Negative pressure wound therapy (VAC)
Formal Definition
Negative pressure wound therapy (NPWT), commercially branded as V.A.C. (Vacuum-Assisted Closure, KCI/3M) — a wound-healing technique using a sealed foam or gauze interface placed in the wound bed, covered with adhesive drape, and connected to a controlled subatmospheric pressure pump (typically -75 to -125 mmHg, either continuous or intermittent); promotes granulation tissue formation, reduces edema, draws wound edges together, removes exudate and infectious material, and is used across complex acute and chronic wounds including open abdominal wounds, large soft tissue defects, sternal wound infections, diabetic foot ulcers, and split-thickness skin graft bolster dressings.
How It's Used on the Ward
"VAC" or "wound vac" — when a complex wound (dehisced laparotomy, infected sternal wound, debrided necrotizing fasciitis defect, large pressure ulcer) is dressed with a sponge, sealed, and connected to a portable suction pump that patients carry; dressed q2-3 days; assessment is by healing trajectory and granulation tissue growth rather than daily evaluation.
Example
""62-year-old diabetic with large sacral decubitus ulcer stage IV down to fascia, debrided by plastic surgery on hospital day 3. Wound bed clean, foul smell resolved, edges well perfused. Plastic surgery places VAC sponge in wound, seals with drape, connects to -125 mmHg continuous suction pump. Dressing change q3 days. Pt to subacute rehab with portable VAC. Follow-up: VAC changed q3 days, granulation tissue growing steadily over 4 weeks, wound reduced from 8x6x3 cm to 4x3x2 cm. Ready for flap closure evaluation at week 6.""
Clinical Context
Indications: open surgical wounds not amenable to primary closure, large soft tissue defects, infected wounds (septic arthritis incision, sternal wound infection), dehisced incisions, traumatic wounds, burns, complex pressure ulcers, diabetic foot ulcers, skin graft bolster. Contraindications: (1) Untreated osteomyelitis (must treat first). (2) Fistulas to body cavities or organs (could enteral fistula, etc., cause fistula drainage problems). (3) Malignancy in the wound (could promote tumor growth). (4) Exposed blood vessels (could damage vessel — relative). (5) Active bleeding. (6) Necrotic tissue with eschar (debride first). Changing dressings: q2-3 days typical; each change involves removing the sponge, irrigating the wound, assessing healing, cleaning the peri-wound skin, replacing the sponge, re-sealing. Patient experience: with portable pumps, patients can be discharged home or to rehab with VAC; large pumps on inpatient floors require nursing education. Documented in EHR: wound size in cm (length × width × depth), tissue type at base (granulation %, slough, eschar, exposed structures), exudate character and amount, surrounding skin integrity, dressing change due date. Counter-concept: wet-to-dry dressings (older, less effective, painful at changes); skin grafting (when wound bed is ready); primary closure (when wound edges can be brought together).