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  • 351.
    Åkesson, Oscar
    et al.
    Dept of Clinical Scienses, Lund University.
    Abrahamsson, Pernilla
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Johansson, Göran
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Blind, Per-Jonas
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Surgery.
    Surface microdialysis on small bowel serosa in monitoring of ischemia2016In: Journal of Surgical Research, ISSN 0022-4804, E-ISSN 1095-8673, Vol. 204, no 1, p. 39-46Article in journal (Refereed)
    Abstract [en]

    Background: Ischemic injury of an organ causes metabolic change from aerobic to anaerobic metabolism. It has been shown in experimental studies on the heart and liver that such conversion may be detected by conventional microdialysis probes placed intraparenchymatously, as well as on organ surfaces, by assaying lactate, pyruvate, glucose, and glycerol in dialysate. We developed a microdialysis probe (S-mu D) intended for use solely on organ surfaces. The aim of this study was to assess whether the newly developed S-mu D probe could be used for detection and monitoring of small bowel ischemia. Methods: In anesthetized normoventilated pigs, a control S-mu D probe was applied on the jejunal serosa 50 cm downstream from the duodenojejunal junction (DJJ). Starting 100 cm from DJJ, a 100-cm long ischemic segment was created by division of all mesenteric vessels. S-mu Ds were applied at 2.5, 5, 20, and 50 cm from the starting point of ischemia by serosal sutures. A standard mu D probe was placed in the abdominal cavity as a further control. Dialysate was harvested before inducing ischemia and subsequently every 20 min for 4 h. Central venous blood was drawn every hour to monitor systemic lactate, C-reactive protein, and white blood cell count. Results: Microdialysis lactate levels were significantly higher than baseline from 20 min on into protocol time in the ischemic segment and in the control S-mu D probe. The peritoneal cavity probe showed no significant elevation. Lactate levels from the ischemic segment reached a plateau at 60 min. Courses of pyruvate, glucose, and glycerol levels were in accordance with transition from an aerobic to anaerobic metabolism in the bowel wall. No statistically significant changes in hemoglobin, white blood cell count, or lactate values in central venous blood were recorded. Conclusions: Assaying the aforementioned compounds in dialysate, harvested by the newly developed S-mu D probe, allowed detection and monitoring of small bowel ischemia from 20 min on following its onset.

  • 352.
    Åkesson, Oscar
    et al.
    Institutionen för Klinisk Vetenskap, Lunds Universitet.
    Falkenback, Dan
    Institutionen för Klinisk Vetenskap, Lunds Universitet.
    Johansson, Göran
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Abrahamsson, Pernilla
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Surface Microdialysis Detects Ischemia After Esophageal Resection: An Experimental Animal Study2019In: Journal of Surgical Research, ISSN 0022-4804, E-ISSN 1095-8673, Vol. 245, p. 537-543Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: After an esophageal resection, continuity is commonly restored by a gastric tube reconstruction and an intrathoracic anastomosis to the remaining proximal esophagus. Ischemia of the anastomotic region is considered to play a pivotal role in anastomotic leakage. Microdialysis (μD) is an excellent method to measure local biochemical substances and parameters in a specific organ or compartment aiming at early detection of ischemia. This animal study evaluates ischemia of the gastric tube reconstruction using a novel method-μD on organ surfaces. This promising method may have the potential to detect an anastomotic leakage before clinical symptoms develop.

    METHODS: Anesthetized normoventilated pigs were used. Surface microdialysis (S-μD) catheters and an intraparenchymal oxygen tension catheter were placed on the stomach. A gastric tube was made and the gastroepiploic artery was divided halfway along the greater curvature to produce severe ischemia at the top of the gastric tube. μD data from four locations (gastric tube, ileum and peritoneal cavity) were recorded every 20 min during the experiment. Tissue samples from all catheter sites underwent histopathological analysis. Intraparenchymal oxygen partial pressure, systemic blood tests, and hemodynamic parameters were recorded.

    RESULTS: S-μD data showed values indicating severe ischemia at the top of the gastric tube and intermediate ischemia at the level of transection of the gastroepiploic artery. Ischemia was verified by histopathological analysis of tissue samples and intraparenchymal oxygen tension data.

    CONCLUSIONS: S-μD can detect and grade severity of local ischemia in real time, in an animal model.

  • 353.
    Öhman, Irma
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Communication among students in peer-assisted training duringsimulations scenarios.2018Independent thesis Basic level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 354.
    Österlund, Barbro
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Anesthesiology and Intensive Care.
    Andersson, Bengt
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Surgery.
    Häggmark, Sören
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Anesthesiology and Intensive Care.
    Jern, Christina
    Johansson, Göran
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Anesthesiology and Intensive Care.
    Seeman-Lodding, Helen
    Biber, Björn
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Anesthesiology and Intensive Care.
    Myocardial ischemia induces coronary t-PA release in the pig2002In: Acta Anaesthesiol Scand, Vol. 46, no 3, p. 271-8Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Tissue-type plasminogen activator (t-PA) is the key factor in initiating endogenous fibrinolysis in the vascular compartment. Regulated release of t-PA from endothelial stores is rapidly induced by several humoral factors as well as coagulation activation products. The aim of the present study was to test the hypothesis that regional myocardial ischemia induces regulated release of t-PA in the coronary vasculature in vivo. METHODS: Healthy anesthetized (pentobarbital) pigs (n=8) were studied before and after a 10-min left anterior descending region coronary artery occlusion (LAD). Coronary fluxes of lactate, total t-PA antigen (ELISA, detecting both complex bound and free fraction) and active t-PA (functional assay detecting biological free fraction) were determined at 1, 3, 5 and 10 min of reflow. RESULTS: Coronary occlusion induced myocardial lactate production in all animals. Net coronary release of total t-PA, which was 21 ng/min during control, increased rapidly during reflow with a peak after only 1 min (136 ng/min), and returned to baseline within 3 min. Net release of active t-PA mirrored the overall net release response, but fell short of statistical significance. CONCLUSION: Data indicate a local myocardial profibrinolytic response following regional ischemia, which may serve as a prompt defence against coronary thromboembolic events.

  • 355.
    Österlund, Barbro
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Gedeon, Andreas
    Krill, Paul
    Johansson, Göran
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Reiz, Sebastian
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    A new method of using gas exchange measurements for the noninvasive determination of cardiac output: clinical experiences in adults following cardiac surgery1995In: Acta Anaesthesiol Scand, Vol. 39, no 6, p. 727-32Article in journal (Refereed)
    Abstract [en]

    New mathematical algorithms have been applied to a computer controlled closed breathing circuit system for non-invasive measurement of cardiac output (COniv). This system has been described in an animal study. Forty patients were studied 5 and 18 hours after cardiac surgery using the thermodilution technique as the reference (COtd). The variables entered into the algorithms for COniv were oxygen uptake, carbon dioxide elimination, end-tidal carbon dioxide partial pressure, tidal volume and arterial oxygen saturation. Mixed venous carbon dioxide partial pressure was obtained from an automatically implemented short rebreathing manoeuvre. Pulmonary perfusion was calculated by a modified Fick equation for carbon dioxide and the shunt flow added to obtain COniv. During mechanical ventilation, there was a good agreement between COtd and COniv (r = 0.8). The bias was -0.14 l/min and the precision was 0.77 l/min. The reproducibility of COniv was 0.03 l/min and for COtd -0.03 l/min with a standard deviation of the difference being 0.35 l/min for COniv and 0.31 l/min for COtd. In awake, but sedated extubated patients, the method proved unsatisfactory on account for uneven tidal volumes and difficulties with leakage around the mouth piece. We conclude that this new technique provides reliable and reproducible measures of cardiac output in sedated, ventilated patients.

  • 356.
    Österlund, Barbro
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Anesthesiology and Intensive Care.
    Holmgren, Anders
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Surgery.
    Häggmark, Sören
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Anesthesiology and Intensive Care.
    Jern, Christina
    Johansson, Göran
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Anesthesiology and Intensive Care.
    Seeman-Lodding, Helen
    Biber, Björn
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Anesthesiology and Intensive Care.
    Surgical stress induces acute coronary release of tissue-type plasminogen activator in the pig2000In: Acta Anaesthesiol Scand, Vol. 44, no 10, p. 1226-31Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Tissue-type plasminogen activator (t-PA) is an endothelium derived key enzyme in the initiation of endogenous fibrinolysis. Acute regulated release of active t-PA occurs within minutes in response to threatening thrombotic vessel occlusion. The aim of this study was to investigate the impact of surgical stimulation on the kinetics of t-PA release in the coronary vascular bed in the pig. METHODS: In anaesthetised pigs (n=16), arterio-venous concentration gradients of t-PA, and plasma flows (retrograde thermodilution) were obtained across the coronary vascular bed before (control) and at 1, 3, 5 and 10 min after sternotomy. RESULTS: At control, no significant coronary net flux (release or uptake) of t-PA was observed, while sternotomy induced a rapid net release of total t-PA (132.6 ng x min(-1)), with an associated increase in active t-PA (93.6 ng x min(-1)). This response, evident already after 1 min, showed a peak at 5 min and returned towards baseline levels within 10 min. No concurrent alterations in aortic levels of active t-PA were found and haemodynamic variables were unaltered. CONCLUSION: The rapidly increasing and transient net coronary release of t-PA after sternotomy suggests that the endothelium actively promotes local endogenous fibrinolysis during surgery. Such events could reflect a dynamic responsiveness to protect the coronary circulation during stress.

  • 357.
    Österlund, Barbro
    et al.
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Anesthesiology and Intensive Care.
    Jern, Christina
    Seeman-Lodding, Helen
    Johansson, Göran
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Anesthesiology and Intensive Care.
    Häggmark, Söran
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Anesthesiology and Intensive Care.
    Broomé, Michael
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Anesthesiology and Intensive Care.
    Biber, Björn
    Umeå University, Faculty of Medicine, Surgical and Perioperative Sciences, Anesthesiology and Intensive Care.
    Intracoronary beta2 receptor activation induces dynamic local t-PA release in the pig2003In: Thromb Haemost, Vol. 90, no 5, p. 796-802Article in journal (Refereed)
    Abstract [en]

    To investigate beta2 -adrenergic agonist-mediated effects on coronary fluxes of local fibrinolytic factors, healthy anaesthetised and instrumented pigs (n=10) were studied during infusion of isoprenaline (IPR) into the left main coronary artery. Coronary net fluxes of total t-PA antigen, active t-PA and total PAI-1 antigen were determined at baseline and at 3, 5, 7 and 10 minutes of IPR infusion. During IPR, net release of total t-PA increased in a biphasic pattern with transiently high levels at 3 (+440 %) and 7 minutes (+620%) and returned towards baseline at 10 minutes. Net coronary release of active t-PA increased with maximum levels at 3 minutes (+50%). Baseline coronary net flux of total PAI -1 showed a decrease which was most pronounced at 10 minutes. To conclude, a fast beta2 agonist-mediated local release of t-PA into the coronary vasculature was demonstrated. For total t-PA, this response was characterised by a biphasic release profile.

  • 358.
    Österlund, Barbro
    et al.
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Jern, Sverker
    Jern, Christina
    Seeman-Lodding, Helen
    Östman, Margareta
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Johansson, Göran
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Biber, Björn
    Umeå University, Faculty of Medicine, Department of Surgical and Perioperative Sciences, Anaesthesiology.
    Impaired myocardial t-PA release in patients with coronary artery disease2008In: Acta Anaesthesiol Scand, Vol. 52, no 10, p. 1375-84Article in journal (Refereed)
    Abstract [en]

    AIMS: Myocardial ischemia remains a significant perioperative complication in coronary artery disease (CAD) patients. We hypothesized that noxious stimuli during major surgery are associated with an acute release of tissue-type plasminogen activator (t-PA) into the coronary circulation, and that this response is reduced by CAD. METHODS AND RESULTS: Two patient groups, with (n=14) and without (n=8) CAD, were studied during the initial phase of heart surgery. After retrograde great cardiac vein catheterizations during closed-chest conditions, coronary arterial-venous concentration gradients of t-PA and plasminogen activator inhibitor type-1 (PAI-1) were measured together with coronary blood flow measurements, allowing derivation of coronary net release rates. Pre-surgery atrial pacing, performed to evaluate the influence of increases in heart rate (+ 40 beats/min) and coronary blood flow (+ 80 ml/min), did not significantly alter coronary net release of t-PA or PAI-1 in either patient group. Sternotomy induced a prominent increase in coronary net release of both total and active t-PA in the non-CAD group. This response was considerably reduced in the CAD group. CONCLUSIONS: This study provides the first analysis of coronary t-PA release during major surgery and demonstrates a deficient local endothelial t-PA release in patients with CAD. This suggests a reduced local fibrinolytic capacity in CAD patients, which may explain the increased risk for coronary thrombosis in this patient group.

5678 351 - 358 of 358
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