目的 研究磁场对锁骨下静脉穿刺置管术中导丝的作用原理，降低异位率。方法 搭建静脉置管的磁场模型。采用磁场引导法避免导丝异位，即借助钕铁硼磁铁对导丝的吸引力引导导丝走向。研究磁场作用下不同静脉角、导丝顶端不同的钩型及朝向对穿刺成功率的影响。结果 距静脉外侧46 mm处放置的磁铁,静脉角≥110°时,提高了穿刺时导丝“J”形钩朝向头臂静脉方向的成功率；对于导丝弯钩朝向胸前，静脉角＜110°时,穿刺成功率有所提高;对于导丝弯钩朝向背部，在所有静脉角情况下均无效果；对于导丝弯钩朝向颈内静脉方向，有些静脉角情况下成功率有一定提高。磁铁有效放置范围在一短边紧邻静脉汇合点，另外两长边分别位于头臂静脉两侧约40 mm的80 mm×90 mm矩形区域。结论 经锁骨下静脉进行穿刺置管时，磁场的存在能有效提高穿刺成功率。

Objective To investigate the effect of magnetic field on guide wire during subclavian vein catheterization (SVC) and decrease the rate of misplacing a catheter. Methods A magnet field model of vein catheterization was built. The magnet field guide method was used to avoid misplacing a catheter, i.e. the direction of guide wire was guided by the attraction of a NdFeB magnet. The effects of different venous angles, wire tips, and directions under the action of magnetic field on the successful puncture rate were explored. Results A NdFeB magnet placing 46 mm away from veins could increase the successful puncture rate when the venous angle was not less than 110° and the ‘J’ tip turned towards the brachiocephalic vein, as well as when the venous angle was less than 110° and ‘J’ tip turned towards the chest. However, the magnet had no effect for any venous angles when ‘J’ tip turned towards the back. The successful puncture rate was increased for some venous angles when ‘J’ tip turned towards ipsilateral internal jugular vein. The effective area for magnet-guided SVC was an 80 mm by 90 mm rectangle with one short side close to the venous junction and two long sides being about 40 mm away from the brachiocephalic vein. Conclusion The presence of magnetic field during SVC can effectively raise the successful puncture rate.