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The relationship between intelligence and duration of circulatory arrest with deep hypothermia
R K Oates1, J M Simpson, J A Turnbull
1University of Sydney, Australia.
Insights
Deep hypothermia with circulatory arrest for pediatric cardiac surgery may impact long-term neurodevelopment. Longer arrest times correlate with lower intelligence quotients in children, suggesting incomplete brain protection.
Area of Science:
- Pediatric Cardiac Surgery
- Neurodevelopmental Outcomes
- Hypothermia Research
Background:
- Congenital heart defects necessitate complex surgical interventions in children.
- Deep hypothermia and circulatory arrest (DHCA) is a technique used during these surgeries.
- Long-term neurodevelopmental effects of DHCA require further investigation.
Purpose of the Study:
- To assess intellectual and neuropsychologic function in children years after cardiac repair using DHCA.
- To compare neurodevelopmental outcomes between children who underwent DHCA and those treated with cardiopulmonary bypass (CPB).
- To investigate the relationship between DHCA duration and cognitive function.
Main Methods:
- Retrospective analysis of 114 children undergoing cardiac repair with DHCA (tetralogy of Fallot, transposition of great arteries, ventricular septal defect).
- Exclusion of children with pre-existing intellectual handicaps or post-operative neurological complications.
- Comparison group of 54 children with atrial septal defects repaired using CPB.
- Neuropsychologic testing conducted 9-10 years post-operation.
Main Results:
- No significant difference in intelligence quotient (IQ) between DHCA and CPB groups.
- DHCA group exhibited significantly longer reaction times (2-3 seconds) compared to the CPB group.
- A significant inverse linear relationship found between DHCA duration and IQ (slope = -0.36, p = 0.002).
- Each 10-minute increase in arrest time was associated with a 3-4 point decrease in IQ.
Conclusions:
- Deep hypothermia with circulatory arrest may not fully protect the pediatric brain during cardiac surgery.
- Longer durations of circulatory arrest are associated with measurable declines in intellectual function.
- Further research is warranted to optimize brain protection strategies during pediatric cardiac operations involving DHCA.
Abstract:
A total of 114 children (51 with tetralogy of Fallot, 30 with transposition of the great arteries, and 33 with ventricular septal defect) who had these defects repaired with the use of deep hypothermia and circulatory arrest were assessed for intellectual and neuropsychologic function at an average of 9 to 10 years after the operation. Children with preoperative intellectual handicaps or postoperative neurologic complications were excluded. These children were compared with 54 who had atrial septal defects repaired with the use of cardiopulmonary bypass. The only significant difference in the neuropsychologic measures was that the bypass group had reaction times 2 to 3 seconds shorter on average than those of the hypothermic circulatory arrest group. Although there was no significant difference in intelligence quotient between the groups, a relationship between intelligence quotient and arrest time was found. Regression analysis of intelligence quotient against duration of arrest showed a significant decrease in intelligence quotient with increasing arrest time (slope = -0.36; p = 0.002; 95% confidence interval, -0.59, -0.14) indicating a decrease of 3 to 4 intelligence quotient points for each extra 10 minutes of arrest time. It appears that deep hypothermia with circulatory arrest for cardiac operations in children does not fully protect the brain, with a linear relationship existing between the amount of impairment and the duration of circulatory arrest.