Kern F H, Ungerleider R M, Quill T J, Baldwin B, White W D, Reves J G, Greeley W J
Department of Anesthesiology, Duke University Medical Center, Durham, N.C.
J Thorac Cardiovasc Surg. 1991 Apr;101(4):618-22.
We examined the relationship of changes in partial pressure of carbon dioxide on cerebral blood flow responsiveness in 20 pediatric patients undergoing hypothermic cardiopulmonary bypass. Cerebral blood flow was measured during steady-state hypothermic cardiopulmonary bypass with the use of xenon 133 clearance methodology at two different arterial carbon dioxide tensions. During these measurements there was no significant change in mean arterial pressure, nasopharyngeal temperature, pump flow rate, or hematocrit value. Cerebral blood flow was found to be significantly greater at higher arterial carbon dioxide tensions (p less than 0.01), so that for every millimeter of mercury rise in arterial carbon dioxide tension there was a 1.2 ml.100 gm-1.min-1 increase in cerebral blood flow. Two factors, deep hypothermia (18 degrees to 22 degrees C) and reduced age (less than 1 year), diminished the effect carbon dioxide had on cerebral blood flow responsiveness but did not eliminate it. We conclude that cerebral blood flow remains responsive to changes in arterial carbon dioxide tension during hypothermic cardiopulmonary bypass in infants and children; that is, increasing arterial carbon dioxide tension will independently increase cerebral blood flow.
我们研究了20例接受低温体外循环的儿科患者中二氧化碳分压变化与脑血流反应性之间的关系。在低温体外循环稳态期间，采用氙133清除法在两种不同的动脉二氧化碳张力下测量脑血流。在这些测量过程中，平均动脉压、鼻咽温度、泵流速或血细胞比容值均无显著变化。发现在较高的动脉二氧化碳张力下脑血流显著增加（p小于0.01），因此动脉二氧化碳张力每升高1毫米汞柱，脑血流增加1.2 ml·100 gm-1·min-1。两个因素，即深度低温（18摄氏度至22摄氏度）和年龄较小（小于1岁），减弱了二氧化碳对脑血流反应性的影响，但并未消除这种影响。我们得出结论，在婴儿和儿童的低温体外循环期间，脑血流对动脉二氧化碳张力的变化仍有反应；也就是说，动脉二氧化碳张力升高将独立增加脑血流。
