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Search Results: 1 - 10 of 9529 matches for " Sandra Lindstedt "
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Effects on heart pumping function when using foam and gauze for negative pressure wound therapy of sternotomy wounds
Malin Malmsj?, Sandra Lindstedt, Richard Ingemansson
Journal of Cardiothoracic Surgery , 2011, DOI: 10.1186/1749-8090-6-5
Abstract: Eight pigs underwent median sternotomy followed by NPWT at -40, -70, -120 and -160 mmHg, using foam or gauze. The heart frequency, cardiac output, mean systemic arterial pressure, mean pulmonary artery pressure, central venous pressure and left atrial pressure were recorded.Cardiac output was not affected by NPWT using gauze or foam. Heart frequency decreased during NPWT when using foam, but not gauze. Treatment with foam also lowered the central venous pressure and the left atrial pressure, while gauze had no such effects. Mean systemic arterial pressure, mean pulmonary artery pressure and systemic vascular resistance were not affected by NPWT. Similar haemodynamic effects were observed at all levels of negative pressure studied.NPWT using foam results in decreased heart frequency and lower right and left atrial filling pressures. The use of gauze in NPWT did not affect the haemodynamic parameters studied. Gauze may thus provide an alternative to foam for NPWT of sternotomy wounds.Cardiac surgery is complicated by poststernotomy mediastinitis in 1-5% of all procedures [1]; a complication that is life-threatening [2]. The reported early mortality using conventional therapy is between 8 and 25% [3,4]. In 1999, Obdeijn and colleagues described the treatment of poststernotomy mediastinitis using vacuum-assisted closure [5], now called negative pressure wound therapy (NPWT). The technique entails the application of negative pressure to a sealed wound. NPWT has remarkable effects on the healing of poststernotomy mediastinitis, and has reduced the rate of mortality considerably [6]. The organs in the mediastinum are haemodynamically crucial, and both vulnerable bypass grafts and heart function should be taken into consideration when performing NPWT after cardiac surgery.NPWT is known to affect the heart pumping function, although the results from different studies on the subject are not consistent [7-11]. Using sonometry, Conquest and colleagues showed that subatmospheric
Sternum wound contraction and distension during negative pressure wound therapy when using a rigid disc to prevent heart and lung rupture
Sandra Lindstedt, Richard Ingemansson, Malin Malmsj?
Journal of Cardiothoracic Surgery , 2011, DOI: 10.1186/1749-8090-6-42
Abstract: Sternotomy wounds were created in eight pigs. The wounds were treated with NPWT at -40, -70, -120 and -170 mmHg in the presence and absence of a rigid barrier between the heart and the edges of the sternum. Wound contraction upon NPWT application, and wound distension under mechanical traction to draw apart the edges of the sternotomy were evaluated.Wound contraction resulting from NPWT was similar with and without the rigid barrier. When mechanical traction was applied to a NPWT treated sternum wound, the sternal edges were pulled apart. Wound distension upon traction was similar in the presence and absence of a the rigid barrier during NPWT.A rigid barrier can safely be inserted between the heart and the edges of the sternum to protect the heart and lungs from rupture during NPWT. The sternum wound edge is stabilized equally well with as without the rigid barrier during NPWT.The use of negative pressure wound therapy (NPWT) for the treatment of deep sternal wound infections has been shown to have remarkable effects on healing [1]. There are, however, increasing numbers of reports of deaths and serious complications associated with the use of NPWT due to heart rupture, lung rupture, bypass graft bleeding and death; the incidence being 4 to 7% of all patients treated for poststernotomy mediastinitis with NPWT after cardiac surgery [2-4]. In November 2009, the FDA filed an alert, and the importance of protecting exposed organs during NPWT and this issue has also been emphasized in the international scientific literature [5-8].We have previously elucidated the cause of heart rupture in pigs using magnetic resonance imaging [9,10]. The heart was shown to be drawn up towards the thoracic wall, the right ventricle bulged into the space between the sternal edges, and the sharp edges of the sternum protruded into the anterior surface of the heart, in some cases resulting in damage to the left ventricle of the heart or damage to a bypass graft to the right coronary artery [
A rigid barrier between the heart and sternum protects the heart and lungs against rupture during negative pressure wound therapy
Sandra Lindstedt, Richard Ingemansson, Malin Malmsj?
Journal of Cardiothoracic Surgery , 2011, DOI: 10.1186/1749-8090-6-90
Abstract: Sixteen pigs underwent median sternotomy followed by NPWT at -120 mmHg for 24 hours, in the absence (eight pigs) or presence (eight pigs) of a rigid plastic disc between the heart and the sternal edges. The macroscopic appearance of the heart and lungs was inspected after 12 and 24 hours of NPWT.After 24 hours of NPWT at -120 mmHg the area of epicardial petechial bleeding was 11.90 ± 1.10 cm2 when no protective disc was used, and 1.15 ± 0.19 cm2 when using the disc (p < 0.001). Heart rupture was observed in three of the eight animals treated with NPWT without the disc. Lung rupture was observed in two of the animals, and lung contusion and emphysema were seen in all animals treated with NPWT without the rigid disc. No injury to the heart or lungs was observed in the group of animals treated with NPWT using the rigid disc.Inserting a rigid barrier between the heart and the sternum edges offers protection against heart rupture and lung injury during NPWT.Cardiac surgery is complicated by poststernotomy mediastinitis in 1 to 5% of all procedures [1], and is a life-threatening complication [2]. The reported early mortality using conventional therapy is between 8 and 25% [3,4]. In 1999, Obdeijn and colleagues described the treatment of poststernotomy mediastinitis using vacuum-assisted closure [5], now called negative pressure wound therapy (NPWT). The technique entails the application of negative pressure to a sealed wound. NPWT has remarkable effects on the healing of poststernotomy mediastinitis, and has reduced the rate of mortality considerably [6].There are, however, increasing numbers of reports of deaths and serious complications associated with the use of NPWT, where right ventricle rupture and bypass graft rupture resulting in death are the most devastating complications; the incidence being 4 to 7% of the patients treated for deep sternal wound infection with NPWT after cardiac surgery [7-9]. We have previously described the cause of heart rupture in pigs usin
No hypoperfusion is produced in the epicardium during application of myocardial topical negative pressure in a porcine model
Sandra Lindstedt, Malin Malmsj?, Richard Ingemansson
Journal of Cardiothoracic Surgery , 2007, DOI: 10.1186/1749-8090-2-53
Abstract: Six pigs underwent median sternotomy. Laser Doppler probes were inserted horizontally into the heart muscle in the LAD area, at depths of approximately, 1–2 mm. The microvascular blood flow was measured before and after the application of a TNP. Analyses were performed before left anterior descending artery (LAD) occlusion (normal myocardium) and after 20 minutes of LAD occlusion (ischemic myocardium).A TNP of -50 mmHg induced a significant increase in microvascular blood flow in normal myocardium (**p = 0.01), while -125 mmHg did not significantly alter the microvascular blood flow. In ischemic myocardium a TNP of -50 mmHg induced a significant increase in microvascular blood flow (*p = 0.04), while -125 mmHg did not significantly alter the microvascular blood flow.No hypoperfusion could be observed in the epicardium in neither normal nor ischemic myocardium during myocardial TNP.Vacuum therapy, or topical negative pressure (TNP), can be regarded as an established clinical routine for wound care, in use since the mid or late 1990's, and it has been shown to promote the healing of chronic and problematic wounds [1-3], for example, post-sternotomy mediastinitis[4,5]. The physiological and molecular biological mechanisms by which TNP accelerates wound healing are to a large extent unknown. However, TNP is known to increase the blood flow as a result of mechanical stress and a pressure gradient across the tissue, and increased blood flow is known to stimulate granulation tissue formation, and angiogenesis in subcutaneous tissue and skeletal muscle [6-10].Mediastinitis is a strong predictor for poor long-term survival after coronary artery by-pass grafting (CABG), when using conventional wound healing techniques (closed irrigation, delayed wound closure, or reconstructing with omentum or pectoral flaps) [11-16]. Recently, the use of TNP has gained acceptance in the treatment of post-sternotomy mediastinitis, and is today the standard mode of treatment in many cardiac su
A Short Period of Ventilation without Perfusion Seems to Reduce Atelectasis without Harming the Lungs during Ex Vivo Lung Perfusion
Sandra Lindstedt,Leif Pierre,Richard Ingemansson
Journal of Transplantation , 2013, DOI: 10.1155/2013/729286
Abstract: To evaluate the lung function of donors after circulatory deaths (DCDs), ex vivo lung perfusion (EVLP) has been shown to be a valuable method. We present modified EVLP where lung atelectasis is removed, while the lung perfusion is temporarily shut down. Twelve pigs were randomized into two groups: modified EVLP and conventional EVLP. When the lungs had reached 37°C in the EVLP circuit, lung perfusion was temporarily shut down in the modified EVLP group, and positive end-expiratory pressure (PEEP) was increased to 10?cm H2O for 10 minutes. In the conventional EVLP group, PEEP was increased to 10?cm H2O for 10 minutes with unchanged lung perfusion. In the modified EVLP group, the arterial oxygen partial pressure (PaO2) was 18.5 ± 7.0?kPa before and 64.5 ± 6.0?kPa after the maneuver ( ). In the conventional EVLP group, the PaO2 was 16.8 ± 3.1?kPa and 46.8 ± 2.7?kPa after the maneuver ( ; ). In the modified EVLP group, the pulmonary graft weight was unchanged, while in the conventional EVLP group, the pulmonary graft weight was significantly increased. Modified EVLP with normoventilation of the lungs without ongoing lung perfusion for 10 minutes may eliminate atelectasis almost completely without harming the lungs. 1. Introduction Lung transplantation continues to be hampered by the number of available donors [1, 2]. Ex vivo lung perfusion (EVLP) has emerged as an essential tool for the reassessment, under a controlled scenario, of lungs from heart-beating donors (HBDs) that initially did not meet transplantation criteria [3–8]. The method is also an excellent tool for reassessing lungs of donors after cardiac death (DCD) [9, 10]. The use of DCD lungs has gained much interest lately. DCDs are classified according to the Maastricht classification and may be subdivided as controlled and uncontrolled [11]. Often the controlled DCDs are of interest since these patients are under hospital care, and their clinical history and lung function are known. It is also logistically easier to handle these donors. These controlled donors are, however, limited in number compared with the potential numbers of uncontrolled DCDs. The disadvantage of using lungs from uncontrolled donors, however, is that lung function is not known and has to be validated before the lungs can be accepted for transplant. There are also some issues regarding the optimal preservation of uncontrolled donor lungs such as how long warm ischemic time the lungs can withstand and whether it is better to harvest the lungs after the period of warm ischemia or cool the lungs inside the deceased body. These
Noninvasive Assessment of Autonomic Cardiovascular Function in Patients after Arterial Switch Operation for Transposition of the Great Arteries  [PDF]
Joanna Hlebowicz, Maja Rooth, Sandra Lindstedt, Johan Holm, Ulf Thilén
Surgical Science (SS) , 2015, DOI: 10.4236/ss.2015.63020
Abstract:

Background: Children born with transposition of the great arteries (TGA) must undergo corrective surgery for survival, arterial switch being the standard surgical procedure. The sympathetic innervation of the heart may be damaged during the operation. This study was designed to determine whether adults who were born with TGA and who had arterial switch operation (ASO) in infancy exhibit denervation of the heart, measured as heart rate variability (HRV) with electrocardiography (ECG). Methods: Nine patients with transposition of the great arteries (four men and five women; mean age 26 ± 1 years) who underwent the ASO at a mean age of 85 ± 35 days, and nine healthy adults (five men and five women; mean age 26 ± 2) were included in the study. Cardiac autonomic nerve function was determined by the variation in RR intervals during maximal deep breathing, monitored by continuous ECG. The mean values were calculated for each group from six inspirations (I) and expirations (E), and the E:I ratios were calculated. Results: The E:I ratio did not differ between patients with an arterial switch and healthy controls (P= 0.161). Two patients had signs of denervation of the heart up to 30 years after the arterial switch operation. Conclusions: Reinnervation of the heartmay take place in patients who have undergone the ASO in infancy, and these patients would not necessarily suffer from autonomic dysfunction. The HRV, measured by ECG, has the potential to identify arterially switched patients at risk of developing silent myocardial ischemia.

Pressure transduction and fluid evacuation during conventional negative pressure wound therapy of the open abdomen and NPWT using a protective disc over the intestines
Sandra Lindstedt, Malin Malmsj?, Johan Hansson, Joanna Hlebowicz, Richard Ingemansson
BMC Surgery , 2012, DOI: 10.1186/1471-2482-12-4
Abstract: Six pigs underwent midline incision and the application of conventional NPWT and NPWT with a protective disc between the intestines and the vacuum source. The pressure transduction was measured centrally beneath the dressing, and at the anterior abdominal wall, before and after the application of topical negative pressures of -50, -70 and -120 mmHg. The drainage of fluid from the abdomen was measured, with and without the protective disc.Abdominal drainage was significantly better (p < 0. 001) using NPWT with the protective disc at -120 mmHg (439 ± 25 ml vs. 239 ± 31 ml), at -70 mmHg (341 ± 27 ml vs. 166 ± 9 ml) and at -50 mmHg (350 ± 50 ml vs. 151 ± 21 ml) than with conventional NPWT. The pressure transduction was more even at all pressure levels using NPWT with the protective disc than with conventional NPWT.The drainage of the open abdomen was significantly more effective when using NWPT with the protective disc than with conventional NWPT. This is believed to be due to the more even and effective pressure transduction in the open abdomen using a protective disc in combination with NPWT.Treatment of open abdomen with negative pressure wound therapy (NPWT) in cases of abdominal sepsis and abdominal compartment syndrome results in a high rate of successful abdominal closure [1-5]. The primary goals of wound management include avoidance of mechanical contamination of abdominal viscera, active removal of exudates, estimation of third space fluid loss, and infection control [6]. NPWT involves application of topical negative pressure to the open wound. A non-adhesive perforated plastic barrier is placed over the viscera and extended laterally under the anterior abdominal wall. This first permeable layer is then covered with a polyurethane sponge and sealed with an airtight plastic sheet. An aspiration system is used to apply suction often ranging between 125 and 150 mmHg. The primary goal of this treatment is to remove contaminated fluid from the peritoneal cavity.Temp
Macroscopic changes during negative pressure wound therapy of the open abdomen using conventional negative pressure wound therapy and NPWT with a protective disc over the intestines
Sandra Lindstedt, Malin Malmsj?, Johan Hansson, Joanna Hlebowicz, Richard Ingemansson
BMC Surgery , 2011, DOI: 10.1186/1471-2482-11-10
Abstract: Twelve pigs underwent midline incision. Six animals underwent conventional NPWT, while the other six pigs underwent NPWT with a protective disc inserted between the intestines and the vacuum source. Macroscopic changes were photographed and quantified after 12, 24, and 48 hours of NPWT.The surface of the small intestines was red and mottled as a result of petechial bleeding in the intestinal wall in all cases. After 12, 24 and 48 hours of NPWT, the area of petechial bleeding was significantly larger when using conventional NPWT than when using NPWT with the protective disc (9.7 ± 1.0 cm2 vs. 1.8 ± 0.2 cm2, p < 0.001, 12 hours), (14.5 ± 0.9 cm2 vs. 2.0 ± 0.2 cm2, 24 hours) (17.0 ± 0.7 cm2 vs. 2.5 ± 0.2 cm2 with the disc, p < 0.001, 48 hours)The areas of petechial bleeding in the small intestinal wall were significantly larger following conventional NPWT after 12, 24 and 48 hours, than using NPWT with a protective disc between the intestines and the vacuum source. The protective disc protects the intestines, reducing the amount of petechial bleeding.An injury to the abdomen or abdominal surgery can result in a wound that cannot be closed immediately. It may be necessary to leave the wound open to allow further treatment, or to allow infection to clear. In this type of open abdomen, laparostomy, the internal organs, including the bowel, may be exposed. Treatment of laparostomy with negative pressure wound therapy (NPWT) for abdominal sepsis and abdominal compartment syndrome has resulted in a high rate of successful abdominal closure. In addition, patients recover more rapidly. In patients with abdominal compartment syndrome, decompressed laparotomy with temporary closure with NPWT might be crucial, whereas in abdominal sepsis and peritonitis NPWT's draining effect and reduction of bacterial load is thought to be of great importance [1-3]. The primary goals of NWPT of the open abdomen include the avoidance of mechanical contamination of abdominal viscera, active remova
The effect of endogenously released glucose, insulin, glucagon-like peptide 1, ghrelin on cardiac output, heart rate, stroke volume, and blood pressure
Joanna Hlebowicz, Sandra Lindstedt, Ola Bj?rgell, Magnus Dencker
Cardiovascular Ultrasound , 2011, DOI: 10.1186/1476-7120-9-43
Abstract: Eleven healthy men and twelve healthy women ((mean ± SEM) aged: 26 ± 0.2 y; body mass index: 21.8 ± 0.1 kg/m2)) were included in this study. The CO, HR, SV, systolic and diastolic blood pressure, antral area, gastric emptying rate, and glucose, insulin, GLP-1 and ghrelin levels were measured.The CO and SV at 30 min were significantly higher, and the diastolic blood pressure was significantly lower, than the fasting in both men and women (P < 0.05). In men, significant correlations were found between GLP-1 level at 30 min and SV at 30 min (P = 0.015, r = 0.946), and between ghrelin levels and HR (P = 0.013, r = 0.951) at 110 min. Significant correlations were also found between the change in glucose level at 30 min and the change in systolic blood pressure (P = 0.021, r = -0.681), and the change in SV (P = 0.008, r = -0.748) relative to the fasting in men. The insulin 0-30 min AUC was significantly correlated to the CO 0-30 min AUC (P = 0.002, r = 0.814) in men. Significant correlations were also found between the 0-120 min ghrelin and HR AUCs (P = 0.007, r = 0.966) in men. No statistically significant correlations were seen in women.Physiological changes in the levels of glucose, insulin, GLP-1 and ghrelin may influence the activity of the heart and the blood pressure. There may also be gender-related differences in the haemodynamic responses to postprandial changes in hormone levels. The results of this study show that subjects should not eat immediately prior to, or during, the evaluation of cardiovascular interventions as postprandial affects may affect the results, leading to erroneous interpretation of the cardiovascular effects of the primary intervention.NCT01027507Several kinds of postprandial cardiovascular changes have been reported in the literature. The postprandial blood flow in the superior mesenteric artery (SMA) seems to be approximately double the fasting value, and initiates an increase in cardiac output (CO) [1]. Postprandial CO increase has been
Relationship between postprandial changes in cardiac left ventricular function, glucose and insulin concentrations, gastric emptying, and satiety in healthy subjects
Joanna Hlebowicz, Sandra Lindstedt, Ola Bj?rgell, Magnus Dencker
Nutrition Journal , 2011, DOI: 10.1186/1475-2891-10-26
Abstract: Twenty-three healthy subjects were included in this study. The fasting and postprandial changes at 30 min and 110 min in CO, heart rate (HR) and blood pressure were measured. Moreover, tissue Doppler imaging systolic (S'), early (E') and late (A') mitral annular diastolic velocities were measured in the septal (s) and lateral (l) walls. Glucose and insulin concentrations, and satiety were measured before and 15, 30, 45, 60, 90, and 120 min after the start of the meal. The GER was calculated as the percentage change in the antral cross-sectional area 15-90 min after ingestion of the meal.This study show that both CO, systolic longitudinal ventricular velocity of the septum (S's) and lateral wall (S'l), the early diastolic longitudinal ventricular velocity of the lateral wall (E'l), the late diastolic longitudinal ventricular velocity of the septum (A's) and lateral wall (A'l) increase significantly, and were concomitant with increased satiety, antral area, glucose and insulin levels. The CO, HR and SV at 30 min were significantly higher, and the diastolic blood pressure was significantly lower, than the fasting. The satiety was correlated to HR and diastolic blood pressure. The insulin level was correlated to HR.This study shows that postprandial CO, HR, SV and LV longitudinal systolic and diastolic functions increase concomitantly with increased satiety, antral area, and glucose and insulin levels. Therefore, patients should not eat prior to, or during, cardiac evaluation as the effects of a meal may affect the results and their interpretation.ClinicalTrials.gov: NCT01027507The digestion of food is known to alter the hemodynamics of the body significantly. Following a meal, the blood flow to the gastrointestinal organs increases, affecting the heart rate (HR), blood pressure, and cardiac output (CO). The mechanisms causing the change in heart function after a meal are not known. These postprandial cardiovascular changes have been shown to resemble the effects of vas
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