Ultrasound methods of positioning guided vascular access devices in the venous system

A method for positioning an instrument in the venous system of a body, comprising:

• inserting the instrument within a vein of the venous system;
• acquiring patient specific data using the instrument prior to moving the instrument within the vein;
• transmitting an in vivo non-imaging ultrasound signal into the vein using an ultrasound transducer on a distal portion of the instrument;
• receiving a reflected in vivo non-imaging ultrasound signal from the vein using the instrument;
• processing, using a processor, the reflected in vivo non-imaging ultrasound signal to generate a processed ultrasound signal;
• calculating, using the processor, one or more non-pulsatile blood flow features extracted from the processed ultrasound signal, wherein the one or more non-pulsatile blood flow features includes a ratio of a blood flow velocity away from the ultrasound transducer and a blood flow velocity towards the ultrasound transducer;
• determining, using the processor, a position of the instrument within the venous system based on the calculated one or more non-pulsatile blood flow features;
• displaying to a user a first indication of the determined position within the venous system;
• moving the instrument based on whether the displayed first indication is a desired indication;
• and
• determining, using the processor, whether the instrument has reached the superior vena cava based on the calculated one or more non-pulsatile blood flow features.