2. Definition
• Vacuum-assisted closure is a system that promotes
wound healing by applying controlled local sub-
atmospheric pressure using a foam interface.
• Use of Vaccum forces on wounds described in 1995
by Fleischmann
• 1997, Drs. Argenta and Morykwas - vacuum assisted
closure (VAC) devices.
• Mechanofibroblast
3. Principle
Works through a combination of mechanisms:
• Wound contraction by mechanically pulling the
wound together-Macrostrain
• Relief of edema - Removes excess pericellular
transudate and wound exudate
• Decreases local interstitial pressure, thus restoring
blood flow to those vessels compressed or
collapsed by the chronic edema
4. • Enhances the formation of granulation tissue
• Decrease in bacterial colonization of the wound
• Tiny pieces of tissue are drawn into a foam contact
dressing causing microdeformations and inducing
mechanical stress, stimulating angiogenesis and tissue
growth.- Microstrain
• Cyclic compression and relaxation of the wound tissue
likely stimulates mechanotransductive pathways that
result in increased growth factor release, matrix
production, and cellular proliferation
5. Cellular and Molecular
At cellular level, NPWT alters wound bed gene
expression with resultant changes in
cytokine/chemokine/growth factor expression and
matrix metalloproteinase (MMP) expression.
Studies show inncreases in anti-inflammatory
cytokines (IL-10) and pro-angiogenic growth factors
(VEGF, FGF, PDGF) have been demonstrated with the
use of NPWT
6. Components
1)Foam
Polyurethane “black” foam
Hydrophobic
Average pore size range of 400-600 microns to maximize
tissue growth
Vast majority of evidence relates to use of this contact
dressing
Polyvinyl alcohol “white” foam
Hydrophilic
Denser pore distribution, 60-270 microns
Useful in areas where rapid rates of granulation tissue are
less desirable
12. Indications
• Acute wounds - Enhances capillary flow
• Isolated therapy until closure - Wound preparation for skin
grafts/flaps
• Surgical wounds not amenable to primary closure Fasciotomy
wounds Abdominal compartment
syndrome
• Subacute wounds - Dehisced incisions
• Chronic wounds: Pressure ulcers, iabetic / Neuropathic ulcers,
Venous ulcers
• Has been used as an SSG dressing for difficult wounds to assist
SSG take
• Salvage in non-healing wounds (Controversial)
13. Contraindications
Absolute:
• Fistulas to organs or body cavities
• Osteomyelitis
• Malignancy
• Exposed arteries or veins
• Necrotic tissue
Relative:
• Active bleeding or difficult hemostasis
• Patients on anticoagulants
• Patient or caregiver unwilling or unable to adhere to
treatment protocol
14. Technique
The wound is cleaned and necrotic tissue debrided -
May need to be done in theatre under
anesthesia.
VAC is applied 48h after debridement if bleeding is a
concern, else immediately
15. • For open body cavities, organs should be covered with
autologous tissue or a suitable synthetic alternative.
• Sponge is cut to fit the wound approximately (or multiple
pieces are laid in the wound).
• The sponge is placed within the wound and a drainage
tube placed in it.
• The whole sponge and the tube is covered with an
adhesive transparent waterproof dressing which overlaps
the surrounding skin, and a seal created with the skin and
the drainage tube.
• Tubing is placed away from bony prominences and away
from skin by pinching the adhesive into a mesentery.
16. The suction tubing is attached to canister at one end. The canister
slots into the suction apparatus
unit.
The suction unit is set to provide the desired negative pressure
(preferentially at -125mmHg, range -50 to -125mmhg) either
continuously or intermittently
The foam should collapse within the wound
If any, leaks can be patched with more of the transparent dressing.
The transparent dressing allows observation of the wound margins
for signs of infection.
Dressing is changed ideally three times a week or more frequently
in infected wound
17.
18.
19.
20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30. Advantages
• Helps in rapid preparation of wound for definitive
coverage
• Decreases the edema and swelling in fasciotomy
wound
• Decreasing frequency of regular dressing -
Increased patient comfort and decreased chance of
transmission of infection
• Promotes rapid formation of granulation tissue
• Manage difficult wounds
31. Disadvantages
• Fluid shift
• The suction fluid is rich in proteins – If drainage is
copious, patient require nutritional supplements
• Cost (Relative, In other terms the decreased
hospital stay and decreased time for healing will
compensate the cost)
32. Complications
• Skin edge erythema, maceration, ulceration
• Mechanical malfunction/failure
• Retained sponge
• Bleeding
• Infection and toxic shock syndrome from partial or
incomplete drainage
34. VAC Instill
• Fluid instillation as an adjunct.
• Most commonly isotonic solution containing
antibiotics or antibacterials.
• Can be intermittent suction (when the pressure is
stopped, the device instills fluid, and when negative
pressure is restarted, the fluid is removed into a
waste canister) or continuous suction (fluid is instilled
at one end of the wound and removed/suctioned at
the other).This technique may contribute to infection
control.
35. Incisional VAC
• Used on closed surgical wounds with early signs of
inadequate healing or on those located at anatomic
sites associated with high complication rates
• Thought to provide continuous evacuation of
excessive drainage, thereby avoiding skin irritation
and bacterial colonization while reducing edema
36. Technique:
• Line incision with thin strips of adhesive dressing just
lateral to the suture or staples.
• Place nonadherent contact dressing over the incision.
• Cut sponge to the length of the incision and place over
the nonadherent dressing, avoiding direct contact with
skin.
• Apply occlusive dressing and pressure of 50 to 125 mm
Hg.
• Discontinue after 2-5 days
