1

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

4

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

11

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

22

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.

\

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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.

65

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

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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.

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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

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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.

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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.

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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

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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