Nursing care
Negative Pressure Wound Therapy: the nurse's role, start to finish
Written and reviewed by Dana Whitfield, RN, MSN · 6 min read · Updated September 2026
Short answer
Nursing management of negative pressure wound therapy centres on maintaining an airtight seal, since the therapy works only while suction is applied continuously to the wound bed. Check the dressing, tubing, and canister at every round, respond immediately to seal or blockage alarms, and monitor for bleeding, pain, or signs of infection under the foam.
Indications and contraindications
Negative pressure wound therapy, commonly known by the brand name VAC, applies controlled suction to a wound through a foam or gauze dressing sealed under an occlusive film. It is used for chronic wounds that have stalled, such as pressure injuries and venous ulcers, for surgical wounds left open to heal by secondary intention, for skin grafts needing even contact pressure, and for large traumatic wounds with significant tissue loss. The suction draws wound edges together, removes exudate, and promotes granulation tissue formation.
It is contraindicated over exposed blood vessels, nerves, organs, or anastomotic sites, over untreated osteomyelitis, in wounds with necrotic tissue that has not been debrided, and in malignancy within the wound. Use caution with patients on anticoagulants given the bleeding risk from the foam interface, and confirm the wound has been assessed and cleared by the treating clinician before therapy starts, since applying negative pressure to the wrong wound type can cause harm rather than promote healing.
Getting the patient ready
Explain to the patient that they will hear and feel the pump, that the dressing will feel snug rather than painful once sealed, and that some pulling or tugging sensation is normal, particularly at dressing changes. Pain during therapy, rather than at application, is not expected and should be reported rather than tolerated as routine. Position the patient to expose the wound fully and to allow the tubing to run without kinking or lying under the patient's body weight once therapy resumes.
Gather the correct foam or gauze dressing type, the transparent adhesive film, the tubing pad, and the canister before starting, since an interrupted application increases the risk of an incomplete seal. Confirm the prescribed pressure setting and mode with the order, and check the patient's skin around the wound for fragility or prior skin breakdown that might affect adhesive placement. If the patient will manage a portable unit at home, this is also the point to begin teaching them what a normal seal looks and sounds like.
Technique and safety checks
Cut the foam or lay the gauze to fit the wound cavity without overlapping onto intact skin, place the tubing pad over the dressing, and seal the whole area with the adhesive film so the border extends several centimetres onto healthy, dry skin. Then activate the pump and confirm suction by observing the foam or gauze shrink and stiffen under the film, and by listening for the alarm to clear.
The seal is the therapy. A dressing that looks correct but has a leak anywhere along its border is not delivering negative pressure to the wound bed at all, regardless of how the foam looks when it was first applied. Check every fold, every skin crease, and every point where tubing exits the film, since these are the places a seal most often fails. If the unit alarms for a leak, do not silence it and move on; find and patch the leak with an extra piece of film, or reseal fully if the leak cannot be located. Confirm canister connections are secure and that the collected exudate matches what would be expected for the wound size and time since the last change.
What can go wrong
A persistent leak alarm despite patching usually means the film has lifted at a skin crease or the tubing connection has loosened; work through the border systematically rather than guessing. A blockage alarm points to thick exudate or a clot obstructing the tubing, and repositioning the tubing pad or clearing visible debris often resolves it, though a dressing that is soaked through needs full replacement rather than troubleshooting.
Bright red blood in the tubing or canister is a medical emergency and the pump should be stopped and the wound assessed immediately, since this can indicate erosion into a vessel, particularly in wounds near major vasculature. Increasing pain during active therapy, foul odour, spreading erythema, or fever suggest infection developing under the dressing and warrant removal and reassessment rather than continuing the current dressing to its scheduled change. Skin maceration or breakdown at the film border is common with frequent changes and should prompt a review of the border technique and possibly a skin barrier product.
Ongoing care
Dressing changes are typically every 48 to 72 hours, or more frequently for infected or heavily draining wounds, per the treating clinician's order. At each change, assess the wound bed for granulation tissue progress, measure the wound, and document exudate colour, amount, and odour in addition to whether the seal held for the full interval. A seal that repeatedly fails before the scheduled change suggests the technique, the dressing size, or the wound location needs reassessment rather than simply resealing the same way again.
Monitor the canister output against expected drainage for the wound size, and change the canister per facility protocol or when full. For patients managing therapy at home with a portable unit, confirm they know how to respond to an alarm, how to check the seal themselves, and when a leak or blockage means calling for help rather than attempting to fix it alone. Continue standard wound care documentation, since negative pressure therapy is an adjunct to, not a replacement for, ongoing wound assessment.
Common exam questions
NCLEX items on negative pressure wound therapy frequently present an alarming pump and ask the candidate to identify the priority action, and the correct sequence is usually to check the seal and tubing for a leak or kink before assuming pump malfunction. A stem describing a dressing that appears correctly placed but with an alarm sounding is testing whether the candidate understands that an intact-looking dressing can still have failed if the seal is broken.
Other common questions test contraindications, particularly exposed vessels or organs and untreated malignancy, and expect the candidate to identify these as reasons to hold therapy and notify the provider rather than proceed. Bright red bleeding in the tubing is a frequent distractor-heavy scenario, and the correct response is to stop the therapy and assess immediately rather than continue monitoring, since delay in that specific presentation can be life-threatening.
The next step on this is the same as on everything else here: answer questions and read the rationales. Our med-surg practice questions are the closest set to what this page covers.
One question from the med-surg set
A client with chronic obstructive pulmonary disease has an oxygen saturation of 88% on 2 L/min via nasal cannula and is alert with no distress. What should the nurse do first?
Rationale
In COPD a saturation of 88–92% is the therapeutic target, not an emergency, and this client is alert with no distress. The first action is the independent nursing intervention that is least invasive and most likely to help: sit them up and reassess. Turning the oxygen up to 6 L/min risks blunting the hypoxic drive, and calling rapid response or drawing an ABG escalates ahead of an assessment you have not finished.
Answer: B
Common questions
What does it mean if a VAC dressing alarms for a leak?
It means air is entering the sealed system somewhere along the dressing border, tubing connection, or film edge, and negative pressure is not being delivered to the wound. Check skin creases, tubing exit points, and connections systematically, and patch or reseal until the alarm clears.
How often are negative pressure wound therapy dressings changed?
Most protocols call for a change every 48 to 72 hours, though infected or heavily exudating wounds may need more frequent changes as ordered by the treating clinician. Follow the specific order rather than a fixed default.
Is pain during active negative pressure therapy normal?
Some pulling sensation is expected, particularly around dressing changes, but ongoing or worsening pain during active therapy is not routine and should be reported. It can signal an inappropriate pressure setting, infection developing under the dressing, or tissue damage.
What should a nurse do if blood appears in the VAC tubing or canister?
Stop the pump and assess the wound and patient immediately, then notify the provider. Frank blood in the system can indicate erosion into a nearby vessel and is treated as an emergency rather than a routine finding.
Why is negative pressure wound therapy contraindicated over exposed blood vessels or organs?
The suction and direct foam contact can cause mechanical trauma or erosion to exposed structures, risking haemorrhage or organ injury. These wounds need surgical management or an alternative dressing until the structure is adequately covered.
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