title: Effects of systemically applied clonidine on intestinal perfusion and oxygenation in healthy pigs during general anaesthesia and laparotomy.
abstract: OBJECTIVE
  Clonidine, which is used for induction of sympatholysis and prevention or treatment of alcohol withdrawal in anaesthesia and intensive care medicine, may have deleterious effects on intestinal mucosal perfusion. This study was designed to investigate the effects of clonidine on intestinal perfusion and oxygenation.
  
  
  METHODS
  Following ethical approval 17 anaesthetized, and acutely instrumented pigs were randomly assigned to two groups: eight animals received intravenous clonidine (2 microg kg(-1) bolus and 2 microg kg(-1) h(-1)), nine animals served as a control group. Measurement points for systemic and regional haemodynamic and oxygenation parameters were 135 and 315 min after starting the clonidine application.
  
  
  RESULTS
  Clonidine elicited systemic haemodynamic changes (median [25-75th interquartile range]): heart rate (106 [91, 126] to 84 [71, 90] beats min(-1)) cardiac output (147 [123, 193] to 90 [87, 107] mL min(-1) kg(-1)) and mean arterial pressure (77 [72, 93] to 69 [61, 78] mmHg) decreased. Despite systemic haemodynamic changes, the superior mesenteric artery blood flow did not change in the clonidine group. The vascular resistance of the superior mesenteric artery decreased. The small intestinal oxygen supply, the mucosal and the serosal tissue oxygen partial pressure did not change.
  
  
  CONCLUSIONS
  Systemic sympatholysis induced by intravenously applied clonidine in addition to basic intravenous anaesthesia elicited a decrease in cardiac output and mean arterial pressure. However, regional macrohaemodynamic perfusion was maintained and intestinal oxygenation did not change. Clonidine does not impair intestinal mucosal and serosal oxygenation under physiological conditions.
authors.affiliation: Universität Rostock, Klinik und Poliklinik für Anästhesiologie und Intensivtherapie, Rostock, Germany. dierk.vagts@medizin.uni-rostock.de
authors.forename: D A
authors.initials: DA
authors.lastname: Vagts
authors.forename: T
authors.initials: T
authors.lastname: Iber
authors.forename: J P
authors.initials: JP
authors.lastname: Roesner
authors.forename: C
authors.initials: C
authors.lastname: Mutz
authors.forename: V
authors.initials: V
authors.lastname: Kurzweg
authors.forename: C
authors.initials: C
authors.lastname: Harkner
authors.forename: K
authors.initials: K
authors.lastname: Brüderlein
authors.forename: G F E
authors.initials: GF
authors.lastname: Nöldge-Schomburg
mesh_terms: D000768:Anesthesia, General; D000818:Animals; D003000:Clonidine / Q000008:administration & dosage / Q000009:adverse effects*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects; D007413:Intestinal Mucosa / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism; D007421:Intestine, Small / Q000098:blood supply / Q000187:drug effects / Q000378:metabolism; D007813:Laparotomy; D010100:Oxygen / Q000378:metabolism*; D013152:Splanchnic Circulation / Q000187:drug effects; D034421:Sus scrofa; D013565:Sympatholytics / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D013565:Sympatholytics; D003000:Clonidine; D010100:Oxygen