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Introduction to Therapeutic Support Surfaces


Therapeutic support surfaces are a vital component to appropriate skin care. However, there are hundreds of options available. How do we know which air bed meets the needs of our patients or loved ones? The answer isn’t entirely simple. It depends heavily on the patient, his or her skin integrity, nutritional status, weight, and care plan. This is by no means a complete inventory of considerations, but a good starting point. In this blog, we will try to condense the information into some basic guidelines.  

The most basic categories of support surfaces are Group I, Group II, and Group III. Group III, also known as air fluidized beds or "bead beds," are highly specialized so we won’t cover those here.  

A Group I support surface is a product designed to reduce the pressure interface and prevent/treat pressure injuries through Stage II. Group I products are primarily considered preventative, and in many cases required before prescribing a group II product. Products include: 

  • Alternating pressure overlay/pad 
  • Foam mattresses 
  • Gel overlay/pads 
  • Hybrid air/foam mattresses 

It is our educated opinion that the traditional AP overlay/pads that look like pool floats are ineffective pressure reduction surfaces that often create more issues than they prevent. We recommend moving to a more advanced foam mattress or gel pad.


Not all foam mattresses are rated as pressure reduction or pressure relief. Therefore, not all foam mattresses qualify as a group I surface. A quality pressure redistributing foam mattress typically has multiple zones (foam densities) to manage pressure across all zones of the body. These are amazing first line defense products. If your patient or loved one is at risk for skin issues start here. 

Gel Overlays are an alternate product to a Group I foam mattress. These are overlays that rest on top of your existing foam mattress. The embedded gel conforms to the patient’s body and reduces the pressure interface. If you don’t have a Group I foam mattress this is a less expensive alternative.  

Hybrid mattresses are a more advanced surface typically consisting of foam-filled air bladders controlled with a series of air valves. These units can be powered (attached to a control unit) or nonpowered. We recommend hybrid mattresses for patients with a history of wounds and patients with existing stage I or stage II wounds. 

Download Support Surface Guide

A Group II support surface is a product designed to provide full pressure relief and treat full thickness pressure ulcers, flaps, and grafts. These products are more advanced than Group I surfaces. Group II products have additional therapeutic value such as microclimate control, moisture dissipation, and higher comfort and pain management values. We recommend moving to a Group II surface when: 

  • The patient has poor skin integrity with a history of wounds 
  • Has a stage III or higher wound on the trunk of the body 
  • Needs pressure redistribution but exceeds the weight limit of a Group I surface 

There are several Group II support surfaces available in the market place. For this article we will focus on the most widely used products: 

  • Alternating pressure surfaces (AP) 
  • Low air loss surfaces (LAL) 
  • Alternating pressure with low air loss surfaces (ALAL) 
  • Rotational therapy surfaces 

Alternating pressure surfaces create two or three individual zones that alternate pressure leaving alternate air cells to float the patient while the other cells deflate creating a zero-pressure interface. In a two zone system every other air cell is a zone. In a three zone system every two air cells remain inflated while the third deflates. These zones cycle according to the control unit’s programming. This is a highly effective therapy for treating patients with complex skin issues. We often suggest our clients use these systems for up to stage III pressure injuries. 

A true low air loss system pushes air through small holes to help manage the microclimate and control moisture. Beware, there are several systems on the market that indicate that they are “low air loss” that will not serve to manage these conditions. True low air loss occurs with a high volume low pressure blower unit (typically over 1,000 liters per minute). Pump units usually provide 10-20 liters per minute with minimal air circulation. If you are looking for climate control, insist on a blower based control unit. Although most manufacturers will rate their LAL units for treatment of up to stage V pressure injuries, we suggest using them for up to stage III and only when climate and moisture are a concern. These units are commonly more expensive than the alternating pressure units. 

Alternating low air loss systems provide the best of both worlds. Full pressure relief coupled with moisture and climate control all neatly bundled in a smart box with a microprocessor for advanced customization. There are some amazing systems on the market right now with data to support the clinical claims. We suggest these units to our clients when they need a system to manage advanced skin issues including stage V pressure injuries, flaps, and grafts. Again, don’t be fooled. Not all ALAL systems are built the same. Several pump units are labeled as ALAL systems, but will not provide the same level of therapy as a blower based unit. If you are not sure ask the vendor. A pump system will typically have volumes under 100 liters per minute while the blower systems have 1,000 liters per minute and above. Blower systems are more expensive, but they are highly versatile allowing you to tailor the therapy to your patient’s needs. 

Rotational therapy surfaces are one of the most misused products in the market. We often receive calls for a rotational therapy mattress because the caregiver is under the impression that the rotational therapy replaces the need to turn the patient. THIS IS FALSE. None of the products listed are a substitution for turning the patient. Rotational therapy can help to reduce pressure interface. However, for patients prone to shear and friction, these systems will likely cause a pressure injury. We normally recommend rotational therapy for patients with pulmonary complications. The constant rotation will help reduce fluid from settling in the lungs.  

Please note that these reccomendations are based on our educated opinions. Listen to your clinicians. We are here to help, and happy to educate, but your wound care staff are the final authorities. 

We have a great “cheat sheet” available for download to help you decide which product is right for your patient needs. Check it out here. Please note that these guidelines are our recommendations, and they are not meant to override the recommendations of your treating physician or nurse. 

If you would like to learn more about Group III support surfaces (bead beds), Northwood Inc. has a great a great overview: 

Download Support Surface Guide

Posted by Chris Hunt at Jan 4, 2018 12:00:08 PM