Failure of the Topical Negative Pressure Abdominal Dressing System in the “Fat” Open Abdomen: Report of a Case and Review of t

Swan and Banwell advocate the use of formal topical negative pressure (TNP) abdominal dressing systems for the treatment of open abdomens in cases of exposed bowel, omentum, or intra-abdominal sepsis.^1,2 The formal TNP abdominal dressing system (V.A.C.® Therapy™ System, KCI, San Antonio, Tex) consists of a fenestrated nonadherent piece of plastic with encapsulated foam, which is placed between the abdominal organs and the peritoneum of the abdominal wall. On top of this, an additional layer of polyurethane foam is placed. This is further covered by an overlying adhesive drape to seal (Figure 1–3). This system has many advantages to earlier versions of TNP in combination with the Bogotá bag.³ The Bogotá bag consists of an
open, sterilized 3-L genitourinary irrigation bag that is sewn (with a 1-0 or 2-0 running monofilament nylon suture) to the patient’s fascia.⁴ However, there are shortcomings to its use, especially with overweight patients in whom wound healing is impaired.⁵ The authors present a case of an obese patient in whom the TNP treatment failed and propose an alternative dressing technique in which the TNP abdominal dressing system is combined with progressive Bogotá bag closure.⁶

Case Report

A 56-year-old man presented to the authors’ hospital with a 5-day history of progressive abdominal pain. Previous history revealed a ventriculo-peritoneal drain (VP drain) placed 3 years earlier for persisting hydrocephalus after a subarachnoid hemorrhage. The patient was obese (weight 120 kg, length 1m78, body mass index 38 kg/m²). His temperature was 37.3˚C. The abdomen was painful on palpation and percussion with a local peritonitis of the right lower abdomen. Laboratory results revealed leukocytosis of 15.0 x 10⁹/L (normal 4.5–10.0 x 10⁹/L), C-reactive protein 282 mg/L (< 3), and glucose 19.0 mmol/L (3.1–6.4). The VP drain could not be visualized on the ultrasound; however, there were signs of appendicitis. A laparotomy was performed in lieu of a diagnostic laparoscopy because distended bowel loops were visible on the plain abdominal x-ray. The laparotomy revealed an extensive serositis of the terminal ileum and cecum. The appendix was clinically not infected. An ileocecal resection with a primary anastomosis was performed due to uncertainty regarding the viability of a small part of the cecum. In the same session, the VP drain was externalized. The patient then was taken to the intensive care unit (ICU).
Post-operatively, a peritonitis of all quadrants developed. Indirect measurement via a urinary catheter in the bladder showed an elevation of intra-abdominal pressure to 20 mmHg (normal < 12 mmHg). Despite extensive fluid resuscitation, the patient experienced oliguria. A possible diagnosis of fecal leakage with abdominal compartment syndrome (ACS) was made, and the patient was taken to the operating room again. Distended small bowel loops were noted, and a total of 2,100 mL of serous fluid was removed. It was impossible to close the abdomen without inducing a new ACS; therefore, a TNP abdominal dressing system was applied (Figures 1–3). The VP drain was removed 2 days later because of a superficial wound infection of the VP drain tract. After an additional 2 days, an external drain for cerebrospinal fluid (CSF) was inserted because a hydrocephalus had again developed. Cultures of the abdominal fluid, the CSF, and the VP drain all grew Candida albicans. It is possible that this microorganism was introduced into the system by the patient’s habitual scratching of the drain reservoir. Presumably, the infection travelled down the drain to infect the abdomen. It also led to Candidal meningitis. The patient was treated with intravenous fluconazole and flucytosine.
The TNP abdominal dressing system was changed twice weekly. A negative pressure of 75–100 mmHg was utilized. Higher pressures were avoided because they induced extensive ascites production (> 500 mL/hour). On the fifth TNP dressing change, it became apparent that the fascia was still retracted and that primary closure or mesh closure would be impossible (Figure 4). In order to prevent further fascia retraction, a Bogotá bag was sutured over the abdominal dressing system at the fascia level (Figure 5). There were 2 weekly changes of the TNP abdominal dressing in the operating room. The Bogotá bag was gradually reduced in size, and due to constant traction, the fascia seemed to mobilize toward the midline.
Unfortunately, the patient also developed a Pseudomonas meningitis. The ventriculostomy catheter was replaced, and the patient was treated with systemic ceftazidime and gentamycin intrathecally. A pneumonia with a multiresistant Pseudomonas strain developed. The patient died almost 6 weeks after the initial operation due to multiorgan failure despite maximal antibiotic treatment, ventilation with high pressures, and repeated bronchoscopy. During the post-mortal pathological examination, the patient had signs of meningitis, ventriculitis, encephalitis, pericarditis, and pneumonia. Pseudomonas was cultured in all infected sites and in the abdominal cavity. Candida albicans could no longer be cultured.

Discussion

Although unusual complications like gastro-intestinal perforation have been described,⁷ infection is the main complication associated with the use of VP drains.^8,9 Between 1% and 39% of patients with cerebrospinal fluid shunts develop infection, most commonly with staphylococci, followed by gram-negative bacilli.⁹ Shunt-related fungal infections constitute 6%–17% of total infection.^8,9 Factors contributing to a rising incidence of fungal infection are the use of broad-spectrum antibiotics, steroids, and the improved survival rates in immunocompromised individuals. Until 2000, only 38 cases of shunt-related candidal meningitis had been described.⁹ In patients with ventriculo-peritoneal drains, various intra-abdominal complications can occur. Occasionally, a common appendicitis can be the cause of an acute infection in the abdomen;¹⁰ infected VP drains have been mistaken for appendicitis.¹¹ The cornerstone of treating infected CSF in the case of ventriculo-peritoneal shunts is removal of the device by externalization of the VP drain, systemic therapy, and insertion of a new shunt when possible.⁸
The TNP system is a modern wound treatment. Literature on use of the device was first published in 1997—since then, more than 100 articles on the subject have been published.¹² At the 2nd World Union of Wound Healing Societies Meeting in 2004, in total 33 (8%) of the 399 oral presentations discussed TNP, indicating the prominence of TNP in modern wound treatment. The technique is simple; a subatmospheric pressure is applied to the wound by means of an open-cell foam that is connected with a tube to a vacuum source and placed in the wound cavity. The fluid is then collected and removed. The technique removes interstitial fluid and potential harmful inflammatory mediators.¹³ It also lowers interstitial pressure and increases peripheral blood flow, but presumed benefits, such as improvement of local oxygenation and reduction of bacterial load, remain to be proven.^14,15 In addition, TNP exerts a mechanical force on the tissues and attracts the wound edges centripetally.¹⁶ The mechanical force applied to the wound edges is not always powerful enough, and a combination with sutures to gradually approximate the wound edges has been described in several situations: sternal wounds, wounds on the extremities, and in pediatric damage-control laparotomies.^17,18 In comparison with conventional moist gauze treatment, TNP is equally expensive.¹⁹ There are numerous indications for TNP, such as complicated surgical wounds, laparostomies, and various chronic wounds.^3,12,20,21 The complication rate of TNP is low; localized superficial skin irritation occurs when a portion of the vacuum foam overlaps normal skin. However, lethal complications, like toxic shock syndrome, formation of bowel fistula, or anaerobic sepsis, have been described.^22,23 Prolonged applications, frequently several weeks, at the expense of early surgical reconstruction might compromise the outcome in selected cases.²⁴ Contraindications to use of TNP are known allergies to any of the device components. The use of oral anticoagulation is a relative contraindication.²⁵ Exposed vascular structures are not a contraindication for TNP.²⁶
Laparostomy (the open abdomen) is the technique of leaving the abdomen open following a laparotomy when surgical re-exploration is desirable or closure is not possible due to severe edema.² It is an effective and practical method of managing patients with severe intra-abdominal infection.^27,28 It allows repeat exploration of the abdominal cavity to check for collection of drainage and/or for treatment of intra-abdominal infection.²⁹ The management of the open abdomen can be a significant challenge and is most often managed in the intensive care department. It consumes a considerable amount of time from the specialists and nurses caring for the patient. The management of leaking wound fluid is especially cumbersome because it irritates the adjacent skin and must be drained as a result.³⁰ These wounds can be left to heal by granulation and contraction with wet gauze and self-adhesive dressing treatment.³¹ Other more advanced techniques include the “zipper,” which has proven to be a useful device for wound management.^32–34 The use of a plastic sheet was first introduced by Londoni, while a chief resident in Bogotá, Colombia, and consists of a open, sterilized 3-L genitourinary irrigation bag that is sewn (with a 1-0 or 2-0 running monofilament nylon suture) to the patient’s fascia.⁴ This technique is now called the Bogotá bag technique and has been described in combination with TNP.^3,35
The formal TNP abdominal dressing system² consists of a fenestrated nonadherent piece of plastic with encapsulated foam, which is placed over the abdominal organs and beneath the peritoneum of the abdominal wall. Over this an additional layer of polyurethane foam is placed. This is further covered by an overlying adhesive drape to seal (Figures 1–3).¹ The TNP system in combination with sutures has been successfully described in larger series, mainly in trauma patients.^30,36–39 The TNP abdominal dressing system protects the abdominal contents from iatrogenic trauma and adhesion development and allows for the active removal of intra-abdominal fluid. The system facilitates re-exploration and management of ongoing pathology.² According to the literature, most open abdomens can be closed within 2 weeks.^36,40,41
However, the herein described case shows that the reverse tissue expansion effect of negative pressure that should aid in skin and fascial approximation may not be powerful enough in obese patients. Therefore, combination with sutures^17,30 or a corsette lacing or shoelace technique^18,41 seems advisable. A Bogotá bag should be used in the case of an open abdomen because sutures may cause damage to exposed abdominal contents. As edema resolves, the abdominal wall edges are gradually approximated by reducing the size of the now loose Bogotá bag. This technique is called the progressive Bogotá bag closure technique.⁶ In addition to this patient’s obesity, another possible reason the abdomen was not closed within 2 weeks was due to an ongoing candidal infection. Additionally, this was a very sick patient with multiple comorbidities, and it is possible that neither TNP nor any other modality would have been successful. Perhaps intraperitoneal local treatment with antifungal medication (as suggested in the literature on fungal continuous ambulatory peritoneal dialysis-peritonitis) would have been another treatment option.⁴²

Conclusion

The TNP abdominal dressing system alone may not be the treatment of choice for the open abdomen in obese patients. In order to prevent retraction of the fascia, the combination of TNP with fascial sutures30 or the Bogotá bag should be considered. This combination preserves the beneficial mechanism of the TNP abdominal dressing system for wound management and preserves the possibility of closing an open abdomen within 2 weeks.