紫绀型与非紫绀型先心病术中乳酸的变化(2)
3.2 CPB术中乳酸变化 乳酸是组织缺氧极为敏感的生化指标，也是灌注不足的早期指标。血乳酸是葡萄糖无氧代谢的最终产物，乳酸合成的唯一途径是细胞内的丙酮酸， 当缺氧导致过量的还原性的3-磷酸甘油醛脱氢酶(NADH)蓄积时，就激活了此代谢通道。当足够的氧保持了3-磷酸甘油醛脱氧酶(NAD+)与NADH适当比例时，丙酮酸就转变为乙酰辅酶A，乙酰辅酶A 进入三羧酸循环。在缺氧的情况下，NADH蓄积，抑制了乙酰辅A 的形成，使丙酮酸通过无氧代谢形成乳酸。乳酸蓄积是对组织缺氧的敏感，早期的特定敏感指标[4]。Ricardo等人[5]对体外循环与非体外循环进行比较，结果表明体外循环组的乳酸值远远高于非体外循环组。尽管二组疾病及CPB期间状况不同，但不同时点乳酸的变化趋势基本是一致的，可见乳酸增高一方面因转流中血液过度稀释，微循环功能障碍导致乳酸增高； 另一方面低温CPB期间存在血液分流，血液向骨骼肌重新分布，而小肠、肝、肾等内脏血流减少，引起部分脏器缺血缺氧，肝脏是乳酸利用的主要脏器，以致肝脏摄取转化乳酸能力下降，乳酸增高[6]。
本实验提示CPB期间机体存在着组织摄氧能力下降，应改善微循环，给予充足的氧供。
参考文献
1 Amitai Y,Blieden L,Shemtov A,et al. Cerebrovascular accidents in infants and children with congenital cyanotic heart disease. Isr J Med Sci,1984,30(4):1143.
2 Trekova NA, Dementyeva 11, Dzemeshkevich Sl et al,Blood oxygen transport function in cardiopulmonary bypass surgery for acquired heart valvular disease .1994，79(1):60-4.
3 Routsi C ,Vincent JL ,Bakker J et al . Relationbetween oxygen consumption and oxygen delivery in patients after cardiac surgery .1993，77(6) :1104-1110.
4 Haisjackl M、Birnbaum J、Redlin M、et al, Splanchnic oxygen transport and lactate metabolism during normothernic cardiopulmonary bypassin humans.1998:86:22-7.
5 Ricardo MM , Laussen PC , Palacio G et al, Change in whole blood lactate levels during cardiopulmonary bypass for surgery for congenital cardiac disease J Thoracic Cardiovascular Surg，2000， 119 (1) : 155 -162
6 Jia LD, Schulze NL, Lincoln C, el al.Oxygen consumption after cardiopulmonary bypass surgery in Children.Thorac Cardiovasc Surg ，2000，119(3)525-33., http://www.100md.com(付春梅 何素丽 卢赛兰)
本实验提示CPB期间机体存在着组织摄氧能力下降，应改善微循环，给予充足的氧供。
参考文献
1 Amitai Y,Blieden L,Shemtov A,et al. Cerebrovascular accidents in infants and children with congenital cyanotic heart disease. Isr J Med Sci,1984,30(4):1143.
2 Trekova NA, Dementyeva 11, Dzemeshkevich Sl et al,Blood oxygen transport function in cardiopulmonary bypass surgery for acquired heart valvular disease .1994，79(1):60-4.
3 Routsi C ,Vincent JL ,Bakker J et al . Relationbetween oxygen consumption and oxygen delivery in patients after cardiac surgery .1993，77(6) :1104-1110.
4 Haisjackl M、Birnbaum J、Redlin M、et al, Splanchnic oxygen transport and lactate metabolism during normothernic cardiopulmonary bypassin humans.1998:86:22-7.
5 Ricardo MM , Laussen PC , Palacio G et al, Change in whole blood lactate levels during cardiopulmonary bypass for surgery for congenital cardiac disease J Thoracic Cardiovascular Surg，2000， 119 (1) : 155 -162
6 Jia LD, Schulze NL, Lincoln C, el al.Oxygen consumption after cardiopulmonary bypass surgery in Children.Thorac Cardiovasc Surg ，2000，119(3)525-33., http://www.100md.com(付春梅 何素丽 卢赛兰)