| 1. |
- Lindstedt Ingemansson, Sandra, et al.
(författare)
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Evaluation of continuous and intermittent myocardial topical negative pressure.
- 2008
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Ingår i: Journal of Cardiovascular Medicine. - 1558-2027. ; 9:8, s. 813-819
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Topical negative pressure, commonly used in wound therapy, has been shown to increase blood flow and stimulate angiogenesis in subcutaneous tissue and skeletal muscle. In wound therapy, intermittent negative pressure is often preferred to continuous negative pressure as tissue exposed to intermittent therapy shows twice as much granulation tissue formation than that exposed to continuous pressure after 2 weeks of therapy. The present study was designed to elucidate the differences in microvascular blood flow in the left anterior descending artery area between continuous and intermittent myocardial topical negative pressure of -50 mmHg. METHODS: Six pigs underwent median sternotomy. Laser Doppler probes were inserted horizontally into the heart muscle in the left anterior descending artery area at depths of approximately 5-6 mm. Measurements of microvascular blood flow were performed in normal myocardium and ischemic myocardium during 20 min of countinuous and intermittent topical negative pressure at -50 mmHg. RESULTS: Both continuous and intermittent topical negative pressure of -50 mmHg significantly increased microvascular blood flow in the underlying myocardium: from 56.2 +/- 13.1 perfusion units (PU) before to 132.8 +/- 7.4 PU during countinuous topical negative pressure application (P < 0.05) and from 75.8 +/- 12.1 PU before to 153.6 +/- 4.7 PU during intermittent topical negative pressure application (P < 0.05). CONCLUSION: No statistically significant difference was found between microvascular blood flow during 20 min of continuous and intermittent topical negative pressure at -50 mmHg in this porcine model.
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| 2. |
- Lindstedt Ingemansson, Sandra, et al.
(författare)
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Impact of different topical negative pressure levels on myocardial microvascular blood flow.
- 2008
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Ingår i: Cardiovascular Revascularization Medicine. - : Elsevier BV. - 1878-0938 .- 1553-8389. ; 9:1, s. 29-35
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: We have previously shown that a myocardial topical negative pressure (TNP) of -50 mmHg significantly increases microvascular blood flow in the underlying myocardium in normal, ischemic, and reperfused porcine myocardium. The present study was designed to elucidate the effect of different TNP levels between -50 and -150 mmHg on microvascular flow in normal and ischemic myocardium. MATERIALS AND METHODS: Seven pigs underwent median sternotomy. The microvascular blood flow in the myocardium was recorded, before and after the application of TNP, using laser Doppler velocimetry. Analyses were performed before left anterior descending artery (LAD) occlusion (normal myocardium) and after 20 min of LAD occlusion (ischemic myocardium). RESULTS: A TNP of -50 mmHg significantly increased microvascular blood flow in both normal (from 320.0+/-56.1 PU before TNP application to 435.7+/-65.5 PU after TNP application, P=.028) and ischemic myocardium (from 110.0+/-36.7 PU before TNP application to 194.3+/-56.2 PU after TNP application, P=.012). TNP between -75 and -150 mmHg showed no significant increase in microvascular blood flow in normal or ischemic myocardium. CONCLUSIONS: Of pressures between -50 and -150 mmHg, a TNP of -50 mmHg seems to be the most effective negative pressure concerning significant increase in microvascular blood flow in both normal and ischemic myocardium.
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| 3. |
- Lindstedt Ingemansson, Sandra, et al.
(författare)
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Topical negative pressure effects on coronary blood flow in a sternal wound model.
- 2008
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Ingår i: International Wound Journal. - 1742-481X. ; 5:4, s. 503-509
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Tidskriftsartikel (refereegranskat)abstract
- Several studies have suggested that mediastinitis is a strong predictor for poor long-term survival after coronary artery bypass surgery (CABG). In those studies, several conventional wound-healing techniques were used. Previously, we have shown no difference in long-term survival between CABG patients with topical negative pressure (TNP)-treated mediastinitis and CABG patients without mediastinitis. The present study was designed to elucidate if TNP, applied over the myocardium, resulted in an increase of the total amount of coronary blood flow. Six pigs underwent median sternotomy. The coronary blood flow was measured, before and after the application of TNP (-50 mmHg), using coronary electromagnetic flow meter probes. Analyses were performed before left anterior descending artery (LAD) occlusion (normal myocardium) and after 20 minutes of LAD occlusion (ischaemic myocardium). Normal myocardium: 171.3 +/- 14.5 ml/minute before to 206.3 +/- 17.6 ml/minute after TNP application, P < 0.05. Ischaemic myocardium: 133.7 +/- 18.4 ml/minute before to 183.2 +/- 18.9 ml/minute after TNP application, P < 0.05. TNP of -50 mmHg applied over the LAD region induced a significant increase in the total coronary blood flow in both normal and ischaemic myocardium.
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| 4. |
- Malmsjö, Malin, et al.
(författare)
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Negative-pressure wound therapy using gauze or open-cell polyurethane foam: similar early effects on pressure transduction and tissue contraction in an experimental porcine wound model.
- 2009
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Ingår i: Wound Repair and Regeneration. - 1524-475X. ; 17:2, s. 200-205
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Tidskriftsartikel (refereegranskat)abstract
- Negative-pressure wound therapy (NPWT), also known as topical negative-pressure therapy, is widely used to manage wounds and accelerate healing. NPWT has so far been delivered mainly via open-cell polyurethane foam, but increasing interest has been directed toward delivering NPWT via gauze. In the present study, the early effects of NPWT on pressure transduction and wound contraction were examined in wounds filled with either polyurethane foam or gauze. An experimental setup of a porcine wound model was used, in which the animals were anesthetized for 12-14 hours. Negative pressures between -50 and -175 mmHg were applied in -25 mmHg increments. Wound bed pressure was measured using a saline filled catheter sutured to the bottom of the wound. The contraction of the wound edges was also determined. The recordings were performed upon reaching steady state, which typically occurred within 1 minute. For both fillers, wound bed negative pressure increased linearly with delivered vacuum with little deviation from set pressure (correlation coefficient 0.99 in both cases). Similar tissue contraction was observed when using foam and gauze. The most prominent contraction was observed in the range of 0 to -50 mmHg with greater vacuum only producing minor further movement of the wound edge. In conclusion, the present experimental study shows that gauze and foam are equally effective at delivering negative pressure and creating mechanical deformation of the wound.
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| 5. |
- Mokhtari, Arash, et al.
(författare)
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The cost of vacuum-assisted closure therapy in treatment of deep sternal wound infection.
- 2008
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Ingår i: Scandinavian Cardiovascular Journal. - : Informa UK Limited. - 1651-2006 .- 1401-7431. ; 42:1, s. 85-89
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. Surgical sites infections are very expensive and the total costs for coronary artery bypass grafting (CABG) surgery followed by deep sternal wound infection (DSWI) with conventional therapy are estimated to be 2.8 times that for normal, CABG surgery. Promising results have been reported with vacuum-assisted closure (VAC) therapy in patients with DSWI. This study presents the cost of VAC therapy in patients with DSWI after CABG surgery. Design. Thirty-eight CABG patients with DSWI, between 2001 and 2005, were treated with VAC therapy. The cost of surgery, intensive care, ward care, laboratory tests and other costs were analyzed. Results. No three-month mortality or recurrent infection was observed. The average cost of CABG procedure and treatment of DSWI was 2.5 times higher than the mean cost of CABG alone. No significant correlations were found between the preoperative EuroSCORE and the cost of DSWI therapy. Conclusions. VAC therapy for patients who underwent CABG surgery followed by DSWI seems to be cost effective, and has low mortality rate.
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| 6. |
- Sjögren, Johan, et al.
(författare)
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Vakuumassisterad sår- behandling ger goda kliniska resultat God läkning vid komplicerade sår--djupa sternuminfektioner ett exempel.
- 2008
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Ingår i: Läkartidningen. - 0023-7205. ; 105:40, s. 2773-2776
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Tidskriftsartikel (refereegranskat)abstract
- acuum-assisted closure (V.A.C.®) is a novel treatment for wound healing, which has been used extensively during the last years in a growing number of clinical applications. This wound-healing technique is based on the application of local negative pressure to a wound. During treatment with vacuum-assisted closure, several beneficial wound healing mechanisms are initiated. Topical negative pressure increases the microvascular blood flow in the surrounding tissue and reduces wound tissue oedema and wound size. Furthermore, the stimulation of growth factors and neoangiogenesis facilitates the formation of granulation tissue in the wound. Vacuum-assisted closure has been widely adopted as a standard treatment for deep sternal wound infections following cardiac surgery since topical negative pressure combines several advantageous features from conventional surgical techniques. However, although it is effective, vacuum-assisted closure must always be used in combination with proper surgical revision and adequate antibiotic therapy in order to obtain optimal results.
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| 7. |
- Torbrand, Christian, et al.
(författare)
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Pressure transduction to the thoracic cavity during topical negative pressure therapy of a sternotomy wound.
- 2008
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Ingår i: International Wound Journal. - 1742-481X. ; 5:4, s. 579-584
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Tidskriftsartikel (refereegranskat)abstract
- The present study was performed to examine pressure transduction to the thoracic cavity during topical negative pressure (TNP) therapy of a sternotomy wound. Seven pigs underwent median sternotomy. Pressure transduction catheters were placed on the anterior surface of the heart (under the foam), in the pericardium (under the heart), in the left pleura and in the oesophagus at the level of the heart. The wound was sealed as for TNP therapy. The vacuum source was set to deliver negative pressures between -50 and -200 mmHg. The pressure on the anterior surface of the heart changed in a linear relationship with the applied negative pressure and was slightly lower than the applied negative pressure (-102 +/- 9 mmHg at delivered -125 mmHg). Further down in the thoracic cavity, in the pericardium (under the heart), in the left pleura and in the oesophagus, the wound pressure was only slightly affected by TNP therapy. In conclusion during TNP therapy, negative pressure is effectively transmitted to anterior portions of the heart. This may explain our recent findings that TNP increases microvascular blood flow in the myocardium. The pressure difference between the anterior and the posterior portions of the heart causes the right ventricle to be sucked up towards the posterior parts of the sternum, where it might be exposed to the sharp edges of the sternal bone, which may result in heart injury.
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| 8. |
- Sjögren, Johan, et al.
(författare)
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Vacuum-assisted closure therapy for deep sternal wound infections: the impact of learning curve on survival and predictors for late mortality.
- 2008
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Ingår i: International Wound Journal. - 1742-481X. ; 5:2, s. 216-223
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate the possible learning curve effects on survival during the introduction of vacuum-assisted closure (VAC) therapy in patients with deep sternal wound infection (DSWI). Furthermore, predictors of late mortality were analysed and causes of late death were examined. Fifty-three patients (early Group, n = 26, January 1999 to July 2001 versus late group, n = 27, August 2001 to March 2003) were all treated with VAC for DSWI. A follow-up was carried out in September 2006. Multivariate analyses were used to evaluate the predictors of late mortality. The 90-day mortality was 0% in both groups. The survival rates at 5 years were 69.2 +/- 9.1% (early group) versus 58.5 +/- 11.7% (late group), P = ns (non significant). The time interval from cardiac surgery to diagnosis of DSWI and prolonged VAC therapy were identified as independent predictors of late mortality. Our concept for VAC therapy in DSWI seems to be readily introduced in clinical practice. There was no difference in survival between our initial cases and later cases. Late diagnosis and prolonged wound therapy were identified as predictors for late mortality.
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| 9. |
- Lindstedt Ingemansson, Sandra, et al.
(författare)
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Myocardial topical negative pressure increases blood flow in hypothermic, ischemic myocardium.
- 2008
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Ingår i: Scandinavian Cardiovascular Journal. - : Informa UK Limited. - 1651-2006 .- 1401-7431. ; 42, s. 345-353
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. Hypothermia protects the myocardium from oxidative injury during ischemic stress and reperfusion. We have previously shown that topical negative pressure (TNP) of -50 mmHg significantly increases microvascular blood flow in the underlying myocardium in normal, ischemic, and reperfused porcine myocardium. The present study was designed to elucidate the effect of TNP between -50 mmHg and -150 mmHg on microvascular blood flow in ischemic myocardium during hypothermia. Design. The microvascular blood flow in the myocardium was recorded, in seven pigs, using laser Doppler velocimetry. Analyses were performed in the epicardium and in the myocardium, after 40 minutes of occlusion of the LAD followed by cooling to 31 degrees C. Results. A TNP of -50 mmHg applied to the epicardium, from 23.3+/-3.8 PU to 104.2+/-31.3 PU (*p <0.05), and in the myocardium, from 35.0+/-7.2 PU to 74.2+/-21.8 PU (*p <0.05). Conclusions. Only a TNP level of -50 mmHg significantly increased the microvascular blood flow in both the epicardium and in the myocardium during hypothermia.
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| 10. |
- Lindstedt, Sandra, et al.
(författare)
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Blood flow changes in normal and ischemic myocardium during topically applied negative pressure
- 2007
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Ingår i: Annals of Thoracic Surgery. - : Elsevier BV. - 1552-6259 .- 0003-4975. ; 84:2, s. 568-573
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Tidskriftsartikel (refereegranskat)abstract
- Background. Topical negative pressure (TNP) therapy has been adopted as a first-line treatment for wound healing. One of the mechanisms by which TNP improves healing is by stimulating blood flow to the wound edge. Among patients with ischemic heart disease, it is of great importance to improve the microvascular blood flow in the myocardium during episodes of ischemia to protect the myocardium from infarction. The present study was designed to elucidate the effect of TNP on microvascular blood flow in the myocardium. Methods. Six pigs underwent median sternotomy. The microvascular blood flow in the myocardium was recorded, before and after the application of TNP, by using laser Doppler velocimetry. Analyses were performed before left anterior descending artery ( LAD) occlusion ( normal myocardium), after 20 minutes of LAD occlusion ischemic myocardium), and after 20 minutes of reperfusion (reperfused myocardium). Results. TNP at -0 mm Hg increased microvascular blood flow in the normal myocardium from 14.7 +/- 3.9 perfusion units (PU) before to 25.8 +/- 6.1 PU after TNP application ( p < 0.05), in the ischemic myocardium from 7.2 +/- 1.5 PU before to 13.8 +/- 2.6 PU after TNP application ( p < 0.05), and in the reperfused myocardium from 10.8 +/- 2.0 PU before to 19.3 +/- 5.6 PU after TNP application ( p < 0.05). Conclusions. TNP increases the microvascular blood flow significantly in normal, ischemic, and reperfused myocardium and may provide a novel therapeutic tool in the treatment of ischemic myocardium.
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