title: A long-term stable normothermic cardiopulmonary bypass model in neonatal swine.
abstract: BACKGROUND
  An appropriate animal model of cardiopulmonary bypass (CPB) is critical in order to study the morbidity and mortality in newborn children undergoing long-term cardiac surgery. Since this has been reported to be technically difficult, this paper describes a neonatal porcine CPB model (3 days old, n = 18) for up to 8 h to study long-term bypass.
  
  
  METHODS
  After anesthesia, neonates had arterial/venous monitoring lines inserted, they were heparinized (300 IU/kg), the aorta was cannulated for arterial retroperfusion, and a two-stage venous drainage catheter was placed in the right atrium. A Medtronic Minimax Plus oxygenator and the bypass circuit were primed with donor blood and CPB was instituted.
  
  
  RESULTS
  Line and mean arterial pressures were kept at 147.7 +/- 73 and 62.7 +/- 9 mm Hg, respectively. Myocardial (38.1 +/- 1.0 degrees C) and rectal temperatures (37.7 +/- 1.0 degrees C) were maintained. Heart rate was 184.8 +/- 34.5 bpm. Hematocrits were 29.6 +/- 6.0%, activated clotting time was sustained above 400 s throughout bypass, blood gas parameters were maintained in the normal range (pH, 7.39 +/- 0.1; PO(2), 123.1 +/- 65.2 mm Hg; PCO(2), 37.2 +/- 8.5 mm Hg; and HCO(3)(-), 21.5 +/- 3.6 mmol/L). CPB was terminated after 8 h and no visceral edema or other imbalances normally associated with swine on bypass were observed.
  
  
  CONCLUSIONS
  Results demonstrate a model of stable long-term bypass in neonatal swine which can be used to study issues critical to children requiring surgical correction and CPB at a young age. Overall effects of surgery and bypass on these younger patients have yet to be explored and therefore a stable long-term normothermic model of CPB would allow the study of numerous parameters associated with this complicated procedure.
authors.affiliation: Departments of Physiology, University of Toronto, Toronto, Ontario, Canada. c.wittnich@utoronto.ca
authors.forename: C
authors.initials: C
authors.lastname: Wittnich
authors.forename: M P
authors.initials: MP
authors.lastname: Belanger
authors.forename: W J
authors.initials: WJ
authors.lastname: Wallen
authors.forename: S M
authors.initials: SM
authors.lastname: Torrance
authors.forename: S
authors.initials: S
authors.lastname: Juhasz
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002315:Cardiopulmonary Bypass; D006439:Hemodynamics; D023421:Models, Animal; D013552:Swine