Removing the Complexities Associated with Traditional Negative Pressure Wound Therapy (tNPWT) Bridging Applications

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Any views and opinions expressed are those of the author(s) and/or participants and do not necessarily reflect the views, policy, or position of ePlasty or HMP Global, their employees, and affiliates.

tNPWT is widely used and is one of the most effective interventions for multiple challenging wound indications.^1-3 The therapy is now considered an integral and vital tool within the armory of the clinician when treating and managing wounds. Following US FDA clearance of the original device in 1995, numerous commercial devices have been developed and adopted by health care professionals. tNPWT has been demonstrated as a safe and versatile technique with low complication rates,⁴ with usage spanning cradle to grave and even encompassing premature neonates.^5-7 Its utilization is multifaceted, supporting wound healing, surgical site management of abdominal compartment syndrome, bolstering of flaps and grafts, and management of excessive exudate.² However, it must be noted that NPWT does have established contraindications, including usage in wounds with untreated osteomyelitis, necrotic tissue with eschar present, exposed nerves, arteries, veins or organs, non-enteric or unexplored fistulas, anastomotic sites, and malignancy (except in palliative care to improve quality of life).² 

It is important to remember that tNPWT is not simply a dressing⁸ but a therapy with a mode of action that includes removing exudate, aiding bacteria clearance,⁹ drawing wound edges closer together (macrostrain), increasing blood flow, promoting granulation tissue through cell micro-deformation (microstrain), and reducing local tissue edema.¹⁰ Therefore, tNPWT has the potential to not only manage fluid removal but also provide active treatment.¹¹ Localized negative pressure is achieved by sealing a wound with film and attaching a delivery port from the wound to the NPWT pump. The delivered negative pressure removes interstitial fluid into a disposable canister and increases mechanical deformation of tissue.¹² Research suggests that optimal therapy occurs with negative pressure between −75 mm Hg and −125 mm Hg.² When dealing with sensitive, poorly perfused tissue or highly exudating wounds,² other pressures may be considered. 

Obtaining a seal is the most crucial element in achieving delivery of tNPWT therapy.⁴ The absence of a seal renders tNPWT useless, as subatmospheric pressure will not be achieved and detrimental effects upon the wound and surrounding tissues may occur.¹³ Leibman et al attribute the application of the film dressing as the most critical step to initiating and maintaining an adequate seal.¹⁴ This is supported by Caputo et al,¹⁵ who describe maintaining a seal over irregular surface structures as the main limitation of tNPWT. As widespread use in many different wound indications has evolved, so has the requirement for innovative techniques of application, particularly in areas where obtaining and maintaining a seal can be deemed problematic. Rollins et al presented a method labelled the "sandwich technique" to combat the complex topography of the foot and hand.¹³ This technique is applied by sealing the entire hand or foot within the tNPWT drape/film dressing to create an adequate seal.  

Another technique, known as "bridging," is described in the literature.^2,4 The clinical scenarios in which this application is most commonly adopted are when it is considered essential to move the tNPWT delivery port away from the wound bed or when treating wounds in close proximity to each other (this allows one port to deliver therapy to multiple sites). The bridging technique helps to avoid pressure injuries and also helps to prevent blockages in the tubing, often caused by kinking under the patient.⁴ Usually this technique is made after applying the initial wound dressing by first protecting the skin with the adhesive dressing and applying the standard foam bridge over that, followed by an additional piece of adhesive dressing with the port at the distal end (usually foam) onto the wound bed, which is then secured with a film dressing.¹⁶ The foam bridging allows subatmospheric pressure to extend or flow from the delivery port, which has been applied to a suitable anatomic location—for example, moving the suction port from the base to the top of the foot or from a groin wound onto the thigh. Anecdotally, bridging may require extra time and resources to perform and may cause inadvertent skin ulceration due to misapplication.⁶ Despite bridging being a common clinical consideration with the use of tNPWT, the successes and pitfalls of this method of application are rarely evaluated or discussed in the literature. Minimizing safety risks associated with tNPWT requires careful patient selection prior to therapy, skillful application of NPWT dressings, and frequent patient assessment and monitoring.¹⁷ One of the considered risks with tNPWT is the possibility of a patient developing an MDRPI, which continue to be a growing concern and cost $2.73 billion to $3.48 billion per year in the United States alone.¹⁸ Up to 30% of pressure injuries acquired are as a direct cause of medical devices.¹⁹ Risk factors include patients who are critically unwell, have reduced mobility, reduced sensory and perfusion function, or malnutrition.¹⁷ Common areas an MDRPI can develop include the heels, sacrum, and buttocks. In 2019, a systematic review by Jackson et al acknowledged that although many MDRPIs occur on mucosal tissue, all medical devices can cause pressure injuries.¹⁸ In terms of a patient developing an MDRPI with an NPWT device, this risk may increase due to hard tubing and/or the delivery port causing tissue injury and necrosis to the wound bed or surrounding tissue, or due to a patient lying or sitting on hard tubing, resulting in pressure against the skin. Therefore, to reduce the personal, psychological, and financial impact of MDRPIs, prevention and the adoption of proactive strategies, including choice of medical devices, are key.

The aim of this research was to explore HCP opinion on 2 leading tNPWT devices in the United States and discover any impact the 2 types of delivery ports (soft and hard) may have on clinical and economic outcomes specifically when adopting the bridging technique. Several questions were posed to HCPs, including the time required to apply dressings, satisfactory clinical outcomes, the impact on resources, and finally, in their opinion, whether bridging can be avoided to simplify treatment goals. The soft port (RENASYS Soft Port, Smith and Nephew) is described as a cushioned channel comprised of 2 layers—a honeycomb structured layer and a foam layer—which are designed to allow the system to deliver negative pressure even if the tubing is kinked or compressed. The hard port (SensaT.R.A.C. Pad, Solventum Corporation) can be described as a rigid port with firm plastic tubing. 

An online quantitative and qualitative survey was commissioned via an independent market research vendor (The Nursery, London, UK) with 200 HCPs. This group encompassed 100 surgeons and 100 registered nurses practicing in the United States, all of whom were actively involved in wound care and had at least 5 years’ experience in initiating and applying NPWT in clinical practice, including the bridging technique and using both tNPWT systems. The HCPs were recruited through Sermo Healthcare panels and requested to complete an anonymous, 10-minute online survey during the period of September 5, 2022, to October 10, 2022. 

Institutional Review Board approval for this survey was not required as this work was solely to capture opinion on 2 tNPWT systems that are commercially available and used on label in the United States. All opinions captured were fully anonymized and data were presented as an aggregate. 

The primary objective of the survey was to explore if the use of a soft port compared to a hard port eased application when administering tNPWT, alleviated concerns when using tNPWT on awkward anatomical areas, and eliminated the need for bridging and, if so, in which clinical scenarios. 

The survey included 46 multiple-choice questions as well as 13 open-ended questions intended to capture more detail on the clinicians’ opinions. Participant information included job role, specialty, care setting, institution size, and their wound management responsibility. Experience and use of tNPWT was qualified through questions relating to the specific tNPWT devices used in their institution, whether they were a tNPWT decisionmaker, how recently they had initiated or managed a patient with tNPWT, and their frequency in using both manufacturers’ devices in the past 12 months. Participants identified their standard patient demographic through questions related to patient age and wound types. The application of tNPWT was quantified by asking what types of wound indications receive tNPWT in their area of practice. Further questions specifically focused on the bridging technique included the most common anatomical areas on which the technique was employed, the volume of resources required, and any perceived challenges on performing the technique. In relation to the products utilized in bridging, feedback was gathered specifically on application of tNPWT and preferences during bridging. The results of the quantitative survey questions were collated and summarized with percentages, and the qualitative responses were grouped into categories and reported.

All respondents (100%, n=200) had used and were familiar with the tNPWT devices from both manufacturers. Of the 2 systems, 64% (n=126) of respondents had used soft port delivery ports and 84% (n=164) had used the hard port within the last 6 months. Of the 100 surgeons, the majority (85%, n=85) worked in acute care, with most specializing in plastic surgery (44%, n= 44), followed by general surgery and trauma (36%, n=36). Of the 100 registered nurses surveyed, 32% (n=32) held a specific wound care qualification while the remaining 68% (n=68) were all considered as having enhanced knowledge of wound management as part of their role.

The majority of respondents used tNPWT for open surgical wounds that have been assessed as healing by secondary intention (89.5%, n=179), surgical dehiscence (83% n=166), pressure injuries (81.5%, n=163), traumatic/orthopedic wounds (76.5%, n=153), lower limb ulcers (75.5%, n=151), flaps and grafts (62.5%, n=125), and burns (47.5%, n=95). Within the respondents’ clinical practice, more than a third reported that they always bridge around the sacrum (36.5%, n=73) and buttocks (36.5%, n=73); these were reported as the anatomical areas that most commonly require this technique. Other anatomical areas where the bridging technique was reported as routine included the back (21.5%, n=43), hips (19%, n=38), heels (18%, n=36), toes (17%, n=34), legs (14.5%, n=29), groin (14.5%, n=29), abdomen (13.5%, n=27), chest (12%, n=24), and arms (9.5%, n=19).  More than half of the clinicians surveyed (67%, n=134) agreed that the bridging technique makes the application of tNPWT "slightly more challenging," with 7.5% (n=15) reporting that bridging makes the application of tNPWT "much more challenging." The survey explored the potential impact on resources when adopting the bridging technique, and the respondents’ opinions on that matter are further detailed in Figure 1.

Most respondents agreed that bridging adds time to a dressing change (73.5%, n=147) and often requires additional barrier film (67%, n=134) and a larger foam dressing kit (57%; n=114). Those who agreed that the bridging technique impacts resources were asked to expand their answers further by completing the open-ended questions, which are summarized by category response in Tables 1, 2, and 3.

Of the total respondents, 53.5% (n=107) agreed that additional staff may be required for dressing applications when the bridging technique is needed, as the more complicated application may require extra hands. Furthermore, 48% (n=96) agreed that a more experienced clinician is necessary to perform bridging application due to its complexity, which often requires additional training and expertise. However, over half of respondents reported that the soft port can eliminate the need for bridging (53%, n=106). The potential clinical scenarios where respondents felt the soft port can eliminate the need for bridging are presented in Figure 2.

The most common clinical scenario clinicians identified where a soft port could be preferable over the bridging technique was a patient lying/resting on the tNPWT system tubing, which could cause a potential pressure injury (36%, n=72). This was followed by wounds that are located on anatomical areas at risk for pressure injury such as the sacrum (31%, n=62), concerns that the position of tubing may cause issues with kinking/twisting (31%, n=62), and wounds with a small surface area (29%, n=58).

In addition, the survey explored clinician preference for a soft port or hard port when considering the general use of tNPWT. Overall, the results indicated that if clinicians were given a choice and not restrained by institutional contracts and formularies, 54.5% (n=109) would choose to use a soft port compared to a hard port 23% (n=46), with the remaining 22% (n=44) of the respondents stating no preference. In specific relation to the bridging technique, 48% (n=96) of clinicians surveyed reported they would rather use a soft port compared to 27% (n=54) preferring hard port, with 26% (n=52) of the respondents stating no preference. Of the clinicians surveyed, 163 (81.5%) were specialist users of NPWT and, of this specific subgroup, the results reflect a preference for the use of soft port (51.5%, n=84).

The bridging technique becomes more commonplace when it is deemed necessary to reposition the tNPWT delivery port away from the actual wound.⁴ The literature reflects clinicians’ concerns that applying a bridge carries its own challenges, including correct application (Table 4). It is imperative that the bridge of foam is not placed directly onto the patient’s skin, as this can cause damage such as maceration and tissue abrasion; the bridge must be totally encapsulated by film dressing to ensure an airtight seal.

However, prolonged use of film on intact skin or irritation caused by multiple dressing changes potentially increases the risk of extended periwound skin damage and/or medical adhesive-related skin injury.²² These potential complications are significant as the excoriated skin may hinder the ability to obtain and maintain a seal, which can lead to the interruption or discontinuation of tNPWT and, in the authors’ experience, often require several days for the skin to recover. Regular application of a skin protection barrier film wipe would be a sensible recommendation to assist with minimizing this risk.²⁰

The results of the current study reveal that the HCPs surveyed believe that bridging extends the time required to apply tNPWT and sometimes requires an extra member of staff to assist with application. The extra time and additional resource may lead to a delay or even an omission of dressing change. tNPWT dressing changes are usually required every 48 to 72 hours.² An online survey in 2022 of 105 doctors and 206 nurses supports these findings, reporting that approximately 24 minutes are spent changing tNPWT dressings.²¹ Clinicians suggest that 26% of patients with tNPWT require bridging, which in turn increases application time by an average of 13 minutes.²¹ In addition, 65% report that bridging with tNPWT is more inconvenient than regular application.²¹ Therefore, it is important when considering the need for bridging that there will be an increase in the time spent and extra resources will be required, potentially having an impact on clinical staff.

Potential challenges associated with tNPWT hard port and plastic tubing prompted the development of a flexible, soft, conformable, and compression-resistant alternative. This design potentially eliminates the risks associated with a hard port, reduces the need to bridge, reduces application time and need for additional human resources, and reduces patient discomfort.²² Providing clinicians with this choice may avoid the complexity of bridging all together, eliminating extended application times that may cause added stress to patients when application is complicated and prolonged. The current survey results revealed that 53% (n=106) of the HCP respondents felt that a soft port eliminates the need for bridging. Considerable differences become apparent between hard and soft ports when examining the differences in the materials from which they are manufactured. A hard port system has a rigid form; this may increase the risk of blockages or a disruption of therapy caused by a kink/twist or a patient lying on the tubing/port. tNPWT devices are designed to alert the HCP when there is a pause or disruption in the flow of negative pressure; in this scenario, blockages could lead to audible alarms that may disturb a patient. In addition, a clinician would need time to troubleshoot the cause of the alarm and find a solution. Patients can experience discomfort when rolling or weightbearing onto a hard port and tubing, increasing the risk of MDRPI.²³

In comparison, the soft port is flexible, soft, and conformable in design and allows continuous delivery of tNPWT despite kinks/twists or pressure applied to the port and/or tubing.²³ This is supported by testing conducted utilizing a wound model and simulated skin by mimicking the delivery of the equivalent force of a bedbound patient to the sacral area.²³ The test revealed that the soft port transfers low levels of pressure to the skin if a patient is resting or has rolled upon it, which may help reduce the likelihood of pressure points. A second test reveals that when a 135° bend in the soft port tubing was exerted, it continued to deliver -120 mm Hg of NPWT to the wound bed.²⁴

Additional advantages of a soft port include the facilitation of patient mobility without risk of blockages if the tubing twists or kinks (Figures 3 and 4). Pedrazzi et al described the advantages of using NPWT compared to conventional dressings to support earlier mobilization and return to function in a systematic review of 466 pediatric patients.⁶ They further discussed the benefit of tNPWT in reducing number of dressing changes, managing fluid, and reducing pain, all of which may impact the challenge of adherence in younger children when managing skin grafts in particular. The first author of this article has direct experience in utilizing tNPWT with soft port and tubing due to its flexibility and lighter weight, which lends itself to this smaller and more fragile group of patients (Figures 5 and 6). In a population study, Santosa et al reported the safe and effective use of tNPWT in more than 3000 infants and children in surgical and nonsurgical disciplines.⁷ Such innovative enhancements to product design provided by a lightweight, flexible port and tubing should be considered to improve this vulnerable, smaller, and often active patient populations’ outcomes and quality of life.

The survey in the current study encouraged clinicians to expand upon their answers using open-ended questions and qualitative responses. When considering the use of hard port, clinician feedback included “more experience because this was first to market” and “for me, it’s just familiarity and sticking with my routine.” Therefore, it may be reasonable to consider that clinicians’ familiarity and routine use of a hard port tNPWT system, as it was previously the only type of delivery tubing for tNPWT, may have influenced participants’ responses. 

The innovation of soft port technology came to market in 2013; therefore, this development in tNPWT may not be as familiar to clinicians. Familiarity bias can significantly impact patient care in several ways. For example, familiar products may be chosen over other evidence-based alternatives, and newer or more effective options may not be considered due to this bias, both of which may result in suboptimal care.²⁷ The benefits described with the utilization of a soft port tNPWT system provide compelling differentiators for clinicians to consider when faced with ensuring optimal patient treatment and care.

Due to the familiarity and routine use of a hard port tNPWT system, survey participants may have potential bias, which is therefore an acknowledged limitation. Future research around this topic may produce different results if the clinicians have equal experience in and exposure to the benefits of soft ports and hard ports when applying tNPWT.

This work was designed to investigate clinicians’ perceptions of and experiences with using a hard port and a soft port tNPWT system, as well as the impact each system may have for patients, clinicians, and economic resources. The quantitative and qualitative survey results reported support laboratory testing demonstrating that a soft port tNPWT system may be beneficial to patients through increased comfort during wear and the reduced risk of MDRPI and periwound trauma. MDRPIs are a major concern for health care facilities and hospitals because staff and resource costs associated with their treatment may not be reimbursed. Therefore, as part of wider strategies to reduce the incidence of MDRPI, adopting the soft port for patients requiring tNPWT may be beneficial. The reduction in the need for bridging could save time and resources for clinicians by reducing the amount of tNPWT-associated consumables such as foam fillers and extra adhesive film dressings. When considering appropriate tNPWT use for patients, the soft port tNPWT system may add value to patients, clinicians, and health care systems through its established design differentiators when compared to hard port tNPWT systems.