Samnegård H, Carlens P
Scand J Thorac Cardiovasc Surg. 1975;9(3):220-8. doi: 10.3109/14017437509138643.
The effect of physical exercise on internal carotid artery (ICA) blood flow in conscious man was studied with the aid of electromagnetic flowmetry. A flow probe was implanted on the ICA in 25 patients after reconstruction of the artery. ICA mean blood flow and brachial artery mean blood pressure were continuously monitored in supine (25 patients) and sitting (24 patients) position at rest, during 5-6 minutes exercise on a bicycle ergometer and at rest after exercise. Arterial carbon dioxide tension (PaCO2) was studied in 6/25 work tests in supine and 7/24 in sitting position. Cardiac output was measured at rest and during exercise in 10/25 patients in supine and 8/24 patients in sitting position. In the supine group, ICA flow increased significantly within 1 minute and reached a maximal flow 15% above control flow within 2 minutes after the onset of exercise. The ICA flow then gradually declined, but remained almost significantly elevated, 7.5% above control, on termination of exercise. At rest, after exercise, the ICA flow decreased almost significantly to a level of 5% below the control flow within 5 minutes. There was a significant PaCO2 increase of 2.6 mmHg during exercise and a highly significant increase (72%) in cardiac output during exercise. The ICA flow at rest, before exercise, was about 15% lower in the sitting group than in the supine group. It increased in average 11.5% with 2 minutes of exercise and then gradually diminished. At rest, after exercise, ICA flow decreased further to a level of 8% below control flow within 5 minutes. PaCO2 increased significantly in average 1.6 mmHg during exercise. Cardiac output increased highly significantly (85%) during exercise. The ICA flow changes obtained during exercise in the present study indicate the presence of a regulatory mechanism counteracting the increasing perfusion pressure, but it is unable to compensate the decreased perfusion pressure when the body position was altered from supine to sitting. The cerebral vascular bed in the present patient material seems to operate above and below the lower limit of its pressure range for an adequate autoregulation.
借助电磁血流测定法，研究了体育锻炼对清醒男性颈内动脉（ICA）血流的影响。在25例患者动脉重建后，将血流探头植入颈内动脉。在静息仰卧位（25例患者）和坐位（24例患者）、在自行车测力计上进行5 - 6分钟运动期间以及运动后静息时，持续监测颈内动脉平均血流和肱动脉平均血压。在仰卧位的25例工作测试中的6例以及坐位的24例中的7例中研究了动脉二氧化碳分压（PaCO2）。在静息时和运动期间，对仰卧位的25例患者中的10例以及坐位的24例患者中的8例测量心输出量。在仰卧位组中，运动开始后1分钟内颈内动脉血流显著增加，运动开始后2分钟内达到比对照血流高15%的最大血流。然后颈内动脉血流逐渐下降，但在运动结束时仍几乎显著升高，比对照高7.5%。运动后静息时，颈内动脉血流在5分钟内几乎显著下降至比对照血流低5%的水平。运动期间PaCO2显著增加2.6 mmHg，运动期间心输出量高度显著增加（72%）。在运动前静息时，坐位组的颈内动脉血流比仰卧位组低约15%。运动2分钟后平均增加11.5%，然后逐渐减少。运动后静息时，颈内动脉血流在5分钟内进一步下降至比对照血流低8%的水平。运动期间PaCO2平均显著增加1.6 mmHg。运动期间心输出量高度显著增加（85%）。本研究中运动期间获得的颈内动脉血流变化表明存在一种调节机制，可抵消灌注压力的增加，但当身体姿势从仰卧位改变为坐位时，它无法补偿灌注压力的降低。本患者材料中的脑血管床似乎在其压力范围下限之上和之下运行，以实现充分的自动调节。
