ASSESSMENT AND IMPACT OF HETEROGENEITIES OF CONVECTIVE OXYGEN-TRANSPORT PARAMETERS IN CAPILLARIES OF STRIATED-MUSCLE - EXPERIMENTAL AND THEORETICAL
ASSESSMENT AND IMPACT OF HETEROGENEITIES OF CONVECTIVE OXYGEN-TRANSPORT PARAMETERS IN CAPILLARIES OF STRIATED-MUSCLE - EXPERIMENTAL AND THEORETICAL
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DOI：
10.1016/0026-2862(88)90089-1
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发表时间：
1988-05-01
影响因子：
3.1
通讯作者：
PITTMAN, RN
中科院分区：
文献类型：
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作者：
ELLSWORTH, ML;POPEL, AS;PITTMAN, RN
在仓鼠颊囊牵开肌的小动脉（n=5）和小静脉（n=5）毛细血管网络中测定对流氧运输参数。同时测定的红细胞速度，线密度，红细胞频率，血红蛋白氧饱和度（SO 2），氧流量（QO 2），纵向SO 2梯度，和直径的值，共获得73个毛细血管，39个在小动脉端的网络（小动脉毛细血管）和34个在小静脉端（小静脉毛细血管）。我们发现两端的血流动力学变量没有差异。然而，并不意外的是，在小动脉毛细血管的上游端，SO2和QO 2显著更高（60.8 ± 0.01）。9.8（SD）%和0.150 ±。0.081 pl/秒）与微静脉毛细血管下游端（39.9 . ±. 13.6%和0.108 ±。0.095 pl/sec）。红细胞流速、线密度、SO2的异质性（通过其变异系数评估）在微静脉毛细血管中显著更大。为了评估这些不均匀性对氧交换的影响，我们将这些独特的实验数据纳入到氧运输的数学模型中，该模型考虑了红细胞频率、线性密度、入口SO2、毛细管直径以及在某种程度上毛细管流路长度的变化。一个意想不到的结果的模拟是，只有在毛细血管的流动路径长度的可变性的结合有任何显着的影响，在休息肌肉中的毛细血管末端的SO2的异质性，由于相邻的毛细血管之间的氧气广泛的扩散分流。我们随后评估，通过模型模拟，这些不均匀性的影响下，增加流量和高耗氧量的条件下。在这些条件下，该模型预测，在血液动力学参数的异质性将有显着的影响，在这肌肉中的氧运输。
Convective oxygen transport parameters were determined in arteriolar (n=5) and venular (n=5) capillary networks in the hamster cheek pouch retractor muscle. Simultaneously determined values of red blood cell velocity, lineal density, red blood cell frequency, hemoglobin oxygen saturation (SO2), oxygen flow (QO2), longitudinal SO2 gradient, and diameter were obtained in a total of 73 capillaries, 39 at the arteriolar ends of the network (arteriolar capillaries) and 34 at the venular ends (venular capillaries). We found that the hemodynamic variables were not different at the two ends. However, not unexpectedly, SO2 and QO2 were significantly higher at the upstream end of arteriolar capillaries (60.8 .+-. 9.8 (SD)% and 0.150 .+-. 0.081 pl/sec, respectively) compared with the downstream end of venular capillaries (39.9 .+-. 13.6% and 0.108 .+-. 0.095 pl/sec, respectively). Heterogeneities in red blood cell velocity, lineal density, SO2, assessed by their coefficients of variation, were significantly greater in venular capillaries. To evaluate the impact of these heterogeneities on oxygen exchange, we incorporated these unique experimental data into a mathematical model of oxygen transport which accounts for variability in red blood cell frequency, lineal density, inlet SO2, capillary diameter, and, to some degree, capillary flow path lengths. An unexpected result of the simulation is that only the incorporation of variability in capillary flow path lengths had any marked effect on the heterogeneity in end-capillary SO2 in resting muscle due to extensive diffusional shunting of oxygen among adjacent capillaries. We subsequently evaluated, through model simulations, the effect of these heterogeneities under conditions of increased flow and high oxygen consumption. Under these conditions, the model predicts that heterogeneities in the hemodynamic parameters will have a marked effect on oxygen transport in this muscle.