绑止血带时其松紧度以刚压住动脉出血为宜。上带过紧易造成止血带处的皮肤、神经、血管和肌肉的损伤，甚至引起肢体远端的坏死，不利于今后伤肢的功能恢复；上带过松只压住静脉未压住动脉，血液只出不进，不仅达不到止血目的反而加重出血。上带成功的标准是，远端动脉性出血停止、动脉搏动消失、肢端变白。
When the tourniquet is tied, its tightness is appropriate to press the artery to bleed. If the upper belt is too tight, it is easy to cause skin, nerve, blood vessel and muscle damage at the tourniquet, and even cause the necrosis of the distal end of the limb, which is not conducive to the functional recovery of the injured limb in the future; if the upper belt is too loose, it will only press the vein without pressing the artery, and the blood will only go out without going in, which will aggravate the bleeding instead of achieving the hemostasis purpose. The criteria for success of the upper band were cessation of distal arterial bleeding, disappearance of arterial pulsation, and whitening of the extremities.