Understanding Negative Pressure Wound Therapy (NPWT): A Complete Guide

Jun 24, 2024

Wound healing can be a complicated and prolonged process for many patients, particularly for those experiencing chronic or severe wounds. Negative Pressure Wound Therapy (NPWT) has developed as a powerful treatment option for these patients. This advanced therapy, called vacuum-assisted wound closure, uses technology-controlled negative pressure to enhance the body’s natural healing processes and offers hope to patients with difficult-to-heal wounds.

Negative Pressure Wound Therapy Pensar Medical

How Does Negative Pressure Wound Therapy Work?

Negative pressure wound therapy works by decreasing the pressure in the bed (sub-atmospheric pressure) of a wound, which helps promote wound healing through multiple methods.

Negative pressure can help remove excess fluid from the wound (exudate). It can also pull the edges of the wound together so that less physical space is required for healing6. The negative pressure also creates minor tissue strain (microstrain), which stimulates cell growth6. This can increase the vascularity of the wound bed to improve circulation (perfusion) and reduce secondary necrosis6.

NPWT systems are composed of a few elements. They utilize an open-cell foam dressing placed on or in the wound, an adhesive dressing to create a sealed negative pressure environment, and a dome with tubing to connect to the vacuum pump. The pump decreases pressure on the wound and suctions away excess drainage.

When is Negative Pressure Wound Therapy Used?

NPWT can be used for the treatment of a variety of wound types if assessed to be appropriate. It can be used in chronic or acute wounds, as well as open or closed wounds12. Some examples include:

  • diabetic / neuropathic ulcers
  • pressure ulcers
  • chronic wounds
  • acute wounds
  • dehisced wounds

Healthcare providers often treat chronic wounds that leave the wounds susceptible to infection. Due to this risk, wound care treatment with NPWT is a great option to manage exudate, help pull wound edges together, and promote cell growth promotion6.

When is Negative Pressure Wound Therapy Contraindicated?

Though NPWT can be a great tool for many wound types, it should not be used for all types. Conditions in which NPWT is contraindicated include:

  • malignant wounds
  • untreated osteomyelitis
  • non-enteric or unexplored fistulas
  • necrotic wounds and eschar

Malignant wounds are not indicated for NPWT due to the increased risk of tumorigenesis and cancer spread12. Because NPWT increases cell proliferation, this would be harmful to the treatment of malignancy.

NPWT is not recommended for patients with untreated osteomyelitis due to the risk of bacterial growth promotion from the wound dressing remaining on the bed of an infected bone5.

Non-enteric or unexplored fistulas should not be treated with NPWT due to the risk of their connection to body cavities or organs that could experience excessive fluid loss12. The negative pressure system could drain too much fluid from the body, leading to dehydration and its associated electrolyte imbalances.

Necrotic wounds should not be treated with NWPT because the negative pressure can exacerbate the wound’s non-healing12. Infection is also at an increased risk. Once necrotic tissue and eschar are removed, NPWT can be utilized.

In addition to the abovementioned conditions, providers should not place NPWT systems over bone12. In wounds with exposed bone or palpable bone (if positive osteomyelitis has been treated), it is crucial to provide a protective barrier over the bone by utilizing a thick layer of a porous, non-adherent wound contact layer. 

Do not place NPWT in direct contact with exposed blood vessels, organs, nerves, or anastomotic sites. If placed near, consult the ordering physician for clarification, and they may suggest protecting that area with the thick layers of non-adherent contact material.  Again, do not place directly on these areas or within proximity.

What Are the Side Effects and Risks of Using Negative Pressure Wound Therapy?

Side effects from using NPWT can include pain, bleeding, infection, and hypersensitivities to the foam or adhesive materials12.

Improper use of the NPWT system can increase the risk of these effects. For example, if the system is not applied correctly, there could be a decrease or a loss of suction. This can lead to inadequate therapy and increased risk for infection12. Infection risk can also be minimized through appropriately scheduled and performed dressing changes.

Bleeding risks can be minimized by careful assessment of wounds for exposed blood vessels before NPWT initiation, as well as monitoring and taking caution for medical conditions and medications that could increase bleeding risk.    

Does NPWT Hurt? Is It Painful?

Patients receiving NPWT may complain of pain. Most often, dressing changes exacerbate this pain. Dressing changes can be particularly uncomfortable as the tissue forming during wound healing can adhere to the foam pieces of the NPWT system, which are then pulled during a dressing change15.

While this pain can be distressing, it’s important to note that no evidence shows that the pain associated with NPWT dressing changes is any greater than the pain associated with traditional wound care dressing changes15. Additionally, NPWT therapy often requires less frequent dressing changes than traditional wound care methods, and this could decrease the frequency of pain14.

Healthcare providers can help minimize the pain associated with NPWT dressing changes by premedicating patients with appropriate analgesia prior to a dressing change. Some physicians may also order a contact layer to further decrease this ingrowth.

What Options Are There for NPWT Systems?

WoundPro Negative Pressure Wound Therapy Device

When it comes to negative pressure wound therapy, there are a number of devices available on the market, and each is designed to meet differing patient needs. These devices fall into three main categories including:

  • Traditional Devices
  • Portable or Disposable Devices
  • Instillation NWPT Devices

Traditional devices are often used for patients with moderate to excessive wound drainage, offering larger volume pumps for drainage collection. Traditional devices can be used for patients in the hospital or patients receiving home care. Of the traditional devices on the market, Pensar Medical stands out with its innovative WoundPro model. The Pensar Medical WoundPro offers powerful suction of up to 8 liters per minute, as well as three different settings of continuous, intermittent, and variable suction. The WoundPro also includes an added level of safety through its built-in system checks to monitor for air leaks, tubing blockages, full canisters, and low batteries. The device also features a 24-hour battery to accommodate patient mobility and travel.  

In addition to the traditional NPWT systems, there is single-use negative pressure wound therapy (sNPWT) systems. sNPWT devices can be used for wounds with low to moderate drainage, such as closed surgical incision wounds7. While several manufacturers of sNPWT systems exist, Pensar Medical offers superior sNPWT technology via its MicroDoc system. The MicroDoc model is small, lightweight, and wearable. This makes it a great option for active, on-the-go patients. It features a simple interface and three pressure settings (-50, -80, and -125 mmHg). Its design also is whisper-quiet to allow for discrete operation.  

Furthermore, there is a technology called Instillation NPWT (NPWTi), which provides negative pressure benefits and allows for wound irrigation with cleansing or antibiotic solutions3. The NPWTi systems work by alternating between periods of cleansing and periods of negative pressure application so that patients receive benefits from both.

Negative Pressure Wound Therapy Dressing Changes

Pensar Medical Negative Pressure Wound Therapy Dressing Kit

NPWT dressing changes are often performed every 48-72 hours14. The exact frequency of dressing changes can differ depending on the characteristics of the wound. For example, wounds with infection may require more frequent dressing changes or wounds from skin grafting may require less frequent dressing changes.

Dressing changes are most frequently performed by a nurse at the hospital, an outpatient clinic, or through home health services. However, a family member or caregiver can also change dressings if they are appropriately trained to do so.

For traditional NPWT, different types of foam can be placed in the wound depending on a patient’s needs. The main varieties of foam include hydrophilic and hydrophobic foams. Hydrophobic foam dressings repel fluids, while hydrophilic dressings attract fluids. Pensar Medical offers hydrophilic and hydrophobic foam options for patients utilizing the WoundPro system. They also offer hydrophobic foam with silver for specialized antimicrobial care.

Pensar Medical offers a self-adapting treatment dressing for patients using single-use negative pressure wound therapy to coincide with their MicroDoc systems. Their unique technology allows the dressing to adjust to a wound’s moisture levels to promote an optimal healing environment. The MicroDoc‘s adaptive dressings are also designed to be hypoallergenic and non-cytotoxic to help minimize patient skin irritation and allergic reactions.

How Is Negative Pressure Wound Therapy Administered?

The first step in a patient’s receiving NPWT is a clinician assessment of the wound and the patient’s current health status to determine if NPWT is a suitable treatment option. Treatment may be delayed if a patient requires treatment for infection or their wound requires surgical debridement.

Once NPWT is selected as an appropriate therapy, a healthcare provider will select and fit NPWT foam into the wound. The foam is then sealed by the adhesive film. A small hole is cut into the film, and the stingray/dome is aligned over the hole. The dressing tubing then connects to the canister tubing for exudate to drain to. The pump is then turned on, and it provides negative pressure to the wound bed.

Users should select the appropriate negative pressure setting on their NPWT device to match a patient’s treatment plan. Pensar Medical’s WoundPro can be adjusted to alter the negative pressure settings and run continuously or intermittently to match the needs of a particular treatment plan. The device should remain plugged in to maintain a full battery, and that way, the Wound Pro will have sufficient battery life to allow patients to travel as necessary.   

Clinicians should follow their institution’s recommended guidelines regarding negative pressure settings for differing wound types.

How Long is Negative Pressure Wound Therapy Used?

NPWT is often administered for weeks, but it could be used for months. The length of therapy is very individualized and is affected by the type and size of the wound and the patient’s overall health and nutritional status.

When Should Negative Pressure Wound Therapy Be Discontinued?

NPWT discontinuation should be considered when the therapy goal has been met. This goal is often expressed as uniform granulation tissue over the wound2.

Discontinuation should also be considered if a patient does not see any clinical response or has little improvement to the wound within two weeks of initiating NPWT2.

Additionally, if a patient develops a contraindication, such as infection or excessive bleeding, discontinuation of NPWT should be considered2.

If bleeding is noted, NPWT should be stopped, pressure placed over the foam dressing, and the dressing should not be removed. The physician should be contacted, and the patient may need to be sent to an ER for additional treatment. 

NPWT Systems for Home Use

Wound care services with NPWT can be administered in a hospital setting, or for patients stable enough to be at home, can be managed at home via homecare services.

Pensar Medical’s WoundPro is a great option for patients receiving homecare NPWT. Its portability, ease of use, and adjustable settings suit hospital and home care environments. Many patients receive effective wound care in the comfort of their homes with the WoundPro system under healthcare professionals’ guidance. However, it’s essential to ensure that caregivers and patients receive proper training and support to use the system correctly and safely in a home care setting.

In addition to the WoundPro system, the MicroDoc system is another option for wound care that extends beyond the hospital environment. It allows patients to continue their daily activities without being held down by large, cumbersome equipment.

Maintaining NPWT Equipment

After disinfection, place the unit in a plastic bag to protect it from dust. Store the unit in a clean area designated for storing electromechanical medical devices in compliance with hospital or facility policies.

How much does NPWT cost?

Much like individual patients’ wound characteristics and treatment plans will differ, the cost of NPWT will differ from patient to patient. Factors such as the length of therapy and the selection of devices used for NPWT may influence the cost.   

When looking for competitively priced traditional devices and accessories, consider Pensar Medical’s WoundPro. They offer reasonable pricing options to both distributors and healthcare providers.

Pensar Medical’s MicroDoc offers cost-effective solutions for many wound types, especially compared to larger, non-disposable NPWT systems.

Units are also available for rental.

Insurance and Billing for NPWT

Billing is often processed through a patient’s insurance plan and is subject to eligibility and coverage.

The WoundPro qualifies for standard negative pressure billing codes that are already established, ensuring that healthcare providers can seek reimbursement for the care and necessary supplies.

Where can NPWT devices be found?

NPWT devices can be found through healthcare providers and manufacturers. Pensar Medical is a manufacturer providing its devices to healthcare facilities through a network of distributors.


Negative pressure wound therapy offers an innovative approach to wound care, encouraging faster and more successful healing of complex wounds.  If you want to learn whether NPWT is a suitable treatment for you, please consult your healthcare professional. For more information about NPWT systems from Pensar Medical, visit Pensar Medical or call +1 (800) 669-4757 to speak with a representative.


  1. Babu, Basil et al. “Comparison of Efficacy of Vacuum Dressing Versus Conventional Dressing Over Autologous Split Skin Grafts in Burn Wounds: A Single-Center Prospective Cohort Study.” Journal of burn care & research : official publication of the American Burn Association vol. 45,2 (2024): 468-477. doi:10.1093/jbcr/irad181
  2. Expert Working Group. “Vacuum assisted closure: recommendations for use. A consensus document.” International wound journal vol. 5 Suppl 4,Suppl 4 (2008): iii-19. doi:10.1111/j.1742-481X.2008.00537.x
  3. Gupta, Subhas et al. “Clinical recommendations and practical guide for negative pressure wound therapy with instillation.” International wound journal vol. 13,2 (2016): 159-74. doi:10.1111/iwj.12452
  4. Gupta, Subhas, and Shigeru Ichioka. “Optimal use of negative pressure wound therapy in treating pressure ulcers.” International wound journal vol. 9 Suppl 1,Suppl 1 (2012): 8-16. doi:10.1111/j.1742-481X.2012.01012.x
  5. Lo Torto, Federico et al. “The effectiveness of negative pressure therapy on infected wounds: preliminary results.” International wound journal vol. 14,6 (2017): 909-914. doi:10.1111/iwj.12725
  6. Orgill, Dennis P, and Lauren R Bayer. “Negative pressure wound therapy: past, present and future.” International wound journal vol. 10 Suppl 1,Suppl 1 (2013): 15-9. doi:10.1111/iwj.12170
  7. Saunders, C et al. “Single-use negative-pressure wound therapy versus conventional dressings for closed surgical incisions: systematic literature review and meta-analysis.” BJS open vol. 5,1 (2021): zraa003. doi:10.1093/bjsopen/zraa003
  8. Scherer, Sandra Saja et al. “The mechanism of action of the vacuum-assisted closure device.” Plastic and reconstructive surgery vol. 122,3 (2008): 786-797. doi:10.1097/PRS.0b013e31818237ac
  9. Seidel, Dörthe et al. “Negative Pressure Wound Therapy vs Conventional Wound Treatment in Subcutaneous Abdominal Wound Healing Impairment: The SAWHI Randomized Clinical Trial.” JAMA surgery vol. 155,6 (2020): 469-478. doi:10.1001/jamasurg.2020.0414
  10. Upton, Dominic, and Abbye Andrews. “Pain and trauma in negative pressure wound therapy: a review.” International wound journal vol. 12,1 (2015): 100-5. doi:10.1111/iwj.12059
  11. “Wound Care Supplies & Accessories” Pensar Medical. https://pensarmedical.com/wound-care-supplies-and-accessories/. Accessed 8 June 2024.
  12. Zaver V, Kankanalu P. Negative Pressure Wound Therapy. [Updated 2023 Sep 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK576388/
  13. Liu, Si et al. “Evaluation of negative-pressure wound therapy for patients with diabetic foot ulcers: systematic review and meta-analysis.” Therapeutics and clinical risk management vol. 13 533-544. 18 Apr. 2017, doi:10.2147/TCRM.S131193
  14. Normandin, Shanel et al. “Negative Pressure Wound Therapy: Mechanism of Action and Clinical Applications.” Seminars in plastic surgery vol. 35,3 (2021): 164-170. doi:10.1055/s-0041-1731792
  15. Upton, Dominic, and Abbye Andrews. “Pain and trauma in negative pressure wound therapy: a review.” International wound journal vol. 12,1 (2015): 100-5. doi:10.1111/iwj.12059