| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
|
Interact CardioVasc Thorac Surg 2008;7:801-804. doi:10.1510/icvts.2008.177527 © 2008 European Association of Cardio-Thoracic Surgery
Management of open chest and delayed sternal closure with the vacuum assisted closure system: preliminary experience
a Department of Cardiothoracic Surgery, Medical University of Vienna, AKH Vienna, Leitstelle 20A, Währinger Gürtel 18-20, 1090 Vienna, Austria Received 11 February 2008; received in revised form 20 May 2008; accepted 21 May 2008
*Corresponding author. Tel.: +43-140-4005620; fax: +43-140-4005640.
The management of open chest with the vacuum assisted closure (VAC) system was evaluated in terms of impact on cardiac hemodynamics, respiratory parameters, complications, incidence of wound infection, overall handling and outcome in 22 patients during 2005 and 2008 after cardiac surgery. The decision to leave the sternum open was made electively in all patients at the time of primary operation or reexploration. In four patients the VAC was implanted during the primary operation. In the remainder the VAC was implanted after a mean of five days after the primary operation. The overall mortality rate was 45% (10/22). None of the patients developed a sternal wound infection, nor were there any VAC related complications. Management of open chest with the VAC system can be considered as an alternative to sterile draping. The VAC has no negative impact on cardiac hemodynamics as well as respiratory mechanics. The feared complication of right ventricular rupture and massive bleeding can be effectively prevented. Through the stabilizing of the thoracic cage, the patient can be easily moved and mobilized for nursing reasons and pneumonia prevention. Furthermore, the VAC effectively prevents the contamination of the wound and the mediastinum with potential subsequent infection.
Key Words: Mediastinal infection; Hemodynamics; Wound closure
The technique of open chest and delayed sternal closure has been reported for indications like reperfusion myocardial edema, hemodynamic instability, refractory bleeding and malignant arrhythmias, with a current incidence up to 4.2% in the adult cardiac surgery population [1, 2]. Through leaving the chest open, it is easily accessible by the surgeon in terms of bleeding control, clot evacuation and cardiac massage [3]. After stabilization of the patient and negative fluid balance, a delayed closure is performed. This has been a proven effective and safe approach for many years in the adult as well as in the pediatric population [1–4]. However, disadvantages of leaving the patient with an open chest have also to be considered and are mainly related to thoracic cage instability. There are several disadvantages of this technique, namely:
It was the purpose of the present study to evaluate the efficacy and safety of the vacuum assisted closure (VAC) system for the management of open chest after cardiac surgery.
During 2005 and 2008, a total of 22 patients (7 female, 15 male) with a mean age of 61.5±15 years (8–79) underwent VAC implantation for the purpose of open chest management. The preceding cardiac surgical procedures are specified in Table 1.
In general, all operations were routinely performed using moderate hypothermic cardiopulmonary bypass with cold blood cardioplegic arrest, by intermittent antegrade and retrograde delivery. The mean EuroSCORE of this population was 11 (1–22). New York Heart Association functional class III/IV was present in 18/22 patients (81%). Twelve out of 22 patients (55%) had a redo procedure and 9 patients (41%) underwent an emergency surgery. Mean operating times were 424±91 min, extracorporal circulation time was mean 170±65 min and aortic cross-clamp time was mean 75±24 min. The decision not to close the sternum was based on the following parameters:
Refer to Table 2 for patient characteristics regarding the indication for open chest management.
VAC implantation and the dressing changes were done either in the operating room or on the intensive care unit. Time intervals between dressing changes depended on the bleeding tendency, with 24–48 h being the most common. Details of the VAC implantation protocol have been previously described in detail [5, 6]. Care was taken to ensure that bypass grafts were covered with one or more layers of a non-adherent dressing. In cases of coagulopathic bleeding, a mediastinal tamponade with several gauze sponges was performed. Thereafter, a piece of a large VAC sponge (KCI Inc., San Antonio, Texas) was cut and fitted between the sternal edges to prevent shear forces between the bony edges and the underlying right ventricle. The sponge was oversized in order to adapt to movements. After placing the adhesive drape in strips for better fitting, two VAC pads were installed, proximal and distal, and connected with the Y piece, to achieve a more uniform distribution of the vacuum and to increase thoracic cage stability. Continuous suction was started with 50 mmHg and subsequently increased, depending on the amount of bleeding and chest tube output. Statistical procedures were done by using SPSS 10.0 (SPSS Inc., Chicago, IL, USA). Data are expressed as mean±S.D.
The sternum was left open after the initial operation in six patients, after the first reexploration in four patients and after the second reexploration in the remaining 12 patients. In four patients the VAC was implanted during the primary operation. In the remainder the VAC was implanted after a mean of five days (1–10) after the primary operation and after a mean of two days following the last reexploration. Pressure settings used were 50 mmHg at the beginning, slowly increasing the pressure up to 125 mmHg, depending on the amount of bleeding. A higher suction would increase the diffuse bleeding because of increased tissue perfusion due to the VAC. When the bleeding tendency decreased, which was the case usually after 12–24 h, we slowly increased the suction. When the pressure was set to 50 mmHg, the pressure was increased to 125 mmHg during nursing activities to facilitate patient movements and physiotherapy. In 20 patients, delayed sternal closure with sternal rewiring could be successfully performed after a mean of 8.7±4.4 days with the VAC. In order to achieve sternal closure, a negative fluid balance with continuous hemofiltration was attempted under ECMO support in order to avoid hemodynamic instability. Antibiotic coverage was routinely performed with Cephazolin 2.2 g, 30 min before incision and after discontinuation of cardiopulmonary bypass, and was broadened with Vancomycin (1 g daily) or Teicoplanin (1200 mg daily), when the situation with a complicated postoperative course with open sternum became evident. Our policy was to explant the VAC and close the sternum first, thereafter wean the patient from ECMO support and finally, weaning off the IABP was performed. In all patients serial transesophaegal echocardiography was performed and showed no signs of interference of the VAC with the hemodynamic performance and additionally to continuous mean arterial pressure, central venous pressure, heart rate, pulmonary artery pressure and serial cardiac output recordings. During the study period, 10 patients died (10/22), constituting the overall mortality rate of 45%. Causes of death were right heart failure after right ventricular assist device explantation in one patient, respiratory insufficiency due to severe uncontrollable pneumonia in three patients, liver failure in one patient and multi-organ failure in five patients. In eight patients the sternum was closed already, whereas in four patients the VAC was still in situ. The surviving patients were discharged home after a mean of 30 days of intensive care unit stay and 50 days in hospital, thus resulting in a hospital survival of 55% (12/22). None of the surviving patients developed a sternal wound infection. Moreover, clinical evidence of sternal wound infection did not occur in the patients who died. At the time of VAC explantation and delayed sternal closure, bacterial cultures were taken, which were negative in all cases.
Delayed sternal closure is a well-established technique for stabilizing myocardial function, controling bleeding in case of inadequate intraoperative hemostasis, prevention of cardiac compression and tamponade and the ability for fast access, and was first described in 1975 [7], with subsequent reports appearing in the 1980s [4]. Whereas in pediatric cardiac surgery, where there are certain indications for leaving the sternum open, there has been some concern regarding infectious complications in the adult population, but nevertheless leaving the sternum open with subsequent delayed sternal closure was mandatory in the specific subset of severely impaired patients [1–5]. Especially, the presence of a thoracic compartment syndrome with elevated right-sided pressure, due to compression of the heart, frequently results in concomitant decreased ventricular pressures, which precludes sternal closure. Many techniques for the maintenance of an open sternum have been described in the literature [1, 2]. However, direct closure of the skin or adaptation of the skin with a latex membrane (Esmark Bandage, Critical Specialties Inc., Westchester, PA), sewn to the skin edges with a monofilament suture have the disadvantage of injury to the skin through recurrent reopening in cases of revisions and loosing sterility when, through ongoing bleeding, the dressing is starting to leak. Reasonably, this raised some concern to infectious complications, especially the feared mediastinitis, when leaving the sternum open for a prolonged period. Jonkers and colleagues recently estimated the incidence of superficial and deep sternal wound infection at 30 days postoperatively to be 6.8% and 4.6%, respectively. Patients with longer operation and cardiopulmonary bypass times had an increased risk of developing a sternal wound infection [8]. The vacuum assisted closure system was introduced into clinical practice in 1997 and evolved as the standard of care in the treatment of sternal wound infections during recent years [6, 9–15]. Compared with the traditional treatment modalities, the uniform negative pressure applied to the wound leads to arteriolar dilatation and increased microcirculation, thereby optimizing the wound environment. By continuous suction, fluid excess and tissue edema are decreased which reduces bacterial colonization. These positive effects on the wound promote granulation tissue proliferation and accelerated wound healing. Furthermore, through the air-tight seal additional wound contamination is effectively prevented [6–15]. In contrast to the most commonly used Esmark bandage, the VAC turns an open wound into a closed one, therefore effectively reducing the chance of bacterial contamination from the surface. Furthermore, the VAC seems to be able to achieve a quantitative reduction of bacterial load for gramnegative species in a sternal wound as shown by Moues et al. [14]. Although we are well aware of the small number of patients in our study cohort, none of our patients developed any signs of wound infection during VAC therapy. The rationale for us to use the VAC system as a bridge to delayed sternal closure was twofold: first we wanted to avoid a contamination and subsequent infection of the wound and the mediastinum as above mentioned. Second, as the VAC stabilizes the thoracic cage and has positive effects on respiratory function and hemodynamics [12–14], this might positively affect the patient, in respect to outcome. In our study collective we did not encounter any negative influence in respect to impairment of central hemodynamics during VAC therapy. This was supported by serial transesophageal echocardiography performed on each patient in addition to the routine hemodynamic parameter recordings. These findings are in accordance with an experimental study of Sjörgen et al. who demonstrated no negative effects on central hemodynamics with the most commonly used pressure settings of 50–125 mmHg [12]. The time until sternal closure was achieved was quite long with a mean of 8, 7 days. The rationale was, that through the decreased risk of infection and the improvement of sternal stability compared to the open sternum, the patients could be slowly weaned from fluid overload, as well as catecholamine support. In almost all patients, coagulopathic bleeding was present after the primary operation. However, this was not a contraindication for VAC implantation per se, but certain precautions have to be met in this setting. Initial pressure settings started with 50 mmHg in order to not enhance or induce some bleeding and might impair the chest tubes. We routinely use 75 mmHg in these cases and increase up to 125 mmHg during the treatment, if there is no bleeding and the patient is weaned from the respirator. We noted no increase in the amount of bleeding during VAC therapy, which is in accordance with a case report by Sjörgen and Gustafsson where the VAC was implanted to achieve mediastinal tamponade and therefore to control coagulopathic bleeding [15]. In conclusion, management of open chest with the VAC system can be considered as an alternative to sterile draping with encouraging results. Besides the primary indication for VAC therapy as a therapy for sternal wound infection, it can be used as effective prophylaxis against infectious contamination of the open wound. Furthermore, the VAC system has no negative impact on cardiac hemodynamics as well as respiratory mechanics. The feared complication of right ventricular rupture and massive bleeding can be effectively prevented. Through the stabilizing of the thoracic cage, the patient can be easily moved and mobilized for nursing reasons and pneumonia prevention, thereby facilitating open chest management.
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
Top
Abstract
1. Introduction