Simplified Negative Pressure Wound
Therapy for Low Resource Settings
Gita N. Mody, M.D., M.P.H.
Danielle R. Zurovcik, Ph.D.
Second WHO Global Forum on Medical Devices
November 24, 2013
Advanced wound care is needed in the
developing world.
The GBD Study 2010, Institute for Health Metrics and Evaluation
NPWT is proved to decrease healing
time.
• Mechanisms
– Reduce edema
– Debridement
– Reduce bacterial burden
– Increase vascularity
– Increase growth factors, fibroblasts
Ad hoc NPWT systems heal wounds
faster than wet to dry dressings.
Perez D., et al. Modern wound care for the poor: a randomized clinical trial comparing the vacuum
system with conventional saline-soaked gauze dressings. American Journal of Surgery, 2010
Simplified Negative Pressure Wound
Therapy was originally developed as a
“DIY” system.
Zurovcik, D. Development of a Simplified Negative Pressure Wound Therapy Device.
Masters of Science in Mechanical Engineering Thesis. MIT. 2007.
We identified early failures during our
pilot phase.
Orgill DP, Zurovcik DR, Mody GN. Reply: Alternative Materials in Vacuum-Assisted
Closure. Plastic & Reconstructive Surgery. 2011; 128(6):785e-786e.
Initial non-integrated tubing failed due
to air leaks.
Dressings need to have integrated
tubes to work with a mechanical drain.
Dressings need to have integrated
joints to work with a mechanical
drain.
11..8
31.7
0
5
10
15
20
25
30
35
40
non-integrated integrated
Ave
rage
NP
WT
Dressing type
Average NPWT duration delivered by dressing type
non-integrated
integrated
Overcoming body surface contours is still necessary
for broad application of sNPWT.
52.7 hours
20.9 hours
33.0 hours
0
10
20
30
40
50
60
easy medium hard
Ave
are
ge
NP
WT
(h
ou
rs)
Wound difficulty
Average NPWT delivered by body surface contour
type
Easy
(flat surface)
Medium
(curved, difficult to reach)
Hard
(joint, movement, fluids)
Anterior/lateral extremity Posterior aspect extremity Sarcum
Abdomen Trochanter Foot
Back Shoulder Heel
p = 0.029
Field observations of dressing
applications identified design targets.
Field observations of dressing
applications identified design targets.
Clinical ProblemsClinical ProblemsClinical Problems
Field observations of dressing
applications identified design targets.
Clinical Problems
Formal Design ProcessFormal Design Process
Field observations of dressing
applications identified design targets.
Engineering SolutionsClinical Problems Engineering SolutionsEngineering Solutions
Field observations of dressing
applications identified design targets.
Engineering SolutionsClinical Problems
Air leak (tube)
Field observations of dressing
applications identified design targets.
Engineering Solutions
Integrated tube
Clinical Problems
Air leak (tube)
Field observations of dressing
applications identified design targets.
Engineering Solutions
Integrated tube
Clinical Problems
Air leak (tube)
Air leak (skin)
Field observations of dressing
applications identified design targets.
Engineering Solutions
Integrated tube
System design
Clinical Problems
Air leak (tube)
Air leak (skin)
Field observations of dressing
applications identified design targets.
Engineering Solutions
Integrated tube
System design
Clinical Problems
Air leak (tube)
Air leak (skin)
Maceration of skin
Field observations of dressing
applications identified design targets.
Engineering Solutions
Integrated tube
System design
Fluid management
Clinical Problems
Air leak (tube)
Air leak (skin)
Maceration of skin
Field observations of dressing
applications identified design targets.
Engineering Solutions
Integrated tube
System design
Fluid management
Clinical Problems
Air leak (tube)
Air leak (skin)
Maceration of skin
Shear forces
Field observations of dressing
applications identified design targets.
Engineering Solutions
Integrated tube
System design
Fluid management
Leverage shear forces
Clinical Problems
Air leak (tube)
Air leak (skin)
Maceration of skin
Shear forces
Field observations of dressing
applications identified design targets.
Engineering Solutions
Integrated tube
System design
Fluid management
Leverage shear forces
Clinical Problems
Air leak (tube)
Air leak (skin)
Maceration of skin
Shear forces
Heat, sweat, humidity
Field observations of dressing
applications identified design targets.
Engineering Solutions
Integrated tube
System design
Fluid management
Leverage shear forces
Novel material design
Clinical Problems
Air leak (tube)
Air leak (skin)
Maceration of skin
Shear forces
Heat, sweat, humidity
Field observations of dressing
applications identified design targets.
Engineering Solutions
Integrated tube
System design
Fluid management
Leverage shear forces
Novel material design
Clinical Problems
Air leak (tube)
Air leak (skin)
Maceration of skin
Shear forces
Heat, sweat, humidity
Final
sNPWT
Device
Acknowledgements
• In-country support– Dr. Agnes Binagwaho, Rwandan Minister of Health
• Mentorship– Dr. Robert Riviello, BWH Center for Surgery and Public Health
– Dr. Alex Slocum, Massachusetts Institute of Technology
• Funding – National Institute of Health Grant: R24TW007988
– Center for Integration of Medicine and Technology (Boston)
– MIT Legatum Center
Mechanical NPWT sources are
available but not affordable.
Hutton DW, Sheehan P. Comparative effectiveness of the SNaP™
Wound Care System. Int Wound J. 2011; 8(2): 196-205.
Other mechanical NPWT designs have
limitations.
Webster, R., et. al. Alternative materials in vacuum-assisted closure.
Plastics and Reconstructive Surgery. 2011; 128(6): 784e-53.