Faxelius G, Lagercrantz H, Yao A
J Pediatr. 1984 Jul;105(1):144-8. doi: 10.1016/s0022-3476(84)80381-9.
The possible influence of sympathoadrenal activity on peripheral blood flow was studied. Limb blood flow was measured with venous occlusion plethysmography at 30 minutes, 2 hours, and 24 hours after birth in 24 healthy, full-term infants, of whom 14 were delivered by elective cesarean section. Mean arterial pressure was simultaneously measured noninvasively, and peripheral vascular resistance calculated. Umbilical artery blood at birth and peripheral venous blood at 2 and 24 hours were analyzed for concentrations of catecholamines and hematocrit. The limb blood flow was significantly lower at 30 minutes in the vaginally delivered infants compared with those delivered by cesarean section. There was a gradual increase in limb blood flow over the 24 hours in those delivered vaginally, whereas in the section group only small changes were observed. The peripheral vascular resistance was higher both at 30 minutes and at 2 hours in those delivered vaginally, which corresponded to the higher catecholamine concentrations at birth and at 2 hours in this group. Two hours after birth there was a significant correlation between noradrenaline levels and peripheral vascular resistance. The results indicate that the sympathoadrenal system influences peripheral circulation at birth and is important in the circulatory adaptation of the newborn infant.
研究了交感肾上腺活动对外周血流的可能影响。对24名健康足月婴儿在出生后30分钟、2小时和24小时时用静脉阻断体积描记法测量肢体血流，其中14名婴儿通过择期剖宫产分娩。同时无创测量平均动脉压，并计算外周血管阻力。分析出生时脐动脉血以及2小时和24小时时外周静脉血中的儿茶酚胺浓度和血细胞比容。与剖宫产分娩的婴儿相比，经阴道分娩的婴儿在30分钟时肢体血流显著较低。经阴道分娩的婴儿在24小时内肢体血流逐渐增加，而剖宫产组仅观察到微小变化。经阴道分娩的婴儿在30分钟和2小时时外周血管阻力均较高，这与该组出生时和2小时时较高的儿茶酚胺浓度相对应。出生后两小时，去甲肾上腺素水平与外周血管阻力之间存在显著相关性。结果表明，交感肾上腺系统在出生时影响外周循环，并且在新生儿的循环适应中起重要作用。
