Abstract
Effects of hypothermic circulatiory arrest on brain morphology were evaluted by computed tomography(CT). Three of 24 patients(12.3±6.1 months)undergoing deep hypothermic open heart surgery with circulatory arrest showed worsening in CT scans performed 38±18 days postoperatively when the patients Were totally free from fluid restriction and administration of cardiotonics or diuretics. None of them had clinical symptoms and signs of neurologic disorders. In those 3 patients, the nasopharyngeal-rectal temperature gradients, blood pressure, PaO2 and and PaCO2 during surface and perfusion cooling were not significantly different from those in the other patients. Also, in those 3 patients, the lowest nasopharyngeal temperature and the length of perfusion using membrane oxygenator and 20μ filter in the arterial line were not significantly deifferent from those in the unaffected patients. However, the duration of total circulatory arrest (60.3±8.1minutes)was significantly longer than that in the unaffected patients(45.4±9.8 minutes) (p<0.01). Serial CT scans in those 3 patients showed full recovery to the preoperative level by 12 months postoperatively. We advise not to extend the circulatory arrest time beyond 60 minutes(to be more secure 50 minutes)to prevent possible occurrence of clinically undetectable brain disorder even at the temperatures of 16-18℃.
