title: Hemodynamic changes induced by laparoscopy and their endocrine correlates: effects of clonidine.
abstract: OBJECTIVE
  We investigated endocrine correlates of the hemodynamic changes induced by carbon dioxide pneumoperitoneum (PNO). We then studied whether clonidine might modulate the hemodynamic changes induced by PNO by reducing release of catecholamines and vasopressin.
  
  
  BACKGROUND
  Both mechanical and neurohumoral factors contribute to the hemodynamic changes induced by carbon dioxide PNO. Several mediators have been proposed, but no study has correlated hemodynamic changes with changes in levels of these potential mediators.
  
  
  METHODS
  We conducted two studies, each including 20 healthy patients scheduled for elective laparoscopic cholecystectomy. In the first study serial measurements of hemodynamics (thermodilution technique) were done during laparoscopy and after exsufflation. Plasma concentrations of cortisol, catecholamines, vasopressin, renin, endothelin and prostaglandins were measured at the same time points. In the second study patients were randomly allocated to receive 8 microg/kg clonidine infused over 1 h or placebo before PNO. Hemodynamics and plasma levels of cortisol, catecholamines and vasopressin were measured during PNO and after exsufflation.
  
  
  RESULTS
  Peritoneal insufflation resulted in a significant reduction of cardiac output (18+/-4%) and increases in mean arterial pressure (39+/-8%) and systemic (70+/-12%) and pulmonary (98+/-18%) vascular resistances. Laparoscopy resulted in progressive and significant increases in plasma concentrations of cortisol, epinephrine, norepinephrine and renin. Vasopressin plasma concentrations markedly increased immediately after the beginning of PNO (before PNO 6+/-4 pg/ml; during PNO 129+/-42 pg/ml; p < 0.05). The profile of vasopressin release paralleled the time course of changes in systemic vascular resistance. Prostaglandins and endothelin did not change significantly. Clonidine significantly reduced mean arterial pressure, heart rate and the increase in systemic vascular resistance. Clonidine also significantly reduced catecholamine concentrations but did not alter vasopressin and cortisol plasma concentrations.
  
  
  CONCLUSIONS
  Vasopressin and catecholamines probably mediate the increase in systemic vascular resistance observed during PNO. Clonidine before PNO reduces catecholamine release and attenuates hemodynamic changes during laparoscopy.
authors.affiliation: Department of Anesthesiology and Intensive Care Medicine, University Hospital of Liège, Belgium. mlamy@chu.ulg.ac.be
authors.forename: J L
authors.initials: JL
authors.lastname: Joris
authors.forename: J D
authors.initials: JD
authors.lastname: Chiche
authors.forename: J L
authors.initials: JL
authors.lastname: Canivet
authors.forename: N J
authors.initials: NJ
authors.lastname: Jacquet
authors.forename: J J
authors.initials: JJ
authors.lastname: Legros
authors.forename: M L
authors.initials: ML
authors.lastname: Lamy
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000008:administration & dosage*; D000328:Adult; D000368:Aged; D002245:Carbon Dioxide / Q000009:adverse effects; D002395:Catecholamines / Q000097:blood; D017081:Cholecystectomy, Laparoscopic / Q000009:adverse effects; D003000:Clonidine / Q000008:administration & dosage*; D004703:Endocrine System / Q000187:drug effects / Q000502:physiology*; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007262:Infusions, Intravenous; D007431:Intraoperative Complications / Q000097:blood / Q000503:physiopathology* / Q000517:prevention & control; D019344:Lactic Acid / Q000097:blood; D010535:Laparoscopy / Q000009:adverse effects*; D008875:Middle Aged; D011028:Pneumoperitoneum, Artificial / Q000009:adverse effects; D014667:Vasopressins / Q000097:blood
chemical_list: D000316:Adrenergic alpha-Agonists; D002395:Catecholamines; D014667:Vasopressins; D002245:Carbon Dioxide; D019344:Lactic Acid; D003000:Clonidine; D006854:Hydrocortisone