Larsen F S, Hansen B A, Ejlersen E, Secher N H, Clemmesen J O, Tygstrup N, Knudsen G M
Department of Hepatology, Rigshospitalet, University of Copenhagen, Denmark.
Eur J Gastroenterol Hepatol. 1996 Mar;8(3):261-5. doi: 10.1097/00042737-199603000-00014.
The effect of high-volume plasmapheresis on hepatic encephalopathy, cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRO2) was investigated in patients with fulminant hepatic failure (FHF).
Twelve consecutive patients (8 women, 4 men, median age 34 years (range 19-51), were studied before and after high-volume plasmapheresis with 10-16 litres fresh frozen plasma, while PaCO2 and body temperature were maintained at 30 (23-34) mmHg and 37.6 degrees C (36.6-38.4), respectively. Blood samples from the internal jugular vein and a radial artery allowed calculation of the cerebral arteriovenous oxygen difference (AVDO2) and oxygen extraction (AVDO2 divided by arterial oxygen content). CBF was determined by a xenon-133 clearance method in eight patients and CMRO2 calculated as AVDO2 times CBF. Cerebral perfusion pressure (CPP) was determined as the difference between mean arterial and subdural pressures in eight patients.
High-volume plasmapheresis was initiated 22 (6-168) h after the development of hepatic encephalopathy and 11 patients had grade 4 encephalopathy. Following high-volume plasmapheresis the grade of encephalopathy improved in four patients. The CBF increased from a median of 31 (16-86) to 45 (18-97) ml/100 g/min and as oxygen extraction remained unchanged (32 (9-41) vs. 29 (7-39)%), CMRO2 increased from 1.24 (0.96-1.82) to 1.86 (1.00-2.07) ml/100 g/min (P < 0.05). The CPP increased from 62 (19-76) to 92 (50-105) mmHg (P < 0.01), whereas the intracranial pressure remained unchanged (19 (3-45) vs. 11 (5-33) mmHg). No statistical difference was found between the relative changes in the above parameters in survivors compared to non-survivors.
Although the clinical status did not improve in all patients, both CBF and CMRO2 increased after high-volume plasmapheresis. The alleviation of brain oxygen metabolism by high-volume plasmapheresis may reflect partial removal of neuroinhibitory plasma factors.
研究大量血浆置换对暴发性肝衰竭（FHF）患者肝性脑病、脑血流量（CBF）和脑氧代谢率（CMRO2）的影响。
连续12例患者（8例女性，4例男性，中位年龄34岁（范围19 - 51岁））在接受10 - 16升新鲜冰冻血浆进行大量血浆置换前后进行研究，同时将动脉血二氧化碳分压（PaCO2）和体温分别维持在30（23 - 34）mmHg和37.6℃（36.6 - 38.4）。采集颈内静脉和桡动脉血样，计算脑动静脉氧差（AVDO2）和氧摄取率（AVDO2除以动脉血氧含量）。8例患者采用氙-133清除法测定CBF，CMRO2计算为AVDO2乘以CBF。8例患者的脑灌注压（CPP）测定为平均动脉压与硬膜下压力之差。
在肝性脑病发生后22（6 - 168）小时开始进行大量血浆置换，11例患者为4级脑病。大量血浆置换后，4例患者的脑病分级有所改善。CBF从中位值31（16 - 86）增加到45（18 - 97）ml/100g/min，由于氧摄取率保持不变（32（9 - 41）%对29（7 - 39）%），CMRO2从1.24（0.96 - 1.82）增加到1.86（1.00 - 2.07）ml/100g/min（P < 0.05）。CPP从62（19 - 76）mmHg增加到92（50 - 105）mmHg（P < 0.01），而颅内压保持不变（19（3 - 45）mmHg对11（5 - 33）mmHg）。在幸存者与非幸存者之间，上述参数的相对变化未发现统计学差异。
尽管并非所有患者的临床状况都有所改善，但大量血浆置换后CBF和CMRO2均增加。大量血浆置换减轻脑氧代谢可能反映了神经抑制性血浆因子的部分清除。
