title: Management of vasodilatory shock after cardiac surgery: identification of predisposing factors and use of a novel pressor agent.
abstract: BACKGROUND
  Cardiopulmonary bypass can be associated with vasodilatory hypotension requiring pressor support. We have previously found arginine vasopressin to be a remarkably effective pressor in a variety of vasodilatory shock states. We investigated the incidence and clinical predictors of vasodilatory shock in a general population of cardiac surgical patients and the effects of low-dose arginine vasopressin as treatment of this syndrome in patients with heart failure.
  
  
  METHODS
  Patients undergoing cardiopulmonary bypass (n = 145) were studied prospectively. Preoperative ejection fraction, medications, and perioperative hemodynamics were recorded, and postbypass serum arginine vasopressin levels were measured. Vasodilatory shock was defined as a mean arterial pressure lower than 70 mm Hg, a cardiac index greater than 2.5 L/min/m2, and norepinephrine dependence. Predictors of vasodilatory shock were investigated by logistic regression analysis. The hemodynamic responses of patients who received arginine vasopressin infusions for vasodilatory shock after cardiopulmonary bypass for left ventricular assist device placement or heart transplantation were analyzed retrospectively.
  
  
  RESULTS
  Eleven of 145 general cardiac surgery patients (8%) met criteria for postbypass vasodilatory shock. By multivariate analysis, an ejection fraction lower than 0.35 and angiotensin-converting enzyme inhibitor use were independent predictors of postbypass vasodilatory shock (relative risks of 9.1 and 11.9, respectively). Vasodilatory shock was associated with inappropriately low serum arginine vasopressin concentrations (12.0 +/- 6.6 pg/mL). Retrospective analysis found 40 patients with postbypass vasodilatory shock who received low-dose arginine vasopressin infusions, resulting in increased mean arterial pressure and decreased norepinephrine requirements.
  
  
  CONCLUSIONS
  Low ejection fraction and angiotensin-converting enzyme inhibitor use are risk factors for postbypass vasodilatory shock, and this syndrome is associated with vasopressin deficiency. In patients exhibiting this syndrome after high-risk cardiac operations, replacement of arginine vasopressin increases blood pressure and reduces catecholamine pressor requirements.
authors.affiliation: Departments of Surgery and Medicine, Columbia University College of Physicians and Surgeons, New York, USA.
authors.forename: M
authors.initials: M
authors.lastname: Argenziano
authors.forename: J M
authors.initials: JM
authors.lastname: Chen
authors.forename: A F
authors.initials: AF
authors.lastname: Choudhri
authors.forename: S
authors.initials: S
authors.lastname: Cullinane
authors.forename: E
authors.initials: E
authors.lastname: Garfein
authors.forename: A D
authors.initials: AD
authors.lastname: Weinberg
authors.forename: C R
authors.initials: CR
authors.lastname: Smith
authors.forename: E A
authors.initials: EA
authors.lastname: Rose
authors.forename: D W
authors.initials: DW
authors.lastname: Landry
authors.forename: M C
authors.initials: MC
authors.lastname: Oz
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000097:blood; D001127:Arginine Vasopressin / Q000008:administration & dosage / Q000097:blood / Q000627:therapeutic use*; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007022:Hypotension / Q000097:blood / Q000188:drug therapy / Q000209:etiology; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000097:blood / Q000188:drug therapy / Q000209:etiology; D011379:Prognosis; D012189:Retrospective Studies; D012769:Shock / Q000097:blood / Q000188:drug therapy* / Q000209:etiology; D014662:Vasoconstrictor Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D014664:Vasodilation / Q000187:drug effects*
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D015415:Biomarkers; D014662:Vasoconstrictor Agents; D001127:Arginine Vasopressin