Faculty of Medicine, Universidad Juárez del Estado de Durango, Victoria de Durango, Durango, Mexico.
Am J Physiol Heart Circ Physiol. 2010 Sep;299(3):H863-7. doi: 10.1152/ajpheart.00496.2010. Epub 2010 Jul 2.
The hematocrit (Hct) of awake hamsters was lowered to 90% of baseline by isovolemic hemodilution using hamster plasma to determine the acute effect of small changes in Hct and blood viscosity on systemic hemodynamics. Mean arterial blood pressure increased, reaching a maximum of about 10% above baseline (8.6 +/- 5.5 mmHg) when Hct decreased 8.4 +/- 1.9% (P < 0.005). Cardiac output increased continuously with hemodilution. These conditions were reached at approximately 60 min after exchange transfusion and remained stationary for 1 h. Peripheral vascular resistance was approximately constant up to a decrease of Hct of about 10% and then fell continuously with lowering Hct. Vascular hindrance or vascular resistance independent of blood viscosity increased by about 20% and remained at this level up to an Hct decrease of 20%, indicating that the vasculature constricted with the lowered Hct. The results for the initial 2-h period are opposite but continuous with previous findings with small increases in Hct. In conclusion, limited acute anemic conditions increase mean arterial blood pressure during the initial period of 2 h, an effect that is quantitatively similar but opposite to the acute increase of Hct during the same period.
通过等容血液稀释使用仓鼠血浆将清醒仓鼠的血细胞比容降低到基线的 90%，以确定血细胞比容和血液粘度的微小变化对全身血液动力学的急性影响。平均动脉血压升高，当血细胞比容降低 8.4 +/- 1.9%时，达到基线以上约 10%的最大值（P < 0.005）。心输出量随着血液稀释而持续增加。这些条件在交换输血后约 60 分钟达到，并在 1 小时内保持稳定。外周血管阻力在血细胞比容降低约 10%之前基本保持不变，然后随着血细胞比容的降低而持续下降。不依赖血液粘度的血管阻力或血管阻力增加约 20%，并保持在该水平，直到血细胞比容降低 20%，表明血管随降低的血细胞比容而收缩。前 2 小时的结果与之前的研究结果相反，但与之前的研究结果一致，即小幅度增加血细胞比容会导致平均动脉血压升高。总之，有限的急性贫血条件会在最初的 2 小时内增加平均动脉血压，这种影响在数量上与同一时期血细胞比容的急性增加相似但相反。
