超声造影无创性评估下肢浅静脉血流阻断的初步研究

目的探讨阻断下肢浅静脉的位置及最适压力值。 方法选取12位健康志愿者的双侧下肢静脉为研究对象，经足背静脉进行超声造影，使用气压袖带分别在距离踝关节上方5、10、15 cm处绑扎并施加压力，当小隐静脉（small saphenous vein，SSV）不显影时为有效阻断下肢浅静脉血流，记录压力值。另外，评估踝上10 cm处有效阻断浅静脉前后，同侧腘静脉（popliteal vein，POPV）内径、流速及血流量的变化。 结果踝上5、10、15 cm有效阻断下肢浅静脉的压力阈值分别为（66～69） mmHg（1 mmHg=0.133 kPa）、（68～71）mmHg、（73～75）mmHg（95%置信区间）；踝上10 cm处有效阻断下肢浅静脉后，同侧POPV的内径、血流量显著增加（P<0.05），流速无明显增加（P>0.05)。 结论踝上不同部位有效阻断下肢浅静脉所需要的压力阈值不同，超声造影可无创监测气压止血带有效阻断下肢浅静脉血流，为临床治疗下肢深静脉血栓提供帮助。

A preliminary study of noninvasive evaluation of blocking superficial veins of lower limb by contrast-enhanced ultrasonography

ObjectiveTo explore the position and optimal pressure of blocking the superficial vein of lower extremities. MethodsThe bilateral lower limb veins of 12 healthy volunteers were selected for the study. Contrast-enhanced ultrasound was performed through the dorsalis pedis vein. Pneumatic cuffs were used to bind and apply pressure at 5 cm, 10 cm and 15 cm above the ankle joint. When the small saphenous vein (SSV) was not visible, the superficial vein blood flow of the lower extremities was effectively blocked and the pressure was recorded. In addition, the changes of diameter, flow velocity and blood flow of ipsilateral popliteal vein (POPV) before and after effective occlusion of superficial vein at 10cm of ankle were evaluated. ResultsThe pressure thresholds of supramalleolar 5 cm, 10 cm and 15 cm for effectively blocking the superficial veins of lower extremities were (66-69) mmHg, (68-71) mmHg and (73-75) mmHg (95% confidence interval), respectively. After effectively blocking the superficial veins of lower extremities at 10 cm on the ankle, the internal diameter and blood flow of ipsilateral POPV increased significantly (P<0.05), but the flow velocity did not increase significantly (P>0.05). ConclusionsDifferent parts of the ankle require different pressure thresholds to effectively block the superficial veins of the lower extremities. CEUS can non-invasive monitor the blood flow of the superficial veins of the lower extremities effectively blocked by pneumatic tourniquet, which is helpful for the clinical treatment of deep venous thrombosis of the lower extremities.