Björkman S Tracey, Foster Kelley A, O'driscoll Stephanie M, Healy Genevieve N, Lingwood Barbara E, Burke Chris, Colditz Paul B
Perinatal Research Centre, Royal Brisbane and Women's Hospital, University of Queensland, Brisbane 4029, Australia.
Brain Res. 2006 Jul 19;1100(1):110-7. doi: 10.1016/j.brainres.2006.04.119. Epub 2006 Jun 12.
A comparison of a constant (continuous delivery of 4% FiO2) and a variable (initial 5% FiO2 with adjustments to induce low amplitude EEG (LAEEG) and hypotension) hypoxic/ischemic insult was performed to determine which insult was more effective in producing a consistent degree of survivable neuropathological damage in a newborn piglet model of perinatal asphyxia. We also examined which physiological responses contributed to this outcome. Thirty-nine 1-day-old piglets were subjected to either a constant hypoxic/ischemic insult of 30- to 37-min duration or a variable hypoxic/ischemic insult of 30-min low peak amplitude EEG (LAEEG <5 microV) including 10 min of low mean arterial blood pressure (MABP <70% of baseline). Control animals (n = 6) received 21% FiO2 for the duration of the experiment. At 72 h, the piglets were euthanased, their brains removed and fixed in 4% paraformaldehyde and assessed for hypoxic/ischemic injury by histological analysis. Based on neuropathology scores, piglets were grouped as undamaged or damaged; piglets that did not survive to 72 h were grouped separately as dead. The variable insult resulted in a greater number of piglets with neuropathological damage (undamaged = 12.5%, damaged = 68.75%, dead = 18.75%) while the constant insult resulted in a large proportion of undamaged piglets (undamaged = 50%, damaged = 22.2%, dead = 27.8%). A hypoxic insult varied to maintain peak amplitude EEG <5 microV results in a greater number of survivors with a consistent degree of neuropathological damage than a constant hypoxic insult. Physiological variables MABP, LAEEG, pH and arterial base excess were found to be significantly associated with neuropathological outcome.
对持续性（持续输送4%的吸入氧分数）和变量性（初始5%的吸入氧分数，并进行调整以诱导低振幅脑电图（LAEEG）和低血压）缺氧/缺血性损伤进行了比较，以确定在围产期窒息的新生仔猪模型中，哪种损伤在产生一致程度的可存活神经病理损伤方面更有效。我们还研究了哪些生理反应促成了这一结果。39只1日龄仔猪接受了持续30至37分钟的持续性缺氧/缺血性损伤，或接受了30分钟的低峰值振幅脑电图（LAEEG<5微伏）的变量性缺氧/缺血性损伤，包括10分钟的低平均动脉血压（平均动脉压<基线的70%）。对照动物（n = 6）在实验期间接受21%的吸入氧分数。在72小时时，对仔猪实施安乐死，取出它们的大脑，固定在4%的多聚甲醛中，并通过组织学分析评估缺氧/缺血性损伤。根据神经病理学评分，仔猪被分为未受损或受损；未存活至72小时的仔猪被单独归为死亡。变量性损伤导致更多仔猪出现神经病理损伤（未受损=12.5%，受损=68.75%，死亡=18.75%），而持续性损伤导致很大比例的仔猪未受损（未受损=50%，受损=22.2%，死亡=27.8%）。与持续性缺氧损伤相比，为维持峰值振幅脑电图<5微伏而变化的缺氧损伤导致更多具有一致程度神经病理损伤的存活者。发现生理变量平均动脉压、LAEEG、pH和动脉碱剩余与神经病理结果显著相关。
