Negative pressure wound therapy, widely known as wound vac, is the most commonly recommended method for temporarily managing an open abdomen. An international consensus conference on open abdomen management endorsed it as the preferred temporary closure technique for draining peritoneal fluid, preventing the fascial edges from pulling apart, and simplifying nursing care.1Journal of Trauma and Acute Care Surgery. International consensus conference on open abdomen in trauma The approach has become standard in trauma centers and surgical intensive care units worldwide, but the story behind how it works, what it costs the body, and what recovery looks like is more layered than the technology’s routine use might suggest.
Why the Abdomen Is Left Open in the First Place
Surgeons do not leave an abdomen open by preference. They do it when closing would be dangerous. The primary reason is to prevent or treat abdominal compartment syndrome, a condition where pressure inside the abdomen rises high enough to compress the organs, cut off blood flow to the kidneys and gut, and push the diaphragm upward so the lungs cannot expand. The indications for an open abdomen generally include any situation in which intra-abdominal pressure is climbing toward that critical threshold.2PubMed Central. The open abdomen, indications, management and definitive closure Massive abdominal trauma, severe peritonitis, ruptured aortic aneurysms, and situations requiring “damage control” surgery where the patient is too unstable for a single definitive operation all commonly lead to an open abdomen.
Once the decision is made to leave the abdomen open, the exposed viscera need protection. Without some form of temporary closure, the bowel dries out, the fascia retracts rapidly, fluid loss becomes uncontrollable, and contamination from the environment becomes a serious risk. That is where the wound vac comes in.
How a Wound Vac Works on an Open Abdomen
The basic setup involves a protective layer placed over the exposed bowel, a sponge or foam dressing fitted into the wound, an adhesive drape to seal everything, and a suction device that applies continuous or intermittent negative pressure. The system works through several mechanisms: it physically draws the wound edges closer together (macrodeformation), removes inflammatory fluid that would otherwise pool in the abdomen, creates a stable wound environment that keeps the bowel moist and protected, and at the cellular level stretches tissue in ways that stimulate new cell growth (microdeformation).3PubMed Central. Negative Pressure Wound Therapy: Mechanism of Action and Clinical Applications
One question that comes up is whether the suction itself raises pressure inside the abdomen, which would defeat the purpose. A study measuring intra-abdominal pressure at various sites found that the vacuum settings did not significantly change abdominal pressure when packing material was absent. When packing was present, only the abdominal wall region showed any pressure change, and even that reached a maximum of about 20% of the set vacuum pressure.4PubMed. Intra-abdominal Pressure Monitoring During Negative Pressure Wound Therapy in the Open Abdomen In other words, the vacuum pulls fluid out without meaningfully squeezing the organs beneath it.
Removing Inflammatory Fluid Is Not Just Housekeeping
The fluid that accumulates in a sick abdomen is loaded with inflammatory molecules. Researchers measuring cytokine levels in patients undergoing damage control surgery with abdominal negative pressure therapy found that concentrations of these inflammatory signals were far higher in the peritoneal fluid than in the bloodstream. Over the course of treatment, some of these molecules cleared substantially. The anti-inflammatory cytokine IL-10 dropped to about 17% of its starting level in the blood and about 41% in the peritoneal fluid. IL-6, a major driver of the systemic inflammatory response, fell to roughly a quarter of its starting level in the blood, although it remained stubbornly high in the peritoneal fluid.5PubMed Central. Cytokine clearance in serum and peritoneal fluid of patients undergoing damage control surgery with abdominal negative pressure therapy for abdominal sepsis
This matters because the systemic inflammatory storm is what kills patients with sepsis and severe trauma. By physically draining the fluid where these signals are most concentrated, the wound vac does not just keep the wound tidy. It appears to act as a kind of crude but effective biological filter, pulling out some of the fuel that drives organ failure.
Closure Rates and How They Compare
The ultimate goal of any temporary abdominal closure method is to get the fascia closed again, ideally in a single hospitalization. A systematic review comparing historical techniques found that wound vac achieved fascial closure in about 61% of patients, which was lower than the Wittmann patch (about 78%) or dynamic retention sutures (about 71%), but the wound vac had the highest rate of delayed primary closure and the lowest mortality among the methods studied.6PubMed. The open abdomen and temporary abdominal closure systems–historical evolution and systematic review That trade-off is worth noting: the wound vac may not always close the abdomen on its own, but it keeps patients alive to get there.
In severe abdominal sepsis specifically, the numbers can be more encouraging. A study of 48 patients treated with negative pressure wound therapy combined with instillation achieved fascial closure in 96% of cases after an average of six days.7PubMed Central. Management of the open abdomen using negative pressure wound therapy with instillation in severe abdominal sepsis A prospective evaluation in patients with both compartment syndrome and severe sepsis also found high closure rates and recommended the wound vac as a first-line option when open abdomen treatment is needed.8PubMed. Prospective evaluation of vacuum-assisted closure in abdominal compartment syndrome and severe abdominal sepsis
Adding mesh-mediated fascial traction to the wound vac setup, a technique that involves sewing a mesh between the fascial edges and gradually tightening it at each dressing change, has also shown excellent results for delayed primary closure in complicated peritonitis.9Journal of Trauma and Acute Care Surgery. Open abdomen with vacuum-assisted wound closure and mesh-mediated fascial traction in patients with complicated diffuse secondary peritonitis Whether adding fascial traction actually reduces mortality is less clear. A meta-analysis pooling nine studies found no significant difference in death rates between patients who had fascial traction and those who did not.10Journal of Trauma and Acute Care Surgery. Management of the open abdomen: A systematic review with meta-analysis and practice management guideline from the Eastern Association for the Surgery of Trauma
The Fistula Problem
The most feared complication of open abdomen treatment with a wound vac is an enteroatmospheric fistula, an abnormal opening from the bowel directly to the external environment through the open wound. Unlike a typical intestinal fistula that tunnels through tissue, this one has no tract to heal. Bowel contents leak directly into the wound, contaminating everything and making closure enormously more difficult.
In patients with secondary peritonitis treated with wound vac, one retrospective analysis found that 37% developed enteroatmospheric fistulas. The length of wound vac therapy and the number of re-explorations were the strongest predictors. A receiver-operating-characteristic analysis in that study identified 13 days as a critical threshold for treatment duration: beyond that, fistula risk rose sharply.11PubMed. High risk of fistula formation in vacuum-assisted closure therapy in patients with open abdomen due to secondary peritonitis-a retrospective analysis That does not mean every patient at day 14 will develop a fistula, but it underlines the clinical urgency of closing the abdomen as soon as the patient’s physiology allows.
A multicentre study looking at what predicts fistula development found that mesenteric ischemia and high preoperative blood lactate levels were the strongest risk factors. Patients whose arterial lactate exceeded 3.5 mmol/L before surgery had dramatically higher odds of developing a fistula. Every patient in the study who had mesenteric ischemia and an intestinal anastomosis ended up with one.12PubMed. Prognostic Factors for Enteroatmospheric Fistula in Open Abdomen Treated with Negative Pressure Wound Therapy: a Multicentre Experience These findings suggest that the fistula risk is not so much caused by the wound vac itself as it is driven by the severity of the underlying disease, though prolonged exposure of compromised bowel to any temporary closure method raises the danger.
What the Body Loses Through the Drain
The wound vac drains a lot of fluid, and that fluid is not just water. In patients with an open abdomen, the median daily exudate volume was over a liter, compared to about a quarter-liter for standard soft tissue wounds. That exudate carried roughly 25 grams of protein per day on average, with a protein concentration of about 2.9 g/dL, not far from the protein content of blood plasma itself.13PubMed. Loss of protein, immunoglobulins, and electrolytes in exudates from negative pressure wound therapy The body is essentially losing a significant portion of its circulating protein through the wound every single day.
The type of wound vac system matters too. A study comparing the ABThera system (a more advanced commercial device) to the simpler Bogotá bag technique found that the ABThera system actually pulled out more protein per liter of fluid, averaging about 44 g/L compared to about 25 g/L with the Bogotá bag. The difference persisted regardless of the patient’s nutritional status or how much protein they were being given.14Revista Colombiana de CirugÃa. Pérdida de proteÃnas en lÃquido peritoneal de pacientes crÃticos con abdomen abierto This is a trade-off worth understanding: the more effective the drainage, the more protein the body loses. Aggressive fluid removal controls inflammation and compartment pressure, but it creates a metabolic debt that has to be repaid through nutrition.
Feeding Through an Open Abdomen
There is a widespread instinct to hold off on feeding patients with an open abdomen, based on the worry that food moving through exposed or edematous bowel might cause leaks or fistulas. The evidence suggests the opposite. A study of 78 trauma patients with open abdomens found that those who received early enteral nutrition had significantly higher rates of early abdominal closure: 74% closed early compared to 49% of those who received late nutrition. Fistula rates were also lower in the early feeding group, at 9% versus 26% in the late group.15PubMed. Feeding the open abdomen
Given the daily protein losses described above, keeping up with the body’s demands requires deliberate, high-protein nutritional support. Clinicians tracking these patients typically aim for protein intake well above the standard critical-care recommendations, and many start enteral feeds through a nasogastric or nasojejunal tube within the first 24 to 48 hours when the gut is functional. Waiting for the abdomen to close before feeding is, by the available data, the riskier approach.
Instillation Therapy as an Add-On
A newer refinement involves periodically instilling saline or antiseptic solution into the wound through the wound vac system, letting it dwell for a set time, and then resuming suction. This approach, called negative pressure wound therapy with instillation, aims to wash out the peritoneal cavity more thoroughly than suction alone. Early clinical experience suggests it may be a useful add-on in the septic abdomen, helping to dilute and remove bacterial contamination.16PubMed Central. Application of Negative Pressure Wound Therapy with Instillation and Dwell Time of the Open Abdomen: Initial Experience
In a cost analysis comparing three temporary closure methods for abdominal sepsis, instillation therapy patients had shorter hospital stays (about 13 days versus 29 for both standard wound vac and Bogotá bag), shorter ICU stays (about 6 days versus 22 for standard wound vac), and fewer surgeries on average. The average treatment cost per patient was roughly half that of the other two methods.17Annals of Medicine and Surgery. Cost evaluation of temporary abdominal closure methods in abdominal sepsis patients successfully treated with an open abdomen These are promising numbers, though they come from a single-center experience and the patient populations across the three groups may not have been perfectly comparable.
Wound Vac Versus Simpler Methods
A comparison in severe diffuse peritonitis found that wound vac was associated with higher overall fascial closure (73% versus 53%), lower rates of necrotizing fasciitis (2% versus 15%), fewer intra-abdominal abscesses (10% versus 20%), fewer enteroatmospheric fistulas (8% versus 19%), shorter ICU stays (about 6 versus 11 days), and shorter hospital stays (about 15 versus 26 days). Mortality was also lower: 31% versus 53%.18BMJ Military Health. Open abdomen and VAC® in severe diffuse peritonitis That said, the wound vac is not without its own side effects. The adhesive drape can cause skin irritation and dermatitis, and there are reports of pain, infection, bleeding, and rare cases of toxic shock syndrome and thrombosis associated with its use.19PubMed Central. Open abdomen in gastrointestinal surgery: Which technique is the best for temporary closure during damage control?
Use in Children and Newborns
Open abdomen wound vac therapy is not limited to adults. In a pediatric series of 25 children, the median duration of therapy was about four and a half days. Among the 16 who survived long enough for closure, the abdomen was successfully closed in all of them, with 14 achieving full fascial approximation and two needing a patch. Only two children (about 13%) developed fistulas. Nine children died before closure could be attempted, reflecting the severity of the conditions that led to the open abdomen rather than a failure of the wound vac itself.20PubMed. Negative pressure wound therapy for children with an open abdomen
In neonates, including premature infants, the technique has also been used. A series of 15 neonates with conditions like necrotizing enterocolitis and gastroschisis showed an overall survival rate of 80%, with one enterocutaneous fistula as the only potential wound-vac-related complication.21European Journal of Pediatric Surgery. Temporary Vacuum-Assisted Closure of the Open Abdomen in Neonates In premature infants, the vacuum pressure is set far lower than in adults. A case report in a preterm newborn with necrotizing enterocolitis used a setting of just -20 mmHg, and the surgeons described the technique as creating an “artificial third space” that helped reduce bowel swelling and intra-abdominal pressure until the baby was stable enough for re-exploration.22PubMed Central. Negative pressure wound therapy (NPWT) in the open abdomen in a preterm newborn with necrotizing enterocolitis: case report
Dressing Changes in the ICU
Dressing changes on an open abdomen wound vac are significant events. The bowel is exposed, the patient is critically ill, and the procedure requires sedation and sometimes muscle relaxants. Traditionally, many centers transported patients to the operating room for every dressing change, which is logistically complex and expensive. A study examining bedside dressing changes in the ICU found that the practice was safe, and that the additional sedation and monitoring could be managed by ICU personnel already caring for the patient.23PubMed Central. Bedside dressing changes for open abdomen in the intensive care unit is safe and time and staff efficient For patients who need frequent changes, this avoids the risks and delays associated with repeated operating room trips.
Long-Term Consequences
Surviving an open abdomen is one thing. Living with the aftermath is another. The most common long-term problem is an incisional hernia, where the abdominal wall weakens and bulges at the closure site. One study using vacuum-assisted fascial closure found a hernia rate of just 2.3% on follow-up.24PubMed Central. Prospective Evaluation of Vacuum-Assisted Fascial Closure After Open Abdomen Planned Ventral Hernia Rate Is Substantially Reduced But longer follow-up paints a different picture. Another study reported a 35% incisional hernia rate, with hernia patients needing significantly more operations afterward.25PubMed. Abdominal wall integrity after open abdomen: long-term results of vacuum-assisted wound closure and mesh-mediated fascial traction (VAWCM) At five years of follow-up, one study found a cumulative hernia incidence of 62%, with about a third of those hernias repaired surgically.26PubMed. Quality of life and hernia development 5 years after open abdomen treatment with vacuum-assisted wound closure and mesh-mediated fascial traction The gap between the early optimistic numbers and the five-year reality is striking, and it underscores the importance of long-term surveillance in these patients.
Whether a hernia develops turns out to be a major determinant of quality of life after recovery. Studies using standardized quality-of-life questionnaires have consistently found that patients who went through open abdomen treatment score lower on physical functioning than the general population.27PubMed Central. Long Term Outcome After Open Abdomen Treatment: Function and Quality of Life But when researchers looked more carefully, the physical impairment was concentrated in patients who had developed incisional hernias or enteroatmospheric fistulas. Patients without hernias showed quality-of-life scores that did not differ from population norms on either physical or mental health dimensions.28Military Medicine. Quality of Life After Open Abdominal Treatment With Vacuum-Assisted Wound Closure and Mesh-Mediated Fascial Traction In contrast, patients who underwent abdominal wall reconstruction after open abdomen treatment showed lower physical scores across the board, and 65% screened positive for depression while about 23% screened positive for PTSD. Roughly 58% of those who had been working before their open abdomen had returned to work by follow-up.29PubMed Central. Quality of Life After Abdominal Wall Reconstruction Following Open Abdomen
Mental Health After Open Abdomen Treatment
The rates of depression and PTSD in the abdominal wall reconstruction cohort deserve more attention than they typically get. These patients often spend weeks in the ICU, undergo multiple surgeries, wake up with an open wound they can sometimes see into, and then face months or years of follow-up operations. The trauma is not just physical. Family members and patients often describe the experience of seeing exposed bowel beneath a transparent dressing as deeply distressing, and the prolonged dependence on machines and tubes compounds the psychological burden.
One finding that offers some reassurance is that mental health scores in patients without hernias did not differ from the general population.30Military Medicine. Quality of Life After Open Abdominal Treatment With Vacuum-Assisted Wound Closure and Mesh-Mediated Fascial Traction This suggests that when the body heals well structurally, the mind often follows. The patients who struggle most long-term are those with ongoing physical complications, particularly hernias and fistulas, that keep pulling them back into the surgical system. Addressing the hernia problem early and decisively may be one of the most important things surgeons can do for the long-term wellbeing of these patients.