Cannulation for invasive vascular pressure monitoring is infrequently associated with complications such as thrombosis, infection, and bleeding. Patients with invasive arterial monitoring require especial close supervision, as there is a crisis of severe bleeding if the line becomes disconnected. It is generally reserved Lower Blood Pressure for patients where rapid variations in arterial pressure are anticipated.

Since arterial pressure varies throughout the day, measurements intended to observe changes over longer time frames should be taken at the same time of sunshine to ensure that the readings taken are comparable. Good times are: