THE RELATIONSHIP BETWEEN INTELLIGENCE AND DURATION OF CIRCULATORY ARREST WITH DEEP HYPOTHERMIA

A total of 114 children (51 with tetralogy of Fallot, 30 with transpos ition of the great arteries, and 33 with ventricular septal defect) wh o had these defects repaired with the use of deep hypothermia and circ ulatory arrest were assessed for intellectual and neuropsychologic fun ction at an average of 9 to 10 years after the operation, Children wit h preoperative intellectual handicaps or postoperative neurologic comp lications 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 ave rage than those of the hypothermic circulatory arrest group, Although there was no significant difference in intelligence quotient between t he groups, a relationship between intelligence quotient and arrest tim e was found, Regression analysis of intelligence quotient against dura tion 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 q uotient points for each extra 10 minutes of arrest time, It appears th at 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 circulat ory arrest.