title: Inotropic therapy for right ventricular failure in newborn piglets: effect on contractility, hemodynamics, and interventricular interaction.
abstract: OBJECTIVE
  To investigate the effect of right ventricular stunning on interventricular relationships in newborn piglets and to determine the effect of three commonly used inotropic treatment strategies.
  
  
  METHODS
  Randomized, placebo-controlled animal study.
  
  
  METHODS
  Aarhus University Hospital, animal laboratory.
  
  
  METHODS
  Twenty-eight newborn (4-d old) farm-bred piglets.
  
  
  METHODS
  Acute right ventricular failure was induced by 10 cycles of alternating 3 minutes of ischemia and reperfusion of the right coronary artery. After right ventricular failure was induced, treatment with epinephrine + milrinone, dopamine + milrinone, dobutamine, or control (saline) was initiated, and the animals were observed for 180 minutes.
  
  
  RESULTS
  Right and left ventricular systolic and diastolic variables were measured using pressure-volume loops recorded by conductance catheters. Arterial and central venous pressures were recorded, and cardiac index was determined by placing a flow probe around the pulmonary artery. Whole-body perfusion was evaluated by measuring pH and lactate in arterial blood samples. Induction of right ventricular stunning resulted in decreased ejection fraction (51% ± 4% vs 40% ± 12%, p = 0.0004); caused an interventricular septum deviation, decreased mean arterial pressure (49 ± 10 mm Hg vs 43 ± 11 mm Hg, p = 0.03), and increased blood lactate (1.85 ± 0.6 mM vs 5.79 ± 3.16 mM, p < 0.00001); and led to a decrease in blood pH (7.37 ± 0.08 vs 7.23 ± 0.13, p < 0.00001). A mortality rate greater than 50% was observed in the control group. All inotropic interventions increased contractility significantly in both the left and right ventricle. The effect of dobutamine on right ventricular failure decreased after 30 minutes and was indistinguishable from the control group after 3 hours. Dobutamine-treated animals had lower perfusion pressures and blood pH compared with epinephrine + milrinone and dopamine + milrinone groups.
  
  
  CONCLUSIONS
  In newborn piglets, dobutamine had a nonsustained effect on right ventricular failure, resulting in decreased contractility and impaired perfusion compared with both dopamine and epinephrine administered in combination with milrinone.
authors: 1Department of Anaesthesiology and Intensive Care, Aarhus University Hospital, Aarhus, Denmark. 2Department of Clinical Medicine, Aarhus University, Aarhus, Denmark. 3Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Aarhus, Denmark. 4The Heart Centre, Division of Cardiology, The Hospital for Sick Children, Toronto, ON, Canada. 5Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark.
authors: Janus A
authors: JA
authors: Hyldebrandt
authors: Christian A
authors: CA
authors: Frederiksen
authors: Johan
authors: J
authors: Heiberg
authors: Susani
authors: S
authors: Rothmann
authors: Andrew N
authors: AN
authors: Redington
authors: Michael R
authors: MR
authors: Schmidt
authors: Hanne B
authors: HB
authors: Ravn
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001794:Blood Pressure; D002316:Cardiotonic Agents / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004280:Dobutamine / Q000627:therapeutic use*; D004298:Dopamine / Q000627:therapeutic use*; D004837:Epinephrine / Q000627:therapeutic use*; D020105:Milrinone / Q000627:therapeutic use*; D013318:Stroke Volume; D013552:Swine; D014655:Vascular Resistance; D018497:Ventricular Dysfunction, Right / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine; D020105:Milrinone; D004298:Dopamine; D004837:Epinephrine