Negative Pressure Wound Therapy (NPWT): A Practical Guide
How wound-vac systems actually work, the wounds they suit, and the real trade-offs between disposable single-use units and traditional canister pumps — explained plainly, with prescriber direction front and center.
Wound & ConsumablesA controlled vacuum that helps a wound close from the inside
NPWT — also called wound-vac or vacuum-assisted closure — seals a wound under an airtight dressing and applies gentle, continuous or intermittent suction. That negative pressure pulls excess fluid out of the wound bed, draws the edges together, and increases blood flow to the tissue that needs to rebuild. The result, in the right wound, is a cleaner bed and faster granulation than a passive dressing can manage on its own.
It is not a cure-all and it is not a self-serve purchase. NPWT belongs on wounds a clinician has assessed and ordered it for: surgical incisions at risk of dehiscence, pressure injuries, diabetic foot ulcers, venous leg ulcers, traumatic wounds, and skin grafts being secured. Wounds with untreated infection, exposed vessels or organs, necrotic eschar, or certain fistulas are off-label or contraindicated — which is exactly why a prescriber, not a catalog, decides candidacy.
The choices that actually shape an NPWT order
Once a clinician orders NPWT, a handful of practical decisions determine which unit fits the wound, the setting, and the person living with it. Here is what each one really means.
Traditional pump vs. single-use disposable
Traditional units are rentable, durable pumps with adjustable settings and higher fluid capacity — the right tool for high-exudate or complex wounds under facility or skilled-nursing oversight. Single-use disposable systems are small, sealed, worn-on-the-body devices that run 7–15 days then get discarded. Disposables suit lower-exudate wounds, closed surgical incisions, and people who want to stay mobile without a tethered pump. Cheaper up front and simpler isn't a downgrade here — for the right wound it's the correct choice.
Canister vs. canister-free
Canister systems collect drainage in a visible, measurable reservoir — essential when a wound is producing meaningful fluid and someone needs to track output. Canister-free designs lock fluid into the dressing itself, which means less to carry and nothing to empty, but they're only appropriate for low-exudate wounds. Matching exudate level to capacity is the single most common mismatch we see; over-spec'ing a canister-free unit leads to leaks and early failures.
Foam vs. gauze filler
The filler is what sits in the wound and distributes the pressure. Open-cell foam encourages aggressive granulation and is the default for deeper, cavernous wounds — but it can adhere and make dressing changes uncomfortable. Antimicrobial gauze is gentler, conforms to irregular or tunneling wounds, and is often preferred for shallow beds, fragile tissue, or pain-sensitive patients. The ordering clinician specifies which; the filler is rarely interchangeable on a whim.
Pressure settings and therapy mode
Most therapy runs between -75 and -125 mmHg, with -125 a frequent default and lower settings used for fragile tissue, grafts, or pain. Continuous mode holds steady suction; intermittent and variable modes cycle the pressure to stimulate the wound bed further but can be less comfortable. These are prescribed parameters — not dials a caregiver should change. If a setting seems wrong, that's a call to the clinician, not an adjustment to make at home.
Noise, portability, and battery life
For home use, the lived experience matters as much as the spec sheet. Quieter pumps and longer battery runtimes make the difference between a device someone tolerates and one they quietly switch off at night. Disposable units are near-silent and pocket-sized; rental pumps are louder but more capable. Ask specifically about decibel level, weight, charge time, and how the alarm behaves — the brochure rarely tells you what living with it is like.
Home use vs. facility, and dressing-change support
NPWT can absolutely run at home, but it doesn't run unattended. Dressing changes happen on a clinician-set schedule (often every 48–72 hours), seals fail and need re-taping, and alarms need someone who knows what they mean. Home use works when there's reliable nursing oversight or trained caregiver support and a clear escalation path. Facility use makes sense when the wound is complex, output is high, or no one at home is positioned to manage changes safely.
Frequently asked questions
Can I just buy a wound-vac and start using it?
No — and we won't sell it that way. NPWT requires a clinician to confirm the wound is a candidate, set the pressure and therapy mode, choose the filler, and own the dressing-change schedule. The wrong wound or wrong settings can do harm. Our role is to help you understand the equipment and support your prescriber's order, not to bypass it.
Is a single-use disposable unit worse than a traditional pump?
Not for the wounds it's designed for. For closed surgical incisions and low-exudate wounds, a disposable unit is often the better fit — quieter, lighter, no canister to manage, and lower cost. The traditional pump earns its place on high-exudate or complex wounds that need adjustable settings and larger fluid capacity. 'More capable' and 'right for you' aren't always the same thing.
How do I choose between canister and canister-free?
It comes down to how much fluid the wound produces. High or unpredictable exudate needs a visible, measurable canister so output can be tracked and the reservoir emptied. Low-exudate wounds can use canister-free designs that lock fluid into the dressing. When in doubt, err toward more capacity — an undersized system leaks and fails early.
Does NPWT hurt, and how often does the dressing change?
Dressing changes are the main source of discomfort, especially with foam fillers that adhere to the bed; gauze and lower pressure settings are gentler options a clinician can specify. Changes typically happen every 48–72 hours on a schedule the prescriber sets. Ongoing pain, increasing redness, or a sudden change in drainage is a reason to call the care team, not to push through.
Will insurance or Medicare cover NPWT at home?
Coverage exists for medically necessary NPWT but depends on documented wound type, prior treatment, and your plan's rules — and it differs for rented durable pumps versus disposable supplies. We can walk you through what documentation prescribers usually need; our Resource Library covers coverage basics, and your plan or supplier confirms specifics for your situation.
Match the unit to the wound, not the wound to a catalog
Bring us your prescriber's order or your questions about candidacy, canister capacity, filler type, and home-use logistics. We'll explain the real trade-offs — including when the simpler, cheaper option is the right one — with no pressure to buy.