Hillier S C, Burrows F A, Bissonnette B, Taylor R H
Department of Anaesthesia, Pediatrics Hospital for Sick Children, Toronto, Ontario, Canada.
Anesth Analg. 1991 Jun;72(6):723-8. doi: 10.1213/00000539-199106000-00001.
Profound hypothermic circulatory arrest (PHCA) is followed by a transient period of increased intracranial pressure and a longer period of neurophysiologic dysfunction. To investigate the effect of cardiopulmonary bypass (CPB) with PHCA on cerebral hemodynamics, we used transcranial Doppler sonography to measure cerebral blood flow velocity in 10 neonates and infants before and after PHCA. Cerebral blood flow velocity was compared before and after PHCA during normothermic cardiopulmonary bypass at the same mean arterial pressure, central venous pressure, hematocrit, and arterial carbon dioxide tension. Cerebral blood flow velocity decreased exponentially with decreasing nasopharyngeal temperature before PHCA (P less than 0.05) and remained decreased after PHCA during normothermic CPB, compared with values for normothermic CPB before PHCA (P less than 0.005). During normothermic CPB after PHCA, the modified cerebral vascular resistance (mm Hg.cm.s-1) was increased above values for normothermic CPB before PHCA (P less than 0.05). The results of this study suggest that the observed increase in intracranial pressure during PHCA is not caused by increased cerebral perfusion, but rather that cerebral perfusion is reduced in response to a decreased demand for cerebral metabolic oxygen.
深度低温循环停止（PHCA）之后会出现一段短暂的颅内压升高期以及一段更长的神经生理功能障碍期。为了研究伴有PHCA的体外循环（CPB）对脑血流动力学的影响，我们使用经颅多普勒超声在10例新生儿和婴儿的PHCA前后测量脑血流速度。在相同的平均动脉压、中心静脉压、血细胞比容和动脉二氧化碳分压下，比较了常体温体外循环期间PHCA前后的脑血流速度。在PHCA前，脑血流速度随着鼻咽温度的降低呈指数下降（P<0.05），并且在常体温CPB期间PHCA后仍保持下降，与PHCA前常体温CPB的值相比（P<0.005）。在PHCA后的常体温CPB期间，改良脑血管阻力（mmHg.cm.s-1）高于PHCA前常体温CPB的值（P<0.05）。本研究结果表明，PHCA期间观察到的颅内压升高并非由脑灌注增加所致，而是由于对脑代谢氧需求减少导致脑灌注降低。
