Publications by authors named "Peter Conzen"

Introduction: Postoperative cognitive dysfunction (POCD) occurs in up to 26% of patients older than 60 years 1 week after non-cardiac surgery. Intraoperative beach chair positioning (BCP) is advantageous for some types of shoulder surgery. However, this kind of positioning leads to a downward bound redistribution of blood volume, with possible hypoperfusion of the brain.

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Inhalational anesthetics have been used for induction and maintenance of general anesthesia for more than 150 years. All of the currently used inhalational anesthetics are chlorinated and fluorinated derivatives of ether. Dosing is carried out using the minimal alveolar concentration (MAC) concept.

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Background: Hypotension and bradycardia are known side effects of general anesthesia, while little is known about further macro- and microhemodynamic changes during induction. Intriguing is furthermore, why some patients require no vasopressor medication to uphold mean arterial pressure, while others need vasopressor support.

Objective: Determination of macro- and microhemodynamic changes during induction of general anesthesia.

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Background: Intravenous fluids can impair coagulation and affect the endothelial glycocalyx, whereas glycocalyx shedding itself can cause an impairment of clot formation and firmness. We hypothesized that hydroxyethyl starch 6% (130/0.4) has a more distinct effect on coagulation and glycocalyx shedding than albumin 5%.

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This prospective cohort study explored whether two distinguished sensory parameters predicted acupuncture effects in chronic pain patients; namely high temporal summation of pain (TS) indicating spinal synaptic facilitation as well as a low vibration detection threshold (VDT) indicating a loss of Aβ-fiber function. Pinprick induced TS and VDT were assessed by standardized, validated methods at the most painful body site and a pain free control site in 100 chronic pain patients receiving six acupuncture sessions as part of an interdisciplinary multimodal pain treatment (IMPT). Immediate change in pain intensity after the first acupuncture session (first treatment on the first day of IMPT) was assessed by the verbal rating scale (VRS, 0-100).

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Background: The endothelial glycocalyx plays a decisive role in maintaining vascular homeostasis. Previous animal models have mainly focused on in-vitro experiments or the isolated beating guinea pig heart. To further evaluate underlying mechanisms of up- and down regulation, knock-out animals seem to be a promising option.

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Article Synopsis
  • The use of artificial colloids in medical settings has decreased, particularly in critical care, but remains common in surgeries, prompting this study on their impact on kidney health.
  • One hundred urologic patients were randomly assigned to receive either albumin 5% or hydroxyethyl starch 6% during elective cystectomy, with kidney function measured through biomarkers like cystatin C before and after surgery.
  • The study found no significant differences in kidney function or injury between the two groups, suggesting both albumin and hydroxyethyl starch are comparably safe for noncritically ill patients undergoing major surgery.
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Glycosaminoglycan hyaluronan (HA), a major constituent of the endothelial glycocalyx, helps to maintain vascular integrity. Preconditioning the heart with volatile anesthetic agents protects against ischemia/reperfusion injury. We investigated a possible protective effect of sevoflurane on the glycocalyx, especially on HA.

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Introduction: It is well established that obesity-related hormones can have modulatory effects associated with the immune response. Ghrelin, a hormone mainly derived from endocrine cells of the gastric mucosa, regulates appetite, energy expenditure and body weight counteracting leptin, a hormone mainly derived from adipocytes. Additionally, receptors of both have been detected on immune cells and demonstrated an immune regulatory function during sepsis.

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Introduction: Acute normovolemic hemodilution (ANH) and volume loading (VL) are standard blood-sparing procedures. However, VL is associated with hypervolemia, which may cause tissue edema, cardiopulmonary complications and a prolonged hospital stay. The body reacts to hypervolemia with release of atrial natriuretic peptide (ANP) from the heart.

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Background: Strategies targeting the protection of the vascular barrier, in particular the endothelial glycocalyx, are subjects of current research. Antithrombin III and hydrocortisone have been shown to reduce shedding of the glycocalyx following ischaemia/reperfusion. Platelet adhesion to endothelial cells is one consequence of ischaemia/reperfusion.

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Background: Obesity is a growing health problem and associated with immune dysfunction. Sepsis is defined as systemic inflammatory response syndrome that occurs during infection. Excessive inflammation combined with immune dysfunction can lead to multiorgan damage and death.

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Background: The current pilot study compares the impact of an intravenous infusion of Ringer's lactate to an acetate-based solution with regard to acid-base balance. The study design included the variables of the Stewart approach and focused on the effective strong ion difference. Because adverse hemodynamic effects have been reported when using acetate buffered solutions in hemodialysis, hemodynamics were also evaluated.

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Introduction: Isotonic crystalloids play a central role in perioperative fluid management. Isooncotic preparations of colloids (for example, human albumin or hydroxyethyl starch) remain nearly completely intravascular when infused to compensate for acute blood losses. Recent data were interpreted to indicate a comparable intravascular volume effect for crystalloids, challenging the occasionally suggested advantage of using colloids to treat hypovolemia.

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Introduction: Vascular leakage after ischemia-reperfusion (IR) is largely attributed to the destruction of the endothelial barrier and its associated negatively charged glycocalyx. In vitro, sevoflurane attenuates these changes. Therefore, we compared sevoflurane with propofol with regard to the protection of the glycocalyx and the release of negatively charged substances in vivo.

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Propofol is widely used for sedating critically ill adult patients because of its rapid onset and short recovery times, even after prolonged use. Propofol may be associated with a life-threatening syndrome, propofol-related infusion syndrome (PRIS), which includes cardiac failure, severe metabolic acidosis, renal failure, and rhabodomyolysis. The pathophysiology is incompletely understood.

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Article Synopsis
  • Ischemia-reperfusion injury involves the adhesion of immune cells and platelets to damaged blood vessels, which worsens heart damage; the glycocalyx protects the vessel lining, but it deteriorates during this process.
  • Pretreatment with sevoflurane, a volatile anesthetic, was analyzed for its potential protective effects on the glycocalyx during ischemia-reperfusion in guinea pig hearts, showing a significant reduction in cell adhesion and protection of the glycocalyx.
  • The study found that sevoflurane significantly decreased the adhesion of leukocytes and platelets after ischemia, suggesting it helps maintain the glycocalyx and reduces heart damage post-ischemia.
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Purpose Of Review: Since the detection of morphine by the pharmacologist Friedrich Sertürner in 1806, opioids have been used as potent centrally acting analgesics. In addition to the central site of action, peripheral endogenous opioid analgesic systems have been extensively studied, especially in the past two decades. This review is not only mentioned to give a brief summary in this well investigated field of peripheral opioid receptors, but also to highlight the role of peripheral opioid receptors in other physiological and pathophysiological conditions.

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Background: Heterogeneity of vascular permeability has been suggested for the coronary system. Whereas arteriolar and capillary segments are tight, plasma proteins pass readily into the interstitial space at venular sites. Fittingly, lymphatic fluid is able to coagulate.

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  • PMN adhesion to coronary endothelium plays a crucial role in cardiac ischemia/reperfusion injury, with ischemia causing degradation of the glycocalyx, leading to increased PMN adhesion.
  • Hydrocortisone and antithrombin treatment effectively reduced glycocalyx shedding and PMN adhesion, suggesting a protective effect post-ischemia.
  • Preservation of the glycocalyx may help minimize vascular leakage, tissue swelling, and inflammation after cardiac ischemia/reperfusion events.
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Article Synopsis
  • The EPPA Trial aims to evaluate the effectiveness of preemptive analgesia using etoricoxib (a cox-2 inhibitor) compared to a placebo in patients undergoing abdominal or thoracic surgery.
  • This double-blinded, randomized study involves 120 patients, who are split into two main treatment groups (preemptive and postoperative), each further divided to receive etoricoxib or placebo before and after the surgery.
  • The primary outcome is the total morphine consumption in the first 48 hours post-surgery, along with secondary measures related to sensory perception and genetic factors.
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Potter and Damiano recently assessed the hydrodynamic dimensions of the endothelial glycocalyx in vivo (mouse cremaster muscle venules) and in vitro (human umbilical vein and bovine aorta endothelium cultured in perfused microchannels) using fluorescent microparticle image velocimetry (Circ Res. 2008;102:770-776). Great discrepancy was observed, the glycocalyx presenting a zone of interaction extending approximately 0.

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Background: Major causes of death after heart transplantation are right ventricular pump failure and, chronically, cardiac allograft vasculopathy. Traditional preservation techniques focus on immediate cardioplegia, without particularly considering vascular demands. Recently, the endothelial surface layer, composed of the endothelial glycocalyx and plasma proteins, was discovered to play a major role in vascular barrier function, edema formation, and leukocyte-to-endothelial interaction.

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Aims: Antithrombin is an important inhibitor of the coagulation system, additionally exerting specific anti-inflammatory effects on endothelial cells. Healthy vascular endothelium is coated by the endothelial glycocalyx, diminution of which increases capillary permeability, e.g.

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