Goplerud J M, Wagerle L C, Delivoria-Papadopoulos M
Division of Neonatal-Perinatal Medicine, Hospital of the University of Pennsylvania, Philadelphia 19104.
J Appl Physiol (1985). 1989 Jun;66(6):2827-32. doi: 10.1152/jappl.1989.66.6.2827.
The hemodynamic response during and after acute asphyxia was studied in 14 newborn piglets. An apnea-like asphyxial insult was produced in paralyzed mechanically ventilated piglets by discontinuing ventilation until the piglets became bradycardic (heart rate less than 80 beats/min). Seven piglets had organ blood flow measured by microspheres at control, during asphyxia (PO2 = 16 +/- 11 Torr, pH = 7.31 +/- 0.07, PCO2 = 47 +/- 9 Torr), and during recovery from asphyxia. During acute asphyxia, rapid organ blood flow redistribution occurred, producing decreased renal and skeletal muscle blood flow, while coronary blood flow increased. Although total brain blood flow changed little during asphyxia, regional cerebral blood flow (rCBF) analysis revealed significant nonhomogeneous blood flow distribution within the brain during asphyxia, with decreases to the cerebral gray and white matter and the choroid plexus, whereas brain stem structures had increased flow. During recovery with reventilation, total brain blood flow increased 24% above control, with a more uniform distribution and increased flow to all brain regions. The time course of rCBF changes during acute asphyxia was then determined in seven additional piglets with CBF measurements made sequentially at 30-60 s, 60-120 s, and 120-180 s of asphyxia. The vasoconstriction seen in cortical structures, concurrent with the reduction in skeletal and kidney blood flow, known to be sympathetically mediated, suggest a selective reflex effect in this brain region. The more gradual and progressive vasodilation in brain stem regions during asphyxia is consistent with chemical control. These findings demonstrate significant regional heterogeneity in CBF regulation in newborn piglets.
对14只新生仔猪在急性窒息期间及之后的血流动力学反应进行了研究。在机械通气的瘫痪仔猪中，通过停止通气制造类似呼吸暂停的窒息损伤，直至仔猪心率减慢（心率低于80次/分钟）。7只仔猪在对照期、窒息期间（PO2 = 16±11托，pH = 7.31±0.07，PCO2 = 47±9托）以及窒息恢复期间，通过微球测量器官血流。在急性窒息期间，器官血流迅速重新分布，导致肾和骨骼肌血流减少，而冠状动脉血流增加。尽管窒息期间全脑血流量变化不大，但局部脑血流量（rCBF）分析显示，窒息期间脑内血流分布存在显著的不均匀性，脑灰质、白质和脉络丛血流量减少，而脑干结构血流量增加。恢复通气后，全脑血流量比对照期增加24%，分布更均匀，所有脑区血流量均增加。然后，在另外7只仔猪中确定急性窒息期间rCBF变化的时间过程，在窒息30 - 60秒、60 - 120秒和120 - 180秒时依次测量CBF。皮质结构中出现的血管收缩，与已知由交感神经介导的骨骼肌和肾脏血流减少同时发生，提示该脑区存在选择性反射效应。窒息期间脑干区域更渐进性的血管舒张与化学控制一致。这些发现表明新生仔猪CBF调节存在显著的区域异质性。
