Department of Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany.
Am J Respir Crit Care Med. 2013 Aug 15;188(4):474-81. doi: 10.1164/rccm.201212-2177OC.
Oxygen uptake is the elemental function of the lung. However, current understanding of this process has largely been derived from theoretical considerations and measurements of global pulmonary gas exchange.
To report the direct visualization of pulmonary oxygen uptake in vivo and its use for the analysis of temporal and spatial oxygenation profiles along individual arteriovenous pathways in lungs of healthy and chronic hypoxic mice.
A murine model for intravital microscopy of the breathing lung under sealed thorax conditions was combined with multispectral oximetry for two-dimensional oxygen saturation mapping. This combination allowed for visualization of the blood oxygenation process from pulmonary arterioles to capillaries and venules in two-dimensional oxygen saturation maps.
Temporal and spatial oxygenation profiles revealed that oxygenation occurs within 100 milliseconds over a distance of approximately 130 μm in the pulmonary microvasculature of the anesthetized mouse. About 50% of total oxygen uptake takes place in precapillary arterioles of less than 30 μm in diameter before the blood enters the alveolar capillary bed. In chronic hypoxic mice, precapillary oxygenation was significantly attenuated as a result of the widened transarteriolar diffusion distance.
Oxygen saturation mapping in the intact lung yields unique insights into the temporal and spatial characteristics of pulmonary gas exchange in intact and diseased lungs. Precapillary gas exchange contributes importantly to blood oxygenation at rest, but is attenuated in remodeled lung arterioles, which may be of relevance in pulmonary hypertension.
氧气摄取是肺的基本功能。然而，目前对这一过程的理解在很大程度上是基于理论考虑和对肺部整体气体交换的测量。
报告体内肺氧气摄取的直接可视化及其在分析健康和慢性低氧小鼠肺部单个动静脉途径的时间和空间氧合曲线中的应用。
将一种用于密封胸腔条件下呼吸肺活体显微镜检查的鼠模型与多光谱血氧计相结合，用于二维氧饱和度映射。这种组合允许在二维氧饱和度图中可视化从肺小动脉到毛细血管和小静脉的血液氧合过程。
时间和空间氧合曲线揭示了在麻醉小鼠的肺微血管中，氧合在大约 130μm 的距离内发生在 100 毫秒内。在血液进入肺泡毛细血管床之前，约 50%的总氧气摄取发生在直径小于 30μm 的小动脉前预毛细血管中。在慢性低氧小鼠中，由于跨动脉扩散距离的增加，前毛细血管氧合明显减弱。
完整肺中的氧饱和度映射为完整和患病肺中的气体交换的时间和空间特征提供了独特的见解。预毛细血管气体交换对休息时的血液氧合很重要，但在重塑的肺小动脉中减弱，这可能与肺动脉高压有关。
