Fukuhara Shinichi, Yamamoto Ken-Ichiro
Department of Medical Engineering, Faculty of Health Science and Technology, Kawasaki University of Medical Welfare, Kurashiki, Okayama, 288, Matsushima701-0193, Japan.
J Artif Organs. 2025 May 16. doi: 10.1007/s10047-025-01505-y.
A venous reservoir (VR) is crucial for safe blood volume regulation during cardiopulmonary bypass (CPB) procedures. Currently, blood volume measurement in VRs relies heavily on visual inspection, which limits its accuracy and responsiveness. In this paper, a method that leverages a laser displacement sensor for blood surface distance change detection in VRs with high accuracy and simplicity is proposed. It enables precise, non-contact, real-time measurements for displacement and position analysis of blood surface. Hard-shell VRs maintain a constant relationship between blood volume and blood surface height. Therefore, we measured the blood surface distance and the distance between the sensors. The findings of this study demonstrate that blood volume correlates with the distance measured from the blood surface to the sensor, showing clear "blood surface distance-volume characteristic" curves specific to each VR. Experimental results confirm excellent reproducibility and low variability, even under different conditions, such as blood dilution and varying ambient light. In addition, the blood volume dynamic behavior during CPB can be captured with measurements that are in good agreement with theoretical predictions. Our findings confirm the potential of blood volume estimation based on blood surface distance measurements, making it a promising alternative for real-time blood volume monitoring during CPB. Integrating this method into CPB systems could improve safety, prevent air embolisms, and improve fluid management, paving the way for more precise and automated circulating blood volume control.
静脉储血器（VR）对于体外循环（CPB）手术期间安全的血容量调节至关重要。目前，VR中的血容量测量严重依赖目视检查，这限制了其准确性和响应性。本文提出了一种利用激光位移传感器高精度、简单地检测VR中血面距离变化的方法。它能够对血面进行精确、非接触式的实时位移和位置分析测量。硬壳VR中血容量与血面高度保持恒定关系。因此，我们测量了血面距离和传感器之间的距离。本研究结果表明，血容量与从血面到传感器的测量距离相关，呈现出每个VR特有的清晰“血面距离-容量特性”曲线。实验结果证实，即使在不同条件下，如血液稀释和不同环境光下，该方法也具有出色的可重复性和低变异性。此外，CPB期间的血容量动态行为可以通过与理论预测高度一致的测量来捕捉。我们的研究结果证实了基于血面距离测量进行血容量估计的潜力，使其成为CPB期间实时血容量监测的一种有前途的替代方法。将该方法集成到CPB系统中可以提高安全性、预防空气栓塞并改善液体管理，为更精确和自动化的循环血容量控制铺平道路。
