The Efficient Application of Instilling Negative Pressure Wound Therapy With a Hypochlorous Acid-Preserved Wound Cleanser: A Case Series and Practical Advice

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First described in the mid-1990s,^1,2 NPWT has become a standard therapy for many different indications.^3-7 NPWTi-d was introduced in the early 2000s as a modality that could aid in debridement.⁸ The use of NPWTi-d has been shown to enhance the mechanical removal of nonviable tissue,^9-13 reduce bioburden,^8,9,14,15 reduce wound volume and tunneling,¹⁶ and promote granulation tissue formation.^9-12,14-16 Solutions used for instillation include acetic acid^10,17; sodium hypochlorite of varying strengths^12,16-18; povidone-iodine¹⁹; polyhexamethylene biguanide 0.1% alone¹⁷ or in betaine 0.1%, a surfactant (Prontosan; B. Braun Medical Inc.)^8,19; 0.6% NS^{10,12,14-17,19}; and hypochlorous acid.^9,10,12,17 With the exception of NS, use of all these solutions can potentially hinder wound healing because of their cytotoxic properties.^20,21 Topical 0.5% and 0.1% sodium hypochlorite solutions have been demonstrated to be proinflammatory and sodium hypochlorite has been demonstrated to have a low therapeutic index.²⁰

Hypochlorous acid is a component of the innate immune system, generated for its antimicrobial activity against bacterial, viral, and fungal pathogens.^22,23 Stabilized, pure hypochlorous acid, or pHA, exhibits a broad spectrum of antimicrobial preservative activity; compared with acetic acid, sodium hypochlorite, and povidone-iodine solutions, pHA is comparatively noncytotoxic and nonirritating to human cells.²⁰ Use of a pHA antimicrobially preserved wound cleansing solution (Vashe Wound Solution; Urgo Medical North America) as the instillation fluid for NPWTi-d (NPWTi-d/pHA [V.A.C. Ulta Therapy; 3M]) has been demonstrated to enhance removal of nonviable tissue^,9,10,12 address bacterial burden,⁹ and increase granulation tissue formation.^9,10,12

For the past several years the treatment regimen for patients with complex wounds, such as those complicated by severe infection and/or heavy contamination (grade IV surgical wounds²⁴), that require surgical debridement at the facilities of all the authors of the current study includes NPWTi-d/pHA (including the use of pHA as the solution for hydrosurgical debridement, when performed) for wound bed preparation. This treatment protocol has resulted in excellent outcomes for several hundred patients, as demonstrated in several previous publications.^9,12,25-38

The current case series provides 3 illustrative examples of the efficacy of NPWTi-d/pHA for wound bed preparation in patients with complex wounds complicated by infection and heavy contamination. In all patients, NPWTi-d/pHa was applied following guideline recommendations for use.¹⁷

Case 1

A 77-year-old male was admitted with altered mental status, difficulty breathing, and increasing redness over his right flank and right upper abdominal quadrant. Multidetector computed tomography with intravenous contrast of the abdomen indicated a right perihepatic fluid collection extending into the right upper abdominal wall with diffuse fasciitis and myositis, and an emphysematous gallbladder that had fistulized through the abdominal wall.

The patient was taken to the operating room for surgical debridement of the right upper quadrant and flank (Figure 1A). The resultant soft tissue defect was covered with a reticulated open cell foam dressing with through holes using a previously described technique²⁵ (Figure 1B, C) in preparation for application of NPWTi-d/pHA at −125 mm Hg cycling every 3 hours with a 15-minute dwell time. The wound was deemed ready for closure after 4 surgical debridement procedures with the application of NPWTi-d/pHA, performed every 48 to 72 hours.

A 10-cm length of the resulting 40-cm × 50-cm (2000 cm²) soft tissue defect was closed primarily with single interrupted sutures using 2-0 nylon suture (Figure 2A). Multiple non-expanded STSGs meshed at a ratio of 2:1 were used to cover the remaining 500 cm² of the soft tissue defect. The surgical site was dressed with a nonadherent dressing and application of standard NPWT. The first dressing change was performed 5 days postoperatively, at which time 100% take of the STSGs was noted. Site remodeling was noted with continued outpatient follow-up (Figure 2B).

Case 2

A 45-year-old female with diabetes presented in septic shock with a necrotizing soft tissue infection of the buttocks and right posteromedial thigh resulting from cosmetic bilateral thigh liposuction and fat transfer to the buttocks performed outside the United States 2 weeks prior to presentation. The patient was admitted for intravenous antibiotic therapy and surgical management. Hydrosurgical debridement using a pHA wound cleansing solution to eliminate embedded prokaryotic microorganisms, as well as NPWTi-d/pHA at −125 mm Hg cycling every 3 hours with a 15-minute dwell time was done for wound bed preparation (Figure 3A, B).

The wound was determined to be ready for closure 77 days following the initial surgical debridement, after multiple surgical debridement procedures with application of NPWTi-d/pHA performed every 48 to 72 hours. Multiple non-expanded STSGs meshed at a ratio of 1:1 were applied to the surgical site. The surgical site was dressed with standard NPWT. The first dressing change was performed 5 days postoperatively, at which time 90% take of the STSGs was noted (Figure 3C).

Case 3

A 19-year-old female presented with inhalation injury requiring intubation and scattered, superficial partial-thickness burn wounds measuring 6% of the total body surface area, including the face, left shoulder, forearm, and hand. The patient also had an open right forearm wound measuring 10 cm × 12 cm complicated by heavy dirt contamination sustained from using her right hand to break a window and jump to safety after awaking to a house fire. The patient landed in the dirt, where she lay for a prolonged period before being transported to the hospital.

The patient was admitted for medical and surgical management. Irrigation and debridement of the right forearm wound was performed, after which NPWTi-d/pHA set at −125 mm Hg cycling every 3 hours with a 15-minute dwell time was applied (Figure 4A-C). The wound was determined to be ready for primary closure 5 days after the initial debridement was performed. The wound healing trajectory over the next 8 months was satisfactory (Figure 4D).

The illustrative cases presented herein demonstrate the utility of NPWTi-d/pHA for wound bed preparation in complex wounds complicated by infection and heavy contamination. The purpose of NPWTi-d is to further assist with mechanical debridement^9-13 and bioburden reduction,^8,9,14,15 in addition to the other known benefits of NPWT.⁸ Guideline-recommended settings for NPWTi-d comprise negative pressure setting of −125 mm Hg, cycling every 2 to 3 hours, with a 10-minute dwell time.¹⁷ The recommended volume of fluid to use with instillation ranges from the subjective, that is, sufficient fluid to cover the wound without compromising the dressings and reducing fluid by 10% to 20% if the dressing becomes oversaturated,³⁹ to the specific, that is, use of 0.2 mL of fluid/cm² of wound area.¹⁷

While guidelines have evaluated several solutions available for use with NPWTi-d, none has recommended the use of a specific instillation solution.^17,39,40 Guideline recommendations for instillation solution selection include NS, due to ease of access,⁴⁰ and topical antimicrobially preserved cleansers based on spectrum of activity, ease of access, tolerability, NPWTi-d device dressing compatibility, and cost.¹⁷ Antimicrobially preserved cleansers have been recommended for use in acutely infected wounds, wounds with high levels of bacterial colonization, and wounds with internal hardware present.¹⁷

Early initiation of NPWTi-d has been shown to reduce the number of required surgical debridements, the duration of subsequent standard NPWT, the time to final wound closure, the length of hospital stay, and the mean total cost of index admission by $10 877.^41-43 Guidelines on the use of the optimal solution for instillation has changed over time from avoiding the use of NS to recommending the use of NS depending on the wound type.¹⁷ The use of topical antiseptic solution as the instillation solution for NPWTi-d is favored in cases of acute infection and in heavily colonized wounds, as well as in cases involving hardware fixation. Hypochlorous acid is among all the authors' (surgeons) personally favored solutions for instillation.

Use of NPWTi-d/pHA has been demonstrated to remove nonviable tissue,^9-13 reduce bacterial growth,⁹ reduce odor,¹⁰ reduce thick exudate,¹² and increase granulation tissue formation^9,10,12 in wounds resulting from infection¹² or necrotizing fasciitis^9,10; in postoperative wounds,¹² including postoperative dehiscence¹⁰ and postoperative infection¹⁰; in pressure injuries^10,12; and in burn wounds,⁹ chronic wounds,¹² and diabetic foot ulcers.¹⁰ While no direct or indirect comparison studies have been published comparing different topical antimicrobially preserved solutions used for instillation with NPWTi-d, NPWTi-d/pHA has been shown to be a safe and effective therapeutic option in the management of complex wounds.^9,10,12 Published reports also indicate improved efficacy and cost-effectiveness associated with the use of a pHA antimicrobially preserved wound cleansing solution compared with NS.^41-43 Alberto et al⁴⁴ evaluated 27 wounds, 19 of which were treated with NPWTi-d/pHA and 8 of which were treated with NPWTi-d using NS (NPWTi-d/NS) as the instillation solution. Wound colonization was present in 78.9% (15 of 19) of the NPWTi-d/pHA–treated wounds and in 62.5% (5 of 8) of the NPWTi-d/NS–treated wounds; polymicrobial infection was present in 80.0% (12 of 15) and 60.0% (3 of 5) of these wounds, respectively. Patients who received NPWTi-d/pHA required fewer surgical wound debridements and had a shorter time to final wound closure and shorter length of hospital stay compared with those who received NPWTi-d/NS, even though the wounds managed with NPWTi-d/pHa initially had a higher rate of wound colonization and polymicrobial infection. Reductions in the number of surgical debridements, time to wound closure, and hospital length of stay have been shown to result in an average 24% cost savings for wounds managed with NPWTi-d/pHA compared with NPWTi-d/NS.^41,42,45 These findings align with the extensive clinical experience of the authors of the current study that the use of NPWTi-d/pHA more effectively facilitates the removal of nonviable tissue compared with NPWTi-d/NS.

Physicians may be hesitant to use NPWTi-d due to reported potential complications specific to this device, including tubing blockage, difficulty maintaining a seal, fluid leakage, and tissue maceration.^14,19,44 Various methods related to dressing application and modification of device settings have been recommended to manage or prevent these complications.^19,39,46,47 Techniques in dressing application include protection of the periwound skin with a skin protectant, barrier drape, stoma paste, or an absorptive dressing, hydrocolloid, or thin foam dressing around the wound bed,^39,47 and use of a dual lumen system (Figure 4C) or 2 separate tubing systems (Figure 1B, C) for application of NPWT and fluid removal at opposite sides of the wound bed.^39,48 The dressing can also be reinforced if complications arise during treatment.^19,47 Device setting modifications include increasing the cycle frequency of NPWT,³⁹ reducing dwell times,³⁹ and reducing solution instillation volume. The efficacy of increasing cycle frequency can be seen when comparing published reports of fluid leakage and maceration complications with NPWTi-d. Three of 4 patients in a case series using NPWTi-d set at −125 mm Hg cycling every 6 to 8 hours with a 10-minute dwell time had fluid leakage and maceration complications.⁴⁶ In contrast, only 1 patient in a case series of 9 patients treated with NPWTi-d set at −125 mm Hg cycling every 3.5 hours with a 10-minute dwell time had a fluid leakage complication that required minor adjustment for correction.¹⁹ No NPWTi-d–related complications were reported in a retrospective series of 30 patients treated with NPWTi-d set at −125 mm Hg to −150 mm Hg cycling every 3.5 hours with a 10-minute dwell time.¹⁵ In the experience of the authors of the current study, the use of separate tubing systems for application of NPWT and solution removal spaced 2 cm to 3 cm apart (Figure 1B, C), ensuring the hole cut in the drape is large enough to facilitate unencumbered instillation and fluid/debris removal, the use of the recommended formula of 0.2 mL/cm² of wound area³⁹ to determine instillation fluid volume, and increasing the cycle frequency has been useful in the prevention and management of fluid leakage and tubing blockage complications. Replacement of the entire NPWTi-d device and dressing can also be considered if complications arise. The authors of the current study recommend inspection of the wound bed for hemorrhage if significant clotting within the tubing is observed. Use of a nonadherent protective barrier applied between the wound bed and the foam dressing, and reducing the negative pressure to −75 mm Hg, may also help mitigate the potential for hemorrhage and clotting in the tube.¹⁴ The authors of the current study have found that use of an open reticulated polyurethane foam dressing with large fenestrations can also be beneficial in this situation.

Limitations of this study include the small number of cases and the noncomparative study design. The primary objective of the current case series is to illustrate the efficacy of NPWTi-d/pHA in wound bed preparation using the clinical approach the authors of the current study have developed and provide insight into how to minimize the risk of complications specific to NPWTi-d. Other facilities, clinicians, and patients may experience different results. However, the results of the illustrative cases presented herein align with other reports of the use of NPWTi-d/pHA in removal of nonviable tissue,^9-13 reduction in bacterial burden,^8,9,14,15 and increase in granulation tissue formation.^9-12,14-16

The 3 illustrative cases presented herein provide further evidence of the benefit of using a pHA wound cleansing solution as the instillation fluid with NPWTi-d for wound bed preparation of complex wounds complicated by infection and heavy contamination. Complications related to NPWTi-d can be minimized using dressing application techniques (eg, protection of the periwound skin, barrier drape, use of a dual lumen system or 2 separate tubing systems) and device setting modifications. 

Authors: Marc R. Matthews, MD, MS, MCG¹; Luis G. Fernández, MD²; Michel H.E. Hermans, MD³; and Debashish Chakravarthy, PhD⁴

Acknowledgments: Technical writing support was provided by Urgo Medical North America and Valerie Marmolejo, DPM, MS, MWC, of Scriptum Medica. 

Affiliations: ¹Department of Surgery, Division of Trauma, Surgical Critical Care, Burns and Acute Care Surgery, Banner University of Arizona/University Medical Center, Tucson, AZ; ²Department of Surgery, Division of Trauma Surgery/Surgical Critical Care, University of Texas Health Science Center, UT Health East Texas, Tyler, TX; ³Hermans Medical Consulting, Hoorn, the Netherlands; ⁴Urgo Medical North America, Fort Worth, TX

Disclosure: Dr Matthews and Dr. are both surgical consultants for 3M. Dr Fernández is also an advisor and consultant for Urgo Medical North America. Urgo Medical North America provided financial support to Valerie Marmolejo, DPM, MS, MWC, of Scriptum Medica, DuPont, Washington, for assistance in preparation of this manuscript. Dr Chakravarthy is an employee of Urgo Medical North America.

Correspondence: Luis G. Fernández, MD; Email: luis.fernandez@uthct.edu

Manuscript Accepted: February 26, 2024