Invasive arterial blood pressure is relative to non-invasive arterial blood pressure monitoring, which is routinely measured with mercury sphygmomanometers or electronic sphygmomanometers and is called non-invasive blood pressure. Invasive blood pressure monitoring requires the insertion of various catheters or monitoring probes through the body surface into the heart or blood vessel cavities to directly determine blood pressure, relative to non-invasive blood pressure, has its own unique advantages, which is not affected by the width of the artificial compression cuff as well as the degree of elasticity, and can be read at any time, which is relatively more accurate and more reliable. It can also determine myocardial contractility based on arterial waveforms and detect changes in blood pressure earlier when applying vasoactive drugs in critically ill patients. So invasive blood pressure monitoring, more suitable for critically ill patients, the disadvantage is invasive and inconvenient to measure, can only be used in the hospital.