title: Can a volume challenge pinpoint the limiting factor in a Fontan circulation?
abstract: OBJECTIVE
  It is difficult to indicate whether the limitation in a failing Fontan circulation lies within the pulmonary vasculature or the heart. Such differentiation is crucial to direct adequate therapy. This study was set out to determine if a volume challenge could identify the limiting factor.
  
  
  METHODS
  Thirty-two catheterizations in 28 patients with a Fontan circulation were included. Pressures and oxygen saturations were measured before and after volume challenge (NaCl 0.9%; 15 cc/Kg). The changes in data were grouped based on the location of the major pressure increase. Ventricular function was measured in the resting state.
  
  
  RESULTS
  The majority of the patients showed an increase in aortic oxygen saturation, mixed venous oxygen saturation, systolic, pulmonary and systemic venous pressures. The arterio-venous oxygen gradient decreased, suggesting an increase in cardiac output. Different patterns in pressure changes were observed. Most (n=17) showed a similar increase of ventricular end-diastolic pressure and mean venous pressure (MVP); some (n=7) showed a lower increase of MVP, suggesting pulmonary reserve and recruitment; others (n=8) showed a significant higher increase in MVP, suggesting increased pulmonary vascular resistance. All volume challenge was well tolerated.
  
  
  CONCLUSIONS
  Most patients were preload-responsive. The pressure changes following volume load showed patterns with a potential of differentiating between patients with a major pulmonary or cardiac limiting factor.
authors.forename: Wim
authors.initials: W
authors.lastname: De Mey
authors.forename: Bjorn
authors.initials: B
authors.lastname: Cools
authors.forename: Ruth
authors.initials: R
authors.lastname: Heying
authors.forename: Werner
authors.initials: W
authors.lastname: Budts
authors.forename: Jacoba J
authors.initials: JJ
authors.lastname: Louw
authors.forename: Derize E
authors.initials: DE
authors.lastname: Boshoff
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Brown
authors.forename: Marc
authors.initials: M
authors.lastname: Gewillig
mesh_terms: D000293:Adolescent; D000328:Adult; D062186:Arterial Pressure; D001810:Blood Volume; D006328:Cardiac Catheterization; D002648:Child; D002675:Child, Preschool; D003326:Coronary Circulation; D005260:Female; D018729:Fontan Procedure / Q000009:adverse effects*; D006801:Humans; D007263:Infusions, Parenteral; D008297:Male; D011237:Predictive Value of Tests; D011652:Pulmonary Circulation; D012307:Risk Factors; D012965:Sodium Chloride / Q000008:administration & dosage*; D013318:Stroke Volume; D017211:Treatment Failure; D014690:Venous Pressure; D016276:Ventricular Function; D055815:Young Adult
chemical_list: D012965:Sodium Chloride
keywords: Fontan; circuit failure; total cavopulmonary connection; volume challenge