[The changes on cerebral hemodynamics during selective cerebral perfusion cooling].
We studied the influence on cerebral hemodynamics with 10 pigs, weighing 25 to 30 kg, when the temperature of perfusion blood changed in both rapid cooling and rewarming, and in slow them. As for the protocol of temperature, we decided that rapid change was the large temperature gradient of more than 0.5 degree C/min, and slow change was the small gradient of less than 0.3 degree C/min. Cardiopulmonary bypass (CPB) was established with a flow rate of 60 ml/kg/min, and core cooling was performed until the temperature of the returned blood from internal jugular vein reached 25 degrees C/min. For selective cerebral perfusion (SCP), blood was infused into aortic arch with the clamp of descending aorta at the temperature of less than 20 degrees C. We measured regional tissue cerebral blood flow (TCBF), intracranial pressure (ICP), carotid arterial flow (CAF), and carotid arterial pressure (CAP), and PCO2 in both CPB and SCP. Rapid cooling during CPB caused an elevation in CAP, and marked decrease in CAF, ICP, and PCO2. In contrast, rapid rewarming caused the significant increase in CAF, ICP. Slow change did not cause marked difference in CAP, CAF, and ICP, and PCO2. Moreover, TCBF was not significant in both rapid and slow changes. On the other hand, rapid change in SCP caused a significant decrease in CAP, significant difference in CAF, ICP. Slow change did not cause significant difference in them as same as in CPB. In conclusion, we presume that the influence on cerebral hemodynamics is less in slow cooling and rewarming than in rapid changes.
Moro
H
H
Second Department of Surgery, Niigata University School of Medicine, Japan.
Ohzeki
H
H
Okazaki
H
H
Nakazawa
S
S
Takahashi
Y
Y
Hayashi
J
J
Miyamura
H
H
Eguchi
S
S
D000818:Animals; D002315:Cardiopulmonary Bypass; D002560:Cerebrovascular Circulation; D006439:Hemodynamics; D007036:Hypothermia, Induced; D007427:Intracranial Pressure; D010477:Perfusion / Q000379:methods; D013552:Swine