Ultrasound-Guided Intravenous Access

Anatomy and Physiology

Ultrasound enables visualization and cannulation of superficial and deep peripheral veins by identifying and mapping vessels in the extremities. Peripheral veins in the upper extremity serve as the primary targets, while vessels in the lower extremity are cannulated less frequently.

Ultrasound displays blood vessels in cross-section as black, anechoic circles. Many veins lie adjacent to corresponding arteries. Applying pressure causes arterial pulsatility, whereas veins remain nonpulsatile (see Media. Ultrasound Assessment for Intravenous Placement, Ultrasound Video of Upper Right Arm Vasculature for Cannulation). Color flow or pulsed wave Doppler further distinguishes arteries from veins. The surrounding muscle tissue appears grey, with lighter striations. Bone appears as a bright white line without visible underlying structures, since ultrasound waves cannot penetrate bone.

The cephalic, antebrachial, median cubital, and basilic veins serve as common targets for USGIV access in the forearm. With the patient’s palm facing anteriorly, the cephalic vein courses along the lateral forearm, the median antebrachial vein near the center, and the basilic vein along the medial aspect (see Media. Forearm Anatomy Review and Ultrasound Probing).

When forearm vessels are inaccessible, the cephalic and basilic veins provide ideal targets in the proximal upper extremity. The cephalic vein runs along the anterior aspect of the biceps, often residing in superficial soft tissue. The basilic vein lies along the medial upper arm and typically remains too deep for palpation-guided cannulation. Unlike other veins, the basilic vein has no corresponding artery. The paired deep brachial veins accompany the brachial artery and major nerves of the arm and should be avoided when easier access options are available. Cannulation should occur as distally as possible to preserve proximal sites for future attempts.[8]

Indications

USGIV insertion is most commonly employed after traditional palpation-based techniques fail or when blind cannulation presents significant challenges.[9] Some institutions require a defined number of unsuccessful attempts without ultrasound before initiating USGIV access. When distal superficial vessels receive priority, ultrasound may support initial venous cannulation attempts. Encouraging learners to practice ultrasound on superficial forearm veins enhances hand-ultrasound coordination. These skills can then extend to cannulating deeper vessels.

Contraindications

Contraindications for USGIV and traditional PIVC placement overlap. Areas with soft tissue infection, recent trauma, or burns should be excluded, as should extremities with arteriovenous fistulas or a history of vascular surgery. Veins recently punctured during prior cannulation attempts should be avoided unless no other viable options exist. USGIV insertion is contraindicated in vessels demonstrating sonographic signs of thrombosis, including hyperechoic intraluminal material, lack of compressibility, or absent flow.

Equipment

Basic intravenous access equipment, including an antiseptic wipe or swab, tourniquet, gauze, extension tubing, saline flush, catheter cap, and securement device, should be prepared as for any PIVC placement. An ultrasound machine with a high-frequency linear probe is recommended for vessel visualization. Other ultrasound probes prove suboptimal for this application.[10] A sterile probe cover, sterile ultrasound gel, and a towel or gauze should be available at the bedside. Sterile probe covers are produced commercially. If unavailable, a sterile adhesive barrier device, such as a transparent film dressing, can serve as an alternative. The probe cover and gel must be applied without air bubbles between the probe and cover to avoid imaging artifacts.

Having catheters of various sizes on hand is prudent. Vessels accessed with ultrasound guidance often lie deeper than those cannulated via traditional techniques, necessitating the use of longer catheters. The optimal catheter size depends on the vessel's depth and diameter, which can be approximated using ultrasound measurements. When cannulating basilic and brachial veins in adults, catheters of at least 2.5 inches in length are advisable.[11] Commercial kits employing a guidewire and a modified Seldinger technique for USGIV placement are also available.[12]

Personnel

Training requirements and prerequisites vary by state and facility. Typically, a single nurse trained in USGIV cannulation performs the procedure.[13] Some institutions require an advanced practice provider or physician to perform USGIV placement. Personnel holding PIVC placement credentials may acquire this skill.

Preparation

All equipment should be gathered at the bedside before the procedure begins. Patient and proceduralist positioning should be optimized. The patient should be positioned comfortably to minimize movement. The ultrasound machine should be placed within the proceduralist’s direct line of sight, allowing the screen and the cannulation site to be viewed simultaneously without requiring the head to be turned.

Vessel Selection

When multiple vessels are suitable for USGIV placement, the most distal site should be selected whenever possible. The depth, diameter, and course of the vessel should be assessed. Cannulation success and catheter longevity are associated with superficial vessels that are larger in diameter.[14] The optimum vessel depth ranges from 0.3 to 1.4 cm, and vessels larger than 0.4 cm in diameter are more likely to be successfully cannulated.[15][16]

If a vein cannot be identified but an artery is visible, pressure on the ultrasound probe should be reduced to relieve compression of adjacent veins, which may collapse easily. Before cannulation is attempted, the vein’s course proximal and distal to the target area should be visualized to enable proper needle direction based on the vein’s trajectory. Areas of vessel branching should be avoided.

Technique or Treatment

Transverse (out-of-plane) and longitudinal (in-plane) techniques are employed for USGIV placement, each offering distinct benefits and limitations. Disagreement exists regarding the optimal technique for beginners.

Transverse (Out-Of-Plane) Technique

The target vessel should be visualized in cross-section at the center of the ultrasound screen, with the probe held perpendicular to the vessel’s course. The probe marker should face the operator’s left. Many ultrasound machines include a “guide” or “centerline” function to identify the probe’s center.

The ultrasound probe is held in the nondominant hand, and the peripheral intravenous (PIV) needle in the dominant hand. With the vessel centered on screen, the needle should be inserted adjacent to the center of the probe. The insertion angle is generally steeper than that used in landmark-based PIV placement. An angle of approximately 45° is appropriate but may be adjusted according to vessel depth.

While holding the probe in place, the needle is slowly advanced through the skin until its tip appears as a bright white dot on the screen. The probe is then gently fanned as the needle is advanced, maintaining continuous visualization of the needle tip. Minor adjustments of the needle path may be required to align with the vessel. Advancement continues until the needle tip is within the vessel lumen, often confirmed by blood return in the needle chamber. The needle should be advanced approximately 0.5 cm further into the lumen before advancing the catheter, avoiding penetration of the vessel’s posterior wall.

Proper catheter placement is confirmed by blood return on syringe aspiration and absence of infiltration during saline flush. Visualization of the catheter within the vessel lumen on longitudinal ultrasound imaging can also confirm placement. The catheter is secured with a securement device, as with any PIV.

The ultrasound probe should be held steady on the patient while the needle is slowly advanced through the skin. The needle tip will appear as a bright white dot on the screen. Once in view, the probe should be slowly fanned as the needle advances, maintaining visualization of the needle tip at all times. Fanning the probe just ahead of needle advancement may facilitate continuous visualization. The needle path may require slight adjustments laterally to remain aligned with the target vessel. Advancement should continue until the needle tip is located within the vessel lumen, which is often confirmed by the presence of a small amount of blood in the needle chamber. Before advancing the catheter, the needle should be inserted approximately 0.5 cm further into the vessel lumen to ensure secure placement, taking care to avoid penetrating the posterior wall of the vessel.

After catheter advancement into the vessel, proper placement is confirmed by blood return during syringe aspiration and absence of infiltration when saline is flushed. Visualization of the catheter length within the vessel lumen on longitudinal ultrasound imaging can provide additional confirmation. The catheter should then be secured with a securement device, as with any PIV.

Longitudinal (In-Plane) Technique

The anechoic lumen of the target vessel is initially identified in a transverse plane. The probe is then rotated 90° so that its long axis aligns parallel to the vessel’s length. The needle is inserted adjacent to the narrow edge of the probe and advanced beneath it, maintaining a path parallel to the vessel. Needle trajectory is adjusted as necessary until the needle tip is visualized moving from one side of the ultrasound screen toward the vessel. The needle is inserted until its tip is positioned no less than 0.5 cm inside the vessel lumen. Catheter advancement and securing follow the same steps described for the transverse technique.

This method enables continuous visualization of the needle entering the vessel within the same imaging plane. The long axis of both the ultrasound probe and needle aligns with the vessel. For novice sonographers, inadvertent probe sliding from vein to adjacent artery or misidentification of fascial planes as vessels may occur. Although considered more technically challenging for inexperienced users, this technique allows improved visualization of the posterior vessel wall and may reduce the risk of vessel perforation.[17]

Complications

Complications of USGIV insertion are similar to those associated with traditional PIVC placement. These adverse events include vessel thrombosis, soft tissue infiltration, hematoma formation, arterial puncture or cannulation, nerve damage, phlebitis, and infection. Proper technique and skilled ultrasound use minimize complication risks. Overall complication rates reported in studies remain low. The failure rate of USGIV access is equal to or lower than that of standard PIVC insertion.

Clinical Significance

USGIV placement enables more efficient cannulation in patients with difficult peripheral access. Use of this technique may reduce reliance on central lines and minimize repeated PIVC attempts. Proficient application of USGIV insertion methods enhances patient satisfaction and helps prevent care delays.

Enhancing Healthcare Team Outcomes

Ultrasound serves a wide range of diagnostic and therapeutic purposes. Point-of-care ultrasound is increasingly used to guide PIVC placement when traditional methods prove difficult or unsuccessful. Studies show higher success rates with ultrasound, particularly in patients with obesity, end-stage renal disease, peripheral vascular disease, diabetes, intravenous drug use, sickle cell disease, or a history of chemotherapy.

Training in USGIV cannulation may benefit clinicians caring for these populations. Repeated failed attempts at PIVC insertion cause frustration for both patients and providers. Although USGIV placement times vary, they may match or even improve upon the time required for successful placement using palpation techniques. Ultrasound use is associated with a reduced need for central venous catheterization, decreased patient discomfort, and greater patient satisfaction.

Greater familiarity with the indications, contraindications, techniques, and complications of USGIV placement may promote its effective use and contribute to improved patient outcomes. Some institutions have implemented USGIV insertion training programs for nursing staff, certified registered nurse anesthetists, and other clinicians, resulting in positive, patient-centered outcomes. These programs have been associated with improved efficiency and higher success rates for USGIV placement.[18][19] Simulation-based practice may further enhance procedural competence.[20]

Increasing the number of trained providers may facilitate faster intravenous access and more timely delivery of critical treatments. Institutions may benefit from integrating USGIV insertion training into standard vascular access education.