Do intra-operative fluids influence the need for post-operative cardiotropic support after a PDA ligation? 
To investigate the effect of intra-operative intravenous fluids on post-operative hemodynamic stability.  We performed a retrospective cohort study of 98 preterm infants who underwent a patent ductus arteriosus (PDA) ligation in one NICU between 2001 and 2007.  The primary outcome was the need for cardiotropic support within 24 hrs of ligation.  Twenty-seven infants (28%) required post-operative cardiotropic support.  The amount of intra-operative fluids varied between 0 and 50.4 mL/kg (median: 10.2 mL/kg).  No intra-operative fluid was recorded in 26 patients.  Fluids were not associated with the need for post-operative cardiotropic support (P=0.10).  Using a multivariate logistic regression model, age at ligation, weight at ligation and pre-operative FiO2 were significant predictors of post-operative cardiotropic support.  Intra-operative fluids do not appear to be associated with the need for post-operative cardiotropic support.  A prospective cohort study may help identify modifiable risk factors and improve outcomes in this population.