Measures to Lower the Stress Response in Pediatric Cardiac Surgery

• The use of Dexmedetomidine in addition to low dose narcotic will lower the stress response as effective as the high dose narcotic. [ Time Frame: stress hormones and cytokines levels will be measured at the following points; after induction, after sternotomy, after starting cardiopulmonary bypass, at the end of the procedure and 24 hours after the procedure ] [ Designated as safety issue: Yes ]
  
• Overall IQ score [ Time Frame: 1-4 yrs. post-surgery ] [ Designated as safety issue: No ]
  Overall IQ score from the assessment of cognitive ability, to determine if different anesthetic techniques during surgery for children with congenital heart disease result in differences in children's intellectual functioning.
  
  

• The use of dexmedetomidine in addition to low dose narcotic will allow early extubation after pediatric cardiac surgery. [ Time Frame: two years ] [ Designated as safety issue: Yes ]
  
• Cognitive factor scores [ Time Frame: 1-4 yrs post-surgery ] [ Designated as safety issue: No ]
  
• Overall measure of developmental status [ Time Frame: 1-4 yrs post-surgery ] [ Designated as safety issue: No ]
  
• A "total problems" score for emotional and behavioral adjustment. [ Time Frame: 1-4 yrs post-surgery ] [ Designated as safety issue: No ]
  

In this study, we aim to demonstrate comparatively that use of dexmedetomidine in addition to low dose narcotics reduces the stress response in cardiac surgical patients and results in less morbidity and mortality. Additionally, dexmedetomidine should facilitate safe early extubation in pediatric cardiac patients, which results in decreased ventilator associated co-morbidities. Patients will be randomly assigned to three groups; one group will receive low dose fentanyl, one will receive low dose fentanyl with dexmedetomidine, and one will receive high dose fentanyl. Blood samples will be collected post-induction, post-sternotomy, after going on cardiopulmonary bypass, at the completion of surgery, and post-operatively to determine the patients' stress hormone levels. The patients will receive standard post-operative care, and clinical data collected as part of this care will be used to determine the incidence of morbidity and mortality. The results of the blood tests will be correlated with the incidence of morbidity and mortality to demonstrate the relative effectiveness of the different anesthesia methods.

Blood samples will be analyzed for the presence of the stress hormones cortisol, epinephrine, norepinephrine, ACTH, Interleukin 8, TNF-alpha, and nitrated albumin. Arterial blood gas, glucose and lactate levels, heart rate, blood pressure, use of vasoactive support, length of ventilator use, post-operative mortality, post-operative morbidity, length of ICU stay, and length of hospital stay will be recorded.

Children previously enrolled in the surgery study will complete assessments of their cognitive ability, developmental status, and emotional and behavioral adjustment. For the neuro-developmental outcome follow up, Children's cognitive ability will be assessed using the Stanford-Binet Intelligence Scales, 5th Edition (SB5). The SB5 is a widely-used measure of intellectual functioning that is normed for ages 2 and up. The test takes 30-50 minutes to administer to young children, and provides an overall IQ score, as well as scores for five primary factors of cognitive ability: Fluid Reasoning, Knowledge, Quantitative Reasoning, Visual-Spatial Processing; and Working Memory. The SB5 has demonstrated excellent reliability and validity.