Overview of Ultrasound-Guided Intravenous Access
Each year in the United States, about 150 to 200 million peripheral intravenous (PIV) catheters, or small tubes inserted into a vein to give fluids or medications, are used. In fact, up to 80% of patients in the hospital will need a PIV at some point during their stay. However, getting a PIV can be complicated by several factors such as obesity, drug abuse via injections, dehydration, along with various long-standing health conditions.
Due to these challenges, medical staff are being trained to use ultrasound, a technology that uses sound waves to create images of the inside of the body, to help place a PIV in patients who have had difficulty getting one in the past. This method of using ultrasound to guide the placement of PIVs has not only significantly decreased the need for more invasive procedures like central venous catheter placement in emergency rooms, but it also has improved patient satisfaction.
Anatomy and Physiology of Ultrasound-Guided Intravenous Access
Ultrasound guidance can help doctors insert a cannula (a tiny tube) into small veins near the surface of your skin (like those usually used for placing an intravenous line or IV). The ultrasound can also show them how to access veins that are deeper under the skin. It’s a good practice for doctors to always start with the veins that are farthest from the heart, to ensure that veins closer to the heart are available for future uses.
Using larger veins that are closer to the skin surface is a better practice because the IV line can be functional for a longer time. Similarly, veins that are larger than 4mm are easier to cannulate (insert the tiny tube).
While using an ultrasound, blood vessels appear as black circles, muscles show up as grey areas with lighter greys running through them, and bones show up as bright white lines. Note that ultrasound can’t penetrate bone, so you typically won’t see any grey echoes beneath the bone.
Despite the variations in individual anatomies, there are certain common veins in your forearm and upper arm that are often targeted when an IV line needs to be inserted. These include the cephalic vein (on the outer side of your arm), the median antebrachial is in the middle of the forearm, and the basilic vein (on the inner side of your forearm).
If these veins in the forearm are not suitable for the IV, the doctors can look up to your upper arm. The cephalic vein in your upper arm that runs along the front of your bicep is a good option as it is closer to the skin surface. Another vein that often becomes a target is the basilic vein which runs along the inner edge of your upper arm. It is typically deep enough that it can’t be located simply by touch or sight.
If the basilic vein isn’t a good fit, the doctor can look for the deep brachial veins in your arm. These veins, however, are located close to the brachial artery and major nerves in your arm and therefore, it’s necessary for the doctor to understand the anatomy of the arm and be trained well before trying to access these veins. Because of these complexities, the deep brachial vein is often not the first choice for inserting an IV. Finally, the deep brachial and basilic veins join to form the axillary vein as they go upwards towards the underarm or the axilla.
Why do People Need Ultrasound-Guided Intravenous Access
Often, ultrasound-guided intravenous (USGIV) procedures are used when the standard method of locating veins by feeling them doesn’t work. In some places, they have rules saying that a certain number of tried-and-failed attempts without an ultrasound need to happen before doing an ultrasound-guided procedure. However, it’s okay to use ultrasound from the start as long as the doctors or nurses try to use the veins that are closer to the surface of the skin first.
If doctors or nurses are learning how to do USGIV procedures, it can be helpful for them to practice on veins that are close to the surface in the forearm. This practice can help them learn how to coordinate their hands with the ultrasound. Once they have become good at this, these skills can be used to access veins that are deeper in the body.
When a Person Should Avoid Ultrasound-Guided Intravenous Access
The reasons for not using an ultrasound-guided intravenous line (USGIVs) are the same as for a regular intravenous line (PIV). These include:
– If there’s an infection or inflammation of a vein (phlebitis) on the skin above the vein,
– If there’s an abnormal connection between an artery and a vein (arteriovenous fistula) in the arm or leg,
– If previous surgeries to the arm or leg have affected the blood vessels, and
– If there’s been an injury or burn near the area.
In these cases, that particular vein might not be the best choice for inserting an intravenous line.
Equipment used for Ultrasound-Guided Intravenous Access
A high-frequency ultrasound machine, fitted with a specific type of attachment called a linear probe, is necessary for carrying out a procedure known as an ultrasound-guided intravenous therapy (USGIV). This machine helps the doctor to clearly see the veins, located near the surface of the skin, which are targeted during this procedure.
The veins that are accessed with the aid of an ultrasound are generally deeper than those accessed using traditional methods. Consequently, it’s necessary to use an IV catheter that is longer than usual. Various sizes and lengths of IV catheters can be used for this process, but it’s essential to ensure that the catheter is long enough. Specifically, when the procedure is performed on the basilic and brachial vessels of an adult patient’s arm, it’s recommended to use a catheter that is at least 2.5 inches long.
Other equipment necessary for a successful USGIV procedure includes a clean cover for the ultrasound probe, an ultrasound gel that’s sterile (free from bacteria), and a towel for wiping off the gel. Covers specifically made for keeping the ultrasound probe clean and bacterium-free are available. Alternatively, a type of clear adhesive film that is often used to secure IVs can be used as a cover for the probe. Other basic IV equipment, like a rubber strap for restricting blood flow (tourniquet), an extending tube, a cap for the IV, and a device to hold the IV in place, will also be required for performing the USGIV procedure.
Who is needed to perform Ultrasound-Guided Intravenous Access?
The rules and skills needed for a certain nurse to do their job can change depending on where they work. Often, only one nurse who is skilled in using ultrasound to place intravenous (IV) lines (a method known as USGIV) is necessary to do this task.
Preparing for Ultrasound-Guided Intravenous Access
Before setting up for the procedure, it’s vital to have all the necessary materials gathered. Comfort is key so setting up in a way that allows the person performing the procedure to easily see both the patient’s arm and the ultrasound screen can really help. Before inserting the IV needle into the patient, the veins’ expected pathways should be clearly visible. It’s best to find one that’s ideal for inserting a small tube known as a cannula. Research shows that surface-level veins that are larger are usually more successful.
After finding a suitable vein, a cover should be placed on the electronic device used called the probe. For IVs that are in the arms or legs, clear sticky plastic sheets can be used as a cover for the probe. When covering, make sure to place it directly onto the side of the probe that emits the sound waves. It’s also crucial to make sure that there are no air bubbles between the probe and the cover as this could affect the image quality on the ultrasound.
How is Ultrasound-Guided Intravenous Access performed
To start an ultrasound-guided IV placement, there are two main methods: one is called the transverse, or out-of-plane, technique and the other is the longitudinal, or in-plane, technique. When using the longitudinal method, you can watch the needle as it goes into the blood vessel on the screen. But, this method is a bit harder if you haven’t used ultrasound a lot. That’s why for beginners, the transverse technique is suggested.
In the transverse method, the nurse or doctor will use the ultrasound probe to find your vein. On the ultrasound screen, the vein should look like a black circle. They will try to make sure the vein is in the center of the screen to make it easier to use the needle. The ultrasound device might have a guide or centerline function to help them find the middle of the screen, while the middle of the ultrasound probe is also marked to ensure the needle goes through the skin just over the vein.
They’ll hold the ultrasound probe in their non-dominant hand and the IV needle in the other hand – their dominant hand. Usually, they’ll need to stick the needle in a steeper angle than for a regular IV. This is because the veins they use for the ultrasound-guided IVs are usually deeper in your body. While a 45-degree angle works well for most situations, the angle might need to be tweaked based on how deep your vein is.
When the needle tip shares the path of the ultrasound beam, it’ll appear like a bright white dot on the screen. They need to keep moving the ultrasound probe along the vein as the needle goes in. When the bright dot from the needle tip shows up on the screen, they will move the probe slightly forward. They do this to avoid mixing up the actual needle tip with other parts of the needle. As the needle goes in, they’ll move it around to keep it in line with the targeted vein. They’ll keep going until the needle is right in the middle of the vein.
The longitudinal method is more difficult than the transverse one. Therefore, it’s not recommended for users who haven’t used ultrasound a lot. Sometimes, they might accidentally move the probe from a vein to an artery next to it, or might mistake tissue layers for the vein.
For this method, they’d find the vein in a transverse plane, then turn the probe 90 degrees so it follows the vein. For this technique, the needle goes in right next to the narrow side of the probe. The needle then gets adjusted to be in the same direction as the ultrasound probe. The probe is held still over the vein, while they adjust the needle until it is seen on the ultrasound screen, going into the vessel.
For both methods, the last steps are the same. They move and secure the catheter the same way as they do with the transverse technique.
Possible Complications of Ultrasound-Guided Intravenous Access
If you have to get a type of intravenous (IV) tube inserted using ultrasound as a guide (USGIV), you might face some complications, which are common to any IV procedure. But, since USGIVs are placed in deeper blood vessels, the signs of any problem might not be very obvious. Complications from USGIVs might include accidentally puncturing an artery, the IV fluid going into the tissues around the vein (infiltration), coming into contact with nearby nerves, and clotting in the blood vessel (thrombosis).
If you’re learning to insert a USGIV, it can be helpful to practice on veins that are closer to the skin and don’t have an adjacent artery. This can reduce the likelihood of complications.
What Else Should I Know About Ultrasound-Guided Intravenous Access?
Ultrasound-guided intravenous insertions (USGIVs) are capable of making it quicker and easier for doctors to insert a needle into a vein, especially in patients who have difficult veins to access. This method could potentially reduce the need for more invasive procedures, like central lines which involve placing a large IV for administering medication or drawing blood. Although learning how to use ultrasound guidance might be challenging at first, it becomes a beneficial technique with regular use.