Peripheral intravenous catheter placement is a skill that is used daily in the hospital. However, many nurses face the challenge of cannulating increasingly complex and difficult-to-access vasculature. Although emergency department clinicians have been using ultrasound to facilitate this procedure for the last 18 years, ultrasound-guided peripheral intravenous catheter placement has not been as rapidly adopted in the critical and acute care nursing realms. Given the benefits of this procedure, including increased patient satisfaction and reduced use of central catheters, its use should be encouraged among all acute care clinicians. The aim of this article is to provide the bedside nurse with a basic understanding of the techniques involved in placing ultrasound-guided peripheral intravenous catheters in patients with difficult venous access.
This article has been designated for CE contact hour(s). The evaluation tests your knowledge of the following objectives:
Identify patients with difficult intravenous (IV) access who are appropriate for ultrasound-guided IV placement.
List 2 risks and 2 benefits associated with ultrasound-guided IV placement.
Describe the equipment and techniques necessary for developing competency and successfully implementing ultrasound-guided IV placement.
To complete evaluation for CE contact hour(s) for test C2053, visit www.ccnonline.org and click the “CE Articles” button. No CE fee for AACN members. This test expires on October 1, 2022.
The American Association of Critical-Care Nurses is accredited as a provider of nursing continuing professional development by the American Nurses Credentialing Center’s Commission on Accreditation, ANCC Provider Number 0012. AACN has been approved as a provider of continuing education in nursing by the California Board of Registered Nursing (CA BRN), CA Provider Number CEP1036, for 1 contact hour.
Physicians have been using ultrasound technology to assist in central venous catheter placement since 1978. In the 1990s, emergency medicine physicians questioned the use of central catheter access for either a onetime procedure or a single dose of intravenous (IV) antibiotics in those considered to have difficult IV access (Table 1), which ultimately led to the implementation of ultrasound-guided peripheral IV catheters.1-5 Ultrasound-guided peripheral IV catheters are an alternative to central and intraosseous catheters in patients with difficult IV access in the emergency department. The skills needed to place ultrasound-guided peripheral IV catheters can be easily acquired by acute and critical care nurses.1-4
The early adopters of ultrasound-guided peripheral IV catheters found them to be safe and effective and to reduce central catheter use.1,3 Expansion of their use in the acute and critical care settings provides an opportunity to empower nurses, decrease the risk of hospital-acquired infections, reduce health care costs, and increase patient satisfaction.1,3,6-9 The goal of this article is to provide the bedside nurse with a manual for how to insert ultrasound-guided peripheral IV catheters in patients with difficult IV access, thus increasing the reach of this valuable innovation.
Risks and Benefits
The true incidence of complications resulting from use of ultrasound-guided peripheral IV catheters is difficult to determine, and the use of ultrasound may actually reduce complications associated with peripheral IV catheter insertion.9-13 Nevertheless, when placing such a device, the nurse must be cognizant of the risk of contact with nerves and/or arteries, as well as extravasation during the maintenance phase. These risks may be reduced by cannulating vessels less than 1.6 cm in depth.14-16
Longer catheters (7.6 cm) have been found to have mean (SD) catheter survival times of 6.19 (5.1) days to 14.7 (11.1) days and are less likely to dislodge or infiltrate.3,17,18 Researchers have hypothesized that the decrease in infiltration rates may be related to the extended length of catheter dwelling within the vein.19 Longer IV catheters may require a special order, as they are not normally available and require additional insertion training. Other findings indicate that use of ultrasound-guided peripheral IV catheters can reduce the number of central catheters placed in a facility, which may ultimately decrease central catheter–associated blood-stream infections.6,11,12
Although research has not specifically outlined the risk associated with fracturing the cannula in ultrasound-guided peripheral IV catheter insertion, the use of extended-length catheters warrants discussion of this adverse event. In an effort to avoid this complication, the catheter should be evaluated for structural defects before insertion. After initiation of cannulation of the vessel with the catheter, the guide needle should never be reinserted during cannulation to avoid fracturing or severing the IV catheter.19
Placement of ultrasound-guided peripheral IV catheters requires fewer attempts, takes less time (approximately 4.9 minutes less), and increases patient satisfaction compared with traditional peripheral IV catheter placement with no difference in infection rates.7-10,20 In a study comparing traditional peripheral IV with ultrasound-guided peripheral IV catheter insertion among patients with difficult IV access, success rates were 20% higher in the latter group.7
Regardless of baseline peripheral IV catheter insertion skills, ultrasound-guided placement requires formal education, simulated application, and supervised cannulations, as the techniques and hand-eye coordination differ significantly.16,21,22 An average of 25 patient encounters are required to achieve 10 successful ultrasound-guided peripheral IV catheter cannulations, 25 attempts are needed to gain proficiency, and 50 attempts are needed to achieve competency.23 Neither health care provider role nor clinical experience affects the ability to acquire the skill.11,16,21,22
Simulators, also known as phantoms or gelatin arms, are a vital part of any ultrasound-guided peripheral IV insertion program. These devices allow the clinician to learn and practice the new skills without pressure and potentially harming a patient. Simulators are commercially available but can also be created at a cost as low as US$7 to US$20, depending on the supplies used to create the phantom or gelatin arm.6,24,25 Multiple resources are available to assist with the development of this equipment.24,25
Ultrasound-guided peripheral IV catheter placement is indicated in any patient who meets criteria for difficult IV access (Table 1). In addition, the nurse may opt to place an ultrasound-guided peripheral IV catheter for other reasons based on their professional judgment, such as patient anxiety related to IV insertion, request for ultrasound-guided placement, limited access due to a greater number of peripheral IV catheters required, or prolonged hospital stay.
Ultrasound-guided peripheral IV access programs can easily evolve in interventional radiology departments, emergency departments, and intensive care units, where ultrasound equipment is often readily available for procedures and diagnostic studies. Catheters 4.5 cm long are feasible depending on the depth of the vessel, but those 5 cm or longer are preferred to increase dwell time and decrease infiltration risks.3,17,18 Lower-gauge, larger-bore IV catheters may be used in the deeper vessels accessed using ultrasound. A list of necessary supplies can be found in Table 2.26
Early adopters of ultrasound-guided peripheral IV catheters found them to be safe and effective and to reduce central catheter use.
Patient Preparation and Positioning
Before placement of the ultrasound-guided peripheral IV catheter, it should be confirmed that the patient is appropriate for this technique based on the difficult IV access criteria (Table 1) or nursing judgment. The patient’s allergies should always be reviewed before catheter placement. To help decrease patient anxiety, the clinician should ask the patient about any concerns, actively listen, educate, and establish expectations regarding the procedure. If possible, the patient’s dominant hand should be avoided so that they can more effectively participate in activities of daily living.
Whether the clinician chooses to sit or stand, the patient must be at a height that allows proper body mechanics and visualization of the ultrasound screen throughout the procedure. Some individuals prefer that the ultrasound device be located on the same side as placement of the catheter, while others prefer the opposite side; either position is acceptable as long as the provider’s head and neck remain neutral.
Ultrasound Probe Selection
A high-resolution, linear array probe is preferred over a curved array probe to ensure better visualization of structures near the surface of the skin.15,16 Higher frequencies are ideal for more superficial vessels, whereas lower frequencies are more appropriate for visualizing deeper vessels; linear array probes are almost always high frequency.15,16
The ultrasound works by reflecting sound waves from the surface of objects within the human body like an echo in a cave. The reflected sound waves return to the probe, creating electrical signals, which produce the image on the screen through calculations. Vessels are anechoic, producing dark circles, and the needle is hyperechoic, appearing as a bright point on the screen (Figure 1).27 Individuals detect gray scales differently; therefore, the clinician should adjust the gain (how dark or light items appear) to their personal preference.27 Vessels should appear as black structures, and soft tissue should appear light gray.27 Along the middle of all ultrasound displays are centimeter depth markers that allow the clinician to evaluate the depth of the vessels (Figure 2). The ultrasound display should be adjusted to the lowest depth (typically 2 cm or less) to ensure that vein selection is appropriate for catheter length and successful IV insertion.27
Each ultrasound probe has an indicator probe notch to assist with orientation to the ultrasound screen via the indicator marker (Figure 2). If the indicator marker is not in the upper left-hand corner of the screen, the ultrasound user’s guide should be reviewed to determine how to correct the indicator marker’s position on the screen. Proper orientation ensures that the image on the screen aligns with the clinician’s movements (ie, when the clinician moves the needle left, the needle on the screen moves left).
Ultrasound Imaging Approaches
The 2 most common ultrasound approaches are short- and long-axis techniques, with some clinicians using a combination of the 2 techniques (Figure 3). Either of these approaches can be used with 1 or 2 operators with no difference in success rate.28 In the 2-operator technique, 1 operator holds the probe while the other cannulates the vessel.
The short-axis, or transverse, method is the most effective approach for novice users to cannulate the vein.21,29 Shorter insertion times and an increase in successful insertions have been found when using the short-axis technique.30 In either method, miniscule movements can dramatically change the visual field; therefore, micro-movements are key to successful catheter insertion.
Vessel Selection Using the Short-Axis Technique
During vessel selection, the probe can be held in the dominant hand, but at the time of insertion, the nondominant hand should be used. The tourniquet is tied around the arm, and then lubricant gel is applied to the skin at the antecubital area and the vessels are evaluated. Nerves are light white and appear as honeycomb structures. Some veins may not collapse owing to calcification and thrombus, and cannulation of these veins should be avoided. Both veins and arteries may be compressed if significant pressure is applied; however, the application of minimal pressure compresses veins and allows observation of the pulsation of arteries.
Individuals detect gray scales differently; therefore, the clinician should adjust the gain (how dark or light items appear) to their personal preference.
In the upper arm, the basilic vein is close to the brachial artery and the ulnar nerve, but distally, the vein separates from these structures.30 The cephalic vein, located laterally on the arm, is free of arteries and nerves.30 Novices should avoid the brachial veins given their proximity to nerves and arteries. The distal basilic vein is an ideal vessel for novices, as it is often larger, more superficial, and safer to cannulate than the brachial veins.30
When the appropriate vessel is selected, the clinician may prefer to mark the site with an indelible marker to easily rediscover and identify the direction of the vessel.
The clinician tracks the vein distally while evaluating bifurcations, the location of the largest diameter, and the depth and curvature of the vein. Depth is calculated using centimeter depth markers at the center of the ultrasound screen (Figure 2). The on-screen centimeter depth markers align with a marker on the center of the ultrasound probe, represented in Figure 2 as the triangle. The on-screen centimeter depth markers should be centered with the chosen vessel, and then the depth of the vessel calculated; each centimeter depth marker correlates to 0.5 cm. Using Figure 3B as an example, the vessel is approximately 0.6 cm in diameter and 0.5 cm below the skin, with the center of the vessel at 0.75 cm.
The ideal vein is at least 0.3 cm in diameter and 3 cm long.15,30 Novices have been 92% successful in cannulating the vein when vessels are 0.6 cm in diameter or larger.31 Superficial veins (<1 cm deep) are more challenging to cannulate for the novice given the likelihood of penetrating through the vessel. Evidence indicates that vessels more than 1.6 cm deep will not be cannulated with standard ultrasound-guided peripheral IV placement techniques.31 Cannulating deeper veins is possible but is reliant on longer IV catheters (greater than 5 cm) and sufficient skill to avoid arteries and nerves.
When the appropriate vessel is selected, the clinician may prefer to mark the site with an indelible marker to easily rediscover and identify the direction of the vessel. The tourniquet is removed and the identified insertion site cleaned with an antiseptic wipe. The gel is removed and either a probe cover or a transparent dressing is applied to the ultrasound probe.16 When applying either barrier, it should be recognized that air will decrease the quality of the image produced by the ultrasound. If a probe cover is used, ultrasound gel must be placed within the probe cover before inserting the probe. When a transparent dressing is used, the probe’s scanning surface must be clean and free of lubricant gel. The dressing is applied securely to the probe, with the clinician attempting to minimize air bubbles as much as possible to ensure a tight fit to the probe (Figure 4). The purpose of either cover is to reduce the risk of contamination when placing the catheter.
The tourniquet is reapplied, and the path of the needle is triangulated by placing the needle tip at a 45 ° angle, bevel up, at a distance from the probe based on the depth of the vessel (Figure 5A).16 For example, in Figure 3B, the vessel is approximately 0.5 cm below the skin; therefore, the clinician will situate the IV catheter 0.5 cm distal to the probe, aligning it with either the triangular marker on the center of the probe (short-axis) or the seam of the probe (long-axis), ensuring that the vessel is centered on the ultrasound screen (Figure 5A and 5B, respectively). By using a 45 ° angle and the distance based on the vessel’s depth, the needle will come into view at the point of penetration of the vessel.
Catheter Insertion Using the Short-Axis Technique
Upon puncturing the skin, the needle and catheter should be slowly guided to the top of the vein, maintaining a 45 ° descent centered on the probe and ultrasound depth markers. The clinician may see the tissue above the vein begin to distort in a concave manner as the needle penetrates the tissue above. Given the density of the over-the-needle catheter, it will appear as a white point on the screen as it comes into view. One may see the vein bow as the needle penetrates the vessel, and then the white point of the needle will be observed. When the needle is seen entering the vein, the angle of the needle should be decreased and the needle and catheter should continue to be threaded until the “target sign” is achieved and the needle tip is centered in the vessel (Figure 1).13 The degree to which the angle is decreased depends on the depth and trajectory of the vein. Ideally, a flash of blood should be observed when the needle enters the vein.
During this step, the novice user is likely to penetrate the posterior wall of the vein; thus, slow, miniscule movements are important. Given the small visual window of the short-axis method, the novice may not recognize that the posterior wall has been penetrated. The use of a “wiggle test” can help the novice determine if the tip of the needle has transected the vessel. When the target sign is observed, the user moves the catheter side to side, or “wiggles” the over-the-needle catheter.27 If the catheter can move freely in the vessel and the tissue below the vessel is static, the user is most likely seeing the tip of the needle in the center of the vessel.27 If the needle does not move when performing the “wiggle test,” the user has penetrated the posterior surface of the vein.27 If the posterior wall is punctured, the novice should retract the needle slowly and attempt to center the needle tip in the vein, obtaining the target sign.16,27
A fanning, or “stick and stop,” technique is then implemented to continually observe the direction and depth of the vein as well as the tip of the needle within the 0.1-cm-wide plane.9,14 This technique involves repeatedly advancing the probe by a small increment, stopping, then tunneling the catheter and needle until the tip is again visualized by the probe, and again stopping (ie, when the target sign is visible on the ultrasound screen). The technique requires practice and slow, meticulous movements to allow for continual visualization of the needle tip in the vein. For example, upon achieving the target sign, the probe should be advanced slightly along the vein and held at this location. The clinician should follow along the probe’s triangular mark with the needle and catheter until the target sign is again seen and then stop. The clinician then subtly moves the probe proximally along the vein, holds the probe’s location, and tunnels the needle and catheter along the vein and probe’s trajectory until the target sign is again achieved and then stops. This process slowly continues until the hub of the needle and catheter is flush with the patient’s skin. Attempting to thread the catheter without visualizing the vessel increases the risk of vessel puncture, vessel inflammation, and catheter failure.
Some clinicians find value in locating the vessel and centering the needle using the short axis and then rotating the probe to the long axis when advancing the needle.
Catheter Insertion Using the Long-Axis Technique
The long-axis technique, although more difficult to learn, allows visualization of the entire needle and vessel (Figure 6). The difficulty of this technique stems from the narrow plane in which one can observe the vessel and the needle. The plane is as thin as a sheet of paper (0.1 cm); therefore, minimal movement can cause one to lose sight of the target vessel and the needle.14,21 Some clinicians find value in locating the vessel and centering the needle using the short axis and then rotating the probe to the long axis when advancing the needle.14 Regardless of preference, one should always evaluate the surrounding structures using the short axis to prevent complications.
Once the optimal vessel is identified, the clinician aligns the probe with the center of the vessel. The technique for identifying the appropriate puncture site is the same as with the short-axis method, except the marker to center the needle is the seam of the probe (Figure 5B). Fanning is not necessary with the long-axis technique, as the needle will enter the vessel at the point of visualization and the needle can continue to be threaded while the vessel and the needle are fully visualized on the ultra-sound screen. The positioning of the probe indicator notch is also based on clinician preference, with some preferring the notch facing toward the user and others away from the user.
Once the hub of the needle reaches the skin, the tourniquet is removed, the needle withdrawn, and the IV tubing or extension set connected to the catheter, with verification that there are no issues with the ability to flush or draw back on the catheter. The long-axis technique can be used to visualize proper catheter placement and evaluate for any complications. When the catheter is centered in the long-axis view, it should be flushed with 10 mL of saline solution to evaluate flow and catheter positioning.
When preparing the site for dressing placement, the clinician should aseptically remove the excess gel thoroughly and consider the use of skin preparation for better dressing securement. The procedure and patient tolerance should be documented in the patient’s medical record. The probe and ultrasound machine should be disinfected per the manufacturer’s instructions and the ultrasound machine returned to its dedicated location.
Placement of peripheral IV catheters has become a common nursing practice, but with the drive to reduce hospital-acquired infections and increase patient satisfaction, the procedure is evolving. The critical care arena is the ideal location for use of this innovation to expand given the ease of access to ultrasound machines. Ultrasound-guided peripheral IV catheter insertion requires a set of skills that demand persistence and practice to develop, but the procedure has the potential to optimize patient and system outcomes. CCN
The authors thank the interventional radiology and emergency department nurses of Lakeland Regional Health. These individuals were vital in helping us develop our knowledge and skills regarding ultrasound-guided intravenous catheter placement and have inspired us to share these skills with others.
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To learn more about peripheral infusions, read “Peripheral Phlebitis Related to Amiodarone Infusion” by Hannibal in AACN Advanced Critical Care, October 2016;27(4):465-471. Available at www.aacnacconline.org.