Rennie J M
Department of Paediatrics, University of Cambridge.
Arch Dis Child. 1989 Jul;64(7 Spec No):897-901. doi: 10.1136/adc.64.7_spec_no.897.
The variability of cerebral blood flow velocity was measured in 20 very low birthweight infants. The area under the curve of the Doppler frequency spectrum was used and was obtained from the anterior cerebral artery in the infants before and after infusions of plasma or dopamine. Both interventions significantly reduced the variability without a demonstrable effect on cardiac output, heart rate, or cerebral blood flow velocity. The reduction was from a median of 13% to 5% after plasma and from 13% to 4% after dopamine. The effect was probably due to an increase in circulating blood volume. It is proposed that appreciable variations in systolic blood pressure occurring in phase with respiration indicate a low central venous pressure in infants, as in adults and animals. The variations could be transmitted to the cerebral circulation in the absence of autoregulation, and their detection in either the aorta or a cerebral artery may prove a useful index of hypovolaemia.
对20名极低出生体重儿的脑血流速度变异性进行了测量。采用多普勒频谱曲线下面积，该面积取自婴儿输注血浆或多巴胺前后的大脑前动脉。两种干预措施均显著降低了变异性，而对心输出量、心率或脑血流速度无明显影响。血浆输注后变异性从中位数13%降至5%，多巴胺输注后从13%降至4%。这种效应可能是由于循环血容量增加所致。有人提出，与呼吸同步出现的收缩压明显变化表明婴儿中心静脉压较低，如同成人和动物一样。在缺乏自动调节的情况下，这些变化可能会传递至脑循环，在主动脉或脑动脉中检测到这些变化可能是低血容量的一个有用指标。
