title: Milrinone, dobutamine or epinephrine use in asphyxiated newborn pigs resuscitated with 100% oxygen.
abstract: BACKGROUND
  After resuscitation, asphyxiated neonates often develop poor cardiac function with hypotension, pulmonary hypertension and multiorgan ischemia. In a swine model of neonatal hypoxia-reoxygenation, effects of epinephrine, dobutamine and milrinone on systemic, pulmonary and regional hemodynamics and oxygen transport were compared.
  
  
  METHODS
  Controlled, block-randomized study.
  
  
  METHODS
  University research laboratory.
  
  
  METHODS
  Mixed breed piglets (1-3 days, 1.5-2.3 kg).
  
  
  METHODS
  In acutely instrumented piglets, normocapnic alveolar hypoxia (10-15% oxygen) was induced for 2 h followed by reoxygenation with 100% oxygen (1 h) then 21% oxygen (3 h). At 2 h of reoxygenation, after volume loading (Ringer's lactate 10 ml/kg), either saline (placebo), epinephrine (0.5 microg/kg/min), dobutamine (20 microg/kg/min) or milrinone (0.75 microg/kg/min) were infused for 2 h in a blinded, block-randomized fashion (n = 6/group).
  
  
  RESULTS
  All medications similarly improved cardiac output, stroke volume and systemic oxygen delivery (vs. placebo-controls, p < 0.05). Epinephrine and dobutamine significantly increased, while milrinone maintained, mean arterial pressure over pretreatment values while placebo-treated piglets developed hypotension and shock. The mean arterial to pulmonary arterial pressures ratio was not different among groups. All medications significantly increased carotid and intestinal, but not renal, arterial blood flows and oxygen delivery, whereas milrinone caused lower renal vascular resistance than epinephrine and dobutamine-treated groups. Plasma troponin I, plasma and myocardial lactate levels, and histologic ischemic features were not different among groups.
  
  
  CONCLUSIONS
  In newborn piglets with hypoxia-reoxygenation, epinephrine, dobutamine and milrinone are effective inotropes to improve cardiac output, carotid and intestinal perfusion, without aggravating pulmonary hypertension. Milrinone may also improve renal perfusion.
authors.affiliation: Department of Pediatrics, University of Alberta, Edmonton, AB, Canada.
authors.forename: Chloë
authors.initials: C
authors.lastname: Joynt
authors.forename: David L
authors.initials: DL
authors.lastname: Bigam
authors.forename: Gregory
authors.initials: G
authors.lastname: Charrois
authors.forename: Laurence D
authors.initials: LD
authors.lastname: Jewell
authors.forename: Gregory
authors.initials: G
authors.lastname: Korbutt
authors.forename: Po-Yin
authors.initials: PY
authors.lastname: Cheung
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001993:Bronchodilator Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002316:Cardiotonic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D004280:Dobutamine / Q000008:administration & dosage / Q000494:pharmacology*; D004837:Epinephrine / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D000860:Hypoxia; D008297:Male; D020105:Milrinone / Q000008:administration & dosage / Q000494:pharmacology*; D010100:Oxygen / Q000008:administration & dosage*; D011897:Random Allocation; D012151:Resuscitation / Q000379:methods*; D013552:Swine
chemical_list: D001993:Bronchodilator Agents; D002316:Cardiotonic Agents; D004280:Dobutamine; D020105:Milrinone; D010100:Oxygen; D004837:Epinephrine