Interact CardioVasc Thorac Surg 2009;8:153-154. doi:10.1510/icvts.2008.188870
© 2009 European Association of Cardio-Thoracic Surgery
Brief communication - Cardiac general |
Efficacy of antimicrobial activity of slow release silver nanoparticles dressing in post-cardiac surgery mediastinitis
Pasquale Totaro* and
Manfredo Rambaldini
Cardiac Surgery, Civic Hospital, Brescia, Italy
Received 21 July 2008;
received in revised form 23 September 2008;
accepted 25 September 2008
*Corresponding author. Via San Vincenzo 38, 20123 Milano, Italy. Tel.: +39 3498465085.
E-mail address: ptotaro{at}yahoo.com (P. Totaro).
 |
Abstract
|
|---|
We report our preliminary experience in post-cardiac surgery mediastinitis using a recently introduced silver-releasing dressing claiming prompt antibacterial activity. Acticoat©, a silver nanoparticles slow release dressing was used in four patients with documented post-cardiac surgery mediastinitis and persistently positive microbiological cultures despite vacuum-assisted closure (VAC) therapy. In all four patients negative cultures were obtained within a maximum of 72 h and patients were discharged within a maximum of 20 days.
Key Words: Cardiac surgery; Mediastinitis
|
1. Introduction
|
|---|
Mediastinitis following cardiac surgery is a relatively rare complication (1–3%) characterized, however, by a poor prognosis. Despite the introduction of new treatments which have contributed to improve clinical results, high mortality (10–40%) and relevant impact in terms of prolonged hospital stay and cost expense, are indeed still reported following such a complication. Here we report our preliminary experience with a silver-releasing dressing claiming prompt antibacterial activity that could be beneficial in reducing hospital stay and, therefore, cost expense in patients presenting with poststernotomy mediastinitis.
|
2. Materials and methods
|
|---|
Silver nanoparticles slow release dressing (Acticoat©, Smith and Nephew Medical Limited, Hull, England) was used in four patients presenting with the following characteristics: a) Documented mediastinitis according to the ACDC criteria; b) Persistent positive microbiological cultures despite specific i.v. antibiotics treatment and vacuum-assisted closure (VAC) therapy (KCL, San Antonio, Texas, USA). Patient characteristics are summarized in Table 1. Patients were readmitted to hospital after 25±9 days from the primary surgical procedure and all of them had positive microbiological culture at the time of readmission. Following the diagnosis of mediastinitis, all patients underwent initial debridement and VAC therapy combined with specific i.v. antibiotic treatment. After 9±2 days of treatment, however, due to the persistence of positive culture, Acticoat© dressing was used in order to enhance antimicrobial activity.
|
3. Results
|
|---|
In patients #1 and #2 Acticoat was used as underlying dressing combined with VAC therapy (Fig. 1a). In patient #2 several holes were made in the Acticoat dressing before usage (Fig. 1b) to enhance drainage by VAC. In patients #3 and #4 Acticoat was used without concomitant VAC therapy. As shown in Table 1, after a mean of 56±14 h, microbiological cultures were negative in all patients. Acticoat treatment was then suspended and, according to the surgeons choice and state of the wound, the treatment was completed with surgical or secondary closure (following a further period of VAC therapy in three out of four patients). All four patients were discharged home within a mean of 13±7 days from the first Acticoat medication.
View larger version (138K):
[in this window]
[in a new window]
|
Fig. 1. (a) A layer of Acticoat 5 cmx5 cm is applied before the polyurethane sponge of VAC is positioned. (b) Several holes are made on Acticoat© dressing before application to enhance drainage effect of VAC.
|
|
|
4. Discussion
|
|---|
Management and treatment of post-sternotomy mediastinitis has been definitively influenced by the introduction of VAC therapy in 1997 [1]. However, despite favourable VAC therapy, effects have been clearly shown in terms of increased rate of granulation tissue and decreased exudates and wound size, clear favourable effects in decreasing bacterial counts have not been demonstrated yet.
Fuchs and colleagues [2] showed a significant improvement in antimicrobial activity using VAC therapy compared to povidon-iodine solution irrigation, however, the mean interval to obtain negative microbiological cultures using VAC remained for up to 16 days (range 10–26 days). Furthermore, no significant difference in complete wound healing time was shown using VAC therapy. Conversely, Weed and colleagues [3] demonstrated increased bacterial colony count during VAC therapy, thus questioning the correlation between bacterial clearances and wound healing rates. Furthermore, in final remarks of their study, Weed and colleagues mentioned the potential of a silver-impregnated sponge in decreasing bacterial load.
Based on this hypothesis and on previous in-vitro and in animal research evidences of strong antibacterial activity of silver nanocrystals slow release dressing [4, 5], we decided to use Acticoat dressing in patients with post-cardiac surgery mediastinitis and persistent positive cultures, despite VAC therapy.
We initially combined Acticoat dressing to VAC therapy. This technique was previously described by Agarwal and colleagues in 2005 but no mention was made in their paper about specific indications for using Acticoat. Our experience with the first two patients demonstrated the feasibility of a combination of Acticoat and VAC therapy, however, in case of reduced amount of exudates, isolated use of Acticoat can also be pursued. Based on our preliminary results, we believe that the best option could be to utilize Acticoat dressing for a limited period (maximum 96 h), with or without VAC therapy (depending on the amount of exudates), as soon as the diagnosis of mediastinitis is clear, in order to achieve a prompt sterilization of the wound. Once bacterial clearance is completed, VAC therapy could be continued alone (or started if it was not combined) and proper surgical or secondary wound closure decided according to wound size. In our opinion this approach could optimize the management of poststernotomy mediastinitis allowing a prompt clearance of bacterial cultures and, therefore, a quicker action of VAC therapy on granulation tissue. More extensive experiences are, of course, mandatory to confirm the effect of such a combined approach in hospital stay and cost reduction.
|
References
|
|---|
- Agarwal JP, Ogilvie M, Wu LC, Lohman RF, Gottlieb LJ, Franczyk M, Song DH. Vacuum-assisted closure for sternal wounds: a first-line therapeutic management approach. Plast Reconstr Surg 2005;116:1035–1040.[CrossRef][Medline]
- Fuchs U, Zittermann A, Stuettgen B, Groening A, Minami K, Koerfer R. Clinical outcome of patients with deep sternal wound infections managed by vacuum-assisted closure compared to conventional therapy with open packing: a retrospective analysis. Ann Thorac Surg 2005;79:526–531.[Abstract/Free Full Text]
- Weed T, Ratliff C, Drake DB. Quantifying bacterial bioburden during negative pressure wound therapy. Does the wound VAC enhance bacterial clearence? Ann Plast Surg 2004;52:276–280.[CrossRef][Medline]
- Heggers J, Goodheart RE, Washington J, McCoy L, Carino E, Dang T, Edgar P, Maness C, Chinkes D. Therapeutic efficacy of three silver dressings in an infected animal model. J Burn Care Rehabil 2005;26:53–56.[CrossRef][Medline]
- Ip M, Lai Lui S, Poon VKM, Lung I, Burd A. Antimicrobial activities of silver dressing: an in vitro comparison. J Med Microb 2006;55:59–63.[CrossRef]
|
|
Top
Abstract
1. Introduction