How Foam Dressings Prevent and Treat Pressure Ulcers

Foam dressings are one of the most widely used wound care products for both preventing and treating pressure ulcers, and the evidence supporting their preventive role is considerably stronger than the evidence for their healing advantage over other modern dressings. A meta-analysis of nine randomized controlled trials involving nearly 4,000 patients found that sacral foam dressings cut pressure injury rates by roughly 63% compared with standard care alone. For treatment of existing ulcers, the picture is murkier: a Cochrane review concluded that the evidence comparing foam to other dressings for healing is of very low certainty. That gap between strong prevention data and weak treatment data shapes how clinicians actually use these dressings, and understanding it helps you make better decisions whether you are a caregiver, a patient, or a nurse choosing products for a wound care cart.

How Foam Dressings Protect Vulnerable Skin

A pressure ulcer forms when sustained force compresses soft tissue against bone, cutting off blood flow. The sacrum (lower back), heels, and the back of the head are the classic trouble spots because bone sits close to the skin surface. Foam dressings work against this in three overlapping ways: they redistribute mechanical load, they manage moisture at the skin surface, and they reduce friction and shear.

The redistribution effect is meaningful. By spreading force over a larger contact area, multilayer silicone foam dressings can reduce local tissue pressure by up to 30 to 40 percent and lower shear forces at the same time.¹ That does not replace turning and repositioning a patient, but it adds a meaningful safety margin, especially when a patient cannot be moved frequently, such as during surgery or mechanical ventilation.

Moisture control matters because skin that is too wet weakens and tears more easily under friction, while skin that is too dry cracks. Multilayer foam dressings with a breathable top film allow water vapor to escape while absorbing sweat and incontinence-related moisture. In a trial comparing multilayer and single-layer polyurethane foams on patients’ heels during surgery, the multilayer design actually lowered skin temperature by about 7°C and kept moisture stable, while the thinner foam raised temperature by about 3°C and increased moisture.² A Brazilian study of sacral dressings confirmed that microclimate humidity stayed stable through six days of continuous wear.³

The shear story is a bit more nuanced. Lab testing of several commercial foam dressings showed that the silicone adhesive layer inside the pad influences how much shear force reaches the skin. Dressings where silicone covered the full contact surface transmitted less shear than those with silicone only at the border.⁴ If you are comparing products, a full-contact silicone layer generally offers better shear protection than a border-only design.

Prevention at the Sacrum

The sacrum is the single most common site for hospital-acquired pressure injuries, and it is where the strongest foam dressing evidence exists. A systematic review and meta-analysis pooling nine randomized trials found that patients given a sacral foam dressing had a significantly lower rate of pressure injuries (about a third the risk of the standard-care group). The benefit held when researchers looked only at stage II and deeper injuries, and even blanching erythema, the earliest visible sign of damage, was less frequent.⁵

A separate feasibility trial in an Australian intensive care unit illustrated how dramatic the difference can be in practice: out of 67 patients randomized to a prophylactic dressing, only one developed a sacral pressure injury.⁶ That is a single trial with a small sample, so the absolute number should be taken with caution, but it aligns with the broader meta-analytic direction.

Prevention at the Heels and Other Sites

Heels are the second most vulnerable spot, and they present a different challenge: the skin is thinner, the bony prominence is sharper, and standard mattress-based pressure relief does not offload heels as effectively as it offloads the sacrum. A large trial (the Border II Trial) in critically ill patients found that no patients in the foam-dressing group developed heel pressure ulcers, compared with 14 patients in the control cohort who developed a combined total of 19 heel ulcers.⁷

Operating rooms are another high-risk environment because patients lie immobile for hours on hard surfaces. A trial comparing multilayer silicone foam with transparent polyurethane film on heels during elective surgery found the foam group had a relative risk of pressure injury of 0.57, meaning nearly half the risk.⁸ The foam group also stayed pressure-injury-free for longer on average, buying roughly 14 more hours of protection before any damage appeared.

Foam Dressings Under Medical Devices

A growing share of pressure injuries in hospitals is caused not by mattresses and chairs but by medical devices: oxygen masks, endotracheal tube holders, cervical collars, pulse oximeter clips, and similar equipment. These device-related injuries are easy to overlook because they occur on unusual sites like the nose bridge, ears, or chin. An expert panel reviewing the evidence concluded that foam dressings capable of redistributing pressure and absorbing moisture should be considered beneath devices, tubing, and fixators, but with an important caveat: the dressing should never be wedged under a device that is already tight, because adding material under a snug strap can increase pressure rather than relieve it.⁹

Non-invasive ventilation masks are a particularly common culprit. A network meta-analysis of studies on facial skin injuries from ventilation masks found that thin foam dressings were the most effective option for preventing early-stage damage. Foam outperformed hydrocolloids, transparent films, and no dressing at all for both stage I and stage II prevention.¹⁰ The key practical detail is to use a thin foam so the mask seal remains intact. A bulky dressing will cause air leaks and make the ventilation less effective.

Treating Existing Pressure Ulcers

Here is where expectations need to be recalibrated. The Cochrane review of foam dressings for treating pressure ulcers found that the evidence was of very low certainty across the board. When foam was compared head-to-head with hydrocolloid dressings (the other major category of moisture-retentive dressing), there was no clear winner for healing probability over short follow-up periods.¹¹ The included trials were small (median sample size of just 20 participants), and the researchers could not draw confident conclusions about healing rates, adverse events, patient satisfaction, pain, or cost-effectiveness.

That does not mean foam dressings are bad at treating pressure ulcers. It means we do not have high-quality evidence showing they are better or worse than the alternatives for healing. In practice, the choice between foam, hydrocolloid, alginate, or hydrofiber dressings for an existing wound often comes down to how much fluid the wound produces, where it is on the body, and how often it needs to be changed. Foam tends to be the default for moderate-to-high exudate wounds because it absorbs well without adhering to the wound bed.

Managing Exudate and Preventing Maceration

A foam dressing’s absorptive capacity is one of its defining features. Laboratory testing of commercially available foam products showed that even the lowest-performing foam absorbed about 40 mL of fluid, well above the estimated daily exudate output of a 10×10 cm wound (roughly 10 to 21 mL per day).¹² Beyond sheer absorption, foam dressings retain that fluid even under compression, which helps prevent maceration, the waterlogging of healthy skin around the wound that slows healing and invites infection.

Foam dressings sit along a spectrum of absorptivity, so the right product depends on how wet the wound is. A highly exudative stage III sacral ulcer needs a thicker, more absorbent foam, possibly with a superabsorbent core. A shallow stage II ulcer with minimal drainage might do fine with a thinner product. Some foams also deliver antimicrobial agents like silver directly to the wound bed; clinical guidelines note that silver-containing foam dressings can help decrease bacterial load in a pressure ulcer when infection is a concern.¹³

Pain and Comfort at Dressing Changes

Dressing changes are often the most painful part of wound care, and the adhesive technology matters enormously. Traditional adhesive dressings can strip fragile periwound skin on removal, causing secondary damage and significant discomfort. A crossover trial comparing two foam dressings found lower pain at removal and less periwound maceration with silicone-bordered foams than with standard adhesive foams.¹⁴ Silicone adhesive peels away gently because it bonds to the skin surface without penetrating the upper cell layers, so removal does not rip off new epithelial cells the way zinc oxide tape or acrylic adhesive can.

This is especially relevant for elderly patients with thin, fragile skin or for anyone on long-term corticosteroids. If you have ever peeled a bandage off a bruised forearm and watched a coin-sized patch of skin come with it, silicone-bordered foam largely eliminates that problem. In a pilot study of skin tears treated with adhesive silicone foam, 86% of wounds had fully healed by three weeks in the per-protocol analysis, compared with 59% treated with a meshed silicone interface dressing.¹⁵

How Often to Change a Foam Dressing

One of the most common questions caregivers have is how long a foam dressing can stay in place. The answer varies by wound, but a real-world study in US hospitals tracked soft silicone multilayer foam dressings used for an average of about 24 days per patient. The most common change schedule was every two to three days, followed by daily changes for heavier wounds and every four to six days for lighter ones.¹⁶ Nearly all clinicians in that study used a built-in change indicator, a feature on some modern foam dressings where colored “lobes” fill as the dressing absorbs fluid, signaling when it is time for replacement.

Changing too frequently wastes supplies and disrupts healing. Changing too infrequently lets the dressing saturate, which defeats its purpose and can cause maceration or infection. If you are a home caregiver, ask the wound care nurse to show you how the particular product signals saturation, because the cues differ by brand.

The Cost Question

Foam dressings cost more per unit than basic gauze, so administrators and families sometimes balk. But the economics flip when you factor in the cost of treating a hospital-acquired pressure ulcer, which involves extended length of stay, additional nursing hours, specialized wound care products, and potential litigation. An economic analysis modeled the use of prophylactic multilayer silicone foam dressings in addition to standard prevention protocols and found that for every 1,000 patients, the foam group experienced about 80 fewer pressure injuries, saving roughly $305 per patient in the US and €179 per patient in Italy.¹⁷

At the individual-patient level, a separate analysis based on a randomized controlled trial in ICU patients estimated that about €2,000 was needed to prevent one sacral or heel pressure ulcer of stage II or higher. Whether that is considered good value depends on perspective: from the patient’s standpoint, avoiding a painful chronic wound is clearly worth it; from the hospital’s standpoint, the upfront investment may feel steep until offset against downstream treatment costs.¹⁸

Common Misconceptions

One persistent myth is that a foam dressing alone can prevent a pressure ulcer. It cannot. Every clinical guideline positions prophylactic dressings as an adjunct to standard prevention: regular repositioning, nutrition support, moisture management, and appropriate support surfaces. The foam buys time between repositioning and adds a safety margin, but a patient left immobile on a standard hospital mattress with nothing but a foam dressing on their sacrum will still develop tissue damage eventually.

Another misunderstanding is that all foams are the same. In practice, products vary widely in their number of layers, their adhesive type, their breathability, their thickness, and whether they incorporate antimicrobial agents. A thin single-layer polyurethane foam for a ventilator mask is a completely different product from a five-layer sacral dressing with a superabsorbent core. Using the wrong product for the situation, a thick sacral dressing under a tight cervical collar, for example, can make things worse rather than better.

Finally, some clinicians assume that hydrocolloids are interchangeable with foam for pressure ulcer treatment. While both maintain a moist wound environment, foams generally handle higher exudate volumes and allow more moisture vapor to escape through their top layer. Hydrocolloids tend to be more occlusive, which makes them better for dry or low-exudate wounds but riskier for heavily draining ones where trapped moisture can cause maceration. The Cochrane review’s finding of no clear healing difference between the two should not be read as proof that swapping one for the other is always harmless; it reflects the poor quality of the available trials rather than true clinical equivalence.

Biodegradable Foams and Negative Pressure Wound Therapy

Most foam dressings are made of polyurethane, a durable synthetic polymer. That durability is an advantage for absorptive wound dressings but a drawback in one specialized application: negative pressure wound therapy, where a foam filler is placed inside a wound cavity and connected to a vacuum pump. The standard filler is polyvinyl alcohol (PVA) foam, which is not biodegradable and must be completely removed at each dressing change, a process that can be painful and occasionally leaves fragments in the wound bed. Researchers have developed a polycaprolactone (PCL) foam through a phase-separation process that performed comparably to PVA foam under negative pressure in laboratory testing while being biodegradable.¹⁹ This is still early-stage work, but if a biodegradable filler reaches clinical use, it could simplify dressing changes and reduce the risk of retained material in deep wounds.

Outside of negative pressure therapy, the environmental footprint of wound dressings is starting to attract attention. Hospitals generate enormous volumes of single-use wound care waste, and polyurethane foam is not recyclable through standard streams. Biodegradable alternatives are years from widespread clinical adoption, but the research pipeline suggests that the foam dressings of the next decade may look quite different from those in use today.