How long can a wound vacuum (wound vac) stay on?

Duration of Wound VAC Therapy

Wound VAC dressings should be changed every 2-3 days, with therapy typically continuing for 4-15 days until systemic signs of infection resolve, quantitative cultures become negative, and adequate granulation tissue forms to allow definitive closure or secondary healing. 1, 2

Standard Dressing Change Protocol

• Change VAC dressings every 2-3 days (most commonly every 2 days for infected wounds, every 3 days for clean wounds) 1, 2, 3
• Each dressing change requires assessment of wound bed, bacterial burden, and granulation tissue formation 2, 4
• Continue therapy until the wound demonstrates adequate preparation for closure or has achieved sufficient healing 2, 3

Total Duration of VAC Therapy by Clinical Context

Infected Wounds (Most Common Indication)

• Average duration: 9.3 days (range 4-15 days) for deep sternal wound infections after cardiac surgery 1
• Therapy continues until systemic signs of infection resolve AND quantitative bacterial cultures become negative 1
• VAC with negative pressure ≥75 mmHg effectively reduces bacterial counts by days 3-5 4

Abdominal Wound Dehiscence

• Duration: 18-40 days depending on wound complexity and patient comorbidities 5, 3
• Continue until fascial integrity can be reestablished surgically or adequate granulation allows secondary healing 3
• May serve as bridge to definitive surgical closure (muscle flap or primary closure) 1, 3

Open Abdomen Management

• Window for primary fascial closure: 7-10 days is the traditional target, though VAC can extend this window 6
• Late closures have been successfully achieved at 18-21 days, and even as late as 49 days with NPWT 6
• The interface layer must be changed with each dressing change to prevent bowel adhesions and fistula formation 6

Critical Monitoring Parameters During Therapy

Discontinue VAC therapy when:

• Quantitative bacterial cultures show <10⁵ colony-forming units per gram of tissue 6
• Systemic signs of infection (fever, leukocytosis) have resolved 1
• Adequate granulation tissue has formed to support closure or grafting 2, 3
• Wound volume and depth have sufficiently decreased 2

Pressure Settings and Their Impact on Duration

• Optimal negative pressure: 75-150 mmHg promotes faster healing through increased VEGF/bFGF expression and angiogenesis 4
• Higher pressures (225-300 mmHg) clear bacteria equally well but may delay granulation tissue formation 4
• Most protocols use continuous suction at -75 to -125 mmHg 3

Special Considerations That May Extend Duration

Contamination risk areas (vulva/perineum):

• Requires meticulous protection from stool/urine contamination using Foley catheters, antimotility agents, or waterproof dressings 6
• May require longer therapy duration due to contamination challenges 6

Compromised healing patients:

• Patients with diabetes, malnutrition, or immunosuppression may require extended therapy (up to 40 days) 5
• VAC can be continued as outpatient therapy to reduce hospitalization 3

Fistula presence:

• Complicates therapy and may require operative intervention, potentially extending total treatment time 3

Common Pitfalls to Avoid

• Never leave VAC dressings unchanged beyond 3 days - this increases infection risk and reduces therapeutic efficacy 2, 4
• Do not apply VAC if purulence is actively present - perform adequate surgical debridement first 6
• Avoid premature discontinuation before adequate granulation tissue forms, as this leads to wound breakdown 2, 3
• In open abdomen cases, failure to use a non-adherent interface layer significantly increases fistula formation risk 6