Funk W, Baldinger V
Department of Anesthesiology, University Hospital, University of Regensburg, Germany.
Anesthesiology. 1995 Apr;82(4):975-82. doi: 10.1097/00000542-199504000-00022.
Because of the passage of water and salt molecules into the interstitial space, volume replacement with crystalloid solutions requires an amount at least four times that of lost blood. The resulting tissue edema may interfere with nutritive capillary perfusion and oxygen delivery. To prove this hypothesis, the effects of isovolemic hemodilution (hematocrit 30%) with Ringer's lactate solution or dextran 60 on tissue perfusion and oxygenation were investigated in awake Syrian golden hamsters.
Experiments were performed by using a chronic dorsal skinfold window giving access to skeletal muscle tissue (musculus cutaneus) with in vivo microscopy, quantitative video image analysis, and surface oxygen partial pressure electrodes. Central venous and arterial pressures were measured by means of chronically implanted jugular venous and carotid catheters.
Isovolemic exchange of blood with dextran caused no significant changes in arterial or central venous pressure, heart rate, capillary flow velocity, functional capillary density, or surface oxygen partial pressure during the 1-h observation period. A volume of Ringer's solution equal to four times of the amount of blood lost maintained arterial pressure and heart rate when central venous pressure was kept at predilution control values. However, tissue perfusion determined by counting perfused capillaries per terminal arteriole was reduced by 62%, and mean tissue oxygen partial pressure decreased from 19 to 8 mmHg.
In this model, volume replacement with artificial colloids yielded hemodynamic stability and adequate tissue oxygen supply, whereas administration of crystalloids alone jeopardized tissue perfusion and oxygenation.
由于水和盐分子进入组织间隙，用晶体溶液进行容量替代所需的量至少是失血量的四倍。由此产生的组织水肿可能会干扰营养性毛细血管灌注和氧气输送。为了验证这一假设，在清醒的叙利亚金黄地鼠中研究了用乳酸林格氏液或右旋糖酐60进行等容血液稀释（血细胞比容30%）对组织灌注和氧合的影响。
通过使用慢性背部皮褶窗口进行实验，该窗口可通过体内显微镜检查、定量视频图像分析和表面氧分压电极观察骨骼肌组织（皮肌）。通过长期植入的颈静脉和颈动脉导管测量中心静脉压和动脉压。
在1小时的观察期内，用右旋糖酐进行等容血液交换对动脉压或中心静脉压、心率、毛细血管流速、功能性毛细血管密度或表面氧分压均无显著影响。当中心静脉压保持在稀释前的控制值时，与失血量四倍等量的乳酸林格氏液可维持动脉压和心率。然而，通过计算每个终末小动脉的灌注毛细血管数量确定的组织灌注减少了62%，平均组织氧分压从19 mmHg降至8 mmHg。
在该模型中，用人造胶体进行容量替代可产生血流动力学稳定性和充足的组织氧供应，而单独给予晶体液则会损害组织灌注和氧合。
