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A Protective Device for Negative-Pressure Therapy in Patients With Mediastinitis

2012; Elsevier BV; Volume: 95; Issue: 1 Linguagem: Inglês

10.1016/j.athoracsur.2012.08.027

1552-6259

Richard Ingemansson, Malin Malmsjö, Sandra Lindstedt,

Pleural and Pulmonary Diseases

A devastating complication associated with negative-pressure wound therapy (NPWT) after cardiac surgical intervention is heart rupture resulting in serious bleeding. The benefit of a rigid barrier between the underlying organs and the sharp sternal edges has been demonstrated in pigs. In the present article, we present our first 6 patients with deep sternal wound infection treated with NPWT in combination with a protective device. The median duration of NPWT was 8 days (range, 6–14 days). No major bleeding or signs of organ damage were observed. The use of a protective device seems to decrease the risk of bleeding complications. A devastating complication associated with negative-pressure wound therapy (NPWT) after cardiac surgical intervention is heart rupture resulting in serious bleeding. The benefit of a rigid barrier between the underlying organs and the sharp sternal edges has been demonstrated in pigs. In the present article, we present our first 6 patients with deep sternal wound infection treated with NPWT in combination with a protective device. The median duration of NPWT was 8 days (range, 6–14 days). No major bleeding or signs of organ damage were observed. The use of a protective device seems to decrease the risk of bleeding complications. Deep sternal wound infection (DSWI) is one of the most feared complications in patients undergoing cardiac operations. The use of negative-pressure wound therapy (NWPT) has gained acceptance in the treatment of DSWI and is today the standard mode of treatment at many cardiac surgery centers. However, there can be serious bleeding complications, with a reported incidence between 4% and 7% of patients treated with NPWT after cardiac operations [1Abu-Omar Y. Naik M.J. Catarino P.A. Ratnatunga C. Right ventricular rupture during use of high-pressure suction drainage in the management of poststernotomy mediastinitis.Ann Thorac Surg. 2003; 763 (author reply 974–5): 974Abstract Full Text Full Text PDF Google Scholar, 2Khoynezhad A. Abbas G. Palazzo R.S. Graver L.M. Spontaneous right ventricular disruption following treatment of sternal infection.J Card Surg. 2004; 191: 74-78Crossref Scopus (25) Google Scholar]. Furthermore, the US Food and Drug Administration has published 2 reports in which they discuss the problem of bleeding resulting from the application of NPWT to the mediastinum [3US Food and Drug AdministrationSerious complications associated with negative pressure wound therapy systems FDA Preliminary Public Health Notification 2009, November 13.http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/PublicHealthNotifications/ucm190658.htmGoogle Scholar, 4US Food and Drug AdministrationFDA Safety Communication: UPDATE on serious complications associated with negative pressure wound therapy systems FDA Preliminary Public Health Notification 2011 February 24.http://www.fda.gov/MedicalDevices/Safety/AlertsandNotices/ucm244211.htmGoogle Scholar]. We have demonstrated that damage to underlying organs can be prevented by inserting a semirigid plastic disc between the anterior part of the heart and the inside of the thoracic wall. Extensive experiments have been performed on pigs, and 4 reports have been published demonstrating improved drainage, better hemodynamics, good wound stability, and less damage and bleeding from the heart and lungs [5Lindstedt S. Ingemansson R. Malmsjo M. Haemodynamic effects of negative pressure wound therapy when using a rigid barrier to prevent heart rupture.Int Wound J. 2011; 84: 385-392Crossref Scopus (4) Google Scholar, 6Lindstedt S. Ingemansson R. Malmsjo M. Sternum wound contraction and distension during negative pressure wound therapy when using a rigid disc to prevent heart and lung rupture.J Cardiothorac Surg. 2011; 6: 42Crossref PubMed Scopus (4) Google Scholar, 7Lindstedt S. Malmsjo M. Ingemansson R. Effects on drainage of the mediastinum and pleura during negative pressure wound therapy when using a rigid barrier to prevent heart rupture.Int Wound J. 2011; 85: 454-458Crossref Scopus (4) Google Scholar, 8Lindstedt S. Ingemansson R. Malmsjo M. A rigid barrier between the heart and sternum protects the heart and lungs against rupture during negative pressure wound therapy.J Cardiothorac Surg. 2011; 6: 90Crossref PubMed Scopus (6) Google Scholar]. This protective disc has been further developed, and we present our experience with our first 6 patients with DSWI who were treated with this new protective device. Six patients, aged 69 to 79 years, were included in the study. They all underwent cardiac operations and returned with DSWI according to the US Centers for Disease Control and Prevention. The protocol for this study was approved by the Ethics Committee at Lund University, Lund, Sweden. The device is rectangular with a base along one edge (Fig 1A). It is covered with a foam sleeve and is inserted into the wound between the sharp edges of the sternum with the base downward. Holes in the device allow drainage of fluid from the wound bed through tubes. The wound was opened and a full revision was performed, 5 tissue cultures were obtained, and the wound was rinsed. A foam pocket was then fitted around the base of the device (Fig 1B). Two layers of Delnet (Delstar Technologies, Inc, Middletown, DE) were used to cover the first foam layer to prevent the foam from coming into direct contact with the heart (Fig 1B). The device was then inserted into the wound so that 25% of the device was standing on the top of the diaphragm. The base of the device covered the heart and lungs, as well as any graft, preventing them from coming into contact with the sternal edges during NPWT (Fig 2A). A second layer of foam was then placed between the sternal edges and the device to help stabilize the sternal edges. A final layer of foam, called the subcutaneous layer, was secured to the surrounding skin by continuous suturing with DERMALON 2-0 sutures (Covidien, Mansfield, MA) (Fig 2B). The wound was then sealed with a plastic drape (Smith & Nephew, St. Petersburg, FL). Holes were made in the plastic drape to allow tubes to be connected to the 2 drainage holes on the top of the device. Finally, 2 Foam ports (Renasys Foam Port, Smith & Nephew) were connected to a negative-pressure device (RENASYS EZ, Smith & Nephew) and a negative pressure of −120 mm Hg was applied (Fig 3). The wound was considered free from infection when C-reactive protein levels were less than 70 mg/L. The sternotomy was rewired with interrupted steel wires (Stahldraht, Johnson & Johnson, Brussels, Belgium). The presternal fascia was carefully mobilized to cover the wires and was sutured with interrupted stitches (Vicryl, Johnson & Johnson). The skin was closed with interrupted stitches (Dermalon 2-0). An Argyle 28 Ch tube (Sherwood Medical, Tullamore, Ireland) was placed behind the sternum, and a negative pressure of 20 cm H2O was applied.Fig 3The device in place with a negative pressure of −120 mm Hg.View Large Image Figure ViewerDownload (PPT) The duration of NPWT ranged from 6 to 14 days; the median was 8 days. The median number of dressing changes including closure was 3 (range, 3–5). The median hospital stay was 18 days (range, 14–31 days). All 6 patients in the study survived the treatment and the sternal infection healed. No adverse events in terms of organ damage or major bleeding were observed. Two-month follow-up revealed no fistulas or recurrent DSWI. The use of a semirigid barrier has been suggested to offer protection against right ventricular rupture by preventing the heart from being drawn up against the sharp edges of the sternum. In the present study, we applied a protective device in 6 patients who underwent treatment for DSWI. The results of this first study in 6 patients indicated several advantages of the new device.1By inserting the device below the sternum, the foam extends deeper into the wound, thereby improving the drainage capacity.2The foam surface area subjected to negative pressure will increase because the bottom of the device will prevent the foam from contracting, thus increasing the foam-wound contact area.3The base of the device helps to spread out the foam laterally so that it comes closer to the pleura, thereby facilitating drainage.4The pressure gradient in the foam from the bottom up to the Foam port can sometimes be substantial, especially in wounds with high fluid secretion. With the current device, fluid will never be transported more than 1 to 2 cm through the foam before it enters the device and can be quickly removed. We suggest that these 4 mechanisms facilitate both pericardial and pleural drainage. An improvement in drainage might speed up wound healing and thus decrease the duration of therapy. A previous study by our group on our first 176 patients treated with traditional NPWT resulting from DSWI showed that the median duration of treatment was 11 days. In the present study, the median duration of treatment was 8 days. In conclusion, the absence of marks, epicardial petechial bleeding, and callus formation on the anterior part of the right ventricle indicates the ability of this device to protect the heart and lungs. These findings lead us to believe that there is a future for this type of protective device in the treatment of patients with DSWI.