What are Support Surfaces?

The Complete Support Surface Guide

What is a pressure injury?

A pressure injury is localized damage to the skin and underlying soft tissue, typically located over a bony prominence or related to a medical condition or other medical device. The injury can present as intact skin or an open ulcer, though either may be painful for the patient. ​The pressure injury occurs as a result of intense and/or prolonged pressure, or pressure in combination with shear.

How do pressure injuries form?

Pressure injuries result from three main contributing factors: pressure, shear, and friction.

Pressure is the force exerted perpendicular to the skin surface. Pressure damages the skin and underlying tissues by distorting the tissue, compressing the small blood vessels, and ultimately hindering blood flow and nutrient supply.

Shear is the force exerted parallel to the tissue. The skin and subcutaneous tissue are distorted and pulled in opposite directions. Shear is a factor in situations such as when the head of the bed is elevated greater than 30 degrees, causing the patient to slide down, or when ‘dragging’ a patient as opposed to lifting while repositioning the patient in bed.

Friction is the result of one body part rubbing against another and/or the body sliding against clothing or bed linens. Friction can cause the epidermis (or top layer of skin) to separate from the dermis (or bottom layer of skin).

Friction, pressure, and shear together cause pressure injuries to develop faster.

Who is at risk of pressure injuries?

Clinicians and healthcare teams look to four risk factors that can increase the likelihood of a patient developing a pressure injury:

Immobility: Patients’ inability to move or change position is the biggest risk factor in developing a pressure injury due to prolonged and sustained pressure.

Lack of Sensory Perception: Patients’ inability to feel pain or discomfort — whether a result of spinal cord injuries, neurological disorders, or other conditions that result in a loss of sensation — can make affected patients more prone to pressure injuries.

Malnutrition/Poor Hydration: An unbalanced diet and/or improper hydration can lead to compromised skin integrity and tissue damage.

Medical Conditions Affecting Blood Flow: Conditions affecting blood flow can increase the risk of tissue damage, such as diabetes, vascular disease, and cardiac disease.

Clinicians will thoroughly evaluate these risk factors in an effort to reduce the patient’s risk of developing a hospital-acquired pressure injury (HAPI). This allows healthcare professionals the opportunity to provide their patients with the best care, while prioritizing pressure injury prevention. A support surface is a proven solution that can be used to prevent the development of HAPIs (Nursing 2020).

What are the most common signs of a pressure injury?

Identifying pressure injuries early is key to preventing serious injury to patients. Bone and muscle infections caused by pressure injuries can lead to sepsis and even death. Be on the lookout for the early warning signs of a pressure injury:

Changes in Skin Color or Texture

Discoloration is typically the first indication of a pressure injury.


The area may feel tender to the touch.


Swelling can be an early sign of infection.


Pus-like drainage from a pressure injury is a sign of infection and requires immediate medical attention.

Changes in Microclimate

The skin in the affected area may feel warmer or cooler to the touch.

Learn to avoid pressure injuries before they occur

What are the stages of a pressure injury?

There are four stages of pressure injury:

Stage 1

  • This skin will begin to show discoloration.
  • The area may appear red in lighter complexions and blue or purple in darker complexions.

Stage 2

  • Sometimes the skin may appear as a blister filled with fluid or a skin break, which will typically be tender and painful.
  • There is visible damage to the top layer of skin, which at this stage is still self-repairable.

Stage 3 (Reportable)

  • The wound extends to the hypodermis, or the fatty layer of skin.
  • Muscle, tendons and bone are not visible.

Stage 4 (Reportable)

This is when the wound extends through to the muscle, tendon, or bone, posing a risk of infection.

When a pressure injury cannot be classified between Stage 1 and Stage 4, it may fall into one of two additional categories:


  • The extent of the damage cannot be determined due to lack of visibility (e.g. from eschar — a collection of dry, dead tissue within a wound).

Deep Tissue

  • Results from intense and/or prolonged pressure and shear forces at the bone-muscle interface.
  • Pain and temperature change typically will appear first​.
  • Presents as intact or non-intact skin with a localized area of non-blanchable deep red, maroon, or purple discoloration, or a blood-filled blister​.

What is the most common cause of pressure injury?

While many factors can contribute to a patient affected by a pressure injury, the common denominator is impaired mobility. Whether under sedation, impacted by mental or physical impairment, or under restraint due to dementia, patients who are exposed to extended periods of limited mobility are prone to pressure injuries.

Experts suggest that patients at high risk of pressure injuries and patients with existing pressure injuries should be placed on support surfaces and not standard hospital mattresses (Nursing 2020).

How do support surfaces prevent pressure injury?

A support surface redistributes the pressure exerted on the skin and tissue that is in direct contact with the support surface. The term support surface refers to specialty beds, mattresses, and mattress overlays that:

  • Address skin and tissue injury, such as pressure, shear, friction, and microclimate management.
  • Redistribute pressure on skin, tissue, and bony prominences.
  • Are constructed of different materials or a combination of materials, such as foam products, air, gel, or liquid.

Studies have shown that the use of pressure redistribution support surfaces can lower the incidence of pressure ulcers by up to 60% (Nursing 2020).

Protect patients from pressure injury in the prone position

What is a support surface?

A support surface is a device designed to redistribute the pressure applied to the patient’s body.

Support surfaces are typically the first line of defense for pressure injury prevention. They protect the bony prominence areas of the body at risk for the development of pressure injuries in supine, prone, and side-lying positions. Support surfaces are one component of a pressure injury prevention care plan that helps to improve patient outcomes and patient satisfaction.

Pressure injuries are preventable and considered a “never event” by the Centers for Medicare and Medicaid Services (CMS). “Never events” are medical errors that should never occur, meaning they do not receive CMS reimbursement. These “never events” impact hospitals on both the financial and patient satisfaction level. In fact, pressure injuries affect over 2.5 million patients per year in the United States, and roughly 60,000 patients die as a direct result. Pressure injuries are the 2nd most common billing claim for hospitals and cost the U.S. Health System over $9 billion a year.

Support surfaces are specialized devices for pressure redistribution designed for management of tissue loads, microclimate, and/or other therapeutic functions. Types of support surfaces include but are not limited to any mattress, integrated bed system, mattress replacement, mattress overlay, seat cushion, or seat cushion overlay. These specialized medical devices are designed to relieve and/or redistribute pressure on the body, in order to prevent and treat pressure injuries (NPIAP S3I 2019).

The NPIAP S3I terms and definitions states that support surfaces may:

  • be powered (i.e. require electrical power to function) or non-powered;
  • be passively redistributing body weight (i.e. reactive pressure redistribution), or mechanically vary the pressure on the body to reduce the duration of pressure on any one point (i.e. active pressure redistribution);
  • be made of a range of materials including, but not limited to air cells, foam materials, fiber materials, gel materials, sheepskin for medical use, and water-bags;
  • be constructed of air-filled cells which have small holes on the surface through which air blows onto the skin (i.e. low-air-loss feature), or have fluid-like characteristics via forcing filtered air through ceramic beads (i.e. air-fluidized feature), or have neither of these features.

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Reactive vs. Active Support Surfaces

Support surfaces can be grouped into one of two categories: active and reactive.


An active support surface is a powered unit that can modify its load distribution with or without an applied load. The powered unit provides inflation and deflation to specific areas of the support surface to alter the pressure exerted on the body, relieving areas of high pressure.


A reactive support surface is either a powered or non-powered unit that changes its load-redistribution properties in response to an applied load (i.e. the patient’s body) by immersion (the body sinking into the support surface) and envelopment (the body conforming to the support surface). Essentially, the patient’s body applying pressure to the device is what allows a reactive surface to redistribute pressure.

What are the types of support surfaces used for pressure injury prevention?

Support surfaces range from low-tech foam mattresses to more complex equipment, such as powered and non-powered alternating pressure devices, or air-fluidized surfaces. Redistribution of pressure or load is based on the design and technology of the support surface.

Support surfaces come in several types: wheelchair and seat cushions, mattress overlays that are placed on top of existing mattresses, devices integrated into mattresses that sit on standard bed frames, and all-in-one solutions that replace standard beds.

Foam support surfaces

  • A pad made from a layer or layers of multi-density foam.
  • Foam degrades over time, reducing the amount of support offered.

Air- or gel-filled support surfaces

  • Redistribute pressure in response to a patient’s load via immersion and envelopment.
  • Requires a manual or automatic pump for inflation.
  • May or may not have holes to provide microclimate control.

Low air loss support surfaces

A pad composed of air-filled compartments like above, but a small amount of air leaks from the compartments over time and travels through a vapor-permeable channel in contact with the patient.

This airflow draws moisture and heat away from the patient and may aid in moderating the moisture level of the patient’s skin (International Review 2010).

Air-fluidized support surfaces

  • A pad filled with silica beads or other particulates which are fluidized by a continuous input of air.
  • Air escapes out the top and presses a contact layer into the skin, absorbing moisture on the skin.

A pressure redistribution surface

When selecting a support surface what factors should be taken into consideration?

When selecting a support surface, there are several factors to consider.

Patient Considerations

  • Weight and size of the patient — support surfaces have weight limits that should not be exceeded.
  • Bariatric models of support surfaces are available for obese patients (as is the case with the Waffle Overlay).
  • Patients may be too light for the support surface to properly redistribute pressure.
  • Surfaces can influence the skin’s microclimate. Foam surfaces tend to increase body temperature, while various static air support surfaces have venting holes to keep patients cool and dry (as is the case with the Waffle Overlay).

Ease of Use

  • How much training is required to use the support surface?
  • Does the support surface have a required setup or acclimation time before use?


  • Is it easy and simple to clean with standard hospital disinfectants?
  • Does the support surface require a specialized off-site cleaning service?

Caregiver Impact

  • Will caregivers need additional assistance while transferring the patient in and out of bed?
  • Can caregivers easily help a patient reposition in bed?

Know the Facts

There are many factors associated with the increased risk of developing pressure injuries. The WAFFLE Overlay is a pressure redistribution support surface designed to help you achieve better patient outcomes.

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When should a support surface be used?

Pressure injury risk assessment tools have evolved over the years as pressure injury prevention has become a priority in the healthcare community. The Braden Scale and the Norton Scale are two of the most widely used; however, the Braden Scale is most frequently used today by healthcare professionals.

The Braden Scale was developed in 1987 by Nancy Braden and Barbara Bergstrom to predict patients at risk for developing a hospital-/facility-acquired pressure injury. The Braden Scale evaluates six criteria, or sub scales, to determine overall risk for pressure injury development. Each of the categories are based on a scale of 1-4; 1 representing a patient at most risk of pressure injury development and 4 representing a patient at least risk of pressure injury development.

The six criteria for the Braden Scale skin assessment are as follows:

  • Sensory Perception
  • Moisture
  • Activity
  • Mobility
  • Nutrition
  • Friction
  • Shear

The scores are added up, and total scores are evaluated to determine a patient’s risk of developing pressure injuries.

15-16 = low risk, 13-14 = moderate risk, 12 or less = high risk.

Healthcare professionals can use a patient’s Braden Scale score in conjunction with clinical assessment to create individualized pressure injury prevention care plans that meet the needs of at-risk patients.

Clinically proven technology

How to measure the effectiveness of support surfaces?

Pressure redistribution support surfaces work by spreading pressure out equally across the surface, to reduce the pressure applied to all areas of the body. This redistribution reduces direct forces applied to bony areas of the body while also lowering the chance of shearing forces causing damage to the skin.

The pressure exerted between the patient and the support surface is measured in terms of interface pressure (IP). “Interface pressure is defined as the pressure exerted by the compression system over the surface of the skin,” (Kumar 2014). To measure interface pressure, clinicians can use pressure mapping to evaluate the effectiveness of the support surfaces they use.

What is pressure mapping?

Pressure mapping is a visual assessment tool that detects and depicts the variations of interference pressure across a patient’s body. The objective is to provide clinicians with quantifiable data to ensure optimal pressure redistribution when selecting support surfaces for pressure injury prevention.

“Patients with prolonged time lying on beds, gurneys, [and] operating room tables for prolonged interventional procedures are at increased risk for developing a pressure injury. As such, all surfaces in hospitals should be pressure mapped for comparison of surfaces to meet the patient’s specific needs and surface selection that provides the best redistribution properties.”13

-Olgen Teleten

The measured pressure from the mapping sensors is converted into millimeters of mercury readings aligned with a color spectrum display. The red tones indicate areas of high-interface pressure, whereas green and yellow tones represent areas of lower pressure, and blue tones depict the areas of the least amount of pressure.

Pressure mapping helps healthcare professionals understand how the support surface responds to and distributes pressure over peak pressure, or at-risk, areas of the body.

What is the purpose and patient benefit of pressure mapping support surfaces?

The exerted pressure, or applied load, will change when a patient changes positions on the support surface, such as turning and repositioning (side-lying), or when the head of the bed is elevated to 30 degrees or higher. For example, elevating a patient’s head of bed to 30 degrees can increase the pressure and shear applied to the patient’s sacrococcygeal region.

The benefit is that the pressure map provides the healthcare professional a visual representation of the changes in peak pressure while the patient transitions from supine position to one with a 30-degree-elevated head of bed (red tones may appear in the sacrococcygeal region). Healthcare professionals can use this information when selecting support surfaces to provide optimal pressure redistribution that is best suited to meet the needs of the patient (e.g. to maintain skin integrity and reduce the risk of pressure injury development).

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The Economic Impact of Pressure Injuries

Reducing pressure injuries among patients is to the benefit of patients and healthcare facilities everywhere. Each year, over 2.5 million people in the United States alone develop pressure ulcers (AHRQ, 2014). This has a rippling effect on the healthcare system as patients are affected by undue pain and risk of infection, while hospitals are tasked with providing additional health care services when already short-staffed. Roughly 60,000 patients die from pressure ulcers each year (AHRQ, 2014).

In addition, the rates of pressure injuries directly affect the revenue of hospitals, through treatment costs, readmission penalties, patient costs, and litigation. Last year, more than $10 billion was spent domestically treating patients with pressure injuries. The cost of care for a patient with a pressure injury can range from $20,900 up to $151,700, while over 17,000 pressure injury-related lawsuits are filed annually (AHRQ 2019). Nearly 80% of hospitals receive some form of CMS penalty as a result of HAPIs (Vitale 2021).

The National Quality Forum (NQF) maintains a list of “never events” — the kind of mistakes that should never happen in the field of medicine. Specifically, these events are categorized as being “unambiguous (clearly identifiable and measurable), serious (resulting in death or significant disability), and usually preventable” (AHRQ 2019).

Because “never events” are medical errors that should never occur, they do not receive CMS reimbursement. As of 2012, “Stage 3 or 4 pressure ulcers acquired after admission to a healthcare facility” are considered “never events” by the NQF.ß

Many states and private insurers have also adopted a policy of not reimbursing for care provided to treat “never events” (AHRQ, 2019).

Consider this example:

If the average 300-bed hospital has 100 Hospital Acquired Pressure Injuries per year, multiplied by the lowest cost of treatment at $20,900 per injury, the average hospital could be spending close to $2.1 million dollars per year treating pressure injuries. This cost of treatment increases when a patient is readmitted with a HAPI under the CMS penalty structure.

Early Intervention is the Key to Pressure Injury Prevention

In order to fully address the risk of HAPIs, hospitals are encouraged to develop and seek out novel preventive solutions to augment current treatment approaches. These proactive, preventative measures should go beyond just purchasing and installing a pressure redistribution support surface. Make sure to utilize an assessment tool like the Braden Scale to identify at-risk patients, incorporate support surfaces that complement each patient’s continuum of care, and use pressure mapping technology to ensure that every at-risk patient is proactively protected to maintain skin integrity.

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