Brusino F G, Reves J G, Smith L R, Prough D S, Stump D A, McIntyre R W
Department of Anesthesiology, Heart Center of Duke Hospital, Duke University Medical Center, Durham, NC 27710.
J Thorac Cardiovasc Surg. 1989 Apr;97(4):541-7.
Cerebral blood flow was measured in 20 patients by xenon 133 clearance methodology during nonpulsatile hypothermic cardiopulmonary bypass to determine the effect of age on regional cerebral blood flow during these conditions. Measurements of cerebral blood flow at varying perfusion pressures were made in patients arbitrarily divided into two age groups at nearly identical nasopharyngeal temperature, hematocrit value, and carbon dioxide tension and with equal cardiopulmonary bypass flows of 1.6 L/min/m2. The range of mean arterial pressure was 30 to 110 mm Hg for group I (less than or equal to 50 years of age) and 20 to 90 mm Hg for group II (greater than or equal to 65 years of age). There was no significant difference (p = 0.32) between the mean arterial pressure in group I (54 +/- 28 mm Hg) and that in group II (43 +/- 21 mm Hg). The range of cerebral blood flow was 14.8 to 29.2 ml/100 gm/min for group I and 13.8 to 37.5 ml/100 gm/min for group II. There was no significant difference (p = 0.37) between the mean cerebral blood flow in group I (21.5 +/- 4.6 ml/100 gm/min) and group II (24.3 +/- 8.1 ml/100 gm/min). There was a poor correlation between mean arterial pressure and cerebral blood flow in both groups: group I, r = 0.16 (p = 0.67); group II, r = 0.5 (p = 0.12). In 12 patients, a second cerebral blood flow measurements was taken to determine the effect of mean arterial pressure on cerebral blood flow in the individual patient. Changes in mean arterial pressure did not correlate with changes in cerebral blood flow (p less than 0.90). We conclude that age does not alter cerebral blood flow and that cerebral blood flow autoregulation is preserved in elderly patients during nonpulsatile hypothermic cardiopulmonary bypass.
采用氙133清除法对20例患者在非搏动性低温体外循环期间的脑血流量进行了测量，以确定年龄对这些情况下局部脑血流量的影响。在鼻咽温度、血细胞比容值和二氧化碳分压几乎相同且体外循环流量均为1.6L/min/m²的情况下，将患者任意分为两个年龄组，测量不同灌注压力下的脑血流量。第一组（年龄小于或等于50岁）的平均动脉压范围为30至110mmHg，第二组（年龄大于或等于65岁）为20至90mmHg。第一组的平均动脉压（54±28mmHg）与第二组（43±21mmHg）之间无显著差异（p = 0.32）。第一组的脑血流量范围为14.8至29.2ml/100g/min，第二组为13.8至37.5ml/100g/min。第一组的平均脑血流量（21.5±4.6ml/100g/min）与第二组（24.3±8.1ml/100g/min）之间无显著差异（p = 0.37）。两组中平均动脉压与脑血流量之间的相关性均较差：第一组，r = 0.16（p = 0.67）；第二组，r = 0.5（p = 0.12）。对12例患者进行了第二次脑血流量测量，以确定平均动脉压对个体患者脑血流量的影响。平均动脉压的变化与脑血流量的变化不相关（p＜0.90）。我们得出结论，年龄不会改变脑血流量，并且在非搏动性低温体外循环期间老年患者的脑血流量自动调节功能得以保留。
