Introduction
Ultrasound-guided insertion of an intravenous catheter (US IV) uses ultrasound (US) imaging to search for suitable peripheral veins that will support intravenous (IV) catheter placement, as well as visualize the IV needle approach and cannulation in real time. This procedure can be done on patients with difficult access due to obesity, burns, IV drug use, chronic illness such as sickle cell disease, or in patients with limited access to one arm, such as dialysis patients and breast cancer survivors. This procedure may be used when veins are not visible or palpable from the surface. Emergency department (ED) technicians (EDTs) who are trained in IV access can be trained to place US IVs.
Benefits to US IV insertion include access to veins that are not accessible to conventional (landmark) technique; decreasing time to diagnostic testing; and administration of IV therapy, such as fluids, medications, and blood transfusion. US IV placement in difficult-access patients also significantly decreases the number of central lines placed in the ED and in doing so decreases the risk of associated mechanical central line complications, such as pneumothorax and hematomas, as well as blood clots, and central line–associated bloodstream infections.
Equipment
The items necessary for placement of US IV are a US machine with a vascular probe, disinfectant for the machine, sterile US gel, and all the equipment typically used for landmark-based IV placement ( Fig. 16.1 ).
ULTRASOUND Machine
US equipment has evolved rapidly in recent years, and clinicians have a wide range of options that are suitable for US-guided vascular access. From cart-based systems, to compact US systems, to hand-carried devices that connect to tablets and smartphones, a wide range of options exist to fit needs and budgets. New developments include handheld devices that display both long- and short-axis views simultaneously, avoiding a long-running debate over the best approach to US IV visualization ( https://www.butterflynetwork.com/iq ). The most important feature to consider when choosing US equipment for needle guidance is the resolution of superficial structures. A high-frequency probe capable of identifying the needle tip, vasculature, nerves, tendons, and soft tissue with a high degree of resolution is essential to successful US IV placement ( Fig. 16.2 ).
IV Catheters
Veins identified on US can be superficial or deep. If a patient has superficial veins visualized, these may be cannulated by a standard IV catheter. When cannulating deeper veins (such as in the medial upper arm), a longer catheter may be necessary in order to have sufficient catheter left in the vessel after transiting the soft tissues, in order to prevent dislodgement and infiltration. In our practice, we use 1.75- and 2-in angiocatheters for deeper vessels ( Fig. 16.3 ).
For smaller, difficult-to-access veins, some operators prefer to use an IV catheter that contains a wire that works as a guide. These catheters are more commonly utilized for arterial access. Once the IV catheter pierces the vessel and there is a flash in the hub, the wire can be advanced, and then the catheter itself can be easily advanced over the wire as a guide.
Sterile Probe Cover
US IV placement is a sterile procedure, and as the probe will be moving back and forth across the area of access, it is important to have a sterile barrier between the probe and the patient, taking care to avoid the inclusion of air bubbles at the probe face, which would disrupt the image. This sterile barrier can be a sterile glove, a sterile US probe cover, or an occlusive dressing. To use a sterile glove, first place gel inside the glove, insert the probe into the glove, then fold the fingers out of the way. The first and fifth digits of the glove can be tied together to keep the other three fingers of the glove folded back. Sterile probe covers are commercially available, typically prepackaged with sterile gel, and are most commonly used for US-guided central line placement. Occlusive dressings (e.g., Tegaderm), most commonly used to secure an IV cannula in place, have been used to cover the face of the probe as a sterile barrier. However, these are not approved by the United States Food and Drug Administration, and many manufacturers in the United States recommend against this, citing concerns of damaging the probe.
Knobology
Although high-end US machines can have a bewildering array of controls, the controls necessary for guidance of insertion of IV catheters are relatively few: power, probe select, orientation marker, depth, gain, color Doppler, and center guideline.
- 1.
Power: Finding the power button is an essential first step. If pressing the power button does not turn the machine on, check to see if the power cord is plugged in and securely seated into the machine, and that the battery is charging. ( Fig. 16.4A and B ).
Fig. 16.4
(A) Control buttons on the Sonosite Edge. (B) The touch screen on the Sonosite Xporte. Both machines have buttons in the top right corner to power on.
- 2.
Probe (also known as “transducer”): If the US machine has multiple probes attached to it, identify the linear probe (also known as a “vascular” or “high frequency” probe) ( Fig. 16.5 ). Controls to select the probe vary by machine manufacturer and can be a button to select the probe, a touch-screen selection, or a manual connection of the probe. Once the linear probe is active, a rectangular imaging window will appear on the screen (as opposed to the pie-shaped sector from the phased array or curvilinear) ( Fig. 16.6 ).
Fig. 16.5
Probes commonly found in portable ultrasound machines in the emergency department.Related posts:
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