Nielsen V G, Baird M S, Brix A E, Matalon S
Department of Anesthesiology, The University of Alabama at Birmingham, 35249-6810, USA.
Anesthesiology. 1999 May;90(5):1428-35. doi: 10.1097/00000542-199905000-00028.
Physicians and their patients are greatly concerned about perioperative blood administration. Although isovolemic hemodilution is utilized to decrease the incidence of transfusion, it is unclear at what degree of hemodilution hepatoenteric ischemia and injury occurs. The authors hypothesized that hepatic ischemia, systemic ischemia, and tissue injury would occur during hemodilution in rabbits, and that the severity of ischemia and injury may be dependent on the fluid administered.
Rabbits anesthetized with isoflurane were assigned randomly to a sham-operated group (n = 8) or groups that underwent four isovolemic hemodilutions (25% of the blood volume removed at hourly intervals), with blood replaced with one of three solutions: balanced electrolyte solutions containing 6% pentastarch (n = 8), 6% hetastarch (n = 9), or 5% human albumin in normal saline (n = 8). Arterial ketone body ratio and plasma lactate, respectively, served as measures of hepatic and systemic ischemia. Gastric, duodenal, and hepatic histologic injury was assessed post mortem.
Hemodilution from a baseline hematocrit of about 33% to about 8% (third hemodilution) with all three colloids did not result in a significant increase in plasma lactate concentration or decrease in arterial ketone body ratio. At a hematocrit of about 5% (fourth hemodilution), the hetastarch group had a significantly (P < 0.05) greater plasma lactate concentration than the sham-operated and 5% human albumin groups. There were no significant differences in arterial ketone body ratio or histologic injury between the groups.
Isovolemic hemodilution (approximately 5% hematocrit) with albumin, pentastarch, or hetastarch solutions does not result in significant hepatic ischemia or injury assessed by histology.
医生及其患者都非常关注围手术期输血。尽管采用等容血液稀释来降低输血发生率，但目前尚不清楚在何种血液稀释程度下会发生肝肠缺血和损伤。作者推测，家兔在血液稀释过程中会发生肝缺血、全身缺血和组织损伤，且缺血和损伤的严重程度可能取决于所输注的液体。
将用异氟烷麻醉的家兔随机分为假手术组（n = 8）或接受四次等容血液稀释组（每隔1小时去除25%血容量），用以下三种溶液之一替代血液：含6% 喷他淀粉的平衡电解质溶液（n = 8）、6% 羟乙基淀粉（n = 9）或生理盐水中5% 人白蛋白（n = 8）。动脉酮体比率和血浆乳酸分别作为肝缺血和全身缺血的指标。术后评估胃、十二指肠和肝脏的组织学损伤。
使用所有三种胶体将血细胞比容从基线的约33% 稀释至约8%（第三次血液稀释），并未导致血浆乳酸浓度显著升高或动脉酮体比率降低。在血细胞比容约为5%（第四次血液稀释）时，羟乙基淀粉组的血浆乳酸浓度显著高于假手术组和5% 人白蛋白组（P < 0.05）。各组之间动脉酮体比率或组织学损伤无显著差异。
用白蛋白、喷他淀粉或羟乙基淀粉溶液进行等容血液稀释（血细胞比容约为5%），通过组织学评估不会导致显著的肝缺血或损伤。
