title: Neonatal cavopulmonary assist: pulsatile versus steady-flow pulmonary perfusion.
abstract: BACKGROUND
  Morbidity and mortality associated with single-ventricle physiology decrease substantially once a systemic venous, rather than systemic arterial, source of pulmonary blood flow is established. Cavopulmonary assist has potential to eliminate critical dependence on the problematic systemic-to-pulmonary shunt as a source of pulmonary blood flow in neonates. We have previously demonstrated feasibility of neonatal cavopulmonary assist under steady-flow conditions. We hypothesized that pulsatile pulmonary perfusion would further improve pulmonary hemodynamics.
  
  
  METHODS
  Lambs (weight 7.2 +/- 1.1 kg, age 7.9 +/- 1.5 days) underwent total cavopulmonary diversion using bicaval venous-to-main pulmonary artery cannulation. A miniature centrifugal pump was used to augment cavopulmonary flow. Pulsatility was created with an intermittently compressed compliance chamber in the circuit. Hemodynamic and gas exchange data were measured for 8 hours. Pulsatile (n = 6), steady-flow (n = 13), and control (n = 6) groups were compared using two-way analysis of variance with repeated measures.
  
  
  RESULTS
  All animals remained physiologically stable with normal gas exchange function. Mean pulmonary arterial pressure was elevated in pulsatile and steady-flow groups compared with the control group and within-group baseline values. Pulmonary vascular resistance was elevated initially in both assist groups but decreased significantly over the last 4 hours of the study and normalized after hour 4 in the pulsatile perfusion group. Pulmonary vascular resistance also normalized to control in the steady-flow group after hour 7.
  
  
  CONCLUSIONS
  Both steady-flow and pulsatile pulmonary perfusion demonstrated normalization of pulmonary vascular resistance to control in a neonatal model of univentricular Fontan circulation. These results suggest that there is no benefit to pulsatile flow in this model.
authors.affiliation: Department of Surgery, Indiana University School of Medicine, James Whitcomb Riley Hospital for Children, Indianapolis, Indiana, USA.
authors.forename: Cynthia D
authors.initials: CD
authors.lastname: Myers
authors.forename: Jack H
authors.initials: JH
authors.lastname: Boyd
authors.forename: Robert G
authors.initials: RG
authors.lastname: Presson
authors.forename: Palaniswamy
authors.initials: P
authors.lastname: Vijay
authors.forename: Aaron C
authors.initials: AC
authors.lastname: Coats
authors.forename: John W
authors.initials: JW
authors.lastname: Brown
authors.forename: Mark D
authors.initials: MD
authors.lastname: Rodefeld
mesh_terms: D000818:Animals; D001166:Arteriovenous Shunt, Surgical; D002404:Catheterization; D003187:Compliance; D003250:Constriction; D004195:Disease Models, Animal; D004867:Equipment Design; D005260:Female; D018729:Fontan Procedure; D006353:Heart-Assist Devices; D006439:Hemodynamics; D008168:Lung / Q000098:blood supply*; D009569:Nitric Oxide / Q000097:blood; D010477:Perfusion; D011247:Pregnancy; D011651:Pulmonary Artery / Q000601:surgery*; D011659:Pulmonary Gas Exchange; D011673:Pulsatile Flow; D012212:Rheology; D012756:Sheep; D013536:Suture Techniques; D014655:Vascular Resistance; D014682:Vena Cava, Inferior / Q000601:surgery*; D014683:Vena Cava, Superior / Q000601:surgery*
chemical_list: D009569:Nitric Oxide