Influence on pressure transduction when using different drainage techniques and wound fillers (foam and gauze) for negative pressure wound therapy

Pressure transduction to the wound bed in negative pressure wound therapy (NPWT) is crucial in stimulating the biological effects ultimately resulting in wound healing. In clinical practice, either foam or gauze is used as wound filler. Furthermore, two different drainage techniques are frequently employed. One involves the connection of a non‐perforated drainage tube to the top of the dressing, while the other involves the insertion of perforated drains into the dressing. The aim of this study was to examine the efficacy of these two different wound fillers and drainage systems on pressure transduction to the wound bed in a challenging wound (the sternotomy wound). Six pigs underwent median sternotomy. The wound was sealed for NPWT using different wound fillers (foam or gauze) and drainage techniques (see earlier). Pressures between 0 and ?175 mmHg were applied and the pressure in the wound was measured using saline‐filled catheters sutured to the bottom of the wound (over the anterior surface of the heart) and to the side of the wound (on the thoracic wall). The negative pressure on the wound bed increased linearly with the negative pressure delivered by the vacuum source. In a dry wound, the pressure transduction was similar when using the different wound fillers (foam and gauze) and drainage techniques. In a wet wound, pressure transduction was better when using a perforated drainage tube inserted into the wound filler than a non‐perforated drainage tube connected to the top of the dressing (?116 ± 1 versus ?73 ± 4 mmHg in the wound at a delivered pressure of ?125 mmHg for foam, P < 0·01), regardless of the type of wound filler. Gauze and foam are equally effective at delivering negative pressure to the wound bed. Perforated drainage tubes inserted into the wound filler are more efficient than a non‐perforated drainage tubes connected to the top of the dressing. The choice of drainage technique may be particularly important in wounds with a large volume of exudate.     

Novel negative pressure wound therapy device without foam or gauze is effective at −50 mmHg

Negative pressure wound therapy (NPWT) promotes healing in acute or chronic wounds. Conventional NPWT devices consist of a filler (such as foam or gauze) that covers the wound and of a permeable membrane and tubing that connects the space under the membrane to a suction pump. The permeable membrane increases airflow and thus increases the required pump capacity that can cause patient discomfort or even ischemia in wounds with compromised vascularity. In addition, foam or gauze may fragment and become colonized with bacteria over time. To mitigate these, negative aspects, we have developed a new impermeable single layer component membrane dressing to deliver NPWT that does not need a foam or gauze to function. Therefore, the purpose of this study was to introduce this novel NPWT system (platform wound device, PWD) and evaluate its usability and effectiveness in the treatment of porcine full‐thickness burns. A total of 48 burn wounds were created across four Yorkshire pigs on the dorsum. Wounds were created on day 0 and continuous NPWT with ?50 mmHg and ? 80 mmHg was initiated immediately. Subsequently, the burns were debrided on day 3 and animals were euthanized on day 7. The efficacy of the PWD on wound healing and reduction of bacterial burden was measured and compared to wounds that did not receive NPWT. The results showed that PWD promoted wound healing by outperforming the wounds that did not receive NPWT and that PWD was efficient at reducing bacteria from the burn eschar and from the wound bed. In conclusion, this study demonstrated that PWD promoted wound healing with a negative pressure as low as ?50 mmHg, which likely benefits healing and avoids potential safety issues.     

Negative-pressure wound therapy using gauze or open-cell polyurethane foam: Similar early effects on pressure transduction and tissue contraction in an experimental porcine wound model

Negative-pressure wound therapy (NPWT), also known as topical negative-pressure therapy, is widely used to manage wounds and accelerate healing. NPWT has so far been delivered mainly via open-cell polyurethane foam, but increasing interest has been directed toward delivering NPWT via gauze. In the present study, the early effects of NPWT on pressure transduction and wound contraction were examined in wounds filled with either polyurethane foam or gauze. An experimental setup of a porcine wound model was used, in which the animals were anesthetized for 12–14 hours. Negative pressures between −50 and −175 mmHg were applied in −25 mmHg increments. Wound bed pressure was measured using a saline filled catheter sutured to the bottom of the wound. The contraction of the wound edges was also determined. The recordings were performed upon reaching steady state, which typically occurred within 1 minute. For both fillers, wound bed negative pressure increased linearly with delivered vacuum with little deviation from set pressure (correlation coefficient 0.99 in both cases). Similar tissue contraction was observed when using foam and gauze. The most prominent contraction was observed in the range of 0 to −50 mmHg with greater vacuum only producing minor further movement of the wound edge. In conclusion, the present experimental study shows that gauze and foam are equally effective at delivering negative pressure and creating mechanical deformation of the wound.     

Comparison of bacteria and fungus‐binding mesh,foam and gauze as fillers in negative pressure wound therapy – pressure transduction,wound edge contraction,microvascular blood flow and fluid retention

Bacteria‐ and fungus‐binding mesh binds with and inactivates bacteria and fungus, which makes it an interesting alternative, wound filler for negative pressure wound therapy (NPWT). This study was conducted to compare the performance of pathogen‐binding mesh, foam and gauze as wound fillers in NPWT with regard to pressure transduction, fluid retention, wound contraction and microvascular blood flow. Wounds on the backs of 16 pigs were filled with pathogen‐binding mesh, foam or gauze and treated with NPWT. The immediate effects of 0, ?40, ?60, ?80 and ?120 mmHg, on pressure transduction and blood flow were examined in eight pigs using laser Doppler velocimetry. Wound contraction and fluid retention were studied during 72 hours of NPWT at ?80 and ?120 mmHg in the other eight pigs. Pathogen‐binding mesh, gauze and foam provide similar pressure transduction to the wound bed during NPWT. Blood flow was found to decrease 0·5 cm laterally from the wound edge and increase 2·5 cm from the wound edge, but was unaltered 5·0 cm from the wound edge. The increase in blood flow was similar with all wound fillers. The decrease in blood flow was more pronounced with foam than with gauze and pathogen‐binding mesh. Similarly, wound contraction was more pronounced with foam, than with gauze and pathogen‐binding mesh. Wound fluid retention was the same in foam and pathogen‐binding mesh, while more fluid was retained in the wound when using gauze. The blood flow 0·5–5 cm from the wound edge and the contraction of the wound during NPWT were similar when using pathogen‐binding mesh and gauze. Wound fluid was efficiently removed when using pathogen‐binding mesh, which may explain previous findings that granulation tissue formation is more rapid under pathogen‐binding mesh than under gauze. This, in combination with its pathogen‐binding properties, makes this mesh an interesting wound filler for use in NPWT.     

Retrospective clinical evaluation of gauze-based negative pressure wound therapy

Negative pressure wound therapy (NPWT) is an established modality in the treatment of challenging wounds. However, most existing clinical evidence is derived from the use of open-cell polyurethane foam at -125 mmHg. Alternative negative pressure systems are becoming available, which use gauze at a pressure of -80 mmHg. This study describes clinical results from a retrospective non comparative analysis of 30 patients treated with Chariker-Jeter gauze-based negative pressure systems (V1STA, Versatile-1 and EZ-Care; Smith & Nephew, Inc.) in a long-term care setting. The mean age of the patients was 72 years. The wounds consisted of chronic (n = 11), surgical dehiscence (n = 11) and surgical incision (n = 8). Wound volume and area were recorded at commencement and at the cessation of therapy. Discontinuation of therapy was instigated upon closure through secondary intention or when size and exudate were sufficiently reduced that the wounds could be managed by conventional wound dressing (median 41 days). An overall median reduction in wound volume of 88.0% (P < 0.001) and a 68.0% reduction in area (P < 0.001) compared with baseline were observed over the course of NPWT. The overall rate of volume reduction (15.1% per week) compares favourably with published data from foam-based systems.     

Patient's pain feedback using negative pressure wound therapy with foam and gauze

Wounds can be caused by different mechanisms and have a significant morbidity and mortality. Negative pressure wound therapy (NPWT) is one of the most successful treatment modalities for wound healing. We have been using both foam and gauze-based NPWT. During application of NPWT, we noticed that the patient's pain was of varying intensity depending on the filler used. The aim of our work was to compare the level of pain and feedback before, during the treatment and at the dressing change after treatment with NPWT with two different fillers. For this study, we compared a pool of 13 gauze-treated patients with a pool of 18 foam-treated patients regarding the level of pain and feedback before, during the treatment and at the dressing change after treatment with NPWT. They were all post-traumatic patients with loss of tissue up to the muscular band. The patients were asked to respond to a questionnaire interviewed by the same physician to assess the level of pain using VNS (verbal numerical scale). We observed similar difference of means before and during the treatment with NPWT with gauze and foam. Regarding the pain at the dressing change, the mean of the scores for the foam was 6·5 while for the gauze was 4·15. In this case, we noticed the most significant difference between means from the scores given: 2·35 which was a statistically significant difference between the two groups (P = 0·046). The finding of this study confirms less pain at the dressing change after treatment with gauze-based NPWT. In our opinion, this finding is related to the more adhesive property of the foam probably because of the ingrowth of the granulation tissue in the micropores present on the foam. Considering this statement, we recommend the foam for neuropathic and paraplegic patients and the gauze for patients with bone and tendon exposition wounds, patients that do not tolerate NPWT with foam and low compliant patient particularly paediatric and old-age patients. We remind that the performance of this study was not sponsored by any company.     

Application of a drainage film reduces fibroblast ingrowth into large‐pored polyurethane foam during negative‐pressure wound therapy in an in vitro model

Negative‐pressure wound therapy (NPWT) is an advantageous treatment option in wound management to promote healing and reduce the risk of complications. NPWT is mainly carried out using open‐cell polyurethane (PU) foams that stimulate granulation tissue formation. However, growth of wound bed tissue into foam material, leading to disruption of newly formed tissue upon dressing removal, has been observed. Consequently, it would be of clinical interest to preserve the positive effects of open‐cell PU foams while avoiding cellular ingrowth. The study presented analyzed effects of NPWT using large‐pored PU foam, fine‐pored PU foam, and the combination of large‐pored foam with drainage film on human dermal fibroblasts grown in a collagen matrix. The results showed no difference between the dressings in stimulating cellular migration during NPWT. However, when NPWT was applied using a large‐pored PU foam, the fibroblasts continued to migrate into the dressing. This led to significant breaches in the cell layers upon removal of the samples after vacuum treatment. In contrast, cell migration stopped at the collagen matrix edge when fine‐pored PU foam was used, as well as with the combination of PU foam and drainage film. In conclusion, placing a drainage film between collagen matrix and the large‐pored PU foam dressing reduced the ingrowth of cells into the foam significantly. Moreover, positive effects on cellular migration were not affected, and the effect of the foam on tissue surface roughness in vitro was also reduced.     

The influence of different sizes and types of wound fillers on wound contraction and tissue pressure during negative pressure wound therapy

Negative pressure wound therapy (NPWT) contracts the wound and alters the pressure in the tissue of the wound edge, which accelerates wound healing. The aim of this study was to examine the effect of the type (foam or gauze) and size (small or large) of wound filler for NPWT on wound contraction and tissue pressure. Negative pressures between --20 and --160 mmHg were applied to a peripheral porcine wound (n = 8). The pressure in the wound edge tissue was measured at distances of 0·1, 0·5, 1·0 and 2·0 cm from the wound edge and the wound diameter was determined. At 0·1 cm from the wound edge, the tissue pressure decreased when NPWT was applied, whereas at 0·5 cm it increased. Tissue pressure was not affected at 1·0 or 2·0 cm from the wound edge. The tissue pressure, at 0·5 cm from the wound edge, was greater when using a small foam than when using than a large foam. Wound contraction was greater when using a small foam than when using a large foam during NPWT. Gauze resulted in an intermediate wound contraction that was not affected by the size of the gauze filler. The use of a small foam to fill the wound causes considerable wound contraction and may thus be used when maximal mechanical stress and granulation tissue formation are desirable. Gauze or large amounts of foam result in less wound contraction which may be beneficial, for example when NPWT causes pain to the patient.     

Effects of foam or gauze on sternum wound contraction, distension and heart and lung damage during negative-pressure wound therapy of porcine sternotomy wounds

The study was performed to compare the effects of negative-pressure wound therapy (NPWT) using gauze and foam on wound edge movement and the macroscopic appearance of the heart and lungs after NPWT. Sternotomy wounds were created in 6×70 kg pigs. Negative pressures of -40, -70, -120 and -160 mmHg were applied and the following were evaluated: wound contraction, distension and the macroscopic appearance of the heart and lungs after NPWT. Wound contraction was greater when using foam than gauze (3.5±0.3 cm and 1.3±0.2 cm, respectively, P<0.01). The application of traction to the lateral edges of the sternotomy resulted in greater wound distention with foam than with gauze (5.3±0.3 cm and 3.6±0.2 cm, respectively, P<0.001). After using foam, the surface of the heart was red and mottled, and lung emphysema and sometimes, lung rupture were observed. After using gauze, the organ surface had no markings. The study shows that foam allows greater wound contraction and distension than gauze. This movement of the wound edges may cause damage to the underlying organs. There is less damage to the heart and lungs when using gauze than foam.     

Negative-pressure wound therapy following cardiac surgery: bleeding complications and 30-day mortality in 176 patients with deep sternal wound infection

Negative-pressure wound therapy (NPWT) has been used for the treatment of deep sternal wound infection (DSWI) with promising results. However, questions have been raised regarding the potential risk of right ventricle (RV) rupture during treatment. In the present study, we evaluate our clinical experience of NPWT focusing on RV rupture and major bleeding complications and its potentially negative impact on 30-day mortality during an 11-year period. Serious bleeding complications during NPWT were reviewed for 176 patients treated for DSWI between January 1999 and April 2010. The 30-day mortality following DSWI was 1.1% (2/176). Four patients (2.3%) suffered bleeding from the RV rupture during NPWT of the sternal wound (two spontaneous and two debridement related). Furthermore, two patients had debridement-related bleedings from the venous bypass grafts during wound dressing change. The very low 30-day mortality (1.1%) following DSWI supports the use of NPWT. Overall, even if major bleeding complications may occur, the risk of RV rupture seems to be outweighed by the benefit of superior infection control. However, surgical experience is recommended when debriding sternal wounds and we recommend the use of a wound dressing, such as paraffin gauze, in order to protect the RV from direct contact with the polyurethane foam.     

Comparative study of the microvascular blood flow in the intestinal wall,wound contraction and fluid evacuation during negative pressure wound therapy in laparostomy using the V.A.C. abdominal dressing and the ABThera open abdomen negative pressure therapy system

To compare the changes in microvascular blood flow in the small intestinal wall, wound contraction and fluid evacuation, using the established V.A.C. abdominal dressing (VAC dressing) and a new abdominal dressing, the ABThera open abdomen negative pressure therapy system (ABThera dressing), in negative pressure wound therapy (NPWT). Midline incisions were made in 12 pigs, which were subjected to treatment with NPWT using the VAC or ABThera dressing. The microvascular blood flow in the intestinal wall, were measured before and after the application at topical negative pressures of ?50, ?75 and ?125 mmHg, using laser Doppler velocimetry. Wound contraction and fluid evacuation were also measured. Baseline blood flow was defined as 100% in all settings. The blood flow was significantly reduced, to 64·6 ± 6·7% (P < 0·05) after the application of ?50 mmHg using the VAC dressing, and to 65·3 ± 9·6% (P < 0·05) after the application of ?50 mmHg with the ABThera dressing. The blood flow was significantly reduced, to 39·6 ± 6·7% (P < 0·05) after the application of ?125 mmHg using VAC, and to 40·5 ± 6·2% (P < 0·05) after the application of ?125 mmHg with ABThera. No significant difference in the reduction in blood flow could be observed between the two groups. The ABThera system gave significantly better fluid evacuation from the wound compared to the VAC system. There was no difference between the dressings regarding the reduction in blood flow, but the ABThera dressing afforded better drainage of the abdomen and better wound contraction than the VAC dressing.     

Effective use of negative pressure wound therapy provides quick wound-bed preparation and complete graft take in the management of chronic venous ulcers

Venous ulcers are characterised by longstanding and recurrent loss of skin integrity. Once occurred, healing is slow and recurrence is high because of inappropriate conditions of the wound bed. This study involves 20 patients with chronic venous ulcers at least 6 weeks of duration treated with negative pressure wound therapy (NPWT). Patients underwent a radical debridement of all devitalised tissues in the first operation. After adequate haemostasis, silver-impregnated polyurethane foam was applied. Once the wounds were determined to be clean and adequate granulation tissue formation was achieved, split-thickness skin grafts were applied. Black polyurethane foam was applied over them. All wounds completely healed without the need for further debridement or regrafting. The mean number of silver-impregnated foam dressing changes prior to grafting was 2·9 (one to eight changes). The mean number of NPWT foam changes was 2·6 after skin grafting (two to five changes). Two patients who did not use conservative treatments for chronic venous insufficiency (CVI) after discharge from the hospital had recurrence of venous ulcers in the follow-up period. Application of NPWT provides quick wound-bed preparation and complete graft take in venous ulcer treatment.     

Effects of negative pressure wound therapy on cellular energetics in fibroblasts grown in a provisional wound (fibrin) matrix

Negative pressure wound therapy (NPWT) using reticulated open cell foam dressing (ROCF) is effective for treatment of recalcitrant wounds; however, the effects of this therapy on cellular metabolism remain to be elucidated. The effect of two different subatmospheric pressure applications on the cell energetics of human fibroblasts grown in a 3D fibrin matrix was studied using two different pressure-manifolding materials, an ROCF or gauze under suction (GUS). It was found that levels of cytochrome c oxidase, energy charge, and adenosine triphosphate/adenosine diphosphate were significantly increased following the application of NPWT using ROCF vs. GUS ( p <0.05). Increases in these parameters likely reflect an improved energetic status. In addition, levels of transforming growth factor-β and platelet-derived growth factor (α and β isoforms) were significantly increased (80 and 53%, respectively; p <0.05) over static control cultures following treatment with NPWT using ROCF but not following GUS. These growth factors are known to be important during wound healing. Clearly, both the material used as the dressing to manifold the subatmospheric pressure and the pressure used have a dramatic effect on cellular response.     

Negative pressure wound therapy using gauze and foam: histological,immunohistochemical, and ultrasonography morphological analysis of granulation and scar tissues

Background

Negative pressure wound therapy (NPWT) is becoming routine for the preparation of wounds prior to grafting for wound closure. With this purpose, we have been using both foam and gauze-based NPWT obtaining similar proportions of closed wounds and observing less pliable scar tissue on the foam-treated patients. The aim of this study was to compare this two different fillers and to identify if there are different indications for their use according to anatomical areas in relation to the type of granulation and scar tissue obtained.

Methods

Both foam and gauze patients were compared in terms of depth and wound location, patients' age, and comorbidities. All foam patients were treated at 125 mmHg for an average of 25 days before skin grafting, while gauze patients were treated at 80 mmHg for an average of 21 days before skin grafting. Biopsies of granulation and scar tissues were taken and stained with hematoxylin-eosin and Masson's trichrome stainings, investigating vascular endothelial growth factor (VEGF) and metalloproteinase (MMP). An ultrasound analysis of the closed wounds was also conducted.

Results

Histological, immunohistochemical, and ultrasonographical results after gauze-based NPWT showed a minor tissue thickness and disorganization and less sclerotic components.

Conclusions

These results support the hypothesis that different fillers generate different scar tissues. The choice of the filler to apply negative pressure should be dictated by the anatomical areas affected by the lesion. Level of Evidence: Level IV, therapeutic study.     

The effect of negative wound pressure therapy on haemodynamics in a laparostomy wound model

We have recently shown that negative pressure wound therapy (NPWT) induces a decrease in microvascular blood flow in the small intestinal loop close to the dressing. The effect of NPWT is thus thought to be local. In this study, we investigate whether the application of NPWT in laparostomy affects the haemodynamics. Midline incisions were made in six pigs followed by NPWT at ?120 mmHg for 20 minutes. The cardiac output, mean systemic arterial pressure, mean pulmonary artery pressu re, central venous pressure, left atrial pressure and superior mesenteric artery blood flow were recorded. The blood flow in a small branch of the superior mesenteric artery was then recorded under NPWT between ?50 and ?175 mmHg. Cardiac output was not affected by NPWT [P = not significant (n.s.)]. Neither the mean arterial pressure nor the mean pulmonary artery pressure was affected by NPWT (P = n.s.). Negative pressures of ?50, ?75, ?100 and ?125 mmHg did not alter the blood flow in the small branch of the superior mesenteric artery (P = n.s.). After application of ?150 mmHg, a significant decrease in blood flow was seen (P < 0·01), while the application of ?175 mmHg resulted in only a slight decrease in blood flow (P = n.s.). The effect of NPWT in laparotomy seems to be local and to have no influence on central haemodynamics or the blood flow to the superior mesenteric artery.     

High bacterial load in negative pressure wound therapy (NPWT) foams used in the treatment of chronic wounds

No earlier study has investigated the microbiology of negative pressure wound therapy (NPWT) foam using a standardized manner. The purpose of this study is to investigate the bacterial load and microbiological dynamics in NPWT foam removed from chronic wounds (>3 months). To determine the bacterial load, a standardized size of the removed NPWT foam was sonicated. The resulting sonication fluid was cultured, and the colony‐forming units (CFU) of each species were enumerated. Sixty‐eight foams from 17 patients (mean age 63 years, 71% males) were investigated. In 65 (97%) foams, ≥ 1 and in 37 (54%) ≥2 bacterial types were found. The bacterial load remained high during NPWT treatment, ranging from 10⁴ to 10⁶ CFU/ml. In three patients (27%), additional type of bacteria was found in subsequent foam cultures. The mean bacterial count ± standard deviation was higher in polyvinyl alcohol foam (6.1 ± 0.5 CFU/ml) than in polyurethane (5.5 ± 0.8 CFU/ml) (p = 0.02). The mean of log of sum of CFU/ml in foam from 125 mmHg (5.5 ± 0.8) was lower than in foam from 100 mmHg pressure (5.9 ± 0.5) (p = 0.01). Concluding, bacterial load remains high in NPWT foam, and routine changing does not reduce the load.     

Evaluation of wound healing effects of micronized acellular dermal matrix in combination with negative pressure wound therapy: In vivo study

Acellular dermal matrix (ADM) grafts can provide coverage for full-thickness skin defects and substitute for dermal defects. We tested the effectiveness of micronized ADM (mADM) as a dressing material, combined with negative pressure wound therapy (NPWT), for managing superficial wounds. We compared the wound healing effect of mADM in combination with NPWT with those of gelatin and mADM applied with a foam dressing. These therapeutic materials were applied to 36 cm² excisional wounds in a porcine full-thickness skin defect model. Wound healing kinetics and new tissue formation were assessed 10 days after the initial treatment by measuring the wound area. Collagen deposition and neovascularization were histologically evaluated. Compared with the other two groups, mADM plus NPWT combination group had a significantly larger wound area at the baseline (P = .0040), but the smallest on the 7th day (P = .0093). In addition, collagen formation and neovascularization were more histologically promoted than in the other two groups. mADM showed better results than the gelatin group but less collagen and revascularization than the combination group, and there was no significant difference in wound area. Our results show that the combination of mADM and NPWT has a synergistic wound healing effect.     

Developing in vitro assays to quantitatively evaluate the interactions of dressings with wounds

Evaluating interactions between dressing and wound is important for understanding wound management. This study quantitatively compared four polyurethane foam‐based wound dressings for their absorption profile, cell penetration, and adherence using two novel in vitro assays. The dressing with uniform pore sizes varying from 25~75 μm showed the highest absorption of both culture media and serum. The same dressing showed a 1.2‐ to 3.6‐fold lower cell adherence (3 hours) than the other dressings, and ~20‐fold lower cell penetration (5 days) than dressings with pore sizes varying from 55 to 343 μm. Additionally, cell and dressing interactions using a 3‐dimensional wound healing assay showed that the dressings with the smallest pore size of 25~75 μm maintained the highest cell viability (76.3%) and promoted cell migration into the wound site. This data suggest that polyurethane foam dressing with smaller and evenly distributed pores promotes wound healing with less cellular adhesion and penetration.     

Effects on heart pumping function when using foam and gauze for negative pressure wound therapy of sternotomy wounds

Background  

Negative pressure wound therapy (NPWT) has remarkable effects on the healing of poststernotomy mediastinitis. Foam is presently the material of choice for NPWT in this indication. There is now increasing interest in using gauze, as this has proven successful in the treatment of peripheral wounds. It is important to determine the effects of NPWT using gauze on heart pumping function before it can be used for deep sternotomy wounds. The aim was to examine the effects of NPWT when using gauze and foam on the heart pumping function during the treatment of a sternotomy wound.     

Negative‐pressure wound therapy for III/IV pressure injuries: A meta‐analysis

This meta‐analysis was conducted to identify the potential benefits and the efficacy of negative‐pressure wound therapy (NPWT) for III/IV pressure injuries (PIs) compared with standard wound care (SWC). Sixteen RCTs with 629 patients were included in our analysis. The methodological quality was assessed by the Cochrane Collaboration Tool. The outcomes included complete ulcer healing rate, wound healing time, pain score, the frequency of dressing change, hospitalization cost, the condition of the exudate, and the wound improvement. The percentage of healing rate was 61.45% for the NPWT group and 36.90% for SWC (95% CI: 1.32‐1.70). There were significant differences in wound healing time (WMD = ?16.47 days, 95% [CI (?22.36, ? 10.59) days, P ≤ .001]). The pain score and hospitalization cost in NPWT was lower compared with SWC group (WMD = ?2.39, 95% CI [?3.47, ?1.30], P ≤ .001); (SMD = ?2.55, 95% CI [?4.07, ?1.03], P < .01). The frequency of dressing change in both NPWT groups was greatly reduced (SMD = ?3.61, 95% [CI (?4.57, ? 2.66) times, P ≤ .001]). Our meta‐analysis indicated that NPWT was associated with greater improvements in improving PIs and shorting healing time for III/IV PIs. However, this conclusion needs to be confirmed by high‐quality multicenter RCTs.