title: Arginine vasopressin and serum nitrite/nitrate concentrations in advanced vasodilatory shock.
abstract: BACKGROUND
  Arginine-vasopressin (AVP) can successfully stabilize hemodynamics in patients with advanced vasodilatory shock. It has been suggested that inhibition of cytokine-induced nitric oxide production may be an important mechanism underlying AVP-induced vasoconstriction. Therefore, serum concentrations of nitrite/nitrate (NOx), the stable metabolite of nitric oxide, were measured in patients suffering from advanced vasodilatory shock treated with either AVP in combination with norepinephrine (NE) or NE alone.
  
  
  METHODS
  This trial was a separate study arm of a previously published prospective, randomized, controlled study on the effects of AVP in advanced vasodilatory shock. Thirty-eight patients were prospectively randomized to receive a combined infusion of AVP (4 U h(-1)) and NE, or NE infusion alone. Serum NOx concentrations were measured at baseline, 24, and 48 h after randomization. The increase in mean arterial pressure during the first hour after study enrollment was documented in all patients.
  
  
  RESULTS
  No difference in NOx concentrations was found between groups throughout the study period. AVP patients demonstrated a significantly greater increase in mean arterial pressure than NE patients (22 +/- 10 vs. 5 +/- 9 mmHg; P < 0.001). The magnitude of pressure response to AVP was not correlated with NOx concentrations before start of AVP infusion (Pearson's correlation coefficient, -.009; P = 0.971).
  
  
  CONCLUSIONS
  Cardiovascular effects of AVP infusion in advanced vasodilatory shock are not mediated by a clinically relevant reduction in serum NOx concentrations. Therefore, hemodynamic improvement of patients in advanced vasodilatory shock during continuous infusion of AVP has to be attributed to other mechanisms than inhibition of nitric oxide synthase. In addition, the magnitude of pressure response to AVP is not correlated with baseline concentrations of NOx.
authors.affiliation: Division of General and Surgical Intensive Care Medicine, Department of Anesthesiology and Critical Care Medicine, Leopold Franzens University of Innsbruck, Innsbruck, Austria.
authors.forename: M W
authors.initials: MW
authors.lastname: Dünser
authors.forename: E R
authors.initials: ER
authors.lastname: Werner
authors.forename: V
authors.initials: V
authors.lastname: Wenzel
authors.forename: H
authors.initials: H
authors.lastname: Ulmer
authors.forename: B E
authors.initials: BE
authors.lastname: Friesenecker
authors.forename: W R
authors.initials: WR
authors.lastname: Hasibeder
authors.forename: A J
authors.initials: AJ
authors.lastname: Mayr
mesh_terms: D000368:Aged; D001127:Arginine Vasopressin / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D006801:Humans; D008875:Middle Aged; D009566:Nitrates / Q000097:blood*; D009573:Nitrites / Q000097:blood*; D011446:Prospective Studies; D017483:Receptors, Vasopressin / Q000502:physiology; D012769:Shock / Q000097:blood* / Q000503:physiopathology; D014664:Vasodilation
chemical_list: D009566:Nitrates; D009573:Nitrites; D017483:Receptors, Vasopressin; D001127:Arginine Vasopressin