Ley David, Oskarsson Gylfi, Bellander Mikael, Hernandez-Andrade Edgar, Lingman Göran, Marsal Karel, Olsson Tomas, Pesonen Erkki, Thorngren-Jerneck Kristina, Werner Olof, Hellström-Westas Lena
Department of Pediatrics, Lunds University Hospital, 221 85 Lund, Sweden.
Pediatr Res. 2004 Apr;55(4):568-75. doi: 10.1203/01.PDR.0000113785.66455.E7. Epub 2004 Jan 22.
Type and duration of fetal asphyxial insult affect the distribution of blood flow to the heart and brain. The purpose of this study was to describe dynamic and quantitative changes in regional myocardial and cerebral blood flow (CBF) during fetal asphyxia induced by total occlusion of the umbilical cord. Eleven exteriorized fetal sheep were subjected to total umbilical cord occlusion and five fetal sheep served as sham controls. Regional blood flow (BF) to the brain and heart was quantified using radioactive microspheres before and after 5 min of occlusion and finally when fetal mean arterial blood pressure had decreased below 25 mm Hg, 9.8 (0.8) [mean (SD)] min after occlusion. Right coronary arterial (RCA) blood flow velocity and carotid BF were registered continuously. Mean values of arterial pH and oxygen content (mL O(2)/100 mL) were 7.08 (0.11) and 4.4 (2.9) before cord occlusion and decreased to 6.83 (0.05) and 1.4 (0.9) at 5 min after occlusion (p < 0.01, respectively). Carotid BF was significantly below preocclusion values by 2.5 min (p < 0.05), whereas RCA velocity time integral per minute remained above preocclusion values for 9 min. CBF decreased from 316 (24) before cord occlusion to 156 (30) mL/min/100 g at 5 min (p < 0.01), whereas right myocardial BF was maintained at 792 (125) and 751 (183) mL/min/100 g, respectively. CBF decreased rapidly after total cord occlusion whereas myocardial BF increased and was maintained until shortly before cardiac arrest, suggesting the myocardium to be better preserved during this type of insult in already partially asphyxiated fetuses.
胎儿窒息损伤的类型和持续时间会影响心脏和大脑的血流分布。本研究的目的是描述在脐带完全闭塞诱导的胎儿窒息期间，局部心肌和脑血流（CBF）的动态和定量变化。11只体外化的胎羊接受了脐带完全闭塞，5只胎羊作为假手术对照。在闭塞5分钟前后以及最终在胎儿平均动脉血压降至25 mmHg以下时（闭塞后9.8（0.8）[平均值（标准差）]分钟），使用放射性微球对大脑和心脏的局部血流（BF）进行定量。连续记录右冠状动脉（RCA）血流速度和颈动脉BF。脐带闭塞前动脉pH值和氧含量（mL O₂/100 mL）的平均值分别为7.08（0.11）和4.4（2.9），闭塞后5分钟降至6.83（0.05）和1.4（0.9）（p均<0.01）。颈动脉BF在闭塞2.5分钟时显著低于闭塞前值（p<0.05），而RCA每分钟速度时间积分在9分钟内仍高于闭塞前值。CBF从脐带闭塞前的316（24）降至闭塞5分钟时的156（30）mL/分钟/100 g（p<0.01），而右心肌BF分别维持在792（125）和751（183）mL/分钟/100 g。脐带完全闭塞后CBF迅速下降，而心肌BF增加并维持到心脏骤停前不久，这表明在这种类型的损伤中，对于已经部分窒息的胎儿，心肌得到了更好的保护。
