|Year : 2018 | Volume
| Issue : 6 | Page : 223-227
Prospective randomized control study comparing gauze-based with foam-based negative pressure wound therapy for the stage 4 pressure injuries
Chiun-Sheng Chen1, Chao-Chin Yu2
1 Division of Plastic Surgery, Tainan Municipal Hospital, Show Chwan Health Care System (Managed by Show Chwan Medical Care Corporation), Tainan, Taiwan
2 Division of Plastic Surgery, Tainan Municipal Hospital, Show Chwan Health Care System (Managed by Show Chwan Medical Care Corporation); Division of General Surgery, An Nan Hospital, China Medical University, Tainan, Taiwan
|Date of Submission||20-Dec-2017|
|Date of Decision||20-Feb-2018|
|Date of Acceptance||03-Jun-2018|
|Date of Web Publication||11-Dec-2018|
Dr. Chao-Chin Yu
Division of Plastic Surgery, Tainan Municipal Hospital (Managed by Show Chwan Medical Care Corporation), Tainan, Taiwan. Division of General Surgery, An Nan Hospital, China Medical University, No. 66, Sec. 2, Changhe Rd., Tainan City 709
Source of Support: None, Conflict of Interest: None
Background: Negative pressure wound therapy (NPWT) has been used to accelerate the formation of granulation tissue and to promote wound closure in the treatment of difficult-to-heal wounds. This study compared the effectiveness between gauze- and foam-based NPWT for stage 4 pressure injuries.
Materials and Methods: A total of 38 patients with 48 wounds of stage 4 pressure injuries were recruited and randomly divided into gauze-based and foam-based groups. After initial debridement therapy, gauze-based and foam-based fillers were used, and clinical observations were recorded when dressings were changed, twice a week for 3 weeks. The system was connected to a 1-bottle water-seal chest drainage system and standard wall suction at 125 mmHg negative pressure. The percentages of wound area reduction (PWAR), the scores of Pressure Ulcer Scale for Healing (PUSH) tool and the scores of Bates-Jensen wound assessment tool (BWAT) were used to evaluate wound healing activity.
Results: Both groups showed significant changing trends in the wound assessments of PWAR, PUSH, and BWAT during follow-up. However, the area of healing at each clinical observation was consistently greater in the foam group than in the gauze group during the follow-up period, while the PUSH score was consistently greater in the gauze group than that in the foam group. The declining trends of BWAT were alike in both groups.
Conclusion: Gauze-based therapy is noninferior to foam-based therapy with respect to PWAR, PUSH, and BWAT for stage 4 pressure injuries.
Keywords: Clinical trial, gauze and foam fillers, negative pressure wound therapy, pressure injury
|How to cite this article:|
Chen CS, Yu CC. Prospective randomized control study comparing gauze-based with foam-based negative pressure wound therapy for the stage 4 pressure injuries. Formos J Surg 2018;51:223-7
|How to cite this URL:|
Chen CS, Yu CC. Prospective randomized control study comparing gauze-based with foam-based negative pressure wound therapy for the stage 4 pressure injuries. Formos J Surg [serial online] 2018 [cited 2019 Mar 21];51:223-7. Available from: http://www.e-fjs.org/text.asp?2018/51/6/223/247308
| Introduction|| |
Negative pressure wound therapy (NPWT) is an established method, which uses a sealed wound dressing connecting to a negative pressure vacuum pump to treat difficult-to-heal acute and chronic wounds., Differences in wound contractions between using foam and gauze as fillers are varied by the types of wound.,,, Limited studies have been conducted to compare the treatment effectiveness between using gauzes and foams for patients with a pressure injury, formerly called as pressure ulcer. In April 2016, the national pressure ulcer advisory panel (NPUAP) replaced the term “pressure ulcer” with “pressure injury.” We conducted a trial at a hospital in southern Taiwan to compare the treatment effectiveness between using polyhexamethylene biguanide (PHMB) impregnated gauze-based and polyurethane (PU) foam-based fillers, for healing the stage 4 pressure injuries.
| Materials and Methods|| |
From January 2010 to December 2015, patients admitted to our hospital for the stage 4 pressure injuries were recruited for participation in this study. Patients with severe wound infection or uncontrolled medical condition were excluded from the study. We explained the study for each potential participant. With signed consent, patients were divided randomly into gauze-based experimental group and foam-based control group, using a computer-generated random table. After debriding the infective wound, wounds of the experimental group were packed with moistened PHMB-impregnated gauzes (Kerlix AMD, Covidien, St. Louis, MO, USA). A noncollapsible drainage tube (Blake, Ethicon, Somerville, NJ, USA) was applied to the wound and then sealed with the 3M™ Tegaderm™ Film (St Paul, MN, USA). The system was connected to a 1-bottle water-seal chest drainage system and to a standard wall suction unit at 125 mmHg negative pressure. The dressing was changed twice a week for 3 weeks. For the control group, the black PU foam dressing (VAC® GranuFoam Standard Dressings Kits, KCI, San Antonio, TX, USA) was used to pack and seal the wound with the same continuous wall suction at 125 mmHg negative pressure. All patients were requested to be hospitalized.
We undertook clinical observation twice a week and evaluated the condition of wounds, with the dressing changed. The percentage of wound area reduction (PWAR, in %), the Pressure Ulcer Scale for Healing (PUSH) score and bates-Jensen wound assessment tool (BWAT) were also assessed during the clinical observation and used as indicator of wound healing. Patient characteristics and wound characteristics were compared between groups and examined using Chi-square test for categorical variables and two-sample t-test for continuous variables. The repeated measure data were analyzed by the intention-to-treat principle using linear mixed model with SPSS statistical software. The sample size was calculated at 5% significance level with 85% power. This clinical study was approved and monitored by Institutional Review Board of Show Chwan Memorial Hospital (Approval No. 990903). This trial has been listed in ClinicalTrials. Gov as NCT03135964.
The study was conducted in accordance with the Declaration of Helsinki and was approved by the local ethics committee of the institute. Informed written consent was obtained from all patients prior to their enrollment in this study.
| Results|| |
[Figure 1] shows the flowchart of recruiting participants for this trial. Overall, 38 patients with 48 wounds of stage 4 pressure injuries were included in the study and were randomly assigned into two groups, 22 wounds in the experimental (gauze) group and 26 wounds in the control (foam) group. There were no striking differences between the two treatment groups for the patient and wound characteristics [Table 1] and [Table 2]. Compared with the foam group, patients in the gauze group were older with fewer women, but differences were not significant between two groups [Table 1]. The baseline mean wound area was smaller in the gauze group than in the foam group, while the baseline mean PUSH scores and BWAT scores were similar between the two groups [Table 2].
|Table 1: Baseline patients characteristics compared between gauze and foam groups|
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|Table 2: Baseline wounds characteristics compared between gauze and foam groups|
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[Figure 2] shows changes in wound areas using PWAR. Wound healing areas were improved with the follow-up time in both groups, but areas of healing were consistently greater in the foam group than in the gauze group. The foam group also showed quicker wound shrinkage in the 1st week of treatment than the gauze group. The PUSH scores in both groups went down with time, showing the wound healing pattern with scores consistently smaller in the foam group than in the gauze group [Figure 3]. The declining trends of BWAT scores were approximately similar in both groups, showing the wound severities were reducing [Figure 4]. Besides, it was seldom to note bleeding from wound base and patient's complaint of pain when changing dressings in both groups.
|Figure 2: Percentage change in wound surface area during 3-week care compared between using gauze (n = 22) and foam (n = 26) groups. Values were mean and standard error (P > 0.99)|
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|Figure 3: Pressure Ulcer Scale for Healing score during 3-week care compared between using gauze (n = 22) and foam (n = 26) groups. Values were mean and standard error (P = 0.134)|
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|Figure 4: Bates-Jensen wound assessment tool score during 3-week care compared between gauze (n = 22) and foam (n = 26) groups. Values were mean and standard error (P = 0.466)|
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| Discussion|| |
All the PWAR, PUSH, and BWAT tools provide valid and reliable means of assessment of pressure injury and prediction of wound healing., The formula to calculate the PWAR over time is (initial wound area − current wound area)/initial surface area × 100%, which was used by Cochrane in 2015 as the endpoint of the pressure injury study. The PUSH tool including surface area, exudate amount, and tissue type for measuring pressure injury healing was developed in 1997 by the NPUAP. BWAT, formerly known as the pressure sore status tool focuses on 13 categories of wound healing including size, depth, edge, undermining, necrotic tissue type and amount, exudate type and amount, skin coloring surrounding the wound, peripheral tissue edema, peripheral tissue induration, granulation, and epithelization. These three wound assessment tools are all still popular in pressure injury studies.
In this NPWT trial for the treatment of stage 4 pressure injuries, we failed to find a significant difference in wound healing between the two groups of patients using gauze-based and foam-based fillers. Judging from the ratio of PWAR, the wound contraction rates observed in the foam group at the six-time points have a comparative advantage, owing to dominant wound contraction in the 1st week of treatment. However, none of the differences between groups at the six-time points and the overall differences between groups (P > 0.99) are statistically significant.
Previous in vivo studies have shown that wounds filled with either foam or gauze make no differences in the degree of blood flow or wound contraction in small wounds (<5 cm in diameter),, although the PU foam could achieve more contraction than the gauze filler could in large wounds (5–10 cm in diameter). Our study shows that the PU foam can cause the wound to shrink more quickly in the 1st week of treatment than the gauze filler. Studies also revealed that microdeformation of the wound bed may also occur underneath either PU foam or gauze., Both PU foam-based and gauze-based fillers could equally deliver negative pressure to the wound bed.
Several small randomized controlled clinical trials on the outcomes of acute wounds found no observable differences in wound size reduction and healing time between foam-based and gauze-based NPWT.,,,, They also found gauze-treated patients experienced less treatment time and less pain at dressing change than foam-treated patients. The in vivo study has demonstrated a lower level of tissue ingrowth in using gauze than in using foam. It is painful for patients to remove the foam and the ingrown tissue, which may cause tissue damage and bleeding. Hurd et al. evaluated a noncomparative series of 152 patients using gauze-based NPWT to treat hard-to-heal wounds, and found 96% of patients without damage to the wound bed during the removal of the filler. There was no notice of wound bed damage in our study. We found the tissue grows slower in patients with chronic ulcer than those with acute wound. It is seldom observed that the tissue grows into the foam dressing or gauze dressing.
Studies have reported that treatment using PU foam could promote rapid growth of thick granulation tissue., On the other hand, gauze can form thinner stable granulation tissue. Thinner granulation tissue reduces fibrosis and scarring.
The recent Cochrane research used four eligible randomized controlled trials involving a total of 149 participants to compare NPWT to other treatments for pressure injuries.,,, Among the four studies, two studies compared dressings, one compared a series of topical treatments and one study evaluated “moist wound healing.” These trials used small sample sizes and were performed in a fairly short or unclear duration, containing limited data on adverse events. There have been no randomized controlled trials evaluating pressure injury using gauze as the wound filler in NPWT. Therefore, using gauze as filler in NPWT to treat pressure injury is still an experimental and unpredictable trial. No other trials are currently underway to compare the effectiveness between foam and gauze using negative pressure for the pressure injury treatment.
| Conclusion|| |
Our study used random method to assign study patients into the two groups by the type of wound filler. There were no significant differences in demographic characteristics and baseline wound characteristics. Selection bias was not likely, and findings are reliable. Our data demonstrate no significant difference in healing between the two types of fillers for the pressure injury wound treatment, although the wound area reduction is consistently better using foam-based fillers than using gauze-based fillers. Our study shows that gauze-based NPWT is not inferior to foam-based with respect to PWAR, PUSH, and BWAT for the stage 4 pressure injuries. In addition, gauze-based dressings are easier, less expensive, and less painful to apply.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2]