Qi Huaying, Wan Chenguang, Feng Xuequan, Li Mu, Chen Li, Wang Yongqiang, Shi Yuan, Liu Lei, Shen Zhongyang
Department of Neurosurgery, Tianjin First Center Hospital, Tianjin 300192, China (Qi HY, Wan CG, Feng XQ, Li M); Department of Clinical Laboratory, Tianjin First Center Hospital, Tianjin 300192, China (Chen L); Department of Critical Care Medicine, Tianjin First Center Hospital, Tianjin 300192, China (Wang YQ); Department of Transplantation Center, Tianjin First Center Hospital, Tianjin 300192, China (Shi Y, Liu L, Shen ZY). Corresponding author: Feng Xuequan, Email:
Zhonghua Wei Zhong Bing Ji Jiu Yi Xue. 2017 Jul;29(7):640-643. doi: 10.3760/cma.j.issn.2095-4352.2017.07.014.
To reproduce a stable animal model of brain death in pigs, observe the change regularity of cerebral oxygen metabolism during the process of brain death, and to evaluate the significance and value of cerebral oxygen metabolism parameters for the diagnosis of brain death.
Twelve landrace pigs were used to create the brain death models using modified method of increasing epidural intracranial pressure (ICP). The mean arterial pressure (MAP) and ICP were monitored continuously during the process. The pigs were divided into four groups according to cerebral perfusion pressure (CPP) decreasing degree during brain death, namely CPP normal group and CPP decreasing 0%-30%, 30%-70%, and 70%-100% groups. Blood gas analysis of the external carotid artery and internal jugular vein were monitored discontinuously. The changes in cerebral oxygen metabolism parameters, including external carotid artery-internal jugular vein bulb oxygen content difference (AJDO), internal jugular bulb-external carotid artery carbon dioxide partial pressure difference (DPCO) and DPCO/AJDO ratio, were observed.
Brain death model were successfully reproduced in 12 experimental pigs. With MAP and ICP monitoring, the models at different stages of CPP could be repeatedly induced. The levels of AJDO and DPCO were increased gradually and then decreased, while the ratio of DPCO/AJDO was constantly increased with the decrease of CPP. The level of AJDO in CPP decreasing 0%-30% group was significantly higher than that in CPP normal group [(5.86±1.21)% vs. (3.92±0.64)%], the levels of DPCO in CPP decreasing 0%-30% and CPP decreasing 30%-70% groups were significantly higher than those in CPP normal group [mmHg (1 mmHg = 0.133 kPa): 10.33±1.83, 11.48±2.32 vs. 6.11±1.43], and the ratios of DPCO/AJDO in CPP decreasing 30%-70% and CPP decreasing 70%-100% groups were significantly higher than those in CPP normal group and CPP decreasing 0%-30% group (2.81±0.53, 4.12±1.07 vs. 1.57±0.64, 1.62±0.81). All the differences above were statistically significant (all P < 0.05).
With the decrease of CPP, cerebral oxygen metabolism showed a regular change during brain death. DPCO combined with DPCO/AJDO is a reliable blood gas analysis index indicating intracranial hypoperfusion, which has certain reference value for the determination of brain death.
建立稳定的猪脑死亡动物模型，观察脑死亡过程中脑氧代谢的变化规律，评估脑氧代谢参数对脑死亡诊断的意义和价值。
采用改良的硬膜外颅内压（ICP）增高法，用12头长白猪建立脑死亡模型。在模型建立过程中持续监测平均动脉压（MAP）和ICP。根据脑死亡过程中脑灌注压（CPP）的下降程度将猪分为四组，即CPP正常组、CPP下降0% - 30%组、CPP下降30% - 70%组和CPP下降70% - 100%组。间断监测颈外动脉和颈内静脉血气分析。观察脑氧代谢参数的变化，包括颈外动脉 - 颈内静脉球部氧含量差（AJDO）、颈内静脉球部 - 颈外动脉二氧化碳分压差值（DPCO）及DPCO/AJDO比值。
12只实验猪均成功建立脑死亡模型。通过MAP和ICP监测，可重复诱导出不同CPP阶段的模型。AJDO和DPCO水平先逐渐升高后下降，而DPCO/AJDO比值随CPP降低不断升高。CPP下降0% - 30%组的AJDO水平显著高于CPP正常组[（5.86±1.21）% vs. （3.92±0.64）%]，CPP下降0% - 30%组和CPP下降30% - 70%组的DPCO水平显著高于CPP正常组[mmHg（1 mmHg = 0.133 kPa）：10.33±1.83，11.48±2.32 vs. 6.11±1.43]，CPP下降30% - 70%组和CPP下降70% - 100%组的DPCO/AJDO比值显著高于CPP正常组和CPP下降0% - 30%组（2.81±0.53，4.12±1.07 vs. 1.57±0.64，1.62±0.81）。以上差异均有统计学意义（均P < 0.05）。
随着CPP降低，脑死亡过程中脑氧代谢呈现规律性变化。DPCO联合DPCO/AJDO是反映颅内低灌注的可靠血气分析指标，对脑死亡的判定有一定参考价值。
