| 1. |
- Malmsjö, Malin, et al.
(författare)
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Preventing heart injury during negative pressure wound therapy in cardiac surgery: assessment using real-time magnetic resonance imaging.
- 2009
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Ingår i: The Journal of thoracic and cardiovascular surgery. - : Elsevier BV. - 1097-685X .- 0022-5223. ; 138:3, s. 712-717
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Heart rupture is a devastating complication to negative pressure wound therapy in cardiac surgery. Also, reduced cardiac output during negative pressure wound therapy has been reported. The present study aimed to examine the effects of negative pressure wound therapy on the position of the heart in relation to the thoracic wall using magnetic resonance imaging in a porcine sternotomy wound model. METHODS: Six pigs had median sternotomy followed by negative pressure wound therapy at -75, -125, and -175 mm Hg. Real-time magnetic resonance imaging movies (10 images/s) were acquired in a midventricular transverse plane or a midsagittal plane during the application of negative pressure wound therapy. RESULTS: Similar finding were observed at all different negative pressures studied. Negative pressure wound therapy caused the heart to be displaced toward the thoracic wall, and in some cases, the right ventricular free wall bulged into the space between the sternal edges, and the sharp edges of the sternum jutted into and deformed the anterior surface of the right ventricular free wall. These events were not affected by the interposition of 4 layers of paraffin gauze dressing but were hindered by the placement of a rigid barrier between the anterior portion of the heart and the inside of the thoracic wall. CONCLUSION: The results show altered position of the heart in relation to the sternum during negative pressure wound therapy. This may explain 2 potentially hazardous events associated with negative pressure wound therapy, namely, risk for heart rupture and reduced cardiac output. Inserting a rigid barrier over the heart may be a protective measure that is clinically practicable.
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| 2. |
- Mokhtari, Arash, et al.
(författare)
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Sternal stability at different negative pressures during vacuum-assisted closure therapy
- 2006
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Ingår i: Annals of Thoracic Surgery. - : Elsevier BV. - 1552-6259 .- 0003-4975. ; 82:3, s. 1063-1067
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Tidskriftsartikel (refereegranskat)abstract
- Background. Vacuum-assisted closure (VAC) is a widely used therapy in patients with poststernotomy mediastinitis. The aim of this study was to evaluate sternal stability during VAC application at seven negative pressures (-50 to -200 mm Hg) in a porcine wound model. Methods. Six pigs underwent median sternotomy and 2 steel wires were fixed at each sternal side and connected to a traction device. The device was connected to a force transducer linked to a force recorder. VAC therapy was applied to the wound. At each negative pressure, the length and width of the wound were measured before and after traction was started. Traction was increased stepwise up to 400 N. Results. The diastasis induced by a certain lateral force was similar in wounds treated with -75, -125, and -175 mm Hg. At -75 mm Hg, a significant improvement (p < 0.01) in sternal stability was seen compared with the open-chest setting. This was not further improved at -125 or -175 mm Hg. High negative pressures (-150 to -200 mm Hg) in combination with a high lateral force (> 200 N) increased the risk of separation of the foam from the wound edges, with air leakage or organ rupture as a result. Conclusions. Our results suggest that low negative pressures (-50 to -100 mm Hg) stabilize the sternum as efficiently as high negative pressures (-150 to -200 mm Hg). Low negative pressures (-50 to -100 mm Hg) were more beneficial, however, because no air leakage or organ rupture was observed at these pressures.
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| 3. |
- Petzina, Rainer, et al.
(författare)
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Effect of vacuum-assisted closure on blood flow in the peristernal thoracic wall after internal mammary artery harvesting.
- 2006
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Ingår i: European Journal of Cardio-Thoracic Surgery. - : Oxford University Press (OUP). - 1010-7940. ; 30:1, s. 85-89
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Vacuum-assisted closure (VAC) is a recently introduced method for the treatment of poststernotomy mediastinitis. The aim was to examine the effects of VAC negative pressure on peristernal soft tissue, blood flow after internal mammary artery harvesting. Methods: Microvascular blood flow was measured using laser Doppler velocimetry in a porcine sternotomy wound model. The effect of VAC negative pressure on blood flow to the wound edge was investigated on the right side, where the internal mammary artery was intact, and on the left side, where the internal mammary artery had been removed. Results: Before removal of the left internal mammary artery, the blood flow was similar in the right and left peristernal wound edges, 2.5 cm from the edge (27 +/- 4 perfusion units (PU) on the right side and 32 +/- 3 PU on the left side, in muscle tissue). When the left internal mammary artery was surgically removed, the blood flow on the left side decreased (19 3 PU, in muscle tissue), while the skin blood flow was not affected. VAC negative pressure induced an immediate increase in wound edge blood flow both on the right side (43 +/- 9 PU, in muscle tissue at -75 mmHg), where the internal mammary artery was intact, and on the left side, where the internal mammary artery had been removed (49 11 PU, in muscle tissue at -75 mmHg). The increase in blood flow was similar on both sides at -75 mmHg and at -125 mmHg. Conclusions: The peristernal wound edge microvascular blood flow is decreased when the left internal mammary artery is removed. VAC therapy stimulates blood flow in the peristernal thoracic wall after internal mammary artery harvesting. (c) 2006 Elsevier B.V. All rights reserved.
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| 4. |
- Petzina, Rainer, et al.
(författare)
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Hemodynamic effects of vacuum-assisted closure therapy in cardiac surgery: assessment using magnetic resonance imaging.
- 2007
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier BV. - 1097-685X .- 0022-5223. ; 133:5, s. 1154-1162
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The hemodynamic effects of vacuum-assisted closure therapy in cardiac surgery are debated. The aim of the present study was to quantify cardiac output and left ventricular chamber volumes after vacuum-assisted closure using magnetic resonance imaging, which is known to be the most accurate method for quantifying these measures. Methods: Six pigs had median sternotomy followed by vacuum-assisted closure treatment in the presence and absence of a paraffin gauze interface dressing. Cardiac output and stroke volume were examined using magnetic resonance imaging flow quantification (breath-hold and real-time). Chamber volumes were assessed using cine magnetic resonance imaging. Results: Cardiac output and stroke volume decreased immediately after application of negative pressures of 75, 125, and 175 mm Hg (13% +/- 1% decrease in cardiac output). Interposition of 4 layers of paraffin gauze dressing over the heart during vacuum-assisted closure therapy resulted in a smaller decrease in cardiac output (8% +/- 1%). Conclusions: Vacuum-assisted closure therapy results in an immediate decrease in cardiac output, although to a lesser extent than shown previously. Covering the heart with a wound interface dressing lessens the hemodynamic effects of vacuum-assisted closure.
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| 5. |
- Petzina, Rainer, et al.
(författare)
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Major complications during negative pressure wound therapy in poststernotomy mediastinitis after cardiac surgery
- 2010
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Ingår i: Journal of Thoracic and Cardiovascular Surgery. - : Elsevier BV. - 1097-685X .- 0022-5223. ; 140:5, s. 1133-1136
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Negative pressure wound therapy is the first-line treatment modality for poststernotomy mediastinitis in many heart centers. The aim of this study was to analyze major complications and possible preventive methods during negative pressure wound therapy in patients with deep sternal wound infections. Methods: We retrospectively analyzed 69 consecutive patients treated with negative pressure wound therapy for poststernotomy mediastinitis between June 2006 and September 2009. Results: Five (7.2%) patients sustained major complications during negative pressure wound therapy. Bleeding from coronary artery venous bypass grafts was observed in 4 patients and fulminant bleeding from an infected homograft of the ascending aorta was observed in 1 patient during routine dressing changes of the negative pressure wound therapy system. Conclusions: Bleeding is the major complication during negative pressure wound therapy for poststernotomy mediastinitis. Covering the heart with several layers of paraffin gauze is a necessary protective maneuver but cannot completely prevent major complications during negative pressure wound therapy. All operative procedures, including dressing changes, should be performed in the operating room under optimal hygienic and monitoring conditions to increase the salvage rate and to guarantee optimal surgical and anesthesiologic conditions in case of negative pressure wound therapy-related complications. (J Thorac Cardiovasc Surg 2010;140:1133-6)
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| 6. |
- Petzina, Rainer, et al.
(författare)
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Negative pressure wound therapy for post-sternotomy mediastinitis reduces mortality rate and sternal re-infection rate compared to conventional treatment
- 2010
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Ingår i: European Journal of Cardio-Thoracic Surgery. - : Oxford University Press (OUP). - 1010-7940 .- 1873-734X. ; 38:1, s. 110-113
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Konferensbidrag (refereegranskat)abstract
- Objective: Negative pressure wound therapy (NPWT) is a recently introduced treatment modality for post-sternotomy mediastinitis. The aim of this study was to compare the mortality rate, the sternal re-infection rate and the length of hospital stay in patients with post-sternotomy mediastinitis after NPWT and conventional treatment. Methods: We retrospectively analysed 118 patients with post-sternotomy mediastinitis after cardiac surgery. One group of 69 patients was treated with NPWT and the other group of 49 patients with conventional therapy. Results: There were no major differences between the two groups concerning preoperative data (EuroScore) or primary cardiac surgery (mainly coronary artery bypass grafting). NPWT therapy was found to reduce mortality rate (P = 0.005) and sternal re-infection rate (P = 0.008) compared with conventional treatment and tended to lead to a shorter length of hospital stay (P = 0.08). Conclusions: NPWT for post-sternotomy mediastinitis demonstrates encouraging clinical results with a reduction of the mortality rate and the sternal re-infection rate compared with conventional treatment. The results support NPWT as the first-line treatment for deep sternal wound infections. (C) 2010 European Association for Cardio-Thoracic Surgery. Published by Elsevier B.V. All rights reserved.
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| 7. |
- Petzina, Rainer
(författare)
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Negative pressure wound therapy in cardiac surgery
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Negative pressure wound therapy in cardiac surgery Rainer Petzina, M.D. Clinical Sciences, Lund, Lund University Poststernotomy mediastinitis is a devastating complication for patients undergoing cardiac surgery. Conventional treatment includes surgical revision, continuous irrigation with drainage and wound closure with the use of the greater omentum and muscle flaps. Widespread adoption of negative pressure wound therapy (NPWT) has been driven through favorable clinical experience and excellent healing effects. The aims of the research in this thesis were: I. To quantify cardiac output and left ventricular chamber volumes after NPWT, using magnetic resonance imaging (MRI). II. To examine the effects of NPWT on peristernal soft tissue blood flow after internal mammary artery harvesting, using laser Doppler velocimetry. III. To study the effect of NPWT on blood and fluid content of the sternal wound edge and bone marrow, using MRI (T2-STIR). IV. To identify the effects of NPWT on the position of the heart in relation to the thoracic wall, using MRI. An uninfected porcine sternotomy wound model was used for all studies. The hemodynamic effects of NPWT in cardiac surgery are debated. MRI measurements show that NPWT results in an immediate decrease in cardiac output, although to a lesser extent than shown in previous studies. MRI is known to be the most accurate method for quantifying cardiac output. Patients with poor blood perfusion of the sternotomy wound edge tissue have a higher risk of developing post-sternotomy mediastinitis. We show that the peristernal wound edge microvascular blood flow is decreased when the left internal mammary artery is harvested. NPWT therapy stimulates blood flow in the in the wound edge both before and after the mammary artery is removed. Stimulating blood flow to the wound edge in patients with impaired microcirculation may be crucial to ensure healing. MRI measurements show that NPWT increases sternotomy wound edge tissue fluid and/or blood content. Presumably, NPWT creates a pressure gradient that draws fluid from the surrounding tissue into the sternal wound edge and into the vacuum source. This “endogenous drainage” may be one possible mechanism by which osteitis is resolved. Heart rupture is a devastating complication to NPWT of sternotomy wounds. MR imaging shows that NPWT causes the heart to be sucked up towards the thoracic wall and, in some cases, the right ventricular free wall to bulge into the space between the sternal edges and the sharp edges of the sternum to poke into and deform the anterior surface of the heart. These can be effectively hindered by the placement of a rigid barrier over the anterior portion of the heart. Taken together, the studies of the present thesis demonstrate the effects of NPWT on the thorax and intrathoracic organs. NPWT alters wound edge microvascular blood flow and fluid content and affects heart pumping and heart position in relation to the thoracic wall. Rainer Petzina, MD Lund, January 15, 2009
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| 8. |
- Petzina, Rainer, et al.
(författare)
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Topical negative pressure therapy of a sternotomy wound increases sternal fluid content but does not affect internal thoracic artery blood flow: assessment using magnetic resonance imaging.
- 2008
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Ingår i: The Journal of thoracic and cardiovascular surgery. - : Elsevier BV. - 1097-685X .- 0022-5223. ; 135:5, s. 1007-1013
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Topical negative pressure therapy has excellent healing effects in poststernotomy mediastinitis. Topical negative pressure therapy reduces bacterial counts, increases wound edge microvascular blood flow and granulation tissue formation, and facilitates healing. No study has yet been performed to examine the effect of topical negative pressure on the blood and fluid content in the sternal bone marrow, which is a crucial component in osteitis. METHODS: Eight pigs underwent median sternotomy, left internal thoracic artery harvesting, followed by topical negative pressure treatment. Magnetic resonance imaging was used to quantify both tissue fluid and/or blood content (T2-weighted short tau inversion recovery [T2-STIR]) and internal thoracic artery blood flow (flow quantification). RESULTS: Before application of topical negative pressure, the T2-STIR signal intensity ratio was lower for the left than for the right hemisternum (left, 1.3; right, 2.6), indicating lower levels of tissue fluid content on the left, devascularized side. On application of topical negative pressure, the T2-STIR signal intensity ratio increased immediately for both the sternal bone and the pectoral muscle (left hemisternum after 4 minutes of topical negative pressure: 2.3), leveled off after 4 minutes, and remained unchanged for the ensuing 40 minutes, suggesting movement of fluid and/or blood into the tissue of the wound edge. Topical negative pressure did not affect blood flow in the right internal thoracic artery. CONCLUSIONS: T2-STIR measurements show that topical negative pressure increases sternotomy wound edge tissue fluid and/or blood content. Topical negative pressure creates a pressure gradient that presumably draws fluid from the surrounding tissue to the sternal wound edge and into the vacuum source. This "endogenous drainage" may be one possible mechanism by which osteitis is resolved by topical negative pressure in poststernotomy mediastinitis.
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