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Abstract of thesis entitled
“Evidence based guidelines for negative pressure wound
therapy in diabetic ulcer and diabetic amputation wounds in
inpatient and outpatient settings”
Submitted by
Ip Man Ying
For the degree of Master of Nursing
at The University of Hong Kong
in July 2014
Background
Diabetic mellitus is common in Hong Kong. One of the common complications of
diabetic mellitus is diabetic foot ulceration which may cause amputation. Wound
healing in diabetics is difficult. Huge cost of wound care and amputation severely
affect the quality of life. Negative pressure wound therapy is an effective practice to
increase wound healing of diabetic ulcer and amputation wounds.
Aim
To set up a guideline with evidence based to implement negative pressure wound
therapy (NPWT) for patients with diabetic ulceration and amputation wounds in
inpatients and outpatient setting.
Method
A systematic literature review was conducted on studies including 4 randomized
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controlled trials and 2 case and control studies. Critical appraisal was done according
to tools from Scottish Intercollegiate Guideline Network (SIGN).
Results
According to literature review, an evidence based guideline was developed from key
recommendation. It includes vascular perfusion assessment, wound staging, ulcer
treatment before application of NPWT, application of material during NPWT,
pressure setting, using SNaP in ambulatory setting, dressing change, complication
monitoring and pain management. Implementation potential was evaluated from
transferability, feasibility and cost- benefit ratio of NPWT implementation. A
communication plan, a pilot study plan and an evaluation plan were set up in
implementation plan. The primary expected outcome is the time reduced for complete
closure of wound in terms of days. Other expected outcome includes to reduce time
for infection control, prevent amputation, acceptance of NPWT by patient and
healthcare provider, compliance and knowledge of healthcare provider, workload,
length of hospital stay and cost effectiveness.
Conclusion
This translational research study shows that NPWT can promote wound healing in
diabetic ulceration and amputation wounds. An evidence- based guideline was set up
for application of NPWT on diabetic ulceration and amputation wounds in inpatient
and outpatient settings.
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Evidence based guidelines for negative pressure wound
therapy in diabetic ulcer and diabetic amputation wounds in
inpatient and outpatient settings
by
Ip Man Ying
B.Nurs. H.K.U.H.K
R.N.H.K.
A thesis submitted in partial fulfillment of the requirement for
the degree of Master of Nursing
at the University of Hong Kong.
July 2014
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Declaration
I declare that this dissertation represents my own work, except where due
acknowledgement is made, and that it has not been previously included in a thesis,
dissertation or report submitted to this University or to any other institution for a
degree, diploma or other qualifications.
Signed
Ip Man Ying
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Acknowledgement
I would like to give my sincere gratitude to my supervisor Miss Cecilia Kong for
her great support and ongoing encouragement during the whole process of dissertation
accomplishment. Her patient teaching and invaluable recommendation guide me to
accomplish the dissertation. Also, I would like to give my thanks to Dr Marie Tarrant
for her great support and invaluable comments in this dissertation. I would like to give
my thanks to all staffs in School of Nursing from University of Hong Kong for the
ongoing support.
I would like to give thanks to Miss Cecilla Kong, Dr Marie Tarrant and Miss Idy Fu
and classmates for invaluable feedbacks during presentation.
I would like to acknowledge Dr Daniel Fong, Dr William Li, Dr Janet Wong and Miss
Patsy Chau for lecture and tutorial teaching.
Finally, I would like to thank my family and friends for their support and
encouragement in the process.
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Table of Contents
Declaration 4
Acknowledgement 5
Table of contents 6
List of figures and tables 11
Appendix 12
Chapter 1 introduction 13
1.1 Background 13
1.2 Significance 13
1.3 Affirming needs 14
1.3.1 Current practice 14
1.3.2 Studies for current studies 15
1.4 Research question, aim and objectives 16
1.4.1 Research question 16
1.4.2 Objectives 17
Chapter 2 Appraisal 17
2.1 Searching 17
2.1.1 Keywords in database 17
2.1.2 Selection Criteria 17
2.1.2.1 Inclusion criteria 17
2.1.2.2 Exclusion criteria 18
2.2 Extraction of Evidence 18
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2.3 Quality Assessment 18
2.3.1 Critical Appraisal 18
2.3.2 Summary of quality assessment from RCTs 18
2.3.2.1 Other limitation 20
2.3.3 Summary of quality assessment from case and control studies 20
2.3.3.1 Other limitations 22
2.4 Summary of Evidence 22
2.4.1 Sample size 22
2.4.2 Sample characteristics 23
2.4.3 Intervention 24
2.4.4 Comparison 25
2.4.5 Follow up 26
2.4.6 Outcome 26
2.5 Synthesis of Evidence 27
2.5.1 Assessment 28
2.5.1.1 Assess risk factors to NPWT 28
2.5.1.2 Assess neuropathy and vascular perfusion 28
2.5.1.3 Assess stage of wound 28
2.5.2 NPWT application 29
Chapter 3 Implementation 30
3.1 Implementation potential 30
3.1.1 Target setting 30
3.1.2 Target audience 30
3.1.3 Transferability of findings 30
3.1.3.1 Target population 31
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3.1.4 Feasibility of implementation 32
3.1.4.1 Time frame 32
3.1.4.2 Staff training 32
3.1.4.3 Availability of equipment and facilities 33
3.1.4.4 Cut of manpower 33
3.1.5 Cost- Benefit ratio of the innovation 34
3.1.5.1 Risk and benefit of the innovation 36
3.1.5.1.1 Potential risk of the patient 36
3.1.5.1.2 Potential benefit of the patient 36
3.1.5.1.3 Potential benefit of the organization and ward nurses 36
3.2 Evidence based guideline of implement NPWT on diabetic foot 37
3.2.1 Target user of guideline 37
3.2.2 Objective of guideline 37
3.2.3 Rating scheme of recommendations 37
Chapter 4 Plan for implementation and evaluation of intervention 42
4.1 Communication Plan 42
4.1.1 Stakeholders identification 42
4.1.2 Content of communication 42
4.1.3 Communication timetable 43
4.1.4 Communication with stakeholders 43
4.1.4.1 Management level 43
4.1.4.2 Top administrative level (DOM) 43
4.1.4.3 Frontline staffs 43
4.1.4.4 Physicians and Physiotherapists 43
4.2 Pilot study plan 44
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4.2.1 Objectives 44
4.2.2 Target setting 44
4.2.3 Subject recruitment process 44
4.2.4 Workflow of pilot study 45
4.2.5 Evaluation of pilot study 45
4.3 Evaluation Plan 46
4.3.1 Expected outcome 46
4.3.1.1 Patient outcome 46
4.3.1.1.1 Primary outcome 46
4.3.1.1.2 Secondary outcome 47
4.3.1.2 Healthcare provider outcomes 47
4.3.1.3 System outcome 48
4.3.2 Clients involved 48
4.3.2.1 Nature of patients 48
4.3.2.2 Number of patients 48
4.3.3 Design 49
4.3.4 Data analysis 49
4.3.4.1 Analysis of patient outcome 49
4.3.4.2 Analysis of healthcare provider outcome 50
4.3.4.3 Analysis of system outcome 50
4.3.5 Criteria for effectiveness 50
4.3.5.1 Patient outcome 50
4.3.5.2 Healthcare provider outcome 51
4.3.5.3 System outcome 51
Chapter 5 Conclusion 52
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Reference 53
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List of figures and tables
Table 1. Material cost of conventional therapy and NPWT 35
Table 2. Cost of training per staff 36
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Appendix
Appendix 1. Tables of Evidence 55
Appendix 2. Table of Critical Appraisal 63
Appendix 3. Search Strategies 75
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Chapter 1 Introduction
1.1 Background
Globally, there are over 120 million patients having diabetic mellitus. Diabetic foot
ulceration is one of the common complications that may cause amputation due to
infection. Diabetic foot is related to problems of peripheral nerve and vessels.
Peripheral neuropathy means nervous system damaged with insensate foot which
causes unawareness of foot injuries. Patients also have microangiopathy from
vascular disease and narrowed arteries that lead to ischemia and ulceration. Wound
healing is difficult due to impairment of immune system from diabetes. Globally,
there are nearly 35 % admissions for hospitalization from diabetic problems (Gupta &
Singh, 2012). There are about 80% cases of non- traumatic lower limbs amputation
from diabetic foot (Gupta & Singh, 2012). The clinical issues of diabetic foot ulcer
and amputation are significant globally.
1.2 Significance
In Hong Kong, 1 out of 10 people have diabetic mellitus (Shiu & Wong, 2011).
There are about 50% amputations from diabetes (Wong, 2005, as cited in Shiu &
Wong, 2011). The life time risk of ulceration is about 25% (Boulton, Vileikyte,
Ragnarson- Tennvall & Apelqvist, 2005). The life time risk of amputation is 15 times
in diabetic patients in America compared to patients without diabetics (Leung, Ho,
Carnett, Lam & Wong, 2001). The amputation figures in Hong Kong may be similar
to those in America due to similar prevalence of diabetes, lifestyle and disease pattern
(Leung et al., 2001). Quality of life is severely disturbed from low productivity after
amputation. Also, wound healing is difficult in diabetic patients. Therefore, due to
high prevalence of diabetes with its complications and high severity level of
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complications, these imply a significant issue to patients. In nursing care, dressing is a
key part of wound care for diabetic ulcer and amputation wounds. It is necessary to
improve our nursing care on wound healing. So, it also implies a significant issue to
nurses.
1.3 Affirming needs
Although there are different types of dressing materials for wound care of diabetic
foot ulceration and amputation wounds, we do not have an evidence based guidelines
of diabetic wound care in our clinical setting. The current practice of dressings
include non- adherent or low- adherence dressing, hydrocolloids, hydrogels, foams,
alginates, iodine preparations, silver- impregnated etc.
1.3.1 Current practice
Non- adherent or low adherence dressing refers to using non- adherent or gauze
with normal saline to provide a moist environment (Hilton, Williams, Beuker, Miller
& Harding, 2004).
Hydrocolloids are semi-permeable to vapor and occlusive to exudates to provide a
moist environment. However, some studies found using hydrocolloids may increase
risk of wound infection (Foster, Spencer & Edmonds, 1997; Lawrence, 1995; Lithner,
1990, as cited in Hilton et al., 2004).
Hydrogels are similar to hydrocolloids except they give more moisture for
debridement wound. However, using hydrogels on ischemia wound may form wet
gangrene that causes serious problems (Hilton et al., 2004).
Foam based dressings can absorb discharge and act as thermal isolation (Hilton et
al., 2004). However, they cannot help wound infection.
Alginates can also absorb exudates. They are bacteriostatic (Hilton et al., 2004).
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Iodine preparations are antiseptics. However, some studies show that it is toxic to
fibroblasts and keratinocytes and there is no difference in wound healing of using
iodine preparation dressing compared to saline dressing with statistical significance
(Balin & Pratt, 2002; Damour et al., 1992, as cited Hilton et al., 2004).
Silver- impregnated dressing can inhibit activity of bacteria (Hilton et al, 2004). It
includes silver nitrates and silver sulfadiazine. Silver nitrate is cytotoxic to bacteria
and treats hypergranulating tissue. Silver sulfadiazine has antimicrobial effect and can
be used on burn and chronic wounds. Silver coated dressing is more effective on
killing bacteria than silver nitrate and silver sulfadiazine (Wright, Lam & Burrel, 1998,
as cited in Hilton et al., 2004). However, there are not much randomized controlled
trials showing effectiveness of these dressings in diabetic foot wounds.
Protease modulating dressings can promote wound healing by decreasing
proteolytic enzymes and inhibiting its activities.
1.3.2 Studies for current studies
However, in systemic review, there is no high quality evidence showing dressing by
“hydrocolloids, iodine- preparation and modulated protease” better in wound healing
than dressing by basic materials (Dumville, Soares, Meara & Cullum, 2002). Also,
there are no evidence showing statistical significant difference in wound healing
between “more expensive and cheaper dressings” and “antimicrobial and non-
antimicrobial dressings” in non- complex wounds (Dumville, Soares, Meara &
Cullum, 2002). And, low or very low quality of evidence showing advanced dressing
is better than the basic one because of bias (Dumville, Soares, Meara & Cullum,
2002). There is lack of high quality evidence showing hydrocolloid is better than any
other dressings. Also, only low quality studies showing hydrogel and foam dressing
are more effective in healing than basic wound care dressings (Dumville, Soares,
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Meara & Cullum, 2002).
In my clinical setting, there are different types of dressing materials used for
diabetic wound care. However, problems of ulceration and amputation are still
significant. In literature review, there is another new practice which is negative
pressure wound therapy (NPWT) for healing of diabetic ulcer and amputation wound.
However, this new intervention is not commonly used in Hong Kong hospital settings
and my clinical area. In my clinical setting, we only use this therapy in wounds with
severe discharge according to UCLA (University of California, Los Angeles) which
claimed that this therapy can be used in wounds with edema, infection, poor blood
supply and trauma. We do not set any guidelines with evidence to implement NPWT
for severe discharge wound, diabetic foot ulceration or diabetic amputation wound.
The practice of diabetic wound care is inconsistent among different health care
professionals. And, there is no any clear evidence based guidelines for dressings used
on diabetic ulceration and amputation wounds. Therefore, there is a need to set a
guideline to standardize the practice by using new intervention of NPWT which is
more effective with evidence of high quality research on diabetic ulceration and
amputation wound.
1.4 Research question, aim and objectives
1.4.1 Research question
Is NPWT effective in treating diabetic ulceration and amputation wound for
diabetic patients in inpatient and outpatient settings?
Aim
To set up a guideline with evidence to implement NPWT for patients with diabetic
ulceration and amputation wounds in inpatient and outpatient setting.
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1.4.2 Objectives
1. To look at therapeutic effectiveness of implementing NPWT for patients with
diabetic ulcer and amputation wounds by reviewing evidence.
2. To evaluate potential of implementation and set up evidence based guidelines of
NPWT for treating diabetic ulcer and amputation wounds in Hong Kong inpatient
and outpatient settings.
Chapter 2 Appraisal
2.1 Searching
2.1.1 Keywords in database
A systematic searching has done until 8th
September, 2013 from several databases
of Medline, CINAHL PLUS and PubMed. The keywords include “vacuum assisted
closure or negative pressure wound therapy”, “diabetic” and “outpatient or home”.
The articles searched were limited to randomized controlled trials (RCTs) during
searching. A searching process is referred to Appendix 3. After excluding those
articles that has been reviewed, there are total 4 articles for inpatient setting and 2
articles for outpatient setting from Medline. The articles searched from CINAHL
PLUS and PubMed are repeated from those in Medline. There are no additional
relevant studies after assessment of reference lists.
2.1.2 Selection Criteria
2.1.2.1 Inclusion criteria
The inclusion criteria include adults aged equal or greater than 18 with diabetic
ulcer or amputation wound. The intervention is VAC or NPWT in inpatient, outpatient
or home. The higher level of design is included like RCTs.
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2.1.2.2 Exclusion criteria
The wounds that are not related to diabetes are excluded.
After searching, there are 4 RCTs for NPWT used in inpatient setting and 2 case and
control studies for outpatient setting.
2.2 Extraction of Evidence
Table of evidence is formed from reviewing selected 6 articles according to Scottish
Intercollegiate Guidelines Network (SIGN). Table of evidence is referred to Appendix
1.
2.3 Quality Assessment
2.3.1 Critical Appraisal
Critical appraisal was done for selected 6 studies according to appraisal checklists
from Scottish Intercollegiate Guideline Network (SIGN). The table of critical
appraisal is referred to Appendix 2.
2.3.2 Summary of quality assessment from RCTs
There are 4 studies conducting RCTs (Armstrong, Marston, Reyzelman & Kirsner,
2012; Paola et al., 2010; Ravari et al., 2013; Sepulveda et al., 2009). All these studies
have an appropriate and clear question and use randomization for assignment of
subjects to treatment and control groups. Two studies use computer randomized
procedure for assignment (Paola et al., 2010; Sepulveda et al., 2009). Armstrong et al.
(2012) uses number blocks. Ravari et al. (2013) uses simple randomization based on
admission date. Therefore, all 4 studies can prevent selection bias by using
randomization for allocation to avoid difference between subjects in intervention and
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control group. Two studies state that using concealment (Armstrong et al., 2012;
Sepulveda et al., 2009). Two studies have single blind about treatment allocation
(Armstrong et al., 2012; Sepulveda et al., 2009). Only researcher for analysis is
blinded in both studies because both mention it is not possible to blind subjects and
clinicians due to nature of difference in treatment devices. Another two studies do not
mention blinding clearly (Paola et al., 2010; Ravari et al., 2013). All these 4 studies
have similar treatment and control groups before conducting trial (Armstrong et al.,
2012; Paola et al., 2010; Ravari et al., 2013; Sepulveda et al., 2009). So, this can
prevent selection threat to avoid preexisting difference between groups before
manipulation and increase level of internal validity. Armstrong et al. (2012) has
similar demographic characteristics except having larger baseline wound size in VAC
group. However, the study uses non parametric analysis of covariance to conduct
analysis by including the baseline wound size and shows non- inferiority of Smart
Negative Pressure (SNaP) to VAC group at most time intervals and shows same result
of having no statistical significant difference in proportion of participants in healing
between groups. So, this baseline wound size difference does not have a significant
affect on outcome. Paola et al. (2010) also has similar baseline demographic
characteristics between groups except the difference in number of subjects having oral
therapy for diabetes. Ravari et al. (2013) also has only the difference in treatment of
ulcer history between treatment and control groups. Both of them do not significant
impact on outcome. On the other hand, four studies show that there is no difference
between groups other than intervention to prevent performance bias and there are no
other confounding factors to affect the relationship between independent (NPWT) and
dependent variables (For example, time of healing) to increase internal validity.
Majority of measurements of outcome in these 4 studies are appropriate and valid to
increase construct validity. However, Paola et al. (2010) uses subjective measure of
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wound and Ravari et al. (2013) does not clearly mention the measure of granulation
formation. 3 studies have no drop out during trials (Paola et al., 2010; Ravari et al.,
2013; Sepulveda et al., 2009). Only Armstrong et al. (2012) has high drop out rate of
37.1% and may result in attrition bias. However, this study uses intention to treat for
analysis to prevent attrition bias. Only 2 studies mention the site of centers
(Armstrong et al., 2012; Sepulveda et al., 2009). Armstrong et al. (2012) uses
multicenter approach while Sepulveda et al. (2009) only uses one center in study.
Another 2 studies do not mention the site of centers clearly (Paola et al., 2010; Ravari
et al., 2013). Using multicenter approach can prevent sampling bias to increase
generalizability in external validity.
2.3.2.1 Other limitation
Sepulveda et al. (2009) has small sample size. However, it uses a pilot study and
calculates sample size by considering 95% confidence interval and 80% power.
Sepulveda et al. (2009) mentions using central suction system for implementation of
NPWT and this prolongs hospitalization. Only Sepulveda et al. (2009) mentions
having trained nurse to carry out treatment, while other studies do not mention it.
Ravari et al. (2013) has small sample size. And, the p-value for percentage of
participants having granulation formation in both groups is not mentioned. Armstrong
et al. (2012) also does not show p- value for complication rate in both groups.
2.3.3 Summary of quality assessment from case and control studies
In outpatient setting, only retrospective studies are found. There are 2 retrospective
studies about participants using NPWT in outpatient setting (Fife, Walker, Thormson
& Otto, 2008; Lavery, Boulton, Niezgoda & Sheehan, 2007). Both these 2 studies
have an appropriate research question. Larvey et al. (2007) assesses proportion of
patients with diabetic foot ulcer to achieve successful outcome with NPWT by
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database analysis compared to standard wound treatment from historical meta-
analysis of RCTs. Fife et al. (2008) assesses safety of VAC used in outpatient
compared to prior to VAC and non - VAC. And both have well defined population,
cases and controls. Lavery et al. (2007) uses population with diabetic foot ulcer with
defined mean original wound size and duration. Lavery et al. (2007) uses population
from data of Kinetic Concept Inc. about medicare reimbursement between 1996 and
2004 to receive NPWT in outpatient setting for wound care as case group while uses
data from a meta- analysis by Margolis‟s study to receive wet to moist therapy as
control group. File et al. (2008) uses population with diabetic foot ulcer by Wagner
grade II and III. Fife et al. (2008) uses data of wounds from Intellicure Inc. in wound
centers from 13/7/2001 to 24/11/2006 to receive NPWT as cases and Non NPWT and
those prior to NPWT as controls. Both 2 studies do not state clearly the selection and
exclusion criteria for cases and controls. Lavery et al. (2007) only mentions selection
criteria. Both studies cannot state percentage of participation in case and control
groups and compare the participants and non participants for difference to ensure the
representativeness of sample. It is because both studies use eligible subjects in
databases as sample population. Since both studies use databases for analysis,
assessors are not blinded for analysis. Both objective and subjective measures are
used in measuring outcome in these 2 studies. Lavery et al. (2007) uses discharge of
wound care to measure successful outcome for cases and controls. Larvey et al. (2007)
may also use subjective evaluation which is not clearly mentioned to evaluate and
document wound condition. Fife et al. (2008) uses the number of antibiotics use,
number of culture, number of pain medication prescription to measure adverse effects
like infection, pain. However, subjective measure of documentation from clinicians
and nurses in electronic medical records is also used for measure drainage and
bleeding. Only Lavery et al. (2007) states the presence of potential confounder. There
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is no information about comorbidities and vascular condition mentioned in NPWT
group and this underestimates the outcome since control group has ruled out these
comorbidities in randomized controlled trials (Lavery et al., 2007). Both studies use
p- value less than 0.05 as statistical significance.
2.3.3.1 Other limitations
Larvey et al. (2007) shows difference in subject characteristics between NPWT and
control groups due to the way of subjects being selected. Although a matching is done
to exclude subjects who aged above 70 and include wounds in more than 1 month and
to stratify data according to original size as well as duration of wound for analysis, it
is not ensured that the subjects in NPWT group are non- ischemic and non-infected as
control group. Another limitation is inconsistency of wound location in NPWT and
control groups (Larvey et al., 2007). Also, the outcome of NPWT and control group
may have a slight difference (Larvey et al., 2007). NPWT group states the outcome of
having sufficient granulation while control group states the outcome of having full
epithelialisation. But, both use discharge of wound care to measure successful
outcome for cases and controls. Both limitations do not have a significant effect to
bias the outcome of NPWT. Fife et al. (2008) does not clearly state the data of adverse
effects and only have the outcome with p - value.
2.4 Summary of Evidence
2.4.1 Sample size
The sample size of 4 RCTs is ranged from 24 to 132 (Armstrong et al., 2012; Paola
et al., 2010; Ravari et al., 2013; Sepulveda et al., 2009). The sample size of 2 cases
and controls is larger with 1299 and 1721(Fife et al., 2008; Lavery, et al., 2007). Only
two studies mention if any loss of follow up data (Armstrong et al., 2012; Sepulveda
23
et al., 2009). Armstrong et al. (2012) mentions to have only 115 data of follow up
while Sepulveda et al. (2009) mentions no loss of follow up. Another two RCT studies
do not mention any loss of follow up. In the two cases and controls studies, Fife et al.
(2008) uses data from Intellicure Inc. in wound centers and Lavery et al. (2007) uses
data from Kinetic Concepts Inc. about Medicare reimbursement for NPWT wound
care and data from a meta analysis in Margolis‟s study. And only 2 RCTs mention
using approaches of one center or multicenter. Armstrong et al. (2012) claims the
study uses 17 wound care centers and Sepulveda et al. (2009) claims the study uses
one vascular surgery department in a hospital.
2.4.2 Sample characteristics
Most participants recruited in these studies are male. The mean age group for the
participants from all studies is above 60 years old. Four studies plus 1 RCT in 1 study
include patients having diabetic ulcers (Armstrong et al., 2012; Fife et al., 2008;
Lavery et al., 2007; Paola et al., 2010; Ravari et al., 2013). One study plus 1 RCT in 1
study include patient with diabetic foot amputation wounds (Paola et al., 2010;
Sepulveda et al., 2009). Majority have diabetic mellitus with or without control. Two
studies mention patients with diabetic mellitus having commodities like dyslipidaemia,
arterial hypertension (Fife et al., 2008; Paola et al., 2010). Three studies mention
patients with peripheral neuropathy (Armstrong et al., 2012; Lavery et al., 2007; Paola
et al., 2010). Three studies mention vascular assessment has been done (Armstrong et
al., 2012; Paola et al., 2010; Sequlveda et al., 2009). For example, include patients
with venous stasis disease, peripheral arterial disease, undergone pulse volume
measurement, revascularization and transcutaneous oxygen pressure (TcPO2)
measurement after revascularization. Size of wound is mentioned in 3 studies ranging
from 9.95cm2 to 39.5cm2 in VAC group and ranging from 1.61 cm2 to 36.9cm2 in
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moist dressing group and 5.37cm2 in SNaP group (Armstrong et al., 2012; Lavery et
al., 2007; Ravari et al., 2013). Wound level is mentioned in 2 studies with diabetic
wound staged at II and III using University of Texas Classification (Fife et al., 2008;
Paola et al., 2010). And 1 study includes stage I wound for skin graft procedure (Paola
et al., 2010). Five studies include diabetic wound treated with therapies before
(Armstrong et al., 2012; Lavery et al., 2007; Paola et al., 2010; Ravari et al., 2013;
Sepulveda et al., 2009). For example, debridement, surgical or medical treatment, off
loading, shower therapy, saline solution. 2 studies include patients with infection
treated with antibiotics before and during therapy (Paola et al., 2010; Sepulveda et al.,
2009).
2.4.3 Intervention
In intervention group, subjects of all studies use NPWT as therapy. Only 1 study
uses SNaP as a type of NPWT in intervention group (Armstrong et al., 2012). While
the other studies use VAC (Kinetic concept Inc.) except 1study does not clearly
mention which type of NPWT (Sepulveda et al., 2009). NPWT consists of several
components and delivers negative pressure to wound. First, it uses foam dressing like
polyurethane ester sponge with large pores (400-600um) for covering (Sepulveda et
al., 2009). Then, a tube of Nelaton 16 is put within foam through aperture of surface
(Sepulveda et al., 2009). Afterwards, a transparent impermeable bandage or non -
occlusive dressing is used to seal up foam dressing (Paola et al., 2010; Sepulveda et
al., 2009). Another side of tube is connected to a machine to deliver negative pressure
for evacuation (Ravari et al., 2013; Sepulveda et al., 2009). The negative pressure is
controlled to a range from 100mmHg to 125mmHg according to 2 studies (Ravari et
al., 2013; Sepulveda et al., 2009). One study uses SNaP (SNaP, Spiracur, Inc.) which
uses mechanical power and springs to deliver negative pressure for use in ambulatory
25
setting (Armstrong et al., 2012). NPWT can be used on diabetic foot ulcers and
amputation wounds. In 5 studies, NPWT is used as therapy for foot ulcers (Armstong
et al., 2012; Fife et al., 2008; Lavery et al., 2007; Paola et al., 2010; Ravari et al.,
2013). One study uses it after skin graft application on foot ulcers (Paola et al., 2010).
Two studies use NPWT on amputation foot wounds including toes (Paola et al., 2010;
Sepulveda et al., 2009). Five studies mention ulcer treatment is done before NPWT
application like debridement, offloading, compression therapy, shower, saline solution,
treated with antibiotics for infection ( Armstrong et al., 2012; Lavery et al., 2007;
Paola et al., 2010; Ravari et al., 2013; Sepulveda et al., 2009). Three studies mention
the time for changing dressing ranging from 3 times per week to every 3 days (Paola
et al., 2010; Ravari et al., 2013; Sepulveda et al., 2009).
2.4.4 Comparison
Five studies include conventional therapy in comparison group. In these 5 studies, 3
studies include wet to moist dressing (Lavery et al., 2007; Paola et al., 2010; Ravari et
al., 2013). It involves cleansing with sterile serum with bandage covering. And only
Ravari et al. (2013) mentions the dressing change twice per day. Lavery et al. (2007)
uses data from a meta- analysis by Margolis‟s study to represent the comparison
group. Paola et al. (2010) uses graft dressing by covering non- adherent gauze. Other
2 studies include more advanced dressing depending on exudates (Paola et al., 2010;
Sepulveda et al., 2009). Paola et al. (2010) mentions advanced dressing including
alginate, hydrofiber, silver dressing or polyurethanes. Sepulveda et al. (2009)
mentions using hydrocolloid, woven gauze, petrolatum emulsion and bandage for
wound with less than 50% saturation while using alginate and bandage for wound
with more than 50% saturation. Only Sepulveda et al. (2009) mentions dressing
change every 48 to 72 hours. Fife et al. (2008) mentions using VAC (prior to therapy)
26
and Non - VAC as comparison group. Armstrong et al. (2012) includes VAC as
comparison group to compare with SNaP (intervention group).
2.4.5 Follow up
The follow up period of all studies is ranging from 14 days to 5 years. Four studies
have follow up period more than 100 days (Armstrong et al., 2012; Fife et al., 2008;
Lavery et al., 2007; Paola et al., 2010). Ravari et al. (2013) has shortest follow up
period with 14 days.
2.4.6 Outcome
Outcome measurement for NPWT has several dimensions. One study uses the
measurement of change in wound size and depth and shows statistically significant
decrease in wound size and depth comparing to moist dressing (Ravari et al., 2013).
Two studies use the percentage of participants having formation of granulation tissue
and percentage of wounds getting closure with sufficient granulation (Lavery et al.,
2007; Ravari et al., 2013). Lavery et al. (2007) shows statistically significant larger
percentage of wounds getting healing with sufficient granulation by using NPWT.
Two studies use measurement of time in terms of days for complete closure with
development of granulation tissue and control of infection in amputation wounds
(Paola et al., 2010; Sepulveda et al., 2009). Sepulveda et al. (2009) specifies healing
time with 90% granulation without infection. Both studies show statistically
significant decrease in time for healing with NPWT. Besides, three studies mention
the percentage of complications (Fife et al., 2008; Paola et al., 2010; Ravari et al.,
2013) Ravari et al. (2013) mentions percentage of amputation while Paola et al. (2010)
mentions the time needed for surgical treatment that having amputation. File et al.
(2008) mentions periwound complications, number of antibiotics and pain medication,
sanguineous drainage of using NPWT. All of these studies show statistically
27
significant lower percentage of amputation, operation time for amputation and less
complication on periwound and antibiotics prescription. The number of pain
medication prescription has no statistically difference in both groups and no one
discontinue NPWT due to adverse effect (Fife et al., 2008). One study shows
statistically significant increase in percentage of complete graft take rate with using
NPWT (Paola et al., 2010). One study shows decrease in cost of NPWT treatment
including cost of a nursing visit and twice nursing visits in control group (Lavery et
al., 2007). One study mentions SNaP shows statistically significance having non -
inferiority (not clinically inferior to control) of decrease in percentage of wound area,
application time and interruption in daily activities compared to VAC with statistical
significance (Armstrong et al., 2012). There is no statistically difference for perceived
level of pain and effectiveness between SNaP and VAC. In patient‟s satisfaction level,
Ravari et al. (2013) shows statistical significant higher percentage of satisfaction level
in NPWT group. Lavery et al. (2007) shows NPWT is beneficial for small wound
healing which is faster in healing than large wound and treatment success of using
NPWT is similar between wounds in different duration. On the other hand, two
studies use photographic documentation (Paola et al., 2010; Sequlveda et al., 2009).
Paola et al. (2010) evaluates at enrollment, intermediate and end stages. Sequlveda et
al. (2009) evaluates weekly. Paola et al. (2010) uses planimetry of superficial wounds
for wound dimensions and use subjective estimation for wound bed, depth and
granulation tissue. Ravari et al. (2013) uses vernier caliper to measure depth of wound
in biggest vertical diameter. Armstrong et al. (2012) uses wound tracings by Visitrak
wound measurement system to measure wound size.
\
28
2.5 Synthesis of Evidence
2.5.1 Assessment
2.5.1.1 Assess risk factors to NPWT
Thoughtful assessment before implementing NPWT for patients is essential. Four
studies mention different risk factors to NPWT which are excluded in studies
(Armstrong et al., 2012; Paola et al., 2010; Ravari et al., 2013; Sepulveda et al., 2009).
For example, infection, untreated osteomyelitis, malignancy receiving chemotherapy
or radiotherapy, ischemia, Charcot foot syndrome, uncontrolled hyperglycemia, renal
failure, used growth factors or hyperbaric oxygen or bioengineered tissue in past
thirty days, severe malnutrition, taken steroid or immunosuppressive drugs and
pregnancy (Armstrong et al., 2012; Paola et al., 2010; Ravari et al., 2013; Sepulveda
et al., 2009).
2.5.1.2 Assess neuropathy and vascular perfusion
Assessment of neuropathy and vascular perfusion are important before using
NPWT. Neuropathy assessment can be performed by using Semmes-Weinstein
10g-monofilament test (Armstrong et al., 2012; Paola et al., 2010). Vascular
assessment for ruling out any ischemia of foot is crucial by assessing pulse or duplex
or transcutaneous oxygen tension (TcPO2) on dorsal part, skin perfusion pressure or
index of ankle brachium (Armstrong et al., 2012; Paola et al., 2010; Sepulveda et al.,
2009). Armstrong et al. (2012) states sufficient peripheral perfusion is either one of
the following including TcPO2 of dorsum greater than 30mmHg, pressure of skin
perfusion greater than 30mmHg, ankle brachial index within 0.7 and 1.2.
Revascularization is needed for those with insufficient peripheral perfusion.
2.5.1.3 Assess stage of wound
29
Diabetic wound staged I, II and III is recommended for using NPWT. Staging
assessment is necessary by using University of Texas Classification. Diabetic wounds
with stage II and III using University of Texas Classification are done in 2 studies
(Fife et al., 2008; Paola et al., 2010). And one study also includes stage one wound for
NPWT application after skin graft procedure (Paola et al., 2010).
2.5.2 NPWT application
Firstly, it uses foam dressing like polyurethane ester sponge with large pores
(400-600um) to cover wound (Sepulveda et al., 2009). Then, a tube of Nelaton 16 is
put within foam through aperture of surface (Sepulveda et al., 2009). Afterwards, a
transparent impermeable bandage or non occlusive dressing is used for sealing up
(Paola et al., 2010; Sepulveda et al., 2009). Another side of tube is connected to a unit
to deliver negative pressure for evacuation (Ravari et al., 2013; Sepulveda et al.,
2009). The negative pressure is controlled to a range from 100mmHg to 125mmHg
according to 2 studies (Ravari et al., 2013; Sepulveda et al., 2009). Five studies use
VAC from Kinetic concept Inc which use electrical power for operation (Armstong et
al., 2012; Fife et al., 2008; Lavery et al., 2007; Paola et al., 2010; Ravari et al., 2013).
One study uses SNaP (Smart Negative Pressure from SNaP, Spiracur, Inc.) which uses
mechanical power and springs to deliver negative pressure in ambulatory setting
(Armstrong et al., 2012). NPWT can be used on diabetic foot ulcers and those after
skin graft procedure and amputation wounds including toes. Time for changing
dressing is recommended within 3 times per week and every 3 days (Paola et al., 2010;
Ravari et al., 2013; Sepulveda et al., 2009). Ulcer treatment can be done before
NPWT application like debridement, offloading, compression therapy, shower, saline
solution, treated with antibiotics for infection (Armstrong et al., 2012; Lavery et al.,
2007; Paola et al., 2010; Ravari et al., 2013; Sepulveda et al., 2009). Also, monitor for
30
adverse effect is important like periwound complication, drainage, infection (Fife et
al., 2008). Pain medication should be given before implementation to increase
compliance (Fife et al., 2008). Also, NPWT is recommended to be used on small
wound which is even healed faster than large wound and can be used on wounds in
long duration that are not healed from other therapies because outcome of success by
using NPWT is similar in wounds with different duration (Larvey et al., 2007). SNaP
is recommended used in ambulatory outpatient setting as it decreases application time
and interruption in daily activities compared to VAC with statistical significance in
Armstrong‟s study to reduce hospitalization. Using NPWT in outpatient can also show
clinical benefit in healing in Lavery‟s study and is safe when using in outpatient
setting in Fife‟s study. Also, using NPWT in home reduces cost compared to
conventional treatments (Larvey et al., 2007).
Chapter 3 Implementation
3.1 Implementation potential
The transferability of findings, feasibility and cost- benefit ratio of NPWT
implementation will be evaluated.
3.1.1 Target setting
The target setting is a mixed general surgical ward in a private hospital in Hong Kong.
There are estimated 10% of admissions admitting for surgical treatment due to
diabetic foot ulcer. There are estimated 25% patients having diabetic mellitus who are
having diabetic ulcer and amputation wounds.
3.1.2 Target audience
The target audience includes wound nurses and ward nurses.
31
3.1.3 Transferability of findings
The findings of studies are all from western countries. This practice can be
transferable to our Chinese society. Because using suction system for promoting
wound healing is acceptable in Chinese culture. In my clinical setting, we have
already used NPWT on wound dressing. However, we only use this therapy on the
wounds with severe discharge. We do not have any guidelines or protocols of using
this therapy on diabetic wounds. In treating diabetic wounds, we only use
conventional therapy which is not based on good quality of evidence. This latest
innovation can be applied in my clinical setting. In our philosophy of care, we have
medical foundation to support research activities, educational activities and
improvement of services to clients. Therefore, it can be transferred to our practice
setting, because the aim of apply evidence- based guidelines to improve our nursing
care. Also, our philosophy is committed to provide a quality total patient care and the
total patient experience is also important. It can be strive for the best medical
treatment and hospital care. Therefore, the innovation technology of NPWT can be
transferred to our setting, because using NPWT on diabetic wounds can increase
wound healing and increase patients‟ quality of care.
3.1.3.1 Target population
The target population in research is the clients with diabetic foot ulcer or diabetic
amputation wounds. From the reviewed studies, the clients are with diabetic foot ulcer
or with diabetic amputation wounds. Some are included in inpatient setting
(Armstrong, Marston, Reyzelman & Kirsner, 2012; Paola et al., 2010; Ravari et al.,
2013; Sepulveda et al., 2009). Some are included in outpatient setting (Fife, Walker,
Thormson & Otto, 2008; Lavery, Boulton, Niezgoda & Sheehan, 2007). In order to
maintain the similarity of the patients to the reviewed study which can be applied the
32
results, after reviewed the ward setting, many patients are having diabetes mellitus.
Some of them even have diabetic foot ulcer and need to have amputation. Patients can
use this therapy to increase healing. So, they can benefit from early discharge and
have follow up in outpatient for dressing with SNaP if necessary in setting. Most
nurses have already acquired skills of using this therapy for wounds with severe
discharge. However, there are no structural guidelines or protocol for using NPWT on
diabetic foot wounds. Therefore, ward nurses may not have sufficient skills and
knowledge to manage diabetic foot wounds.
3.1.4 Feasibility of implementation
3.1.4.1 Time frame
Nurses in the ward have low degree of freedom to carry out any new innovation like
NPWT on diabetic foot wounds patients. They have low degree of freedom to join
pilot study. Nurses would be required to report to organization first. The coordinators
of organization will make decision to apply this therapy. If undesirable effect of
innovation is notified, nurses can terminate the therapy first but need to report the
situation to organization before the termination of therapy. The implementation of this
therapy may fit smoothly with our current staff function due to limited disturbance to
present routine care. However, some barriers like inadequate knowledge, acceptability
and attitude may affect smooth implementation. Therefore, develop training
workshops can improve knowledge.
3.1.4.2 Staff training
The training workshop includes information presentation and training of
demonstration. The information section include etiology of diabetic foot ulcer,
introduction of NPWT and SNaP, assessment of diabetic foot wounds for NPWT,
ulcer therapy before NPWT, application of NPWT, administration of analgesia,
33
complication monitoring and evaluation of NPWT on diabetic foot wounds. Training
includes the demonstration of NPWT application and return demonstration.
Compulsory training workshops should be provided and compensate working hours
for staffs to increase cooperation. Training trainers is also important, because senior
nurses can become role models for implementation.
Although our organizational climate is conducive to evidence - based practice, their
acceptability and attitude and resource constraints may affect implementation.
Therefore, evidence, clear vision of objectives and significance and cost and benefit
ratio should be stated to gain support. Consensus should be developed among staffs
and administrators that NPWT is beneficial and should be tested in a pilot test. Well
communication can be facilitated in my setting through conference, staff intranet and
questionnaires. Majority of nurses may welcome for this new therapy since it can help
to reduce workload as dressing change is suggested every 2 to 3 days (Paola et al.,
2010; Ravari et al., 2013; Sepulveda et al., 2009) compared to daily dressing change
in conventional therapy. Communication among physicians, organization and nurses
can be facilitated through weekly conference to get mutual agreement. In ward setting,
nurse can inform the physicians about the need for revascularization and debridement
through documentation for implementation.
3.1.4.3 Availability of equipment and facilities
Although our hospital has already had NPWT for wounds with severe discharge, more
machines and materials should be purchased for implement on diabetic foot wounds
patients.
3.1.4.4 Cut of manpower
Nurses do not need to free from ward duty to implement this therapy as using NPWT
can save more time on dressing changes when compared to using conventional
34
therapy.
However, there is lack of measuring tools for evaluation on diabetic foot wound when
patients implement NPWT.
3.1.5 Cost- Benefit ratio of the innovation
During implementation of NPWT, patients can increase healing of diabetic foot
wounds and reduce potential of infection due to heavily discharge. The time for
complete closure of diabetic foot wounds by using NPWT decreases from 98 days to
65 days in average compared to conventional therapy (Paola, et al., 2010). Dressing
change from daily reduces to every 2 to 3 days for NPWT (Paola et al., 2010; Ravari
et al., 2013; Sepulveda et al., 2009). In material cost, using NPWT can save cost of
dressing including materials, manpower and inpatient daily cost due to decreased
hospital length of stay which require for dressing change. The nursing time spend on
dressing change for each patient decreases from 98 hours to 22 hours. The material
costs of implementing NPWT compared to conventional therapy shows in table 1. It
shows that hospital can save HKD$ 66053.6 for each patient when using NPWT and
overall cost of using NPWT in long term can be further lowered. Besides, table 2 will
show the cost of training section for NPWT education. The total cost of training one
staff for learning NPWT is $ 208.3.
35
Table 1 Material cost of conventional therapy and NPWT
Conventional wound therapy NPWT
Cost of each dressing materials (HKD$) 40 300
Daily rental cost of machine (HKD$) 0 700
Length of stay for complete healing
(days)
98 65
Dressing change per patient 98 22
Nursing time spend on dressing per
patient (hours)
1/2 x 98 = 49 1/2 x 22 = 11
Nursing salary per dressing (HKD$) 40,000/ (44 x 4) x 1/2 = 113.6 40,000/ (44 x 4) x 1/2 = 113.6
Total cost of dressing( material +
manpower) (HKD$)
(40 + 113.6) x 98
= 15052.8
(300 + 113.6) x 22
= 9099.2
Inpatient daily cost per patient (HKD$) 3200 3200
Total cost per patient (HKD$) 15052.8 + 3200 x 98
= 328,652.8
9099.2 + 3200 x 65 + 700 x
65 = 262,599.2
Saved on each patient if apply NPWT
(HKD$)
328,652.8- 262,599.2
= 66053.6
36
Table 2 Cost of training per staff
Cost of training Subtotal
Whole lesson (12 sections per month) 20000/12 $ 1666.7
1 hour training (20 staffs) 30,000/ 30/ 8 x 20 $ 2500
Stationary Free
Total cost of one training section $ 4166.7
Total cost of training per staff $4166.7/ 20 $ 208.3
3.1.5.1 Risk and benefit of the innovation
3.1.5.1.1 Potential risk of the patient
The potential nonmaterial costs of implementing NPWT may be the adverse effect
related to NPWT and SNaP including infection, maceration, allergic reaction to
dressing, pain, blisters (Armstrong et al., 2012). The adverse events of NPWT can be
avoided by close monitoring of system.
3.1.5.1.2 Potential benefit of the patient
The percentage of periwound complication of using NPWT is statistically
significant lower than that of using conventional therapy (File et al., 2008). Time for
infection control by using NPWT is statistically significant less than that by using
conventional therapy (Paola et al., 2010). Number of amputation by using NPWT is
statistically significant less than that by using conventional therapy (Ravari et al.,
2013). Quality of life is strongly related to amputation. Also, satisfaction level of
using NPWT from patients is statistically significant higher than that of using
conventional therapy (Ravari et al., 2013).
3.1.5.1.3 Potential benefits of the organization and ward nurses
37
On the other hand, the potential nonmaterial benefits of implementing NPWT to
organization are increase in reputation of organization due to reducing hospitalization
and medical cost and increase healing of wound. Better job satisfaction and decrease
in stress are the expected outcome due to decreasing workload of dressing change.
3.2 This section is to set up an evidence based guideline of implement NPWT on
diabetic foot after evaluating implementation potential.
3.2.1 Target user of guideline
Wound nurses and general nurses in inpatient and outpatient settings
3.2.2 Objective of guideline
To increase wound healing of diabetic foot
3.2.3 Rating scheme of recommendations
Grade will be present according to grading system and level of evidence from SIGN.
Level of evidence of 1+ and 2+ which refer to well conducted randomized controlled
trial and case control respectively are given.
Recommendation 1 (A)
Vascular perfusion assessment is needed before implementation by measuring pulse
or duplex or transcutaneous oxygen tension (TcPO2) on dorsum, pressure of skin
perfusion or ankle brachium index. Sufficient perfusion is showed by either one of the
followings including present pedal or posterior tibia pulse, height of pulse wave larger
than or equal to 5 mm, systolic pressure larger than or equal to 50 mmHg, TcPO2 of
dorsum larger than 30 mmHg, skin perfusion pressure larger than 30 mmHg, ankle
brachial index ranged from 0.7 and 1.2 or at least greater than or equal to 0.5.
38
Supporting evidence
Vascular assessment is done by evaluating pulse and using duplex scan and TcPO2
on dorsum to assess arterial situation so as to decide for need to perform
revascularization (Paola, et al., 2010) (1+)
Criteria of adequate perfusion can be showed through either presence of pedal or
posterior tibia pulse, height of pulse wave, systolic pressure of foot, ankle brachial
index greater than or equal to 0.5 and previous successful revascularization
(Sepulveda et al., 2009) (1+)
Definition of adequate perfusion is either TcPO2 of dorsum more than 30 mmHg,
skin perfusion pressure more than 30mmHg, or ankle brachial index within 0.7 and
1.2 (Armstrong et al., 2012) (1+)
Recommendation 2 (A)
Stage I, II and III diabetic foot wounds are suggested for using NPWT. Staging
procedure is done by either using University of Texas Classification or Wagner-
Meggitt wound classification.
Supporting evidence
Stage II and III diabetic foot wounds are included to use NPWT under Texas
Classification. Stage I diabetic foot wounds is recommended to use NPWT after skin
graft procedure to increase take rate (Paola, et al., 2010) (1+)
Stage II and III diabetic foot wounds under Wagner grade are included to use
NPWT (File, et al., 2008) (2+)
Recommendation 3 (A)
Ulcer treatment can be done before NPWT like debridement, offloading,
compression therapy, received shower, saline solution and antibiotics.
39
Supporting evidence
Debridement, offloading and compression therapy performed before therapy
(Armstrong et al., 2012). (1+)
Debridement is done before therapy (Lavery et al., 2007). (2+)
Antibiotic treatment is done before skin graft procedure and during therapy (Paola
et al., 2010). (1+)
Debridement, offloading and antibiotic treatment are performed before therapy
(Paola et al., 2010). (1+)
Shower therapy, saline solution, debridement, and antibiotic treatment to resolve
etiology from infection are done before therapy (Sepulveda et al., 2009). (1+)
Recommendation 4 (A)
Use foam dressing of polyurethane ester sponge with large pores of 400 to 600 um
with a Nelaton 16 catheter put within foam and use a transparent impermeable
bandage or non occlusive dressing for seal up. The tube is connected to a system to
give negative pressure.
Supporting evidence
Use polyurethane ester sponge with large pores of 400 to 600 um as foam dressing
and put a Nelaton 16 catheter inside foam (Sepulveda et al., 2009). (1+)
Use a transparent impermeable bandage or non - occlusive dressing to seal up
dressing (Paola et al., 2010; Sepulveda et al., 2009). (1+)
The tube of system is connected to a unit to give negative pressure for evacuation
(Ravari et al., 2013; Sepulveda et al., 2009). (1+)
Recommendation 5 (A)
Negative pressure is set within 100mmHg to 125 mmHg.
40
Supporting evidence
Suction system deliver 100 mmHg negative pressure (Sepulveda et al., 2009). (1+)
Negative pressure is controlled at 125 mmHg (Ravari et al., 2013). (1+)
Recommendation 6 (A)
SNaP (Smart Negative pressure from SNaP, Spiracur, Inc.) can be used in
ambulatory setting.
Supporting evidence
SNaP uses mechanical power to give negative pressure (Armstrong et al., 2012).
(1+)
Use SNaP statistical significantly decreases application time and interruption in
daily activities compared to vacuum assisted closure (Armstrong et al., 2012). (1+)
Recommendation 7 (A)
Time for dressing change of NPWT is ranged from every 2 to 3 days.
Supporting evidence
Dressing change for NPWT is 3 times per week (Paola et al., 2010). (1+)
Dressing change for NPWT is 48 to 72 hours (Sepulveda et al., 2009). (1+)
Dressing change for NPWT is every 3 days (Ravari et al., 2013). (1+)
Recommendation 8 (A)
Observe drainage and monitor complication during therapy including bleeding,
infection, maceration, allergic reaction to dressing, pain and blisters.
Supporting evidence
The adverse effect related to NPWT and SNaP including Infection, maceration,
allergic reaction to dressing, pain, blisters (Armstrong et al., 2012). (1+)
41
One subject from NPWT therapy presented bleeding (Sepulveda et al., 2009). (1+)
Recommendation 9 (A)
Adequate pain medication should be given before NPWT implementation.
Supporting evidence
There is no statistical significant difference in pain medications provision between
VAC and non VAC groups (File et al., 2008). (2+)
The perceived pain level has no statistical difference between SNaP and VAC
(Armstrong et al., 2012). (1+)
Recommendation 10 (C)
NPWT can be used on small wounds and wounds in long duration.
Supporting evidence
The healing time of small wound by using NPWT is shorter than that of large
wound (Lavery et al., 2007). (2+)
The wounds in long duration which are not healed from other treatments are
recommended to use NPWT as outcome of success is similar on wounds in different
duration (Lavery et al., 2007). (2+)
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Chapter 4 Plan for implementation and evaluation of intervention
4.1 Communication Plan
4.1.1 Stakeholders identification
In communication plan, it is important to firstly identify who are the stakeholders in
proposal. A stakeholder is the one who is affecting or being affected by the proposed
change. The stakeholders in this proposal include top administrative level like
Departmental Operational Manager (DOM), management level like Ward Manager,
frontline staffs like Ward nurses and Wound nurse specialist, physicians,
physiotherapists and patients with diabetic foot.
After identified the stakeholders, it comes to identify who are the most important to
affect feasibility and plan who should be talked to first. The Management level will be
talked to first followed by top administrative level, frontline staffs, physicians and
physiotherapists. Administrators are the one to make decision of approval to use
NPWT and frontline staffs are the one to implement NPWT for patients. Besides,
physicians are the one to make decision of debridement with infection and pain
control while physiotherapists will provide pressure relieving device.
4.1.2 Content of communication
In the process of communication, a clear vision with deadline should be given to
initiate the change. In presentation, a clear vision and accomplishment achieved
should be clearly explained. Comparative outcome of patients, staffs and system with
evidence should be presented. Data of healing time, length of hospital stay, workload
of staffs, cost and benefit for healthcare system should be discussed. Besides, flow of
implementation, scheme for staff training and additional support like resource manual,
43
measurement for evaluation and adjustment will also be given in presentation.
Success stories sharing in presentation can help increase engagement.
4.1.3 Communication timetable
A timetable of communication plan is needed to set up. One month is required to
set up communication team. One month is required to make appointment of ward
manger and give presentation. One month is required to make appointment of
administrative level (DOM), send documents and give presentation. One month is
required to communicate with frontline staffs. One month is required to communicate
with physicians and physiotherapists, send documents and present during group
meeting.
4.1.4 Communication with stakeholders
4.1.4.1 Management level
Communicate with ward manager is the first priority. Individual meeting and
presentation are required. High valued recommendation of feasibility in local setting
will be given. Therefore, adjustment of guideline can be discussed to increase
feasibility. Ward manager is the key person to firstly approve the intervention and
increase support from top management administrative.
4.1.4.2 Top administrative level (DOM)
Communicating with DOM is important because DOM decides the approval of
guideline. Individual meeting and presentation are needed.
4.1.4.3 Frontline staffs
Information of new guideline can be showed in posters, newsletter and hospital
internet. Focus groups can be formed for group discussion.
4.1.4.4 Physicians and Physiotherapists
44
Discussion with physicians and physiotherapists can be done during
multidisciplinary meeting every month.
4.2. Pilot study plan
A pilot study plan with evaluation is to determine feasibility of implementing
NPWT in order to avoid unexpected difficulties. The evaluation in pilot study plan is
used for revision and adjustment of guideline.
4.2.1 Objectives
The objective of setting up a pilot study plan to try out feasibility involving subject
recruitment process, workflow of guideline, staff training, compliance of using NPWT,
acceptance from patients and other healthcare workers.
4.2.2 Target setting
The target setting in pilot study will be a general surgical ward. The target audience
will be wound nurses and general nurses.
4.2.3 Subject recruitment process
Convenience sampling will be used for recruiting subjects. Convenience sampling
is a non - probability sampling and subjects are selected due to their convenient
accessibility. It is not selected by random selection. In pilot study, using convenient
sampling allows to get basic data without complication from using randomized
sample. The eligibility criteria with inclusion and exclusion are the same as the actual
study. There are totally about 100 patients admitted due to diabetic foot ulcer and
diabetic amputation in one year from 2013-2014 and 70 cases among them meet
eligibility criteria. After including 20% dropout rate from the treatment group, there
are 4 to 5 cases recruited. Therefore, about 1.5 months is required to recruit 7 cases.
45
Informed consent will be done during the process.
4.2.4 Workflow of pilot study
In the beginning, an in - service training will be provided. There are totally 32
nurses. Two training sessions per week is set up and each lasts for 6 hours. Total
number of 4 staffs will attend for each session. Therefore, 1 month is required to
finish training of 32 nurses. After training, another 1.5 months is required for
recruitment including assessment of eligibility criteria, signing informed consent and
undergoing debridement by physicians. After that, NPWT will be started during
period of 12 weeks. The time for complete closure of diabetic foot wounds by
implementing NPWT is 65 +/- 16 in term of days (Paola, et al., 2010). After
completion of NPWT, the patients may refer to physiotherapists for offloading and
exercise according to prescription during next 2 weeks. Then, the patient may be
discharged and follow up in outpatient area for 1 month. The measured outcomes
include wound healing, percentage of secondary amputation, acceptance of NPWT
from patients and health care workers, knowledge and skills during application of
NPWT and compliance of using NPWT. It will take 1 month to analysis of the
outcome measurement and evaluation of pilot result. Therefore, 8 months are required
to finish the whole pilot study.
4.2.5 Evaluation of pilot study
Evaluation for recruitment process, knowledge, skills and compliance are measured
by audit form in English. Wound healing will be measured by quantities of epithelial
and granulated tissues which are assessed by ward nurses and verified by physician
and nurse specialist. Percentage of amputation will also be measured. Acceptance of
NPWT from patients will be measured by asking a question after completion of
therapy. The question is “Do you find using negative pressure wound therapy
46
acceptable for your diabetic foot wound?” Patients are given 5 point likert scale.
Acceptance of NPWT from healthcare worker including nurses, physicians and
physiotherapists will be measured by asking “Do you find using negative pressure
wound therapy acceptable in your daily work?” after completion of therapy. They are
also given 5 point likert scale. Two questions will be asked by Chinese.
During evaluation, having review with management level by one to one interview
and frontline staffs by focus group interview to collect feedbacks can help revise
guideline and thus increase feasibility. Each focus group has 8 staffs. Four focus
groups are required for collection of feedbacks until data saturated.
4.3 Evaluation Plan
An evaluation plan include to identify expected outcome, nature and number of
clients involved, measurements, data collection, data analysis and criteria for an
effective guideline.
4.3.1 Expected outcome
The expected outcomes consist of 3 aspects including patient, healthcare provider
and system.
4.3.1.1 Patient outcome
4.3.1.1.1 Primary outcome
The Primary outcome is the time reduced for complete closure of wound in terms
of days. The complete closure of wound refers to complete coverage of epithelial
tissue and granulation (Lavery et al., 2007; Paola, et al., 2010). The quantity of
granulated tissue will be assessed by ward nurses and verified by physicians and nurse
specialist. Clinical photos will also be taken. Clinical photos will be reviewed by ward
47
nurses and verified by physicians and nurse specialist.
4.3.1.1.2 Secondary outcome
The secondary outcome for patient include the time reduced for infection control of
diabetic wound in terms of days, the percentage of amputation and acceptance of
NPWT.
Control of infection is the first step for wound healing. It is measured by
performing microbiological exam and assessing clinical signs. For example, exudates
production, extent of granulation. To control infection, NPWT requires 10 days while
advanced dressings require 19 days with statistical significance (Paola, et al., 2010).
Wound condition can be evaluated in first 10 days to anticipate wound healing and
thus make adjustment of therapy for continuing of NPWT.
Preventing amputation is an important outcome for patient because amputation
brings traumatized impact. The percentage of amputation will be measured.
Patient acceptance is related to compliance of therapy. A question will be asked
after completion of NPWT. The question is “Do you find using negative pressure
wound therapy acceptable for your diabetic foot wound? The 5 point likert scale will
be used to measure acceptance with 0 as totally unacceptable and 4 as totally
acceptable.
4.3.1.2 Healthcare provider outcomes
Healthcare provider outcomes include compliance, knowledge, skill, workload and
acceptance. The compliance, knowledge and skills will affect therapeutic outcome for
patient. They will be measured by using audit form. Workload of nurses is measured
by number of dressing changes. Acceptance of healthcare workers is related to
satisfaction and compliance. The question” Do you find using negative pressure
wound therapy acceptable in your daily work?” will be asked after completion of
48
NPWT and 5 point likert scale (0- 4) is given.
4.3.1.3 System outcome
System outcomes include length of hospital stay and the cost effectiveness. Faster
rate of healing helps reduce length of hospital stay which can be measured by using
discharge record. Cost effectiveness includes material and non - material costs like
cost of preventing amputation. Therefore, cost effectiveness cannot be measured
quantitatively.
4.3.2 Clients involved
4.3.2.1 Nature of patients
The nature of patients is based on eligibility criteria. It includes age of greater than
18 with diabetic foot ulcer or amputation wounds of stage I, II and III by using
University of Texas Classification (Fife et al., 2008; Paola et al., 2010). It includes
patient with sufficient peripheral perfusion. The transcutaneous oxygen tension
(PcPO2) of dorsal part is larger than 30 mmHg (Armstrong et al., 2012). Skin
perfusion pressure is greater than 30 mmHg (Armstrong et al., 2012). Ankle brachial
index is within 0.7 and 1.2 (Armstrong et al., 2012). The risk factors including
infection, untreated osteomyelitis, malignancy, ischemia, uncontrolled hyperglycemia,
Charcot foot syndrome, renal failure, used growth factors, hyperbaric oxygen or
bioengineered tissue during past 30 days, malnutrition, used steroid and
immunosuppressive medication and pregnancy should be excluded (Armstrong et al.,
2012; Paola et al., 2010; Ravari et al., 2013; Sepulveda et al., 2009).
4.3.2.2 Number of patients
The sample size is calculated from primary outcome. A two sample two - tailed
paired t – test will be used for analysis. The values of sigma are 16 and 45 and the true
49
difference of means is 33 (Paola et al., 2010). Take the power of 80% and 0.05 level
of significance, the sample size calculated is 36. After considering 20% dropout rate,
sample size required is 42.
4.3.3 Design
Convenient sampling method will be used. Because it is easy to use and the
participants are readily available. Demographic data of control group will be collected
from administrative data in hospital. Demographic data of study group will be
collected by nursing assessment during recruitment. The follow up will last for 150
days. All data will be collected every week for data comparison. Data of granulation,
exudates and infection status will be collected by wound assessment. Data of
compliance, knowledge and skill will be collected by audit form and return
demonstration. Only the question for acceptance from patient and healthcare provider
will be asked at the end of 150 days.
4.3.4 Data analysis
4.3.4.1 Analysis of patient outcome
In primary outcome, evaluation objective is to determine if time reduced for
complete closure of wound in terms of days. A two- tailed paired t-test for each
follow- up visit will be used.
In secondary outcomes, one of the evaluation objectives is to determine the time
reduced for infection rate of diabetic wound in terms of days and a two- tailed paired
t-test will be used. Another objective is to determine if the amputation rate is changed
after implementation of NPWT and a two- tailed z-test for testing proportion will be
used.
The value of study group will be compared to that of using advanced moist dressing
during same period in year 2014. A mean value for acceptance of NPWT from patient
50
will be obtained as there is no comparison value.
4.3.4.2 Analysis of healthcare provider outcome
The compliance, knowledge and skill of using NPWT will be evaluated by using
audit form. The percentage of compliance, knowledge and skill will be calculated. To
measure workload, the mean number of dressing change for each patient by using
NPWT in study period will be compared to that by using advanced moist dressing in
the same period of time in 2014. A two- tailed paired t-test will be used to determine if
the number of dressing change is reduced. A mean value for acceptance of NPWT
from healthcare provider will be obtained as there is no comparison value.
4.3.4.3 Analysis of system outcome
Length of hospitalization will be evaluated by using a two- tailed paired t-test to
determine if the length of hospitalization is reduced. The length of hospitalization for
each patient by using NPWT in study period will be compared to that by using
advanced moist dressing in the same period in year 2014.
4.3.5 Criteria for effectiveness
4.3.5.1 Patient outcome
The guideline is considered as effective if time for wound healing is reduced by 33
days after using the guideline compared to that of not using the guideline in 150 days.
It is because the complete wound closure requires 65+/- 16 days for NPWT group and
98+/- 45 days for advanced dressings group with statistical significance (Paola et al.,
2010). Therefore, 150 days is required for period of follow up. The difference in
wound healing time is 33 days when compared the outcome of using NPWT to that of
using advanced dressings (Paola et al., 2010). The guideline is also considered as
effective if time for infection control of wound reduces by 9 days after using the
51
guideline compared to that of not using the guideline in 150 days. The mean value of
time to control infection by using NPWT and advanced dressing is 10 days and 19
days respectively with statistical significance (Paola et al., 2010). Wound condition
can be evaluated in first 10 days to anticipate wound healing and make adjustment of
therapy in early period.
The effective guideline should show the rate of amputation by using NPWT during
study period is lower than that by using advanced moist dressing in the same period in
2014.
The mean value of acceptance from patient should be higher than 2 in the range of
0 to 4 showing that the acceptance is above neutral.
4.3.5.2 Healthcare provider outcome
The compliance, knowledge and skill are being audited. The rate should be above
80% because close monitoring with sufficient skill and knowledge is required to
prevent complication. The number of dressing change should be reduced after using
NPWT to decrease workload. The mean value of acceptance from healthcare provider
should be higher than 2 in the range of 0 to 4 showing that the acceptance is above
neutral.
4.3.5.3 System outcome
The number of hospitalization is expected to be reduced after using NPWT for an
effective guideline.
52
Chapter 5 Conclusion
Diabetic mellitus is common in Hong Kong. One of the common complications of
diabetic mellitus is diabetic ulceration which may lead to amputation. The risk of
amputation in diabetes is high due to difficulty of wound healing. The high cost of
wound management and amputation severely affect their quality of life and give
negative impact on patient, healthcare provider and system. The current practice
includes different types of dressings mentioned and its effectiveness cannot be shown
from high quality of evidence.
In this translational research study, literature review from selected studies to show
evidence of implementing NPWT on diabetic foot wounds. Critical appraisal was
done for selected 6 studies to assess quality. Summary and synthesis of evidence was
developed in literature review.
An evidence - based guideline was set up from recommendations in literature
review to implement NPWT for patients with diabetic ulceration and amputation
wounds in inpatient and outpatient setting. It includes vascular perfusion assessment,
wound staging, ulcer treatment before application of NPWT, application of material
during NPWT, pressure setting, using SNaP in ambulatory setting, dressing change,
complication monitoring and pain management. Implementation potential was
evaluated from transferability, feasibility and cost-benefit ratio of NPWT
implementation. A communication plan, a pilot study plan and an evaluation plan
were set up in implementation plan. The evidence- based guideline is expected to
show the effectiveness of NPWT on diabetic ulceration and amputation wounds
including to reduce time for complete closure of wound, infection control and prevent
amputation.
53
Reference
Armstrong, D.G., Marston, W. A., Reyzelman, A. M., & Kirsner, R.S. (2012).
Comparative effectiveness of mechanically and electrically powered negative
pressure wound therapy devices: a multicenter randomized controlled trial. Wound
repair and regeneration, 20, 332-341.
Boulton, A.J., Vileikyte, L., Ragnarson-Tennvall, G., & Apelqvist, J. (2005). The
global burden of diabetic foot disease. Lancet, 366, 1719- 1724.
Dumville, J.C., Soares, M.O., Meara, S.O., & Cullum, N. (2012). Systematic review
and mixed treatment comparison: dressings to heal diabetic foot ulcers.
Diabetologia, 55(7), 1902-1910.
Fife, C.E., Walker, D., Thomson, B., & Otto, G. (2008).The safety of negative
pressure wound therapy using vacuum- assisted closure in diabetic foot ulcer
treated in the outpatient setting. International wound journal, 5, 17-22.
Gupta, S.K., & Singh, S.K. (2012). Diabetic foot: a continuing challenge. Advance
expert medical biology, 771, 123-38.
Hilton, J.R., Williams, D.T., Beuker, B., Miller, D.R., & Harding, K.G. (2004). Wound
dressings in diabetic foot disease. Clinical infection disease, 39, 100-3.
Lavery, L.A., Boulton, A.J., Niezgoda, J. A., & Sheehan, P. (2007). A comparison of
diabetic foot ulcer outcomes using negative pressure wound therapy versus
historical standard of care. International wound journal, 4 (2), 103-113.
Leung, H.B., Ho, Y.C., Carnett,J., Lam, P.K.W., & Wong, W.C. (2001). Diabetic foot
ulcers in Hong Kong chinese. Hong Kong medical journal, 7 (4), 350-5.
Margolis, D.J., Kantor, J., Santanna, J., Strom, B.L., Berlin, J.A. (2000). Risk factors
for delayed healing of neuropathic diabetic foot ulcers: a pooled analysis. Archives
54
of dermatology, 136, 1531-5.
Paola, L.D., Carone, A., Ricci, S., Russo, A., Ceccacci, T., & Ninkovic, S. (2010). Use
of vacuum assisted closure therapy in the treatment of diabetic foot wounds. The
Journal of diabetic foot complications, 2 (2).
Ravari, H., Modaghegh, M, S., Kazemzadeh, G. H., Johari, H.G., Vatanchi, A. M.,
Sangaki, A., & Shahrodi, M. V. (2013). Comparison of vacuum- assisted closure
and moist wound dressing in the treatment of diabetic foot ulcers. Journal of
cutaneous and aesthetic surgery, 6 (1).
Sepulveda, G., Espindola, M., Maureira, M., Sepulveda, E., Fernandez, J.I., Oliva, C.,
Sanhueza, A., Vial, M., & Manterola, C. (2009). Negative- pressure wound therapy
versus standard wound dressing in the treatment of diabetic foot amputation. A
randomised controlled trial. Cirugia espanola, 86 (3), 171- 177.
Shiu, A,T,Y., & Wong, R.Y.M. (2011). Diabetes foot care knowledge: a survey of
registered nurses. Journal of clinical nursing, 20 (15-16), 2367- 2370.
55
Bibliograph
ic citation
Study
type
Patient characteristics
VAC SNaP
Intervention(s) Comparison Length of
follow up
Outcome measure Effect size Tool
Armstrong,
Marston,
Reyzelman &
Kirsner 2012
RCT
(1+)
1. Age
2. Diabetic Ulcer
3. Male
4. DM
5. Peripheral Neuropathy
6. Venous Stasis Disease
7. Peripheral Arterial Disease
8. Lower extremity edema
9. Anticoagulation/ Coumadin
10. Immobility
11. Steroid use
12. Immunosuppressed
13. Poor Nutrition
14. Baseline wound size (cm2)
15. Wound Age (randomization)
16. Wound Age (initial tx)
65.6
30.9%
63.2%
58.8%
44.1%
70.6%
16.4%
58.2%
29.9%
20.6%
6%
1.5%
1.5%
9.95
16.9
17.2
65
31.3%
48.4%
68.8%
40.6%
78.1%
23.4%
60.9%
32.8%
28.1%
4.7%
1.6%
7.8%
5.37
12.9
13.1
SNaP ( Smart
Negative
Pressure)
- Use mechanical
power and
specialized
springs to deliver
subatmospheric
pressure
- Can use in
ambulatory
setting due to
eliminate
constraints from
electric pump
VAC (Vacuum
assisted closure
therapy system), use
electrical power to
deliver
subatmospheric
pressure
Evaluate weekly
until complete
closure of wound
(complete
reepithelialization
with no drainage)
or up to 16 weeks
of treatment
1. Decrease in wound area at
4,8,12,16 weeks (%)
2. Proportion of subjects not healed
(%)
3. Proportion of subjects with
adverse incidence (%)
4. Time of application (mins)
5. Survey for activities of daily
living, overall activity, sleep,
noise, social situation,
wearability pain, perceived
effectiveness and satisfaction
1.4 weeks: -16.1
(p-value: 0.003)
8 weeks:1.2
(p-value: 0.013)
12 weeks:-3.6
(p-value: 0.0051)
16weeks:8.3
(p-value: 0.0044)
Non- inferiority:
p<0.0482
2.-10 (p=0.962)
3.-18.5 (no p-value
showed)
4.-8.02 (p<0.0001)
5.SNaP: less
interruption
(p<0.05) except no
sig diff. for pain&
perceived
effectiveness
Wound size:
wound tracings by
Visitrak wound
measurement
system
Neuropathy: a
five point,
Semmes-
Weinstein
monofilament test
-Debridement of necrotic tissue performed for specific
wound type ( Max. once/ week)
-Off loading performed for diabetic foot ulcer and
compression therapy used with venous ulcer
Appendix 1
56
Bibliographic
citation
Study
type
Patient characteristics Intervention(s) Comparison Length of follow
up
Outcome measure Effect size Tool
Fife,
Walker,Thormson
& Otto, 2008
Case
and
control
(2+)
-Data of wounds from Intellicure Inc. in wound
centers from 13/7/2001 to 24/11/2006
-Mean age: 60.4 years
-Comorbid medical problems (mean): 6
-Tobacco use: 10.7%
-DFU: Wagner grade II and III ulcers (II:
5.3% ,III: 6.2% used VAC)
VAC (during therapy) VAC (prior to therapy)
and Non VAC therapy
From 13/7/2001 to
24/11/2006
1. Number of
periwound
complications
2. Number of
antibiotic
prescriptions
3. Number of culture
taken
4. Number of pain
medications
prescriptions
5. Sanguineous
drainage
6. Discontinue
treatment
1. Less periwound
complications
(p<0.05)
2. Less antibiotic
prescriptions
(p<0.05)
3. Less culture done
(p<0.05)
4. No statistical diff.
in pain medication
use
5. No cases to use
sanguineous as
drainage in both
treatments
6. No VAC grouped
needed
discontinuation due
to bleeding
(No numbers of data
mentioned)
-Ulcers graded by
maximum Wagner
grade and
maximum volume
57
Bibliograph
ic citation
Study
type
Patient
characteristics
Intervention group
(s)
Comparison group Length of
follow up
Outcome
measures
Effect size
Lavery,
Boulton,
Niezgoda
& Sheehan,
2007
Case
and
control
(2+)
-Age( years)
NPWT:
58.5(+/-9.4)
Control: 58
-Gender(%male)
NPWT: 64.5
Control: 73.2
-Initial wound size
2( cm2, mean)
NPWT: 13.8+/-
15.8
Control: 1.61
-Wound duration
2 (weeks, mean)
NPWT: 26.5+/-
24.7
Control: 30
-Received NPWT( data collected by Kinetic Concepts Inc.(Medicare
Part B) from patients treated for wound care with NPWT in outpatient
setting as Medicare reimbursement between 1996 and 2004
-Complete wound therapy programme should have been tried before
NPWT
-Diabetic/ neuropathic chronic ulcer
-Debridement has done
-Comprehensive diabetes management
-Reduction in pressure of affected ulcer
-Description of wound size ( length & width)and duration (more or less
than 1 month) before NPWT
Exclusion criteria:
-untreated osteomyelitis or cancer within wound
-No record of treatment termination or no reason for treatment
termination or multiple treatment termination entries( exclude patients
with multiple wounds)
(n=1135)
-Patients older than 70 years and those with wounds of less than 1
month in duration (more „matched‟ demographics with control group)
-Received standard wet
to moist wound therapy
(data from a meta-
analysis by Margolis et
al)
-Neuropathic diabetic
foot ulcer participated in
control groups of five
different RCTs published
between 1992 and 1998
-Chronic wounds
-Diabetic/ neuropathic
ulcers
-appropriate offloading
-presence of adequate
perfusion
-Infection control
-Debridement of necrotic
tissue (n= 586)
After 12
and 20
weeks of
treatment
Primary outcome:
1.Wounds
achieved a
successful
treatment
endpoint (%) after
12 and 20 weeks,
data stratified by
initial wound size
and wound
duration
2.Expected 20
weeks cost ($)
including one
nursing visit/ day
and two nursing
visit/ day in
control group
1.-12weeks: +15.6 ( p<0.001)
-20weeks: +13.5 (p<0.001)
Initial wound size after 12 weeks:
-Small (<2cm2) :+13.7 (p<0.05),
-Medium (2-4cm2) :+25.8 (p<0.05)
-Large (>4cm2): +24 (p<0.05)
Initial wound size after 20 weeks:
-small: +11.4 (p<0.05), - Medium:+23.3 (p<0.05)
-Large:+22.5 (p<0.05)
Wound duration after 12 weeks:
-<6months (short): +10.1(p<0.05)
6-12months (medium): +11.2 (p>0.3)
->12 months (long) :+20.5 (p<0.05)
Wound duration after 20 weeks:
-<6months (short): +5.8 (p>0.3)
-6-12 months (medium) :+8.1 (p>0.3)
->12 months (long): +20.3(p<0.05)
2.One nursing visit in control group: +1475
Two nursing visit in control group: -11958
58
1. Successful endpoint: no longer requiring wound care services and expected discharge from wound care clinical services. NPWT Successful treatment endpoint: closure through secondary intention or through a surgical intervention or if adequate granulation for closure by
these methods. Wet to moist wound therapy treatment endpoint: wound closure with no drainage or full epithelialisation with no drainage
2. Sample size: (<2 cm2)NPWT: 181, Control: 347, (2-4cm2)NPWT: 167, Control: 123, (>4cm2) NPWT: 787, Control: 116. (<6 months)NPWT: 787, Control: 202, (6-12 months)NPWT: 169, Control: 88, (>12 months)NPWT: 179, Control: 189.
59
Bibliographic
citation
Study type Patient characteristics
I
C
Intervention(s) Comparison Length of follow up Outcome measure Effect size Tool
Paola et al.,
2010
Two
parallel
randomized
controlled
trials (1+)
Male 69% 66% V.A.C. therapy
immediately after
applying skin graft in
operation threatre
(n= 35)
Graft dressing covered
with non- adherent
gauze
(n= 35)
6 months Primary outcome:
(1) Complete graft take rate
(%)
(1) + 12
(p= 0.05)
-Photographic
documentation at
enrollment,
intermediate and end
phases
-Semmes-Weinstein
10g-monofilament test
and absence of
tendo-Achilles
reflexes for
neuropathy
-Clinical evaluation of
pulse, duplex scan,
transcutaneous oxygen
tension on dorsum of
foot for vascular
assessment
Age 64 60
Diabetic duration 16 15
HbA1c 7.4% 7.1%
Insulin therapy 74% 89%
Oral diabetes therapy 26% 11%
PVD 66% 60%
TcPO2 after revascularization 42 43
Neuropathy 97% 94%
Wound level (UTC)(I) 100% 100%
-Ankle and foot ulcers to have meshed skin graft
treatment
- Dimensions: >=4 cm2
-Treated with antibiotics if getting infection before
skin graft procedure (become non-infected state)
and during therapy
60
Bibliographic
citation
Study
type
Patient characteristics
I C
Intervention
(s)
Comparison Length of
follow up
Outcome measures Effect size Tool
Paola et al.,
2010 (con‟t)
Two
parallel
RCT
(1+)
Male 85% 82% -Received V.A.C. therapy
following instruction from
manufacturer
-Non occlusive dressing used
on exposed tendons/ vessels for
protection
-Change dressing 3 times/ week
Advanced dressings
included alginate,
hydrofiber, silver- dressing,
or polyurethanes( choice
depends on exudates and
infection)
6 months Primary outcome:
(1) Time needed for complete
closure of wound (healing
time)after surgical closure or
secondary intention (days)
Secondary outcome:
(2) Time needed for development
of compact, well vascularized
granulation tissue that covered
exposed bone (days)
(3) Time needed for control of
infection (extent of
granulation tissue, reduction
in exudates production and
visual aspect of wound) (days)
(4) Time needed for surgical
treatment (OT activity) after
follow up period that major
amputations carried out (days)
(1)-33
(p=
0.005)
(2)-18
(p= 0.03)
(3)-9
(p= 0.05)
(4)-0.146
(p=0.02)
-Photographic
documentation at
enrollment,
intermediate and
end phases
-planimetry of
superficial wounds
for dimensions of
wounds
-subjective
estimation of
wound bed, depth
of wound and
granulation tissue
-Microbiological
examinations
-Inspect wound
bed during each
dressing change
Age 65 64.5
Diabetes duration(yrs) 18 14.8
HbA1c (%) 7.4 7.1
Insulin therapy 89% 92%
Oral hypoglycemics 28% 23%
PVD 82% 89%
TcPO2 after revascularization 45.3 44.9
Neuropathy 94% 89%
Wound level U.T.C. II 31% 34%
Wound level U.T.C.III 69% 66%
-Infected ulcers, open amputations, surgical dehiscence
after foot surgery (minor amputation)
-After surgical debridement and wait minimum 24 hours
after recent debridement before VAC therapy
-Undergo diagnosis of bone infection before enrollment
-Have offloading by fiberglass casts/ orthopaedic footwear
(depend on type and location of wound)
-Treated target antibiotics for infection after repeat exam
61
Bibliographic
citation
Study
type
Patient characteristics Intervention(s) Comparison Length of follow up Outcome measure Effect size Tool
Ravari et al.,
2013
RCT
(1+)
1.VAC (7 males, 3 females), Moist dressing (8
males, 5 females) (p>0.05)
2. Osteomyelitis diagnosed in 14 patients, 9
(VAC), 5 (moist dressing)
3. Malnutrition: 1 (VAC), 2 ( Moist dressing)
4. Most ulcers in right forefoot, followed by left
hind foot and right hind foot
5. No sig. difference in type of DM, with and
without control of DM, duration of
ulcer.(p=0.43,0.44,0.13)
6. History of ulcer treatments are sig.(p=0.05),
most patients have surgical treatment( VAC),
medical and surgical therapies (Moist dressing)
7. Size of ulcer(cm2) 39.5(I) 36.9(C)
Depth of ulcer(mm) 19(I) 17(C)
NPWT:
-a unit generate negative
pressure consisting of
disposable canister and a
pad having an evacuation
tube
-125mmHg controlled
negative pressure
-suction and resilient,
foam- surfaced dressing
done simulanteously
-dressing changed every 3
days
(n= 10)
Moist dressing:
-wash with sterile serum
and bandage
-dressing changed twice
daily
(n= 13)
-Measurement: every 3
days
-Period: 2 weeks
1. Change in depth of ulcer
(mm)
2. Change in size of ulcer
(cm2)
3. Participants had
formation of granulation
tissue (%)
4. Patients‟ satisfaction level
(%)
5. Major and minor
amputation (%)
1.-10 (p=0.02)
2. -28 (p=0.03)
3. 20 (no p value)
4.76.9 (p=0.004)
5. -46.19
(p=0.03)
-Depth of ulcer
measured by
vernier caliper in
biggest vertical
diabeter of ulcer
-Wagner scale for
improvement of
ulcer
62
Bibliographic
citation
Study
type
Patient characteristics
I C
Intervention
(s)
Comparison Length of
follow up
Outcome measures Effect size Tool
Sepulveda et
al., 2009
Rando
mized
control
led
trial
(1+)
Age 61.5 62.1 -NPWT (cover with
polyurethane ester
sponge with large pores:
400-600um,
-A fenestrated drainage
tube (Nelaton No.16),
put between sponge and
a transparent
impermeable adhesive
bandage (act as seal)
-Central suction system
deliver continuous sub-
atmospheric pressure of
100mmHg
- Treated every 48 to 72
hours and review weekly
(n=12)
Conventional therapy
depends on saturation of
secondary bandage
-<50%: use gel
hydrocolloid, woven gauze
impregnated with a
petrolatum emulsion with
bandage
-> 50%: covered with
alginate and a bandage
- Treated every 48 to 72
hours and review weekly
(n=12)
51 days Primary outcome:
Average 90% granulation time
(without necrotic tissue, bone or
tendon exposure and without local
signs of infection) (days)
-13.5
days( p=
0.007)
-Evaluated weekly
with digital
photography
(crosshatched,
analyzed square by
square to get
fraction of
granulated tissue in
each square.
-The percentage of
granulation is from
average of all
fractions of all of
squares
Male 83% 75%
Dyslipidaemia (normal) 58.3% 58.3%
Dyslipidaemia (need drugs) 41.7% 33.4%
Arterial hypertension (1or >2 drugs) 66.7% 50%
HbA1c (%) 9.5(2) 9.7(2)
Pulse volume (Transmetatarsal) 126.9 154.3
Revascularization 25% 16.7%
Only first toe amputation 25% 25%
Two or more toes amputation 25% 25%
Tarsometatarsal of foot 50% 50%
Left side amputation 41.7% 33.3%
-Transmetatarsal amputation: first toe/ 2 or more contiguous toes
-Resolved etiology from infection and vascular with sufficient
perfusion
-Between 3rd and 5th day after surgery with not bleeding or active
infective wound
-Received shower therapy, saline solution, debridement before
assignment
63
In a well conducted RCT study…Armstrong, Marston, Reyzelman & Kirsner, 2012 Does this study do it?
1.1 The study addresses an appropriate and clearly focused question. Yes
1.2 The assignment of subjects to treatment groups is randomized. Yes
1.3 An adequate concealment method is used. Yes
1.4 Subjects and investigators are kept „blind‟ about treatment allocation. Single blind (Primary outcome analysis: Visitrack data)
1.5 The treatment and control groups are similar at the start of the trial. Yes (Except larger baseline wound size in VAC group, it does not have a significant affect on outcome)
1.6 The only difference between groups is the treatment under investigation. Yes
1.7 All relevant outcomes are measured in a standard, valid and reliable way. Yes
1.8 What percentage of the individuals or clusters recruited into each treatment arm of the study
dropped out before the study was completed?
12.88%
1.9 All the subjects are analyzed in the groups to which they were randomly allocated (often referred to
as intention to treat analysis).
Yes
1.10 Where the study is carried out at more than one site, results are comparable for all sites. Yes
2.1 How well was the study done to minimise bias?
Code as follows:
++ High quality
2.2 Taking into account clinical considerations, your evaluation of the methodology used, and the Yes
Appendix 2
64
statistical power of the study, are you certain that the overall effect is due to the study intervention?
2.3 Are the results of this study directly applicable to the patient group targeted by this guideline? Yes
2.4 Notes. Provides mechanically power NPWT has similar efficacy of wound healing compared to electrically powered NPWT, but has less interruption on quality of life and faster time for application. So, SNaP device can be
a choice for ambulatory setting especially in outpatient setting.
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In an well conducted case control study…Fife, Walker,Thormson & Otto, 2008 Does this study do it?
1.1 The study addresses an appropriate and clearly focused question Yes
1.2 The cases and controls are taken from comparable populations Yes
1.3 The same exclusion criteria are used for both cases and controls. Can‟t say Not clearly defined
1.4 What percentage of each group (cases and controls) participated in the study?. Can‟t say Use eligible subjects in databases as sample population
1.5 Comparison is made between participants and non-participants to establish their similarities or
differences.
Can‟t say Use eligible subjects in databases as sample population
1.6 Cases are clearly defined and differentiated from controls Yes
1.7 It is clearly established that controls are non-cases.. Yes
1.8 Measures will have been taken to prevent knowledge of primary exposure influencing case
ascertainment.
Not applicable Studies based on analysis of databases
1.9 Exposure status is measured in a standard, valid and reliable way.. Can‟t say Both objective and subjective outcome measures used
1.10 The main potential confounders are identified and taken into account in the design and analysis No No confounders discussed
1.11 Confidence intervals are provided.
Yes p<0.05
2.1 How well was the study done to minimise the risk of bias or confounding? +
2.2 Taking into account clinical considerations, your evaluation of the methodology used, and the medium
66
statistical power of the study how strong do you think the association between exposure and
outcome is?
2.3 Are the results of this study directly applicable to the patient group targeted by this guideline? Yes
2.4 Notes.
67
In an well conducted case control study…Lavery, Boulton, Niezgoda & Sheehan, 2007 Does this study do it?
1.1 The study addresses an appropriate and clearly focused question Yes
1.2 The cases and controls are taken from comparable populations Yes
1.3 The same exclusion criteria are used for both cases and controls. Can‟t say Except control does not clearly define exclusion criteria
1.4 What percentage of each group (cases and controls) participated in the study?. Can‟t say Use eligible subjects in databases as sample population
1.5 Comparison is made between participants and non-participants to establish their similarities or
differences.
Can‟t say Use eligible subjects in databases as sample population
1.6 Cases are clearly defined and differentiated from controls Yes
1.7 It is clearly established that controls are non-cases.. Yes
1.8 Measures will have been taken to prevent knowledge of primary exposure influencing case
ascertainment.
Not applicable Studies are based on analysis of databases
1.9 Exposure status is measured in a standard, valid and reliable way.. Can‟t say Both objective and subjective outcome measure used
1.10 The main potential confounders are identified and taken into account in the design and analysis Yes
1.11 Confidence intervals are provided.
Yes (p< 0.05)
2.1 How well was the study done to minimise the risk of bias or confounding? +
2.2 Taking into account clinical considerations, your evaluation of the methodology used, and the medium
68
statistical power of the study how strong do you think the association between exposure and
outcome is?
2.3 Are the results of this study directly applicable to the patient group targeted by this guideline? Yes
2.4 Notes.
69
In a well conducted RCT study…Paola et al., 2010 Does this study do it?
1.1 The study addresses an appropriate and clearly focused question. Yes
1.2 The assignment of subjects to treatment groups is randomized. Yes
1.3 An adequate concealment method is used. No
1.4 Subjects and investigators are kept „blind‟ about treatment allocation. No
1.5 The treatment and control groups are similar at the start of the trial. Yes
1.6 The only difference between groups is the treatment under investigation. Yes
1.7 All relevant outcomes are measured in a standard, valid and reliable way. Yes
1.8 What percentage of the individuals or clusters recruited into each treatment arm of the study
dropped out before the study was completed?
No drop out
1.9 All the subjects are analyzed in the groups to which they were randomly allocated (often referred to
as intention to treat analysis).
Not applicable
1.10 Where the study is carried out at more than one site, results are comparable for all sites. Can‟t say
2.1 How well was the study done to minimise bias?
Code as follows:
+ Acceptable
2.2 Taking into account clinical considerations, your evaluation of the methodology used, and the -Statistical analysis of confidence interval at 95%. However, no concealment and blinding in this study. It only
70
statistical power of the study, are you certain that the overall effect is due to the study intervention? mentions the study cannot blind the clinicians because they need to evaluate the outcome.
2.3 Are the results of this study directly applicable to the patient group targeted by this guideline? Yes
2.4 Notes.. Own assessment: show effectiveness of NPWT on outcome on diabetic foot wounds under statistical significance. Some limitations: subjective measure of outcome with no clear evidence, no concealment and
blinding on researcher for analysis.
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In a well conducted RCT study…Ravari et al., 2013 Does this study do it?
1.1 The study addresses an appropriate and clearly focused question. Yes
1.2 The assignment of subjects to treatment groups is randomized. Yes (a (Date of admission)
1.3 An adequate concealment method is used. No
1.4 Subjects and investigators are kept „blind‟ about treatment allocation. No
1.5 The treatment and control groups are similar at the start of the trial. Yes
1.6 The only difference between groups is the treatment under investigation. Yes
1.7 All relevant outcomes are measured in a standard, valid and reliable way. Yes (except the measure of formation of granulation is not clearly mentioned)
1.8 What percentage of the individuals or clusters recruited into each treatment arm of the study dropped
out before the study was completed?
No drop out
1.9 All the subjects are analyzed in the groups to which they were randomly allocated (often referred to as
intention to treat analysis).
Not
applicable
1.10 Where the study is carried out at more than one site, results are comparable for all sites. Can‟t say
2.1 How well was the study done to minimise bias?
Code as follows:
+ Acceptable
2.2 Taking into account clinical considerations, your evaluation of the methodology used, and the statistical RCT, use p value less than 0.05, but no mention blinding and concealment.
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power of the study, are you certain that the overall effect is due to the study intervention?
2.3 Are the results of this study directly applicable to the patient group targeted by this guideline? Yes
2.4 Notes. RCT, outcome is well measured except formation of granulation. No significant difference between groups in demographic characteristics. P value is mentioned except the formation of granulation tissue in groups.
No concealment and blinding is mentioned. Sample size is 23.
73
In a well conducted RCT study…Sepulveda et al., 2009 Does this study do it?
1.1 The study addresses an appropriate and clearly focused question. Yes
1.2 The assignment of subjects to treatment groups is randomized. Yes
1.3 An adequate concealment method is used. Yes
1.4 Subjects and investigators are kept „blind‟ about treatment allocation. Yes (only research team are blinded in analysis)
1.5 The treatment and control groups are similar at the start of the trial. Yes
1.6 The only difference between groups is the treatment under investigation. Yes
1.7 All relevant outcomes are measured in a standard, valid and reliable way. Yes
1.8 What percentage of the individuals or clusters recruited into each treatment arm of the study
dropped out before the study was completed?
No drop out
1.9 All the subjects are analyzed in the groups to which they were randomly allocated (often referred to
as intention to treat analysis).
Yes
1.10 Where the study is carried out at more than one site, results are comparable for all sites. Not applicable
2.1 How well was the study done to minimise bias?
Code as follows:
+ + High quality
74
2.2 Taking into account clinical considerations, your evaluation of the methodology used, and the
statistical power of the study, are you certain that the overall effect is due to the study intervention?
It has done a pilot study to calculate sample size using confidence interval of 95% and power of 80%. It has
concealment, blinding to research team and use intention to treat analysis and have a statistically significance result
2.3 Are the results of this study directly applicable to the patient group targeted by this guideline? Yes
2.4 Notes. Author‟s conclusions: NPWT is an effective and safe treatment for treating partial foot amputation wounds in diabetics that reach 90% granulation in shorter time and few complications when compared to
conventional treatments. After considering the methodology of study, it not only can answer my research question and provide high level of evidence. One limitation of the study is to use device contained negative pressure from
central suctioning system (prolong hospital stay), not to use industrially manufactured device.
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Appendix 3
Medline CINAHL PLUS PubMed
Search Terms (VAC OR NPWT)
AND diabetic
(VAC OR NPWT) AND
diabetic AND (outpatient
OR home)
(VAC OR NPWT) AND
diabetic
(VAC OR NPWT) AND
diabetic
(VAC OR NPWT) AND
diabetic
(VAC OR NPWT) AND
diabetic AND (outpatient OR
home)
Total 222 18 10 0 197 15
Limit 15 (RCT) 18 2 (RCT) 0 15(RCT) 15
Manual selection
by criteria screen
11 (RCT) 3 2 0 11 3
Full Text 9 2 2 0 9 2
After exclude
those have been
reviewed
4 2 1 0 3 2
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