pH strategies and cerebral energetics before and after circulatory arrest.
pH strategies and cerebral energetics before and after circulatory arrest.
复制标题
停循环前后的 pH 策略和脑能量学。
DOI：
10.1016/s0022-5223(95)70321-7
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Jonas,RA
中科院分区：
文献类型：
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作者：
Hiramatsu,T;Miura,T;Forbess,JM;DuPlessis,A;Aoki,M;Nomura,F;Holtzman,D;Jonas,RA
PH-STAT策略与α-STAT策略相比，在猪低温循环停止1小时后，可更快地恢复脑部高能磷酸盐储存和细胞内pH。这种差异的可能机制是：(1)深低温停循环前改善了氧输送和脑降温的均质性；(2)复温期由于细胞外酸中毒而增加了脑血流量，减少了再灌注损伤。为了确定哪一种机制是主要的，我们研究了49头4周龄的小猪，它们经历了1小时的深度低温停循环。根据降温/复温策略定义了四个组：α/α、α/pH、pH/α和pH/pH。用磁共振波谱技术测定24只动物(α/α组7、α/pH组5、pH/α组7、pH/pH 5)的脑高能磷酸盐水平和细胞内pH。用标记微球测定25只动物的脑血流量，用氧和葡萄糖抽提法测定脑组织代谢率，用近红外光谱仪测定细胞色素aa3的氧化还原状态和血红蛋白氧合(α/α组7，α/pH组5，pH/α组7，pH/pH组6)。降温期间，pH-STAT的脑血流量高于α-STAT(56.3%±3.7%比32.9%±2.1%，p<；0.001)。细胞色素aa3值在用α-STAT降温时比在pH-STAT降温时降低更多(p=0.049)。PH/pH组再灌注后45分钟内三磷酸腺苷水平恢复较其他组快(p=0.029)。PH/pH组在最初30分钟内脑细胞内pH恢复较α/α组快(p=0.026)。细胞内pH在再灌流早期仅在α/α组变得更酸性，而在其他组则持续恢复。这项研究表明，在深低温停循环前后的降温和复温阶段都存在有效的机制，与更碱性的策略相比，这可能有助于改善pH状态下的脑预后。(J THORAC心血管疾病杂志1995；109：948-58)
The pH-stat strategy compared with the alpha-stat strategy provides more rapid recovery of brain high-energy phosphate stores and intracellular pH after 1 hour of hypothermic circulatory arrest in pigs. Possible mechanisms for this difference are (1) improved oxygen delivery and homogeneity of brain cooling before deep hypothermic circulatory arrest and (2) greater cerebral blood flow and reduced reperfusion injury owing to extracellular acidosis during the rewarming phase. To identify which of these mechanisms is predominant, we studied 49 4-week-old piglets undergoing 1 hour of deep hypothermic circulatory arrest. Four groups were defined according to cooling/rewarming strategy: alpha/alpha, alpha/pH, pH/alpha, and pH/pH. In 24 animals cerebral high-energy phosphate levels and intracellular pH were measured by magnetic resonance spectroscopy (alpha/alpha group 7, alpha/pH group 5, pH/alpha group 7, pH/pH group 5). In 25 animals cerebral blood flow was measured by labeled microspheres, cerebral metabolic rate by oxygen and glucose extraction, and the redox state of cytochrome aa3and hemoglobin oxygenation by near infrared spectroscopy (alpha/alpha group 7, alpha/pH group 5, pH/alpha group 7, pH/pH group 6). Cerebral blood flow was greater with pH-stat than alpha-stat during cooling (56.3% ± 3.7% versus 32.9% ± 2.1% of normothermic baseline values, p < 0.001). Cytochrome aa3values became more reduced during cooling with alpha-stat than with pH-stat (p = 0.049). Recovery of adenosine triphosphate levels in the initial 45 minutes of reperfusion was more rapid in group pH/pH compared with that in the other groups (p = 0.029). Recovery of cerebral intracellular pH in the initial 30 minutes was faster in group pH/pH compared with that in group alpha/alpha (p = 0.026). Intracellular pH became more acidic during early reperfusion only in group alpha/alpha, whereas it showed continuous recovery in the other groups. This study suggests that there are mechanisms in effect during both the cooling and rewarming phases before and after deep hypothermic circulatory arrest that could contribute to an improved cerebral outcome with pH-stat relative to more alkaline strategies. (J THORAC CARDIOVASC SURG 1995; 109: 948-58)