title: Influence of clonidine induced sympathicolysis on anaemia tolerance in anaesthetized pigs.
abstract: Clonidine effectively decreases perioperative mortality by reducing sympathetic tone. However, application of clonidine might also restrict anaemia tolerance due to impairment of compensatory mechanisms. Therefore, the influence of clonidine induced, short-term sympathicolysis on anaemia tolerance was assessed in anaesthetized pigs. We measured the effect of clonidine on anaemia tolerance and of the potential for macrohemodynamic alterations to constrain the acute anaemia compensatory mechanisms.
  
  
  
  After governmental approval, 14 anaesthetized pigs of either gender (Deutsche Landrasse, weight (mean ± SD) 24.1 ± 2.4 kg) were randomly assigned to intravenous saline or clonidine treatment (bolus: 20 μg · kg-1, continuous infusion: 15 μg · kg-1· h-1). Thereafter, the animals were hemodiluted by exchange of whole blood for 6 % hydroxyethyl starch (MW 130.000/0.4) until the individual critical haemoglobin concentration (Hbcrit) was reached. Primary outcome parameters were Hbcritand the exchangeable blood volume (EBV) until Hbcritwas reached.
  
  
  
  Hbcritdid not differ between both groups (values are median [interquartile range]: saline: 2.2 (2.0-2.5) g · dL-1vs. clonidine: 2.1 (2.1-2.4) g · dL-1; n.s.). Furthermore, there was no difference in exchangeable blood volume (EBV) between both groups (saline: 88 (76-106) mL · kg-1vs. clonidine: 92 (85-95) mL · kg-1; n.s.).
  
  
  
  Anaemia tolerance was not affected by clonidine induced sympathicolysis. Consequently, perioperative clonidine administration probably has not to be omitted in view of acute anaemia.
authors.affiliation: Clinic of Anesthesiology and Intensive Care Medicine, Sana Klinikum Offenbach, Offenbach, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Lauscher
authors.affiliation: Division of Anaesthesiology, Balgrist University Hospital Zurich, Zurich, Switzerland.
authors.forename: Harry
authors.initials: H
authors.lastname: Kertscho
authors.affiliation: Clinic of Anesthesiology and Intensive Care Medicine, Sana Klinikum Offenbach, Offenbach, Germany.
authors.forename: Malte
authors.initials: M
authors.lastname: Krömker
authors.affiliation: Division of Kardiology, Department of Internal Medicine, University Hospital Frankfurt, Frankfurt am Main, Germany.
authors.forename: Barbara
authors.initials: B
authors.lastname: Haberichter
authors.affiliation: Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Frankfurt am Main, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Zacharowski
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Tübingen, Tübingen, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Rosenberger
authors.affiliation: Department of Anesthesia and Intensive Care, Faculty of Medicine of the Kepler University Linz, 4021, Linz, Austria. jens.meier@akh.linz.at.
authors.forename: Jens
authors.initials: J
authors.lastname: Meier
mesh_terms: D000740:Anemia / Q000503:physiopathology*; D000818:Animals; D001810:Blood Volume; D003000:Clonidine / Q000494:pharmacology*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D006454:Hemoglobins / Q000378:metabolism*; D006895:Hydroxyethyl Starch Derivatives / Q000008:administration & dosage; D008297:Male; D019990:Perioperative Care; D013552:Swine; D013565:Sympatholytics / Q000494:pharmacology*
chemical_list: D006454:Hemoglobins; D006895:Hydroxyethyl Starch Derivatives; D013565:Sympatholytics; D003000:Clonidine
keywords: Anaemia; Clonidine; Critical haematocrit; Hemodilution; Oxygen consumption; Sympathicolysis