Ultrasonography-Assisted Peripheral IV (PIV) Catheter Placement

Ultrasound (US) guidance for the insertion of peripheral intravenous (PIV) catheters offers the following advantages over the traditional method of gaining PIV access[1, 2, 3, 4, 5, 6, 7] :

• Allows cannulation of veins that are neither visible nor palpable.

• Reduces the need for a central line and its potential complications.

US-guided PIV cannulation can be performed in 3 simple steps: survey of venous anatomy, preparation, and needle insertion, which are easily performed by a single operator. Lidocaine 1-2% with or without epinephrine may be used at the site of insertion. The patient may be in the sitting or supine position.

The traditional method of PIV catheter insertion requires knowledge of vascular anatomy for estimation of the location of the target vessel and requires visualization or palpation of the vessel for accurate puncture.

The traditional approach carries numerous inherent problems that include the following:

• Location of vessels can vary considerably because of anatomic variability.

• Veins can be distorted as a result of scarring from previous cannulation attempts or sclerosis.

• Veins are difficult to palpate in patients who are obese or edematous.

• Patients with difficult access are routinely subjected to multiple insertion attempts by different operators and are at increased risk of complications. In addition to increased discomfort, such patients often have their blood draw and laboratory test results delayed.

• When the traditional approach fails, the alternative means of gaining intravenous access are blind placement of a PIV catheter, generally in the deep brachial vein; placement of an external jugular (EJ) catheter; or insertion of a central venous catheter (CVC). Each of these options has its own disadvantages.

• Most practitioners are not skilled in blind brachial vein catheterization. The technique has high rates of failure and complication.[8]

• The external jugular vein is not visible in all patients. Patients often cannot tolerate the Trendelenburg positioning used to place EJ catheters.

• While CVCs provide additional information and are necessary in many situations, they have a higher complication rate than PIV catheters (eg, pneumothorax, deep vein thrombosis). CVCs should be used when clinically indicated or when alternative options have been attempted unsuccessfully.

Studies have shown that ultrasound-guided PIV catheter placement results in higher overall and first-pass success rates and very low complication rates. Keyes et al concluded that ultrasound-guided brachial and basilic vein cannulation in the emergency department for patients with difficult access is safe and rapid and has a high success rate.[9]  Costantino et al compared ultrasound-guided PIV access with the traditional blind technique and found that ultrasound-guided placement was more successful, required less time, reduced the number of needle punctures, and improved patient satisfaction.[3]  Several studies have also shown that in addition to emergency physicians and residents, trained emergency nurses and technicians can safely and effectively perform ultrasound-guided PIV catheterization, reducing the number of procedural tasks required by emergency physicians.[10, 11]

Complications

The complications associated with ultrasound-guided peripheral line placement are usually minor and occur with significantly lower frequency than those associated with traditional blind techniques. Potential complications include the following:

• Arterial puncture (brachial): Arterial puncture can be avoided by distinguishing vein from artery through compression or use of color flow Doppler and pulsed-wave spectral Doppler. It can be further avoided by not cannulating the deep brachial vein when other options, such as the cephalic or basilic veins, exist.

• Paresthesia: This complication occurs secondary to injury to the median or median cutaneous nerves.[12]

The most common infectious complications with PIV insertion are phlebitis and cellulitis. One observational study reported PIV complications occurring in approximately half of all patients, with the most common complications being phlebitis, hematoma formation, and fluid/blood leakage.[13]

Indications for performing ultrasound-guided peripheral intravenous (PIV) cannulation include, but are not limited to, the following:

• Failure to cannulate by using the traditional technique.

• Cannulation of a patient who is severely dehydrated.

• Cannulation in patients who are obese.

• Cannulation in the presence of peripheral edema.

• Cannulation in patients who use intravenous drugs or who have had multiple intravenous catheters placed in the past (eg, patients with sickle cell disease).

• Cannulation in the presence of burns that overlie the cannulation site.

The Society of Hospital Medicine recommends that providers use real-time ultrasound guidance for the placement of peripheral intravenous lines in patients with difficult peripheral venous access to reduce the total procedure time, needle insertion attempts, and needle redirections. Ultrasound-guided PIV insertion is also an effective alternative to central venous catheter insertion in patients with difficult venous access. In addition the guidelines suggest using real-time ultrasound guidance to reduce the risk of vascular, infectious, and neurologic complications during PIV insertion, particularly in patients with difficult venous access.[14]

Lidocaine 1-2% with or without epinephrine may be used at the site of insertion, as in traditional peripheral catheterization. Since ultrasound-guided PIV placement is usually of short duration and associated with limited discomfort, local infiltration is often not necessary. (For more information, see Local Anesthetic Agents, Infiltrative Administration.)

In pediatric patients, depending on the urgency of placement, a topical anesthetic cream (eg, eutectic mixture of local anesthetics [EMLA]; lidocaine, epinephrine, and tetracaine [LET]) can be applied. These agents require as long as 30 minutes to take effect. (For more information, see Anesthesia, Topical.)

When local anesthetic infiltration is used with traditional peripheral intravenous (PIV) cannulation, the swelling that results from the infiltration can make the target vein difficult to see or palpate. This is not a problem under ultrasonographic guidance.

The equipment needed for ultrasound-guided peripheral intravenous (PIV) cannulation include an ultrasound machine, probes/transducers, PIV catheters, traditional angiocatheters, and additional materials, such as a tourniquet, saline-filled syringes, skin prep materials and solutions, and sterile gel.

Probes/transducers

Probes and transducers include linear array probes, curvilinear probes, and intracavitary (endovaginal) probes.

Linear array probes (see the image below) are the probe of choice, favored by most practitioners. This probe has a flat footprint and results in an image on the screen that is rectangular or square (ie, linear scanning format). Linear probes are high-frequency probes (7.5 to 10 MHz) and produce high-resolution images of superficial structures. 

Linear probe.

Curvilinear probes (see the image below) have a large, curved footprint and are usually used to scan deeper, larger structures, such as in the abdomen or thorax. They typically have a frequency range of 2-5 MHz. When using this probe to place PIVs, select the higher frequency (the frequency can be manipulated on most ultrasound machines). The higher the frequency, the greater the resolution but the lower the penetration. For vascular imaging, a higher resolution (ie, 5 MHz) should be selected. Compression of vessels (to identify veins) may be more difficult with a curvilinear probe than with a flat linear array transducer.

Curvilinear probe.

Intracavitary (endovaginal) probes are curvilinear probes that have a tight footprint and are designed to be inserted into an orifice for closer proximity to the organ of interest. If a linear probe is not available for vascular access, this probe is a practical alternative given its small footprint and high frequency. It has a wide field of view (up to 180º) and has a frequency range of 8-13 MHz. These higher frequencies produce images with improved resolution at the expense of depth of penetration.

Traditional angiocatheters

Traditional angiocatheters come in standard and longer lengths, such as the following:

• 1.18 inch (standard length)

• 1.25 inch (used by Costantino et al)[3]

• 1.8 to 2.0 inch (used by Keyes et al)[9]

The authors recommend 1.88 to 2.5 inch catheters, as shown below. Longer-length PIV catheters have been shown to have better longevity and are less likely to result in IV infiltrations than standard-length PIV catheters[15]

Standard versus longer (1.88 to 2.5 in) catheters.

Arterial catheterization with the Seldinger technique

To incorporate a guidewire and a catheter, first complete venipuncture with a needle. Then, place the guidewire into the lumen of the vein, position the catheter over the guidewire, and remove the needle. A 1.75-inch catheter is commonly used with this technique. Stone used a 4.25-inch (10.8 cm) catheter with good success.[16]

In a study of ultrasound-guided PIV catheterization of a deep arm vein for a maximum of 7 days in 29 patients, after PIV cannulation failure, the catheterization was successful for all patients. The authors found that catheters inserted with the Seldinger method are adapted to prolonged peripheral deep vein infusion. They added that ultrasound can play a role in catheter monitoring by identifying early thrombosis formation.[17]

Additional items

Additional materials (see the image below) needed include the following:

• Transducer cover (eg, Tegaderm [3M, St. Paul, Minn]) to protect the probe during cannulation attempts

• Tourniquet

• Extension tubing

• Saline-filled syringes for flushes

• Skin preparatory materials (eg, Betadine, chlorhexidine, alcohol)

• Sterile gel: Packaged water-based lubricant gel, such as that used for digital rectal and vaginal examinations, is sterile and is the preferred choice during ultrasound-guided PIV catheter placement. The ultrasound gel used for regular brightness mode scanning (in large plastic bottles) is not sterile and may have bacterial contaminants.

• Gauze

Peripheral access materials.

The patient may be sitting or supine. Both the patient and operator should be comfortable. Practitioners often prefer to be seated at the bedside.[18]

A study by Yamagami et al showed that in 80 patients 20 to 64 years of age, vein size during tourniquet application was greater in the supine position than in the seated position even in cases of difficult peripheral intravenous cannulation.[18]

When cannulating upper-extremity veins, the arm should be abducted and externally rotated to fully expose the anteromedial aspect. Preferred and alternative machine placement are shown below.

Preferred machine placement.

Alternate machine placement.

Placement of peripheral intravenous (PIV) catheters

Ultrasound-guided PIV cannulation can be performed in 3 simple steps: (1) survey of venous anatomy with ultrasound, (2) preparation, and (3) needle insertion and manipulation under ultrasonographic guidance. These steps are easily performed by a single operator and involve a combination of short-axis (transverse) and long axis approaches.

Survey of venous anatomy

To survey the vessels, start in the antecubital fossa. Slide the transducer up and down the humerus.

Upper extremity venous anatomy.

Upper extremity target veins include the basilic, brachial, and cephalic veins. Choosing which vein to cannulate is based on the following factors: diameter of vein (the larger the better), depth of the vein (distance from skin surface), and path of travel (straight veins are easier to cannulate than tortuous ones). The basilic vein most frequently meets each of these conditions. However, a retrospective study demonstrated that deep veins in the proximal upper arm are associated with reduced PIV catheter longevity, thus recommending superficial veins in the antecubital fossa for cannulation.[19]

Start by positioning the transducer over the antecubital fossa in the transverse orientation, with the probe indicator pointing to the patient's right side. Another, simpler rule regarding probe orientation is to keep the probe marker directed to the operator's left. In this orientation, the probe marker corresponds to the left side of the image seen on the ultrasound screen.

While surveying the venous anatomy, fully compress the vessels to differentiate veins from arteries. Patent peripheral veins easily and completely collapse when gentle pressure is applied with the transducer. In contrast, arteries do not completely collapse, though slight deformation of artery walls can be seen. Arteries can often be seen pulsating.

Color-flow Doppler and pulsed-wave spectral Doppler can both help identify veins and differentiate them from arteries (see the images below).

Basilic vein; brachial vein and artery.

Drag the transducer up and down the target vein to better determine the direction and depth in which it travels.

An article by Witting et al demonstrated higher success rates with picking a vein of a diameter of at least 0.4 cm and a depth no greater than 1.5 cm.[20]

Preparation

Place a cover (eg, Tegaderm) directly on to the probe face without any gel between them, as shown below. This protects the transducer from the preparatory solution or bodily fluids and maintains a sterile insertion site.

Probe cover.

Apply a tourniquet high up around the arm near the axilla.

Prepare the arm from the antecubital fossa to the proximal humerus.

Apply sterile gel to the transducer and the arm, as shown below.

Needle insertion and locating the needle tip

Hold the needle with the dominant hand and hold the ultrasound probe with the nondominant hand.

Center the vessel on the ultrasound screen; the center of the probe corresponds to the center of the display monitor.

Before puncturing the skin, slide the catheter between the transducer and the skin to look for the shadow artifact, as shown below.

Needle shadow artifact.

Align the shadow artifact with the vein on the ultrasound screen.

Take note of the depth of the chosen vein by using the depth markers on the side of the ultrasound screen.

Use a needle approach angle of 45 degrees perpendicular to the skin, as shown below. By using this approach angle, the point of skin insertion should be the same distance in front of the transducer as the depth of the vein.

After initial needle puncture, identify the needle tip on ultrasound by scanning back and forth just beyond the point of needle insertion. Failing to locate the needle tip can lead to misdirection and difficulty assessing the proximity of the needle tip to the target vessel.

When advancing the needle, focus on the ultrasound screen and not on the probe or skin surface. Repeated adjustments of the course of the needle are crucial to successful cannulation of peripheral veins.

At times, the needle tip may be difficult to visualize directly. The following maneuvers may help locate the tip of the needle:

• Dragging or fanning the probe back and forth over the needle, looking for the needle tip.

• Gently bouncing the needle within the soft tissue to obtain a better sense of where the needle tip is located.

• Ring-down artifact, as shown below.

  Needle ring-down artifact.

• Acoustic shadowing, as shown below.

  Needle shadow artifact.

Confirm cannulation of the vein with flashback of blood or with direct visualization of the needle tip within the lumen of the vessel (ie, bull's eye sign).

Put down the transducer and continue with placement of the PIV catheter as per the usual technique.

• Advance the catheter.

• Attach the extension tubing.

• Draw blood and then flush the catheter.

• Wipe gel off the arm.

• Secure the catheter.

Mistakes to avoid

Mistakes to avoid include the following:

• Not advancing the probe while advancing the needle (see the first video below).
• Not tracking the needle and locating the needle tip (see the second video below).
• Failing to locate the needle tip results in puncturing through the back wall and overshooting the vessel. To avoid falling behind the needle tip, move the probe ahead of the needle, then advance the needle until it enters the ultrasound beam and comes into view on the screen.

Additional issues

Additional issues of which to be aware include the following:

• Static versus dynamic, real-time imaging: Because of the smaller size and increased anatomic variability of peripheral vessels, ultrasound-guided PIV placement is best performed in real time. With central line placement, however, the operator has the option of locating and marking the vessels with ultrasound first, and then performing the cannulation in the traditional manner. ^[5]
• One-person versus two-person technique: Although ultrasound-guided PIV cannulation can be performed by a team of 2 people, the authors recommend a single operator. Considerable coordination is required between 2 people if one of them controls the transducer and the other moves the needle.
• Transverse versus longitudinal orientation: The transverse approach, shown below, has advantages and disadvantages. The advantage of the transverse approach is better lateral resolution, which results in a higher success rate. The main disadvantage is the challenge of not losing sight of the needle tip. In this approach, the operator must move the probe forward along with the needle tip as it is advanced.

The longitudinal approach, shown below, also has advantages and disadvantages. The advantage of the longitudinal approach is that the entire needle can be visualized as it advances and enters the vein. The depth orientation is better with this approach. For some operators, this approach is also more intuitive. The disadvantage of the longitudinal approach is poor lateral resolution. A needle located just to the side of a vessel can be appear to be in the same plane. In addition, operators must be careful not to accidentally rotate off the vein and onto an adjacent artery as they obtain the longitudinal view.

Although long-axis views are sometimes used to guide central venous access, this technique is not as useful for identifying smaller veins in the periphery.[5]  Blaivas et al found that the transverse short-axis approach was easier for novices to learn than the long-axis approach.[21] Mahler et al showed that a short-axis approach to PIV insertion was faster and resulted in a higher success rate than a long-axis orientation.[22] Sandhu et al, however, demonstrated the use of the longitudinal approach to cannulate the basilic or cephalic vein in over 120 difficult-access patients without inducing nerve injury.[23]

In a meta-analysis comparing short- and long-axis techniques for ultrasound-guided PIV placement, the short-axis technique was successful in 125/128 placements (97.7%), and the long-axis technique was successful in 114/128 placements (89.1%). There was an odds ratio of 5.35 (95% CI: 1.46-19.58) in favor of the short-axis technique. There was no difference in the mean number of needle passes. Time to insertion varied between studies. The authors concluded that short-axis technique may be considered as the first approach for ultrasound-guided PIV placement among providers comfortable with both techniques, though further studies were needed.[24]

Placement of midline catheters

PIV catheters often become infiltrated or dislodged. In one of the earlier reports of ultrasound-guided PIV insertion, Keyes et al concluded that the technique was safe, rapid, and highly successful.[9] They also noted that 8% of the catheters infiltrated or fell out within 1 hour after placement, despite the use of relatively long catheters (1.8 to 2.0 in). They surmised that the rate of infiltration may have been caused by the proximity of the intravenous site to the biceps muscle and tendon, the securing of the intravenous tubing across the antecubital fossa, and the greater depth of the veins in larger patients. Their conclusion was that longer-than-normal catheters should be used for this procedure.

Longer PIV catheters (2.5 in) are commercially available. They do, however, present their own challenges. Flash-back is delayed with longer catheters, and many practitioners find them somewhat harder to control.

Mills et al proposed the placement of a midlength catheter into a deep brachial or basilic vein under ultrasonographic guidance as a solution to the problem of infiltration.[12] They devised the following 2-step process:

• First, under ultrasonographic guidance, the deep brachial or basilic vein is cannulated with a catheter of standard length (32 mm).

• A guidewire is then passed through the catheter into the vein. The initial catheter is then removed, and a 15-cm, 16-gauge catheter is inserted over the wire into the vein.

Using this 2-step process, Mills et al reported a success rate of 92%, with an infiltration rate of 4%.[12] The median time to complete the procedure was 8 minutes. The catheters remained in place a median time of 26 hours. Patients demonstrated a high degree of satisfaction. The authors concluded that this technique offers a safe and rapid alternative to central line placement in adult patients with difficult intravenous access in the emergency department setting.

A midline catheter is a variation of a peripherally inserted central venous catheter (PICC line). A PICC is usually 50 cm or longer, inserted into an arm vein, and advanced until the tip is located in the superior vena cava. These catheters are used in inpatient and outpatient settings when long-term intravenous access is needed.

Placement of a PICC line is an involved procedure that often takes an hour or more to complete. If the procedure is performed in a radiology suite, fluoroscopy can be used for guidance. In addition, the position of the catheter must be confirmed with radiology before use. For these reasons, PICC lines are not placed in emergency departments and other acute care settings. 

Midlines extend approximately to the level of the patient's shoulder and are much faster and easier to insert than PICC lines. They combine the best characteristics of traditional peripheral and central venous catheters.

(See the videos below for the step method.)

To avoid catheter dislodgement and infiltration, use longer angiocatheter needles (1.88 to 2.5 in). Catheter length should be selected based on anticipated distance to the vein to ensure that a sufficient portion of the catheter will remain in the vessel.[4]

Use great care when cannulating the wall of the vein, as they are prone to buckle, and the needle may puncture through both the anterior and posterior walls.

Passing the needle into the vein typically results in flashback.

If no return of blood appears after the plastic catheter is advanced, the vein has likely been overshot (ie, the needle has punctured the posterior wall). Scan distally or rotate the probe into the longitudinal approach to determine if the needle tip has passed beyond the vessel. When this occurs, try attaching a saline-filled syringe to the catheter and, with gentle aspiration, slowly withdraw the catheter tip until venous blood is obtained. Once blood is seen, slowly advance the catheter again.

If the needle appears to be in the vessel but no flash or return of blood has occurred, release forward pressure on the needle and see if the needle still appears to be in the vein. If the needle tip is above the vein, advance the needle and look for the vein to pop open. After feeling the pop of the needle passing through the vein wall, look for flashback and for the bull's eye sign.

Before flushing the catheter at the end of placement, remember to release the tourniquet. Otherwise, the vein might rupture.

Be mindful of the amount of pressure applied to the transducer. Peripheral veins collapse easily and, when collapsed, cannot be visualized on the monitor.

The catheters used are long, so the flash may take a few seconds to appear. Be careful not to keep advancing the needle while waiting for flashback, as doing so results in overshooting the vessel.

On the monitor, watch the needle enter the vessel and then stop advancing. Wait a few seconds and look for subsequent blood flash to confirm that the needle is truly in the vessel.

To avoid problems with probe orientation, always keep the marker on the probe pointing toward the operator's left. If the needle tip is lost, try gently wiggling or bouncing it back and forth in the tissue to find it. (See the video below.)