Plasma Angiopoietin Levels in Children Following Cardiopulmonary Bypass

• Change from baseline in pro- and anti-inflammatory protein levels after modified ultrafiltration [ Time Frame: baseline to completion of MUF, on average 2 hours ] [ Designated as safety issue: No ]
  Modified ultrafiltration (MUF) is the process after cardiopulmonary bypass during which a filtration unit is added and blood is filtered and returned back to the patient. The goal of this project is to evaluate the effect of MUF on concentrations of Angiopoietin-2 (Ang-2) and IL 8, two known pro-inflammatory markers involved in capillary leakage, as well as Ang-1 and IL 10, two anti-inflammatory mediators. Levels will be drawn prior to bypass, after MUF and at ICU admission.
  
  
• Change from baseline in pro- and anti-inflammatory protein levels at ICU admission [ Time Frame: baseline to ICU admission, on average 7 hours ] [ Designated as safety issue: No ]
  Modified ultrafiltration (MUF) is the process after cardiopulmonary bypass during which a filtration unit is added and blood is filtered and returned back to the patient. The goal of this project is to evaluate the effect of MUF on concentrations of Angiopoietin-2 (Ang-2) and IL 8, two known pro-inflammatory markers involved in capillary leakage, as well as Ang-1 and IL 10, two anti-inflammatory mediators. Levels will be drawn prior to bypass, after MUF and at ICU admission.
  
  

• Biomarker correlation with patient outcome [ Time Frame: Duration of pediatric ICU admission, on average 7 days ] [ Designated as safety issue: No ]
  The biomarkers will be compared to the age of patient, type of surgery performed as well as to post procedure outcome measurements to see if specific protein levels correlate with patient outcomes.
  
  
• Pro- and anti-inflammatory protein presence in ultrafiltration fluid [ Time Frame: Upon MUF completion, on average 2 hours ] [ Designated as safety issue: No ]
  MUF fluid samples will be drawn following bypass. Ang-2, Ang-1, IL-8 and IL-10 levels will be measured to determine if present.
  
  

During cardiopulmonary bypass (CPB) for corrective or palliative congenital heart surgery, a child's blood is subjected to hemodilution, hypothermia, nonpulsatile blood flow and exposure to foreign and non-endothelialized surfaces. These non-physiologic conditions trigger the host's innate systemic inflammatory response which results in capillary leak, increased total body water and can lead to end organ dysfunction. Since the early 1990's, modified ultrafiltration (MUF) has been shown to decrease excess tissue edema, reduce postoperative bleeding, improve cardiac contractility, maintain hemodynamic stability, and decrease hospital length of stay. Angiopoietins are a family of vascular growth factors necessary for both normal and abnormal blood vessel formation and appear to play a role in capillary leak. Though MUF has been shown to improve clinical outcome following CPB, there continues to be conflicting reports whether this is a result of the filtration of inflammatory cytokines or simply excess fluid removal. Since angiopoietins appear to play a role in both inflammation and capillary leak, the investigators aim to determine whether MUF's clinical benefit is also secondary to its ability to filter out these molecules, more specifically angiopoietin-2.