Venous catheterization doesn't need to be completely fixed like an artery; rather, it has some mobility so the doctor can move it up or down to adjust the depth. Unlike the arterial outlet, veins lack pumping force and may clog if the flow is not smooth.
Based on this principle, Student Duan seized the opportunity to swiftly instruct the extracorporeal circulation technician and anesthesiologist to cooperate. During the catheter insertion period, they were to perform a preliminary test of the parallel circulation. Parallel circulation means starting the extracorporeal circulation machine while the patient's heart is still beating, allowing the heart and extracorporeal circulation to run simultaneously. Starting the machine early can help detect any blood leakage or circulation issues at the catheter insertion point. If no problems are found, then the heart can be stopped.
