Sekhon Mypinder S, Griesdale Donald E, Czosnyka Marek, Donnelly Joseph, Liu Xia, Aries Marcel J, Robba Chiara, Lavinio Andrea, Menon David K, Smielewski Peter, Gupta Arun K
Division of Critical Care Medicine, Department of Medicine, Vancouver General Hospital, University of British Columbia, West 12th Avenue, Vancouver, BC, V5Z 1M9, Canada,
Neurocrit Care. 2015 Oct;23(2):210-6. doi: 10.1007/s12028-015-0141-x.
Red blood cell (RBC) transfusion is associated with inconsistent changes in brain tissue oxygenation (PbO2). Previous studies have failed to consider alterations in cerebral autoregulation. Our objective was to investigate the effect of RBC transfusion on cerebral autoregulation, as measured by pressure reactivity index (PRx).
Retrospective analysis of 28 severe traumatic brain injury (TBI) patients from a prospective registry between 2007 and 2014. We recorded hemoglobin (Hb) concentration, intracranial pressure, PbO2, cerebral perfusion pressure, PRx, and cerebral lactate/pyruvate ratio for 6 h before and after RBC transfusion. We also recorded body temperature, PaO2, PCO2, pH, and fraction of inspired oxygen. Subgroups of normoxia (PbO2 >20 mmHg) and hypoxia (PbO2 <20 mmHg) prior to transfusion were defined a priori.
The median age was 36 years [interquartile range (IQR) 27-49], 32% were female. The median admission Glasgow Coma score was 5 (IQR 4-9) and injury severity score was 16 (IQR 9-21). Overall, mean Hb concentration [80 g/L (SD 7) to 89 g/L (SD 8), p < 0.001] and PbO2 increased [23.5 mmHg (SD 8) to 25.0 mmHg (SD 9), p = 0.033] following transfusion. PRx increased post-transfusion [0.028 (SD 0.29) to 0.11 (SD 0.24), p = 0.034], indicating worsening cerebrovascular pressure reactivity. In patients with mean PbO2 >20 mmHg pre-transfusion (n = 20), the PRx increased significantly [-0.052 (SD 0.24) to 0.079 (SD 0.22), p = 0.007] but did not change in patients with PbO2 <20 mmHg: PRx [0.22 (SD 0.34) to 0.18 (SD 0.30), p = 0.36].
RBC transfusion in severe TBI patients results in worsening PRx, indicating impaired cerebral autoregulation.
红细胞（RBC）输血与脑组织氧合（PbO2）的变化不一致有关。以往的研究未能考虑脑自动调节的改变。我们的目的是研究红细胞输血对脑自动调节的影响，通过压力反应指数（PRx）来衡量。
对2007年至2014年间前瞻性登记的28例重度创伤性脑损伤（TBI）患者进行回顾性分析。我们记录了红细胞输血前后6小时的血红蛋白（Hb）浓度、颅内压、PbO2、脑灌注压、PRx以及脑乳酸/丙酮酸比值。我们还记录了体温、动脉血氧分压（PaO2）、二氧化碳分压（PCO2）、pH值和吸入氧分数。输血前正常氧合（PbO2>20 mmHg）和低氧（PbO2<20 mmHg）的亚组是预先定义的。
中位年龄为36岁[四分位间距（IQR）27 - 49]，32%为女性。入院时格拉斯哥昏迷评分中位数为5（IQR 4 - 9），损伤严重程度评分为16（IQR 9 - 21）。总体而言，输血后平均Hb浓度[从80 g/L（标准差7）升至89 g/L（标准差8），p<0.001]和PbO2升高[从23.5 mmHg（标准差8）升至25.0 mmHg（标准差9），p = 0.033]。输血后PRx升高[从0.028（标准差0.29）升至0.11（标准差0.24），p = 0.034]，表明脑血管压力反应性恶化。在输血前平均PbO2>20 mmHg的患者（n = 20）中，PRx显著升高[从 - 0.052（标准差0.24）升至0.079（标准差0.22），p = 0.007]，但在PbO2<20 mmHg的患者中未改变：PRx[从0.22（标准差0.34）降至0.18（标准差0.30），p = 0.36]。
重度TBI患者的红细胞输血导致PRx恶化，表明脑自动调节受损。
