6.3 Support Surface Types and Selection

6.3 Support Surface Types and Selection

Quick Answer: Use National Pressure Injury Advisory Panel (NPIAP) Support Surface Standards Initiative (S3I) language: reactive surfaces redistribute only when loaded; active surfaces are powered and can change load with or without applied load (alternating pressure). Choose overlay versus mattress replacement, then judge immersion and envelopment. Low air loss targets microclimate; air-fluidized beds are typically CMS Group 3. Heels still need floating. A surface never replaces turning. CMS Groups 1/2/3 are US reimbursement categories, not WOCNCB-owned rules.

A support surface is a mattress, overlay, integrated bed, or cushion designed for pressure redistribution and, on some products, microclimate or shear management. Selection is a clinical match: risk, existing injuries, body weight and shape, ability to reposition, pulmonary status, moisture, and care setting. Brand names are less testable than function. OpenExamPrep uses S3I and commonly used CMS group language so CWCN candidates can talk to vendors and case managers without treating those categories as board statutes.

Reactive versus active (S3I)

Reactive support surface: powered or non-powered; changes load distribution only in response to applied load. Foam, gel, static air, and many low-air-loss surfaces behave reactively: the body sinks in and the surface pushes back.

Active support surface: powered; can change load distribution with or without applied load. Classic example: alternating pressure that cyclically inflates and deflates cells so contact areas shift over time.

Exam trap: powered does not automatically mean active. A powered low-air-loss mattress can still be reactive if it only maintains a set inflation in response to the person's weight.

Overlay versus mattress replacement

An overlay sits on top of an existing mattress (foam overlay, static-air overlay, some powered overlays). A mattress replacement removes the standard mattress and substitutes a full therapeutic surface. Overlays can help at-risk people on a decent base mattress; they can also raise bed height (fall and rail issues) and they fail if the underlying mattress is already collapsed. Replacement is typical when the base mattress is poor, the person bottoms out, or Group 2/3 function is required. Integrated bed systems combine frame and surface; the surface may not work if removed.

Immersion, envelopment, and the bottoming-out check

Immersion is how deeply the body sinks into the surface (more contact area, lower peak pressure if the design is sound). Envelopment is how well the surface conforms around irregularities—heels, contracted limbs, postoperative hardware. A stiff foam that barely indents has poor immersion. A surface that lets the person sink to the bed frame has too much immersion and is bottoming out. You want enough sink and wrap to spread load without bony prominences hitting a hard underlayer.

Bottoming-out check (used in CMS Group 1/2 bedside language): place an outstretched hand palm up between the undersurface of the overlay or mattress and the bony prominence (coccyx or lateral trochanter). If you readily palpate bone, the surface has failed. Test supine with the head flat, supine with the head slightly elevated (no more than 30 degrees), and side-lying.

Low air loss, alternating pressure, and air-fluidized

Low air loss (LAL): a construction that uses airflow through or around cushions. Clinically it is used when microclimate (heat and moisture at the skin-surface interface) is a driver—diaphoresis, incontinence-associated dermatitis plus pressure risk, moist sacral skin. S3I reminds clinicians that low air loss is a design feature, not a guaranteed moisture-removal score; CWCN-style items still treat LAL as the surface family for microclimate plus redistribution.

Alternating pressure (AP): active cyclic unloading. Useful when the person cannot be turned as often as needed or has trunk/pelvis injuries that need periodic offload. Watch for a motion sensation that disturbs sleep, bottoming out between cells, and tubing kinks. AP is not a reason to stop turning.

Air-fluidized: silicone-coated beads blown into a fluid-like medium; very high immersion and envelopment. Typically the surface people mean by CMS Group 3. Useful for selected people with extensive posterior full-thickness ulcers. Limits: pulmonary toilet (a soft surface can make coughing less effective; dry airflow can thicken secretions), transfers and mobility (hard to mobilize), leaks, unit weight, and the need for a trained caregiver. Occlusive dressings may be needed so wound moisture is not dried out. CMS language also flags coexisting pulmonary disease as a reason an air-fluidized bed may not be reasonable.

CMS Group 1 / 2 / 3 as a US reimbursement classification

Teach these as commonly used CMS durable medical equipment categories in US practice, not as rules owned by WOCNCB. Local Coverage Determinations (for example L33830 Group 1, L33642 Group 2, L33692 Group 3) define Medicare medical necessity. Facilities may still choose a surface clinically before a billing group is assigned.

Group 2's comprehensive program is the clinical point: a powered mattress without turning, moisture control, and nutrition is not the coverage story and is not good prevention. Group 3 conservative care in CMS language includes frequent repositioning (often described as every 2 hours), a Group 2 surface, infection treatment, nutrition optimization, debridement as needed, and moist wound care.

Heels, turning, pulmonary status, and matching the person

Heels still need floating on specialty mattresses. The heel's small radius can peak-pressure even when the sacrum is well immersed. Pillow-float so the heel is in air and the Achilles is not jammed, or use a heel-specific device.

A surface does not replace turning. CMS conservative-treatment language for Group 3 still lists frequent repositioning. Charting low-air-loss mattress, therefore turns every 4 hours is not automatic physiology.

Match the surface to the person using this checklist:

• Risk and existing injuries — prevention versus large posterior ulcers
• Weight and body habitus — bariatric-rated surfaces; do not put an adult on a pediatric overlay
• Ability to reposition — active surfaces when independent movement is gone
• Pulmonary status — air-fluidized and some powered surfaces complicate coughing, mobility, and head-of-bed strategy
• Moisture — low air loss when microclimate dominates
• Care setting — home caregiver skill, electricity, floor load; air-fluidized units can exceed about 1,600 lb

Scenario: Group 1 failure

Mr. J had two Stage 2 sacral and ischial ulcers, a foam overlay (Group 1), and turns when we can. After 5 weeks the ulcers are larger and a new Stage 3 is on the trochanter. He bottoms out at the coccyx on a palm-up check. He is diaphoretic.

Clinical next step is a comprehensive program: actually turn, control moisture, involve nutrition, continue wound care, and step up to a Group 2 powered low-air-loss or alternating-pressure replacement—not another overlay on a failed foam. Float the heels. If he later has extensive Stage 3/4 after a documented month of conservative care including Group 2, air-fluidized (Group 3) may enter the conversation, provided pulmonary status and caregiver support allow it. CMS groups describe that reimbursement path; they do not replace bedside judgment about cough, transfers, or whether the person can still mobilize.