) supports which are usually not powered. The following interventions are classified as continuous low‐pressure, low‐technology supports (CLP): static air‐filled supports; water‐filled supports; contoured or textured foam supports; gel‐filled supports; sheepskins; bead‐filled supports; silicone‐filled supports.
Comparison 1: Profiling bed with foam mattress versus hospital bed with foam mattress (1 study with 100 participants including 14 participants with pressure ulcers)
Outcome: Proportion of healed Grade 1 ulcers.
Keogh 2001 compared a bed that enabled individual profiling (Contour 880) and a foam mattress (Pentaflex) with a flat‐based hospital standard bed and a pressure‐relieving mattress. Both groups also had a pressure‐reducing foam mattress or cushion. Study participants , were expected to stay in bed for at least 12 hours a day, and had a Waterlow score of 15 to 25 (high risk to very high risk) on initial assessment. Fourteen of the 100 randomised participants from both medical and surgical hospital wards had existing pressure ulcers at the start of the study and these participants were not evenly distributed between treatment groups. The study authors reported that healing occurred in all four of the experimental group participants, and in two of the 10 control group participants. Only 70 of the 100 participants were included in the analyses. No analyses were performed by the study authors to examine the statistical significance of these findings. It is very uncertain whether profiling beds improve the proportion of pressure ulcers which heal because the certainty of the evidence is very low (risk ratio (RR) 3.96, 95% confidence interval (CI) 1.28 to 12.24; Analysis 1.1) (downgraded twice due to risk of bias, twice due to imprecision and once due to imprecision) (summary of findings Table for the main comparison).
Comparison 2: Polyester overlays versus gel overlays (1 study with 72 participants)
Outcome: Pressure ulcer healing
Cassino 2013 investigated wound healing in 72 long‐term care residents by randomising participants to either a 3D polyester overlay (Aiartex) or a gel polyurethane overlay (Akton). The primary outcome measure, pressure ulcer healing, was reported as unchanged/worsened, unreliable, improved or resolved. Results were presented per participant rather than per wound with no raw extractable data available for further analysis. Other secondary outcomes included participant comfort, formation of new ulcers and ease of nursing assistance. We were unable to carry out further analysis.
Comparison 3: Non‐powered mattress versus low‐air‐loss mattress (1 study with 20 participants)
Outcome: Pressure ulcer healing
Branom 2001 randomised 20 people from long‐term and subacute care centres to either a PressureGuard non‐powered mattress or a low‐air‐loss mattress (LAL) (each facility enrolled in the study used the brand most familiar to them) and two different LAL mattresses were used in this study. Participants were bedridden and had Grade 3 or worse pressure ulcers on the trunk or pelvis. There were insufficient data (no variance data reported) available from the study to calculate the difference in mean rates of pressure ulcer healing between the two interventions and it was not clear how many ulcers were healed. The study authors reported that the rate of wound healing at the end of the study for those on the PressureGuard mattress was 9% compared with 5% for those on the LAL mattress. We were unable to carry out further analysis. It is uncertain whether the use of a non‐powered mattress improves the proportion of pressure ulcers which heal compared with using low‐air loss mattresses because the certainty of the evidence is low. The evidence was downgraded due to risk of bias and imprecision.
Comparison 4: Water filled supports versus foam replacement mattress (1 study with 120 participants)
Outcome: Pressure ulcer healing
Groen 1999 conducted a trial of 120 nursing‐home residents, 60 years of age and above, with Grade 3‐4 ulcers. The trial investigated the effect of a foam replacement mattress compared with a Secutex water mattress overlay on the proportion of participants with healed pressure ulcers at the four‐week follow‐up. It is uncertain whether water filled supports improves the proportion of pressure ulcers which heal because the certainty of the evidence is low (RR 0.93, 95% CI 0.63 to 1.37) (Analysis 2.1), (downgraded due to risk of bias and imprecision) (summary of findings Table 2).
Comparison 5: Standard hospital mattress with sheepskin overlay versus standard hospital mattress (1 study with 36 participants)
Outcome: Pressure ulcer healing
One small trial at high risk of bias, involving 36 participants in an elderly care setting, compared standard hospital mattresses with, and without, sheepskin overlays (Ewing 1964). There were 8 events in the control group compared with none in the intervention group (RR 0.06, 95% CI 0.00 to 0.95). The reported results should be regarded with caution due the age of the study, insufficient data and the poor definitions used to classify pressure ulcers. It should also be noted that since the publication of this study in the 1960s, the hospital "standard" mattress has changed. The certainty of the evidence is very low (downgraded once for risk of bias and twice for imprecision).
High‐tech pressure supports
High‐tech support surfaces include:
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Alternating‐pressure (AP) mattresses/overlays: air‐filled sacs that inflate and deflate sequentially to relieve pressure at different anatomical sites for short periods; these may incorporate a pressure sensor.
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Air‐fluidised beds: warmed air circulates through fine ceramic beads covered by a permeable sheet; allowing support over a larger contact area (CLP).
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Low‐air‐loss beds: a series of air sacs through which warmed air passes (CLP) supports the person.
Low‐air‐loss (LAL)
Comparison 1: Low‐air‐loss beds versus low tech mattress overlays (3 studies with 210 participants) *No pooling was undertaken due to the different way in which outcomes were measured.
Outcome: Pressure ulcers completely healed
The study by Ferrell 1993 compared a LAL bed (KINAIR) with a foam overlay placed on top of a standard mattress in a group of 84 nursing‐home residents. The trial reported on change in pressure ulcer surface area in participants randomised to the LAL bed compared with participants on the foam overlay (reported P = 0.0002), and change in surface area for this group (reported P = 0.004) was reported. However no further analyses were conducted. From analyses performed for the purpose of this review, however, it is uncertain whether LAL beds reduce pressure ulcer size because there is no clear difference between trial arms. The certainty of the evidence is low (RR 1.30, 95% CI 0.87 to 1.96), downgraded due to risk of bias and imprecision (Analysis 3.1) summary of findings Table 3.
The hospital‐based study by Day 1993 examined the change in mean ulcer size in 77 participants allocated to either an air suspension bed (Therapulse) or a foam mattress overlay (Geomatt). It included participants with pressure ulcers Grade 2 to 4, whose activity was limited to a chair or bed during hospitalisation. Analysis of covariance (to remove possible bias from the difference in the initial ulcer size between the two groups, which were significantly different at baseline) to assess the difference in the healing of pressure ulcers in the two groups was done (reported P > 0.05). There were insufficient data to carry out further analysis. It is uncertain whether air suspension beds improve pressure ulcer healing compared with low tech mattress overlays because the certainty of the evidence is low. The evidence was downgraded due to risk of bias, indirectness and imprecision.
The study by Mulder 1994 examined pressure ulcer healing using pressure ulcer volume and surface area in 49 nursing‐home residents from 25 nursing homes. Participants were randomised to either an air suspension bed (Therapulse), or a convoluted foam mattress overlay (Geomatt), and all participants were turned every two hours. Change in pressure ulcer size (initial entry area minus exit area) in participants randomised to the LAL bed was reported (reported P = 0.042) by the study authors however there were insufficient data (no variance data) available to calculate the mean difference between the two interventions. We assessed this as very low evidence (downgraded due to risk of bias, indirectness and imprecision).
Comparison 2: Different low‐air‐loss surfaces (1 study with 93 participants)
Outcome: Changes in pressure ulcer size
Only one trial compared different types of LAL support surfaces (Caley 1994 [pers comm]), i.e. an LAL bed (Monarch) and an LAL overlay (SPR Plus), in 93 hospital patients. This study examined changes in pressure ulcer surface area, healing progress over time, and the relative costs of each device. The study reported on changes in surface area (reported P =.060), and average perimeter of the pressure ulcers (reported P = 0.171). The median changes in pressure ulcer surface area using overlay therapy and bed therapy were 3.9 cm2 and 1.9 cm2 respectively, and the mean changes in pressure ulcer surface area were 10.2 cm2 and 3.8 cm2 respectively. There were insufficient data available from the study to carry out further analysis. It is very uncertain whether the use of an LAL bed results in a change in pressure ulcer size compared with the use of an LAL overlay because the certainty of the evidence is very low. The evidence was downgraded due to risk of bias and imprecision.
Alternating‐pressure (AP) support surfaces
A variety of alternating‐pressure (AP) supports (mattresses and overlays) is used in hospitals and in the community and these are commonly grouped as ‘high‐tech’ devices. Depth of air cells and mechanical robustness can vary between devices and these factors may be important in determining effectiveness. It is worth emphasising that most of the trials of AP supports did not describe the equipment being evaluated adequately, and did not specify the size of the air cells.
Comparison 1: Different AP mattress (2 studies with182 participants) *no pooling was undertaken due to the different way in which outcomes were measured.
Outcome: Pressure ulcers completely healed and decrease in pressure ulcer size
Devine 1995 reported a comparison of the Nimbus I DFS (composed of rows of figure‐of‐eight‐shaped cells) and the Pegasus Airwave for the treatment of existing pressure ulcers in 41 hospital patients. Participants had pressure ulcers that were Grade 2 and above. Specifically, this study looked at the rate of complete healing/reduction in pressure ulcer size at four weeks, participant comfort and the median rate of reduction in pressure ulcer area (cm2/day). It is uncertain which intervention under investigation is better at improving the proportion of pressure ulcers which healed as the certainty of the evidence is low (RR 0.57, 95% CI 0.26 to 1.27) (Analysis 4.1), as is the evidence pertaining to the intervention effect on reducing pressure ulcer size (RR 0.58, CI 95% 0.21 to 1.65) (Analysis 4.2). Low‐certainty evidence (downgraded due to risk of bias and imprecision) (summary of findings Table 4).
A larger, more recent trial, of 141 geriatric patients with pressure ulcers Grade 2 and above (Russell 2000), also found that there is no clear difference in pressure ulcer healing and improvement between two newer AP devices, namely the Nimbus 3 (combined with four‐hourly turning and use of an Aura cushion) and the Pegasus Cairwave therapy system (combined with eight‐hourly turning and use of a Proactive 2 Seating cushion) (RR 0.99, CI 95% 0.90 to 1.09) (Analysis 4.3). The certainty of evidence was rated low, downgraded due to risk of bias and imprecision (summary of findings Table 4).
Comparison 2: AP mattress versus AP mattress overlay (3 studies with 2161 participants) * pooled analysis was not possible due to differences in the devices evaluated, insufficient raw data to enter into RevMan for analysis, the co‐interventions used, and different techniques for measuring outcomes.
Outcomes: Pressure ulcer healing and pressure ulcer improvement
A study by Evans 2000, conducted in hospital and nursing home settings, compared an AP mattress replacement system (Huntleigh Nimbus 3) with either an AP mattress overlay (AlphaXcell/Quattro), or another AP mattress replacement system (Pegasus Biwave/Pegasus Airwave/AlphaXcell/Pegasus Cairwave). Thirty‐two participants were recruited; 20 from a nursing home (Huntleigh Nimbus 3, n = 10; AlphaXcell, n = 9; Quattro, n = 1), and 12 from a hospital (Huntleigh Nimbus 3, n = 7; Pegasus Biwave, n = 1; Pegasus Airwave, n = 1; AlphaXcell, n = 1; Pegasus Cairwave, n = 2). This study aimed to investigate the change in wound surface area as well as participant comfort. The study author reported no differences between the hospital‐based group and the nursing home group for the outcomes under investigation. There were insufficient data available in the study report to calculate the mean difference between the two interventions. It is uncertain whether the use of an AP mattress improves the healing of pressure ulcers compared with the use of an AP mattress overlay because the certainty of the evidence is low, downgraded due to risk of bias and imprecision.
The large Russell 2003 trial (158 hospital‐based patients) also compared an AP mattress (Nimbus 3) with a static fluid overlay mattress (RIK ® static). Patients with pressure ulcers of all grades were included. It is uncertain which intervention under investigation is better at improving the proportion of pressure ulcers which healed as the certainty of the evidence is low (RR 0.97, 95% CI 0.80 to 1.17) (Analysis 5.1). However, in this trial the co‐intervention of re‐positioning frequency was not standardised, and participants could request additional turning. It is, therefore, difficult to discern whether the lack of treatment effect was due to the non‐effect of the experimental device or the effect of the differential co‐intervention, or both. The evidence was downgraded due to risk of bias and imprecision (summary of findings Table 5).
Another study evaluated the differences between an AP overlay and an AP mattress on pressure ulcer development and healing (as measured by complete epithelialisation and time to healing) in a hospital setting with 1971 participants with Grade 2 or above pressure ulcers (Nixon 2006a). This was a large study with over 11 different sites and was of high‐methodological quality. It was reported that of the 113 participants with existing pressure ulcers at randomisation, 20/59 in the overlay group and 19/54 in the mattress group, had complete pressure ulcer healing by the end of the study. The use of an AP overlay may lead to no clear difference in pressure ulcer healing compared with the use of an AP mattress (RR 0.96, 95% CI 0.58 to 1.60) (Analysis 5.2). Low‐certainty evidence downgraded due to risk of bias and imprecision (summary of findings Table 5).
Comparison 3: AP mattresses versus air‐filled devices (1 study with 50 participants)
Outcome: Proportion of participants with pressure ulcers healed
One study investigated the healing success of existing pressure ulcers (at least Grade 2) in a group of 50 patients from one hospital (care of the elderly, neurological or surgical wards) and eight nursing homes (Osterbrink 2005). These participants were randomised to either the air‐filled device (REPOSE system) or to the AP device (either small‐cell or large‐cell) on which they were being nursed at the time of recruitment. The air‐filled device consisted of a range of air‐filled products, including a mattress overlay, foot protectors and a wedge pillow. The small‐cell AP mattresses were grouped with the large‐cell AP mattresses during the calculation of the effect size and were treated as the control group. It is uncertain which intervention under investigation is better at improving the proportion of pressure ulcers which healed as the certainty of the evidence is low (RR 5.50, 95% CI 0.73 to 41.44) (Analysis 6.1). The evidence was downgraded due to risk of bias and imprecision (summary of findings Table 6).
Comparison 4: AP cushion versus dry flotation cushion (1 study with 25 participants)
Outcome: Pressure ulcers completely healed
One study involving 25 participants from hospitals and nursing homes with pressure ulcers Grade 2 and above (Clark 1998), found no difference between a dry flotation cushion (ROHO Quadtro) and an alternating‐pressure cushion (Pegasus) in the number of ulcers completely healed. These participants had pressure ulcers on the sacrum or ischial tuberosities with a surface area of between 2 cm2 and 15 cm2. The authors of the study reported that the mean reduction in pressure ulcer area (cm2/day) in the 14 participants assigned to the AP cushion was 0.13, and 0.27 for the 11 participants assigned to the dry flotation cushion. The reduction in volume of pressure ulcers (cm3/day) was also reported for the cohort as being 0.56, and 0.49 for the AP cushion and dry flotation cushion respectively. The authors did not state whether either set of results were statistically significant. Overall, three pressure ulcers in the AP cushion group, and five in the dry flotation group, healed completely, i.e. had restoration of complete epithelial cover. However, it is uncertain which intervention under investigation is better at improving the proportion of pressure ulcers which healed or the size of pressure ulcers as the certainty of the evidence is low (RR 0.47, 95% CI 0.14 to 1.56) (Analysis 7.1). The evidence was downgraded due to risk of bias and imprecision (summary of findings Table 7).
Comparison 5: Air‐fluidised therapy versus with standard/conventional therapy (3 studies with 202 participants) *pooling of data was inappropriate due to the different methods of outcome measurement and incomplete reporting of data (for example, no variance data).
Outcome: Change in pressure ulcer size
Allman 1987 included 65 surgical patients with pressure ulcers of all stages on the sacrum, buttocks, trochanters or back, with mobilisation limited to a bed or chair for at least one week and life expectancy of at least one week, and no skin graft or flap planned for the pressure ulcer within one week. Participants were randomised to either conventional treatment (including two‐hourly turns, heel and elbow protectors and AP mattress) or to the air‐fluidised therapy (CLINITRON). There was a high rate of dropouts in those allocated the AF intervention (32%), which was higher than in those allocated to conventional treatment (24%). Wound healing was defined as 'healed', 'much improved' or 'a little improved'. Median change in pressure ulcer surface area and improvement in the pressure ulcer healing was measured on the basis of assessment by photographs. There were insufficient data available from the study to calculate the difference in effects between the two interventions using RevMan. It is very uncertain whether air‐fluidised therapy leads to a change in pressure ulcer size compared with standard therapy because the certainty of the evidence is very low. The evidence was downgraded due to risk of bias and imprecision).
The air‐fluidised therapy was also investigated by Munro 1989 in a group of 40 male hospital patients with grade 2 or 3 pressure ulcers expected to say in hospital for at least 15 days. The air‐fluidised bed (Clinitron) was compared with standard hospital care, defined as positioning or massage as well as sheepskins or gel pads placed under the pressure ulcers. Change in mean pressure ulcer area, nursing time per shift, participant satisfaction and self‐perceived pain were investigated. Standard deviations were not given for mean changes in pressure ulcer area. However, the study authors presented results on the mean size of pressure ulcers in the air‐fluidised therapy group compared with pressure ulcer size in the standard care group (reported P =0.05). The only raw data presented in the study were the mean ulcer sizes for days one, two, eight and 15. There were insufficient variance data available from the study to calculate the mean difference between the two interventions. It is very uncertain whether air‐fluidised therapy leads to a difference in pressure ulcer size compared with standard therapy because the certainty of the evidence is very low. The evidence was downgraded due to imprecision.
Strauss 1991 examined pressure ulcer improvement in 97 participants retrospectively by means of photographs evaluated by blinded assessors who made a judgement on whether the ulcer was improved (progressed to a lower stage, smaller surface area, reduced inflammation or reduced eschar), unchanged, or worse, on the basis of descriptions in the medical records. The study was home‐based, and participants had at least one grade 3 or 4 pressure ulcer. Home air‐fluidised therapy (CLINITRON) was compared with conventional therapy (prescribed, patient‐specific devices including mattresses and pads). Study authors reported that a higher proportion of participants randomised to the air‐fluidised therapy had pressure ulcers classified as "improved". The reporting of results and tabular representation of the results was poor and it was not clear whether all those enrolled in the study were included in the analysis. In addition, there were insufficient data available from the study to calculate the mean difference between the two interventions. The certainty of the evidence is very low downgraded due to risk of bias and imprecision.
Discussion
Despite the frequency of pressure ulcer incidence and the myriad of types of support surfaces that have been evaluated, there is a paucity of good‐quality evidence to guide current clinical practice with respect to the most effective support surfaces for treating existing pressure ulcers.
Other shortcomings in this group of trials were the variety of outcome measures used, which prohibited the pooling of studies, even when similar interventions were evaluated. Subjective outcome assessments that relied on retrospective assessment of outcomes and judgements of "better, worse, unsure" are unreliable and of questionable validity when complete healing is the goal. There is a need for those involved in wound care research to set standards for outcome reporting. Furthermore, we were concerned, after critical appraisal of many of the studies, that important variables such as number of ulcers healed or mean change in size of ulcers were often inadequately reported. For example, failure to report both the numerator and denominator; only wound surface area rather than a more clinically significant volume measure; standard deviation alongside the mean; or selective reporting of significance tests for some outcomes (comfort, healthcare resource utilisation), but not for healing outcomes. Pressure ulcers of different stages were included in some studies, and it was not possible to separate out results that included grade 1 pressure ulcers from all other grades. In addition, the number of pressure ulcers healed was included in some studies as the outcome, while in others the number of participants with healed pressure ulcers was the outcome and unit of analysis. This complicated comparison of results across studies.
In conclusion, the quality of most of the evidence is poor and the results unclear. We are unable to provide decision makers and patients with a clear message regarding the relative effects of alternative support surfaces for the treatment of pressure ulcers.
Summary of main results
Nineteen randomised trials of support surfaces for pressure ulcer treatment were identified.
Five studies analysed 318 participants and compared low‐tech CLP support surfaces. It is uncertain whether there is a difference in ulcer healing between different low‐tech CLP support surfaces because the quality of evidence is low or very low. The evidence was downgraded for risk of bias and imprecision due to small sample sizes from single‐study outcome results, which we were unable to pool. Fourteen studies analysing 2923 participants compared different high‐tech support surfaces. It is uncertain whether there is a difference in ulcer healing.
In this updated version of the review, one study was added that examined a polyester overlay compared with a gel overlay among long‐term care patients. The included studies provided little valid or reliable evidence for any differential effects of alternative support surfaces in improving healing rates. The relevant studies, however, were small and with methodological limitations that need to be addressed before firm conclusions can be made. The lack of evaluations of seat cushions is surprising given their widespread use by wheelchair users and others. There is no conclusive evidence to suggest that alternating‐pressure devices, low‐air‐loss therapy or continuous low‐pressure supports are more effective than alternatives in the treatment of existing pressure ulcers.
Overall completeness and applicability of evidence
Most of the included trials were under‐powered and, therefore, bring the great risk of failing to detect that clinically significant differences are statistically significant. The evidence is generally applicable to hospital and community settings. In many studies, participants with existing pressure ulcers constituted a small subgroup of the larger trial population under investigation and, therefore, this subgroup was underpowered. In addition, the age of some trials (some being 20 years old), means that other technologies may have superseded those investigated.
Quality of the evidence
Thirty‐seven per cent of studies reported clear evidence of adequate random sequence generation and fifty‐three per cent reported clear evidence of adequate allocation concealment. This is a slight increase on the previous update in terms of the percentage of studies reporting these elements. Intention‐to‐treat analysis was reported as undertaken by only 37% of trials.
The confidence with which firm conclusions could be drawn from the studies and meta‐analyses performed was greatly tempered by: (a) the poor quality of many of the trials, including incomplete reporting of data; and (b) the heterogeneity of the sample populations, interventions, outcome measurements and study settings reported amongst the studies. Reporting of results was inadequate in some studies (for example, failure to report P values, numerators and denominators, and statistical information such as standard deviations), which hampered data pooling. The results were from single‐study outcomes with very small sample sizes. Of the studies included in the 'Summary of Findings' tables, the above methodological flaws significantly contributed to studies being graded as low‐ or very low‐certainty evidence.
Potential biases in the review process
The strengths of this review included the systematic searches that were conducted to identify all relevant trials. Nonetheless, it is accepted that no search strategy is infallible and, consequently, we may not have identified all unpublished eligible trials. This means that the effect of publication bias on this review should not be discounted.
Agreements and disagreements with other studies or reviews
We identified a systematic review that evaluated support surfaces for treating pressure ulcers (Reddy 2008). This reported on 12 randomised controlled trials (RCTs); the authors found no clear evidence to favour one support surface over another in the treatment of pressure ulcers. Readers are also referred to other Cochrane Reviews relating to the healing of pressure ulcers (Choo 2014; Dumville 2015a; Dumville 2015bLanger 2014; Moore 2016; Moore 2015b; Moore 2015c; Naing 2017; Norman 2016; Walker 2017; Westby 2017). These reviews also found the evidence regarding the relative effects of these treatments wanting due to the poor quality or small size of the available evidence (where trials existed).
Study flow diagram.
'Risk of bias' graph: review authors' judgements about each risk of bias item presented as percentages across all included studies.
'Risk of bias' summary: review authors' judgements about each risk of bias item for each included study.
Comparison 1 Low‐tech bed versus foam mattress (Hospital standard), Outcome 1 Pressure ulcer healing.
Comparison 2 Water filled support versus foam replacement mattress, Outcome 1 Pressure ulcer healing.
Comparison 3 Low‐air‐loss versus low‐tech overlay, Outcome 1 Pressure ulcers completely healed.
Comparison 4 Different alternating pressure mattresses, Outcome 1 Pressure ulcers completely healed.
Comparison 4 Different alternating pressure mattresses, Outcome 2 Decrease in pressure ulcer size.
Comparison 4 Different alternating pressure mattresses, Outcome 3 Pressure ulcers completely healed.
Comparison 5 Alternating‐pressure mattress versus alternating‐pressure mattress overlay, Outcome 1 Pressure ulcer improvement.
Comparison 5 Alternating‐pressure mattress versus alternating‐pressure mattress overlay, Outcome 2 Pressure ulcer healing.
Comparison 6 Alternating‐pressure mattress versus air‐filled devices, Outcome 1 Proportion of patients with healed pressure ulcer.
Comparison 7 Alternating‐pressure cushion versus dry flotation cushion, Outcome 1 Pressure ulcers completely healed.
| Profiling bed with foam mattress compared with hospital bed with foam mattress | ||||||
| Patient or population: patients from two surgical and two medical wards | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of Participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Foam mattress | Profiling bed | |||||
| Pressure ulcer healing | Study population | RR 3.96 | 70 | ⊕⊝⊝⊝ | ||
| 200 per 1000 | 792 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded twice for multiple high risks of bias, twice for imprecision (low numbers of participants resulting in wide fragile confidence intervals) and once for indirectness as only a minority of participants had pressure ulcers at enrolment | ||||||
| Water mattress overlay compared withlow‐tech mattress | ||||||
| Patient or population: nursing home patients, > 59 years old | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of Participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Foam replacement mattress | Water mattress support | |||||
| Pressure ulcer healing | Study population | RR 0.93 | 120 | ⊕⊕⊝⊝ | ||
| 483 per 1000 | 450 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded once for risks of bias including Incomplete outcome data and once for imprecision resulting in wide confidence intervals | ||||||
| Low‐air‐loss bed compared with low‐tech mattress overlay | ||||||
| Patient or population: elderly nursing home residents with multiple medical problems | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of Participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Low‐tech mattress overlay | Low‐air‐loss bed | |||||
| Pressure ulcers completely healed | Study population | RR 1.30 | 84 | ⊕⊕⊝⊝ | ||
| 463 per 1000 | 602 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded once for risks of bias including incomplete outcome data and once for imprecision resulting in wide confidence intervals | ||||||
| Alternating pressure mattresses | ||||||
| Patient or population: varied | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of Participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Control | Alternating pressure mattress | |||||
| Ulcers completely healed | Study population | RR 0.57 | 30 | ⊕⊕⊝⊝ | ||
| 625 per 1000 | 356 per 1000 | |||||
| Decrease in pressure ulcer size | Study population | RR 0.58 | 30 | ⊕⊕⊝⊝ | ||
| 429 per 1000 | 249 per 1000 | |||||
| Ulcers completely healed | Study population | RR 0.99 | 141 | ⊕⊕⊝⊝ | ||
| 929 per 1000 | 919 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded once for risk of bias including high rates of withdrawal and once for imprecision resulting in wide confidence intervals 3 Downgraded once for selection bias and once for imprecision resulting in wide confidence intervals which include the possibility of both benefit and harm. | ||||||
| Alternating‐pressure mattress compared with alternating‐pressure mattress overlay | ||||||
| Patient or population: varied | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of Participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Alternating‐pressure mattress overlay | Alternating‐pressure mattress | |||||
| Pressure ulcer improvement | Study population | RR 0.97 | 158 | ⊕⊕⊝⊝ | ||
| 747 per 1000 | 724 per 1000 | |||||
| Pressure ulcer healing | Study population | RR 0.96 | 113 | ⊕⊕⊝⊝ | ||
| 352 per 1000 | 338 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded once for risk of attrition bias and once for imprecision resulting in wide confidence intervals | ||||||
| Alternating‐pressure mattress compared with air‐filled devices | ||||||
| Patient or population: patients with pressure ulcers | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of Participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Air‐filled devices | Alternating‐pressure mattress | |||||
| Proportion of patients with healed pressure ulcer | Study population | RR 5.50 (0.73, 41.44) | 50 | ⊕⊕⊝⊝ | ||
| 38 per 1000 | 206 per 1000 | |||||
| Moderate | ||||||
| 39 per 1000 | 209 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded once for possible selection bias and attrition bias due to limited details provided and once due to imprecision resulting in wide confidence intervals | ||||||
| Alternating‐pressure cushion compared with dry flotation cushion | ||||||
| Patient or population: patients with pressure ulcers | ||||||
| Outcomes | Illustrative comparative risks* (95% CI) | Relative effect | No of Participants | Quality of the evidence | Comments | |
| Assumed risk | Corresponding risk | |||||
| Dry flotation cushion | Alternating‐pressure cushion | |||||
| Pressure ulcers completely healed | Study population | RR 0.47 | 25 | ⊕⊕⊝⊝ | ||
| 455 per 1000 | 214 per 1000 | |||||
| *The basis for the assumed risk (e.g. the median control group risk across studies) is provided in footnotes. The corresponding risk (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). | ||||||
| GRADE Working Group grades of evidence | ||||||
| 1 Downgraded once for risk of bias due to lack of an ITT analysis and once for imprecision resulting in wide confidence intervals | ||||||
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Pressure ulcer healing Show forest plot | 2 | Risk Ratio (M‐H, Fixed, 95% CI) | Subtotals only | |
| 1.1 Profiling bed | 1 | 14 | Risk Ratio (M‐H, Fixed, 95% CI) | 3.96 [1.28, 12.24] |
| 1.2 Sheepskin bed | 1 | 36 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.06 [0.00, 0.95] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Pressure ulcer healing Show forest plot | 1 | 120 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.93 [0.63, 1.37] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Pressure ulcers completely healed Show forest plot | 1 | 84 | Risk Ratio (M‐H, Fixed, 95% CI) | 1.30 [0.87, 1.96] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Pressure ulcers completely healed Show forest plot | 1 | 30 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.57 [0.26, 1.27] |
| 2 Decrease in pressure ulcer size Show forest plot | 1 | 30 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.58 [0.21, 1.65] |
| 3 Pressure ulcers completely healed Show forest plot | 1 | 141 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.99 [0.90, 1.09] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Pressure ulcer improvement Show forest plot | 1 | 158 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.97 [0.80, 1.17] |
| 2 Pressure ulcer healing Show forest plot | 1 | 113 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.96 [0.58, 1.60] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Proportion of patients with healed pressure ulcer Show forest plot | 1 | 50 | Risk Ratio (M‐H, Fixed, 95% CI) | 5.5 [0.73, 41.44] |
| Outcome or subgroup title | No. of studies | No. of participants | Statistical method | Effect size |
| 1 Pressure ulcers completely healed Show forest plot | 1 | 25 | Risk Ratio (M‐H, Fixed, 95% CI) | 0.47 [0.14, 1.56] |
