Original Article
Vacuum-assisted closure system in treatment of postoperative mediastinitis
Asian Cardiovascular & Thoracic Annals 21(6) 708–712 ß The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0218492313479353 aan.sagepub.com
Mohamed Ahmed Elawadi and Farouk Oueida
Abstract Objectives: Post-cardiac surgery mediastinitis is a serious complication with high morbidity and high financial costs. Using a vacuum-assisted closure system is the established line of treatment for mediastinitis, which improves outcome, especially in the high-risk group of patients. Methods: From January 2007 to April 2011, a retrospective study was carried out to evaluate the outcome of vacuumassisted closure in the treatment of postoperative mediastinitis. Results: There were 34 patients; 27 were male and 7 female. Mean time from infection to vacuum-assisted closure was 3.34 1.10 days. The duration of vacuum-assisted closure was 6.51 1.85 days (3-9 days). The mean amount of discharge was 759.60 175.28 mL (range, 354–990 mL). Of the 34 patients, 21 (61.76%) had direct surgical wound closure and 13 (41.16%) had re-wiring. Two patients had bilateral pectoral flaps. One patient had chronic fistula formation, and one had a tear in the right ventricle. Mean hospital stay was 11.28 2.09 days (range, 6–16 days). Conclusion: Vacuum-assisted closure therapy is a safe, reliable, and cost-effective modality of treatment for postoperative mediastinitis. It improves the outcome and can be combined with other modalities of conventional treatment, especially in high-risk groups such as the elderly or patients with diabetes.
Keywords Cardiac surgical procedures, mediastinitis, Negative-pressure wound therapy, Postoperative complications, Sternum, Surgical wound infection
Introduction Postoperative mediastinitis is a rare but serious complication with high morbidity and financial costs. Although the patient population has become increasingly older with multiple risk factors, the incidence of mediastinitis has not changed during the last 30 years, ranging between 1% and 3%.1,2 The treatment of postoperative mediastinitis includes surgical debridement with closed irrigation, open packing, and vacuumassisted closure (VAC) followed by primary or secondary closure with or without muscle or omental flaps. There is a lack of consensus on using a single line of treatment or a combination of these procedures, especially in high-risk patients.3 Some reports recommend immediate debridement and reconstruction with pectoralis major muscle flaps after diagnosis of mediastinitis, especially in cases of deep sternal wound infection involving the upper two-thirds of the sternum.4 Due to the numerous morbidities associated with muscle or
omental flap techniques (pain, hernia, chest wall instability, bleeding, recurrence of infection, and decreased respiratory function and exercise capacity), a clean and relatively dry field is needed to avoid associated morbidities. Argenta and colleagues6 showed that the application of negative pressure to wounds promotes the formation of granulation tissue. The use of VAC removes excess interstitial fluid that may contain toxic products of infection and prolonged inflammation, and transmits a mechanical force to the tissues, producing deformation of the extracellular matrix and promoting a reduction in wound size.6 Tissue bacterial
Department of Cardiac Surgery, Saud Al-Babtain Cardiac Center, Dammam, Saudi Arabia Corresponding author: Mohamed Ahmed Elawadi, Department of Cardiac Surgery, Saud Al-Babtain Cardiac Center, Dammam, Saudi Arabia. Email: [email protected]
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counts in infected wounds were also reduced by 21% with VAC compared to a control group, which would improve wound healing.7 Obdeijn and colleagues8 introduced the application of VAC followed by secondary closure with pectoral muscle flap or omentum transposition for deep sternal wound infection. Nowadays, VAC is used in many hospitals as the first-line therapy for post-sternotomy mediastinitis, either as the sole treatment for more superficial wounds or as adjuvant therapy for deeper wounds, allowing surgical repair such as primary closure or plastic reconstructive surgery, more safely and earlier than before.9 Some studies have confirmed a reduction in cardiac output and stroke volume following initiation of VAC for mediastinitis after open heart surgery, which is of real concern, particularly in pediatric patients with Fontan or Rastelli procedures, or those with low cardiac output.10 Since 2007, our center has been using VAC routinely in adult patients with postoperative mediastinitis. We conducted this study to evaluate the outcome of VAC therapy for postoperative mediastinitis.
Patients and methods We retrospectively evaluated the outcome of using the VAC system in 34 patients with postoperative mediastinitis in Saud Al-Babtain Cardiac Center, KSA) from January 2007 to April 2011. The total number of surgeries in the same period was 1658, with an incidence of infection of 2.04%. According to our center’s policy, patients were followed up at the surgical clinic for 3 months after discharge, then at the cardiology clinic if there were no surgical complications. We followed up the patients for I year after hospital discharge. The demographic, operative, and postoperative data were collected, including the interval between time of surgery and the occurrence of sternal wound infection, readmission after discharge, hospital stay from the onset of mediastinitis until discharge home, and the surgical procedures required. Operative and postoperative complications were recorded. According to the protocol for management of sternal wound infection in our center, all patients had a full clinical assessment including examination of sternal stability, depth and extension of the wound. Laboratory assessment included swab culture and sensitivity of wound discharge, complete blood picture with differential counts, erythrocyte sedimentation rate, C-reactive protein, and complete liver and renal function tests. Radiological assessment included chest radiography in posteroanterior and lateral views, transthoracic echocardiography, and chest computed tomography with contrast in a selected group of patients when loculated pleural or posterior pericardial effusion was suspected.
Table 1. Demographic, preoperative and operative data of 34 patients who had vacuum-assisted closure. Variable
No. of patients
Age (years) Male Female Hypertensive Smoker Chronic renal failure Diabetes mellitus COPD Ejection fraction Creatinine (mgdL1) Urea (mgdL1) Bilirubin (mgdL1) EuroSCORE (additive) Valve surgery CABG LIMA þ RIMA (skeletonized) LIMA (skeletonized) LIMA (pedicled) Reopening
61.33 8.26 27 (79.41%) 7 (20.58%) 28 (82.35%) 22 (64.70%) 2 (5.88%) 30 (88.23%) 1 (2.94%) 41.76% 4.79% 1.9 0.18 28.13 6.80 0.80 0.28 3.01 1.37 4 (11.76%) 30 (88.23%) 13 (38.23%) 12 (35.29%) 9 (26.47%) 10 (29.41%)
CABG: coronary artery bypass grafting; COPD: chronic obstructive pulmonary disease; LIMA: left internal mammary artery; RIMA: right internal mammary artery.
Table 1 summarizes all demographic, preoperative and operative data of the 34 patients. The severity of the infection was classified as: mild: minimal indications of an active mediastinitis, no pus or retrosternal fluid collections, and no necrosis or active infection of the sternum; moderate: presence of pus or retrosternal fluid collections but no necrosis or infection of the sternum; severe: necrosis or active infection of the sternum. There were 15 case of mild infection, 12 of moderate infection, and 7 were classified as severe. After a wound swab was taken, all patients were started on intravenous antibiotic empirically until the results of culture and sensitivity tests. Tables 2 and 3 summarize the results of culture and sensitivity tests and the antibiotics used. After debridement of necrotic tissues and cleaning the wound, VAC was applied, including a tailored piece of black polyurethane foam cut to fit into the wound cavity exactly, with a transparent adhesive drape in which the non-collapsible evacuation tube was embedded. The tube was connected to a negative-pressure vacuum which was initiated in auto continuous mode. We used an AntiV.A.C. system (KCI, Inc., San Antonio, TX, USA). The VAC dressing was changed every 3 days.
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Table 2. Type of organism according to culture.
Table 4. Results of VAC therapy.
Organism
No. of patients
Variable
No. of patients
Staphylococcus epidermitis Staphylococcus aureus MRSA Klebsiella pneumoniae Pseudomonas
13 11 1 6 3
Table 3. Antibiotic used according to culture and sensitivity.
Readmission after surgery Surgery-to-infection interval (days) Infection-to-VAC interval (days) Duration of VAC therapy (days) Total amount of discharge (mL) Hospital stay after VAC (days) Direct surgical wound closure Re-wiring Pectoral flap Chronic fistula
27 6.68 1.18 3.34 1.10 6.51 1.85 759.60 175.28 11.28 2.09 21 13 2 1
Antibiotics
No. of patients
VAC: vacuum-assisted closure.
Vancomycin Cloxacillin Cephalexin Ciprofloxacin Gentamicin Imipenem-cilastatin Amoxicillin-clavulanate
10 2 3 8 4 4 3
MRSA: methicillin-resistant Staphylococcus aureus.
Data of VAC treatment were collected, including duration of therapy and changes in the amount and nature of the drainage fluid. Routine follow-up laboratory studies included complete blood picture, erythrocyte sedimentation rate, C-reactive protein, and complete liver and renal function tests. The VAC was removed when there was no or low-grade fever, a decrease in white blood cell count, negative bacterial cultures from the wound, and a continuous decrease in the daily fluid discharge. After VAC removal, a full clinical assessment for further surgical intervention was made, including wound debridement, rewiring, or surgical flaps, according to the extension of the wound, sternal stability, and response to VAC therapy. Values of continuous variables are expressed as mean and standard deviation. Analyses were performed with SPSS version 18.0 statistical software (SPSS, Inc., Chicago, IL, USA).
Results Table 4 summarizes the results of VAC therapy. Of the 34 patients treated with VAC, 27 were readmitted from the outpatient clinic or emergency room, and 7 had infection before discharge home. The duration of VAC therapy was 6.51 1.85 days (range, 3–9 days). The mean amount of discharge was 759.60 175.28 mL (range, 354–990 mL). Twenty-one (61.76%) patients had direct surgical wound closure, de-wiring, or just
tightening of the sternal wires, whereas 13 (41.16%) need debridement of the sternum and re-wiring; 2 of these patients need bilateral pectoral flaps to close the soft tissue defect. One patient had chronic fistula formation and need de-wiring and curettage of the fistula 4 months after discharge home. Intraoperatively, one patient suffered a tear in the right ventricle during removal of the polyurethane sponge, which was controlled surgically. Mean hospital stay after VAC application was 11.28 2.09 days (range, 6–16 days). There was one recorded death due to postoperative cerebral infarction and multiorgan failure, unrelated to VAC therapy.
Discussion Mortality due to mediastinitis has been reported to range between 16% and 29% in recent studies.3 The treatment costs of mediastinal infections after open heart surgery are considerable, including the frequency of wound care, the prolonged duration of hospitalization, and the surgical interventions required. The use of VAC for treatment of mediastinitis is increasing. Negative-pressure application increases local and dermal blood flow, reduces tissue edema and bacterial colonization rates, removes chronic wound fluid and necrotic tissue, enhances wound closure, and prevents wound dehydration due to the occlusive dressing. It also promotes healing of the wound by eliminating matrix metalloproteinases, which have been shown to suppress endothelial cell and fibroblast proliferation.11 Song and colleagues12 reported high success rates for VAC as the first-line therapy for sternal wounds. They showed that VAC therapy alone leads to a significant decrease in the number of dressing changes and soft tissue flaps needed for closure. In addition, patients treated with VAC therapy had a trend towards a decreased number of days between debridement and
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closure. Using VAC in multimodality treatment of postoperative mediastinitis improves outcome by achieving early negative mediastinal microbiological cultures with a decease in C-reactive protein level. Many studies have found that total hospital stay is shorter, rewiring could be carried out earlier, and survival was higher compared to other modalities of treatment.13–15 Other studies found VAC to be an effective therapy for mediastinitis following debridement or before placement of a vascularized tissue flap, especially in high-risk patients and those who needed reconstructive surgery.16–18 Bleeding was the major complication during VAC therapy, mainly from a tear in the right ventricle due to direct contact with the foam sponge or the sternum with the underlying ventricle, and there are reports of ventricular rupture caused by direct contact of the sharp edges of the loose sternum with tissues underneath.19,20 Covering the heart with several layers of paraffin gauze is a protective maneuver but it cannot completely prevent major complications during VAC therapy.20 In our study, one patient had a tear in the right ventricle during removal of the sponge intraoperatively, which was managed successfully by direct suturing. Some rare complications such as a retained part of the foam sponge in the mediastinum or erosion of the aorta, leading to massive bleeding, have been recorded.21,22 Although VAC therapy is a safe and reliable option for the treatment of sternal wound infection, prolonged use of a VAC system only as a replacement for surgical closure of sternal wounds appears to be associated with recurrent problems of the sternal wound.23 A successful strategy is the early use of VAC therapy within multimodality lines of treatment including other surgical options, with early removal of VAC to avoid its complications. From a financial point of view, the use of VAC is very effective as it deceases the daily cost of conventional treatment including intravenous antibiotics and the need for more complex surgical procedures, as well as deceasing hospital stay. Thus the use of VAC is not only as a ‘‘bridge to surgery’’ but it is also cost effective.24 We concluded that VAC therapy is a safe, reliable, and cost-effective option for treatment of postoperative mediastinitis. VAC should be used with other treatment options, especially in high-risk cases such as the elderly, those with diabetes, and female patients. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Conflicts of interest statement None declared.
References 1. De Feo M, Renzulli A, Ismeno G, et al. Variables predicting adverse outcome in patients with deep sternal wound infection. Ann Thorac Surg 2001; 71: 324–331. 2. Gummert JF, Barten MJ, Hans C, et al. Mediastinitis and cardiac surgery—an updated risk factor analysis in 10,373 consecutive adult patients. Thorac Cardiovasc Surg 2002; 50: 87–91. 3. Immer FF, Durrer M, Muhlemann KS, Erni D, Gahl B and Carrel TP. Deep sternal wound infection after cardiac surgery: modality of treatment and outcome. Ann Thorac Surg 2005; 80: 957–961. 4. Douville EC, Asaph JW, Dworkin RJ, Handy JR, Canepa CS and Grunkemeier GL. Sternal preservation: a better way to treat most sternal wound complications after cardiac surgery. Ann Thorac Surg 2004; 78: 1659–1664. 5. Jang YJ, Park MC, Park DH, Lim H, Kim JH and Lee IJ. Immediate debridement and reconstruction with a pectoralis major muscle flap for poststernotomy mediastinitis. Arch Plast Surg 2012; 39: 36–41. 6. Morotomi N, Saitoh M, Takanashi S, Nagayama M and Mizuma M. After omental flap transposition, respiratory function and exercise capacity decrease. Ann Thorac Cardiovasc Surg 2010; 16: 9–15. 7. Argenta LC, Morykwas MJ, Shelton Brown and McGuirt W. Vacuum-assisted closure: a new method for wound control and treatment: animal studies and basic foundation. Ann Plast Surg 1997; 38: 553–562. 8. Urschel JD, Scott PG and Williams HT. The effect of mechanical stress on soft and hard tissue repair; a review. Br J Plast Surg 1988; 41: 182–186. 9. Obdeijn MC, de Lange MY, Lichtendahl DH and de Boer WJ. Vacuum-assisted closure in the treatment of poststernotomy mediastinitis. Ann Thorac Surg 1999; 68: 2358–2360. 10. Petzina R, Ugander M, Gustafsson L, et al. Hemodynamic effects of vacuum assisted closure therapy in cardiac surgery: assessment using magnetic resonance imaging. J Thorac Cardiovasc Surg 2007; 133: 1154–1162. 11. Jones SM, Banwell PE and Shakespeare PG. Advances in wound healing: topical negative pressure therapy [Review]. Postgrad Med J 2005; 81: 353–357. 12. Song DH, Wu LC, Lohman RF, Gottlieb LJ and Franczyk M. Vacuum assisted closure for the treatment of sternal wounds: the bridge between debridement and definitive closure. Plast Reconstr Surg 2003; 111: 92–97. 13. Domkowski PW, Smith ML, Gonyon DL, et al. Evaluation of vacuum-assisted closure in the treatment of poststernotomy mediastinitis. J Thorac Cardiovasc Surg 2003; 126: 386–390. 14. Ennker IC, Malkoc A, Pietrowski D, Vogt PM, Ennker J and Albert A. The concept of negative pressure wound therapy (NPWT) after poststernotomy mediastinitis—a single center experience with 54 patients. J Cardiothorac Surg 2009; 4: 5. 15. Cowan KN, Teague L, Sue SC and Mahoney JL. Vacuum-assisted wound closure of deep sternal infections
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Asian Cardiovascular & Thoracic Annals 21(6) in high-risk patients after cardiac surgery. Ann Thorac Surg 2005; 80: 2205–2212. Petzina R, Hoffmann J, Navasardyan A, et al. Negative pressure wound therapy for post-sternotomy mediastinitis reduces mortality rate and sternal re-infection rate compared to conventional treatment. Eur J Cardiothorac Surg 2010; 38: 110–113. Sjogren J, Gustafsson R, Nilsson J, Malmsjo M and Ingemansson R. Clinical outcome after poststernotomy mediastinitis: vacuum-assisted closure versus conventional treatment. Ann Thorac Surg 2005; 79: 2049–2055. Vos RJ, Yilmaz A, Sonker U, Kelder JC and Kloppenburg GT. Primary closure using Redon drains vs vacuum-assisted closure in post-sternotomy mediastinitis. Eur J Cardiothorac Surg 2012; 42: 53–57. Sjo¨gren J, Gustafsson R, Nilsson J, Lindstedt S, Nozohoor S and Ingemansson R. Negative-pressure wound therapy following cardiac surgery: bleeding complications and 30-day mortality in 176 patients with deep sternal wound infection. Interact Cardiovasc Thorac Surg 2011; 12: 117–120.
20. Petzina R, Malmsjo¨ M, Stamm C and Hetzer R. Major complications during negative pressure wound therapy in poststernotomy mediastinitis after cardiac surgery. J Thorac Cardiovasc Surg 2010; 140: 1133–1136. 21. Saeed MU and Kennedy DJ. A retained sponge is a complication of vacuum-assisted closure therapy. Int J Low Extrem Wounds 2007; 6: 153–154. 22. Grauhan O, Navarsadyan A, Hussmann J and Hetzer R. Infectious erosion of aorta ascending aorta during vacuum-assisted therapy of mediastinitis. Interact Cardiovasc Thorac Surg 2010; 11: 493–494. 23. Bapat V, El-Muttardi N, Young C, Venn G and Roxburgh J. Experience with vacuum-assisted closure of sternal wound infections following cardiac surgery and evaluation of chronic complications associated with its use. J Card Surg 2008; 23: 227–233. 24. Mokhtari A, Sjo¨gren J, Nilsson J, Gustafsson R, Malmsjo¨ M and Ingemansson R. The cost of vacuum-assisted closure therapy in treatment of deep sternal wound infection. Scand Cardiovasc J 2008; 42: 85–89.
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Corrigendum
Corrigendum
Asian Cardiovascular & Thoracic Annals 2015, Vol. 23(1) 117 ß The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0218492314556587 aan.sagepub.com
Vacuum-assisted closure system in treatment of postoperative mediastinitis, by Mohamed Ahmed Elawadi and Farouk Oueida, Asian Cardiovascular and Thoracic Annals December 2013 21: 708–712, DOI: 10.1177/ 0218492313479353 For the above paper the affiliation details for Mohamed Ahmed Elawadi were incomplete, they should have read: 1 2
Department of Cardiac Surgery, Saud Al-Babtain Cardiac Center, Dammam, Saudi Arabia Cardiothoracic Surgery Department, Banha Faculty of Medicine, Banha University, Egypt
Vacuum-assisted closure system in treatment of postoperative mediastinitis
Asian Cardiovascular & Thoracic Annals 21(6) 708–712 ß The Author(s) 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0218492313479353 aan.sagepub.com
Mohamed Ahmed Elawadi and Farouk Oueida
Abstract Objectives: Post-cardiac surgery mediastinitis is a serious complication with high morbidity and high financial costs. Using a vacuum-assisted closure system is the established line of treatment for mediastinitis, which improves outcome, especially in the high-risk group of patients. Methods: From January 2007 to April 2011, a retrospective study was carried out to evaluate the outcome of vacuumassisted closure in the treatment of postoperative mediastinitis. Results: There were 34 patients; 27 were male and 7 female. Mean time from infection to vacuum-assisted closure was 3.34 1.10 days. The duration of vacuum-assisted closure was 6.51 1.85 days (3-9 days). The mean amount of discharge was 759.60 175.28 mL (range, 354–990 mL). Of the 34 patients, 21 (61.76%) had direct surgical wound closure and 13 (41.16%) had re-wiring. Two patients had bilateral pectoral flaps. One patient had chronic fistula formation, and one had a tear in the right ventricle. Mean hospital stay was 11.28 2.09 days (range, 6–16 days). Conclusion: Vacuum-assisted closure therapy is a safe, reliable, and cost-effective modality of treatment for postoperative mediastinitis. It improves the outcome and can be combined with other modalities of conventional treatment, especially in high-risk groups such as the elderly or patients with diabetes.
Keywords Cardiac surgical procedures, mediastinitis, Negative-pressure wound therapy, Postoperative complications, Sternum, Surgical wound infection
Introduction Postoperative mediastinitis is a rare but serious complication with high morbidity and financial costs. Although the patient population has become increasingly older with multiple risk factors, the incidence of mediastinitis has not changed during the last 30 years, ranging between 1% and 3%.1,2 The treatment of postoperative mediastinitis includes surgical debridement with closed irrigation, open packing, and vacuumassisted closure (VAC) followed by primary or secondary closure with or without muscle or omental flaps. There is a lack of consensus on using a single line of treatment or a combination of these procedures, especially in high-risk patients.3 Some reports recommend immediate debridement and reconstruction with pectoralis major muscle flaps after diagnosis of mediastinitis, especially in cases of deep sternal wound infection involving the upper two-thirds of the sternum.4 Due to the numerous morbidities associated with muscle or
omental flap techniques (pain, hernia, chest wall instability, bleeding, recurrence of infection, and decreased respiratory function and exercise capacity), a clean and relatively dry field is needed to avoid associated morbidities. Argenta and colleagues6 showed that the application of negative pressure to wounds promotes the formation of granulation tissue. The use of VAC removes excess interstitial fluid that may contain toxic products of infection and prolonged inflammation, and transmits a mechanical force to the tissues, producing deformation of the extracellular matrix and promoting a reduction in wound size.6 Tissue bacterial
Department of Cardiac Surgery, Saud Al-Babtain Cardiac Center, Dammam, Saudi Arabia Corresponding author: Mohamed Ahmed Elawadi, Department of Cardiac Surgery, Saud Al-Babtain Cardiac Center, Dammam, Saudi Arabia. Email: [email protected]
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counts in infected wounds were also reduced by 21% with VAC compared to a control group, which would improve wound healing.7 Obdeijn and colleagues8 introduced the application of VAC followed by secondary closure with pectoral muscle flap or omentum transposition for deep sternal wound infection. Nowadays, VAC is used in many hospitals as the first-line therapy for post-sternotomy mediastinitis, either as the sole treatment for more superficial wounds or as adjuvant therapy for deeper wounds, allowing surgical repair such as primary closure or plastic reconstructive surgery, more safely and earlier than before.9 Some studies have confirmed a reduction in cardiac output and stroke volume following initiation of VAC for mediastinitis after open heart surgery, which is of real concern, particularly in pediatric patients with Fontan or Rastelli procedures, or those with low cardiac output.10 Since 2007, our center has been using VAC routinely in adult patients with postoperative mediastinitis. We conducted this study to evaluate the outcome of VAC therapy for postoperative mediastinitis.
Patients and methods We retrospectively evaluated the outcome of using the VAC system in 34 patients with postoperative mediastinitis in Saud Al-Babtain Cardiac Center, KSA) from January 2007 to April 2011. The total number of surgeries in the same period was 1658, with an incidence of infection of 2.04%. According to our center’s policy, patients were followed up at the surgical clinic for 3 months after discharge, then at the cardiology clinic if there were no surgical complications. We followed up the patients for I year after hospital discharge. The demographic, operative, and postoperative data were collected, including the interval between time of surgery and the occurrence of sternal wound infection, readmission after discharge, hospital stay from the onset of mediastinitis until discharge home, and the surgical procedures required. Operative and postoperative complications were recorded. According to the protocol for management of sternal wound infection in our center, all patients had a full clinical assessment including examination of sternal stability, depth and extension of the wound. Laboratory assessment included swab culture and sensitivity of wound discharge, complete blood picture with differential counts, erythrocyte sedimentation rate, C-reactive protein, and complete liver and renal function tests. Radiological assessment included chest radiography in posteroanterior and lateral views, transthoracic echocardiography, and chest computed tomography with contrast in a selected group of patients when loculated pleural or posterior pericardial effusion was suspected.
Table 1. Demographic, preoperative and operative data of 34 patients who had vacuum-assisted closure. Variable
No. of patients
Age (years) Male Female Hypertensive Smoker Chronic renal failure Diabetes mellitus COPD Ejection fraction Creatinine (mgdL1) Urea (mgdL1) Bilirubin (mgdL1) EuroSCORE (additive) Valve surgery CABG LIMA þ RIMA (skeletonized) LIMA (skeletonized) LIMA (pedicled) Reopening
61.33 8.26 27 (79.41%) 7 (20.58%) 28 (82.35%) 22 (64.70%) 2 (5.88%) 30 (88.23%) 1 (2.94%) 41.76% 4.79% 1.9 0.18 28.13 6.80 0.80 0.28 3.01 1.37 4 (11.76%) 30 (88.23%) 13 (38.23%) 12 (35.29%) 9 (26.47%) 10 (29.41%)
CABG: coronary artery bypass grafting; COPD: chronic obstructive pulmonary disease; LIMA: left internal mammary artery; RIMA: right internal mammary artery.
Table 1 summarizes all demographic, preoperative and operative data of the 34 patients. The severity of the infection was classified as: mild: minimal indications of an active mediastinitis, no pus or retrosternal fluid collections, and no necrosis or active infection of the sternum; moderate: presence of pus or retrosternal fluid collections but no necrosis or infection of the sternum; severe: necrosis or active infection of the sternum. There were 15 case of mild infection, 12 of moderate infection, and 7 were classified as severe. After a wound swab was taken, all patients were started on intravenous antibiotic empirically until the results of culture and sensitivity tests. Tables 2 and 3 summarize the results of culture and sensitivity tests and the antibiotics used. After debridement of necrotic tissues and cleaning the wound, VAC was applied, including a tailored piece of black polyurethane foam cut to fit into the wound cavity exactly, with a transparent adhesive drape in which the non-collapsible evacuation tube was embedded. The tube was connected to a negative-pressure vacuum which was initiated in auto continuous mode. We used an AntiV.A.C. system (KCI, Inc., San Antonio, TX, USA). The VAC dressing was changed every 3 days.
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Table 2. Type of organism according to culture.
Table 4. Results of VAC therapy.
Organism
No. of patients
Variable
No. of patients
Staphylococcus epidermitis Staphylococcus aureus MRSA Klebsiella pneumoniae Pseudomonas
13 11 1 6 3
Table 3. Antibiotic used according to culture and sensitivity.
Readmission after surgery Surgery-to-infection interval (days) Infection-to-VAC interval (days) Duration of VAC therapy (days) Total amount of discharge (mL) Hospital stay after VAC (days) Direct surgical wound closure Re-wiring Pectoral flap Chronic fistula
27 6.68 1.18 3.34 1.10 6.51 1.85 759.60 175.28 11.28 2.09 21 13 2 1
Antibiotics
No. of patients
VAC: vacuum-assisted closure.
Vancomycin Cloxacillin Cephalexin Ciprofloxacin Gentamicin Imipenem-cilastatin Amoxicillin-clavulanate
10 2 3 8 4 4 3
MRSA: methicillin-resistant Staphylococcus aureus.
Data of VAC treatment were collected, including duration of therapy and changes in the amount and nature of the drainage fluid. Routine follow-up laboratory studies included complete blood picture, erythrocyte sedimentation rate, C-reactive protein, and complete liver and renal function tests. The VAC was removed when there was no or low-grade fever, a decrease in white blood cell count, negative bacterial cultures from the wound, and a continuous decrease in the daily fluid discharge. After VAC removal, a full clinical assessment for further surgical intervention was made, including wound debridement, rewiring, or surgical flaps, according to the extension of the wound, sternal stability, and response to VAC therapy. Values of continuous variables are expressed as mean and standard deviation. Analyses were performed with SPSS version 18.0 statistical software (SPSS, Inc., Chicago, IL, USA).
Results Table 4 summarizes the results of VAC therapy. Of the 34 patients treated with VAC, 27 were readmitted from the outpatient clinic or emergency room, and 7 had infection before discharge home. The duration of VAC therapy was 6.51 1.85 days (range, 3–9 days). The mean amount of discharge was 759.60 175.28 mL (range, 354–990 mL). Twenty-one (61.76%) patients had direct surgical wound closure, de-wiring, or just
tightening of the sternal wires, whereas 13 (41.16%) need debridement of the sternum and re-wiring; 2 of these patients need bilateral pectoral flaps to close the soft tissue defect. One patient had chronic fistula formation and need de-wiring and curettage of the fistula 4 months after discharge home. Intraoperatively, one patient suffered a tear in the right ventricle during removal of the polyurethane sponge, which was controlled surgically. Mean hospital stay after VAC application was 11.28 2.09 days (range, 6–16 days). There was one recorded death due to postoperative cerebral infarction and multiorgan failure, unrelated to VAC therapy.
Discussion Mortality due to mediastinitis has been reported to range between 16% and 29% in recent studies.3 The treatment costs of mediastinal infections after open heart surgery are considerable, including the frequency of wound care, the prolonged duration of hospitalization, and the surgical interventions required. The use of VAC for treatment of mediastinitis is increasing. Negative-pressure application increases local and dermal blood flow, reduces tissue edema and bacterial colonization rates, removes chronic wound fluid and necrotic tissue, enhances wound closure, and prevents wound dehydration due to the occlusive dressing. It also promotes healing of the wound by eliminating matrix metalloproteinases, which have been shown to suppress endothelial cell and fibroblast proliferation.11 Song and colleagues12 reported high success rates for VAC as the first-line therapy for sternal wounds. They showed that VAC therapy alone leads to a significant decrease in the number of dressing changes and soft tissue flaps needed for closure. In addition, patients treated with VAC therapy had a trend towards a decreased number of days between debridement and
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closure. Using VAC in multimodality treatment of postoperative mediastinitis improves outcome by achieving early negative mediastinal microbiological cultures with a decease in C-reactive protein level. Many studies have found that total hospital stay is shorter, rewiring could be carried out earlier, and survival was higher compared to other modalities of treatment.13–15 Other studies found VAC to be an effective therapy for mediastinitis following debridement or before placement of a vascularized tissue flap, especially in high-risk patients and those who needed reconstructive surgery.16–18 Bleeding was the major complication during VAC therapy, mainly from a tear in the right ventricle due to direct contact with the foam sponge or the sternum with the underlying ventricle, and there are reports of ventricular rupture caused by direct contact of the sharp edges of the loose sternum with tissues underneath.19,20 Covering the heart with several layers of paraffin gauze is a protective maneuver but it cannot completely prevent major complications during VAC therapy.20 In our study, one patient had a tear in the right ventricle during removal of the sponge intraoperatively, which was managed successfully by direct suturing. Some rare complications such as a retained part of the foam sponge in the mediastinum or erosion of the aorta, leading to massive bleeding, have been recorded.21,22 Although VAC therapy is a safe and reliable option for the treatment of sternal wound infection, prolonged use of a VAC system only as a replacement for surgical closure of sternal wounds appears to be associated with recurrent problems of the sternal wound.23 A successful strategy is the early use of VAC therapy within multimodality lines of treatment including other surgical options, with early removal of VAC to avoid its complications. From a financial point of view, the use of VAC is very effective as it deceases the daily cost of conventional treatment including intravenous antibiotics and the need for more complex surgical procedures, as well as deceasing hospital stay. Thus the use of VAC is not only as a ‘‘bridge to surgery’’ but it is also cost effective.24 We concluded that VAC therapy is a safe, reliable, and cost-effective option for treatment of postoperative mediastinitis. VAC should be used with other treatment options, especially in high-risk cases such as the elderly, those with diabetes, and female patients. Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Conflicts of interest statement None declared.
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Corrigendum
Corrigendum
Asian Cardiovascular & Thoracic Annals 2015, Vol. 23(1) 117 ß The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0218492314556587 aan.sagepub.com
Vacuum-assisted closure system in treatment of postoperative mediastinitis, by Mohamed Ahmed Elawadi and Farouk Oueida, Asian Cardiovascular and Thoracic Annals December 2013 21: 708–712, DOI: 10.1177/ 0218492313479353 For the above paper the affiliation details for Mohamed Ahmed Elawadi were incomplete, they should have read: 1 2
Department of Cardiac Surgery, Saud Al-Babtain Cardiac Center, Dammam, Saudi Arabia Cardiothoracic Surgery Department, Banha Faculty of Medicine, Banha University, Egypt
