Svensén Christer H, Brauer Kirk P, Hahn Robert G, Uchida Tatsuo, Traber Lillian D, Traber Daniel L, Prough Donald S
Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas 77555-0591, USA.
Anesthesiology. 2004 Sep;101(3):666-74. doi: 10.1097/00000542-200409000-00015.
The purpose of this study was to determine the influence of varying large crystalloid infusion volumes, ranging from a volume that has been safely administered to volunteers to a volume that greatly exceeds a practical volume for studies in normovolemic humans, of rapidly infused 0.9% saline on the elimination rate constant in sheep.
Six sheep underwent three randomly ordered, 20 min, intravenous infusions of 0.9% saline in volumes of 25 ml/kg, 50 ml/kg and 100 ml/kg. Repeated measurements of arterial plasma dilution were analyzed using the volume kinetic approach to determine the apparent volumes of the central (V1) and peripheral (V2) body fluid spaces, the elimination rate constant (kr) describing clearance from the central fluid space and the rate constant (kt) for the diffusion of fluid between the central and the peripheral fluid spaces. The latter constant was split in to two constants, one describing flow out from the central fluid space and one describing flow into the central fluid space. Urinary output was measured in all sheep.
kr was comparable at each infused volume (38.3 +/- 4.5, 32.2 +/- 4.2, and 36.7 +/- 7.0 ml/min, respectively, in the 25 ml/kg, 50 ml/kg, and 100 ml/kg protocols). However, for the largest infusion, other kinetic parameters were influenced by the magnitude of the infusion. V2 was significantly increased (P < 0.05) and the area under the dilution-time curve divided by the infused volume was 20% lower for the largest infusion (P < 0.03). Although urinary output increased as the infusion volume increased, only 59% of the administered volume had been excreted at 180 min after the 100 ml/kg infusion as compared with approximately 90% after the other two infusions (P < 0.01).
Elimination from the central fluid space of large, rapidly infused volumes of saline solution is independent of infused volume. Larger volumes are apparently cleared from the central fluid space (V1) by expansion of a peripheral volume (V2) as renal excretion fails to increase in proportion to the volume of infused fluid.
本研究的目的是确定不同大剂量晶体液输注量（范围从已安全给予志愿者的剂量到大大超过正常血容量人体研究实际剂量）的快速输注0.9%生理盐水对绵羊消除速率常数的影响。
6只绵羊接受3次随机排序的、每次20分钟的静脉输注0.9%生理盐水，输注量分别为25ml/kg、50ml/kg和100ml/kg。使用容量动力学方法分析动脉血浆稀释的重复测量值，以确定中央（V1）和外周（V2）体液空间的表观容量、描述从中央体液空间清除的消除速率常数（kr）以及中央和外周体液空间之间液体扩散的速率常数（kt）。后一个常数分为两个常数，一个描述从中央体液空间流出的流量，一个描述流入中央体液空间的流量。测量所有绵羊的尿量。
在每个输注量下kr相当（在25ml/kg、50ml/kg和100ml/kg方案中，分别为38.3±4.5、32.2±4.2和36.7±7.0ml/min）。然而，对于最大输注量，其他动力学参数受输注量大小的影响。V2显著增加（P<0.05），最大输注量时稀释时间曲线下面积除以输注量降低20%（P<0.03）。尽管尿量随输注量增加而增加，但在100ml/kg输注后180分钟，仅59%的给药量被排出，而其他两次输注后约为90%（P<0.01）。
大量快速输注的盐溶液从中央体液空间的清除与输注量无关。随着肾排泄未能与输注液体量成比例增加，更大的量显然通过外周容量（V2）的扩张从中央体液空间（V1）清除。
