Stein J C, Ellis C G, Ellsworth M L
Department of Pharmacological and Physiological Science, St. Louis University School of Medicine, Missouri 63104.
Am J Physiol. 1993 Aug;265(2 Pt 2):H537-42. doi: 10.1152/ajpheart.1993.265.2.H537.
We evaluated the relationship between end-capillary and systemic venous PO2 values in the retractor muscle of 14 anesthetized hamsters during both nonhypoxic and hypoxic ventilation to ascertain whether the level of tissue oxygenation could be reliably estimated from the systemic parameter. End-capillary PO2 was estimated from measurements of oxygen saturation in capillaries at the venular end of the network obtained using in vivo video microscopy and computer-aided image-analysis techniques at three different levels of inspired oxygen (0.3, 0.21, and 0.1). Measurements of systemic arterial and venous blood gases were made in conjunction with these capillary determinations. In addition, in a portion of the study we utilized an oxygen microelectrode to determine the PO2 in the first-order venule draining the portion of the muscle containing the capillaries under study. We found that only when the animals were made acutely hypoxic was there any correspondence between the systemic venous and end-capillary PO2 values. In addition, these data provide support for the presence of arteriovenous shunting of oxygen during nonhypoxic ventilation.
我们评估了14只麻醉仓鼠牵张肌在非低氧和低氧通气期间毛细血管末端与体静脉PO₂值之间的关系，以确定是否可以从全身参数可靠地估计组织氧合水平。毛细血管末端PO₂是通过体内视频显微镜和计算机辅助图像分析技术，在三种不同吸入氧水平（0.3、0.21和0.1）下，对网络小静脉末端毛细血管中的氧饱和度进行测量来估计的。在进行这些毛细血管测定的同时，还测量了全身动脉和静脉血气。此外，在部分研究中，我们使用氧微电极来测定引流含有所研究毛细血管的那部分肌肉的一级小静脉中的PO₂。我们发现，只有当动物急性缺氧时，体静脉和毛细血管末端PO₂值之间才存在任何对应关系。此外，这些数据支持了在非低氧通气期间存在氧的动静脉分流。
