Search

Placement of peripheral intravenous (IV) catheters is a fundamental skill that all health care professionals should possess. Unfortunately, it can be difficult to obtain IV access in some patients, including obese patients, children, and patients who have undergone placement of many IVs or who have a history of difficult IV access. Ultrasound guidance enables visualization of veins that are not apparent on physical examination, resulting in fewer needlesticks, more rapid cannulation, and less discomfort in patients with difficult IV access. 1-3 Ultrasound-guided IV placement is indicated when it is difficult or impossible to use traditional techniques. There is no contraindication to ultrasound-guided IV placement, but it is unnecessary when traditional techniques are sufficient. Health care providers who are proficient in standard placement techniques will find it relatively easy to learn ultrasound-guided techniques. There are two common approaches to the position of the transducer during ultrasound-guided placement of IV catheters: transverse and longitudinal. The transverse approach is easier to learn, but the longitudinal approach is preferred by many experienced providers because it allows better visualization of the needle. 4,5 It is best to learn both techniques. Potential cannulation sites are the hand, the antecubital veins of the forearm, and the basilic, cephalic, and brachial veins of the upper arm. Preparation To get started, wash your hands, adhere to universal precautions, clean the ultrasound transducer with a germicidal solution, place a tourniquet, and apply sterile gel or surgical lubricant to the transducer. Adjust the gain and depth settings of the ultrasound system so that vessels appear black and are in the center of the ultrasound image. Find an appropriate vein by scanning the arm in the transverse orientation, which provides a cross-sectional view of the anatomy and allows simultaneous visualization of veins, arteries, and other structures (Fig. 1). Vessels appear as circular structures, and veins are easily distinguished from arteries because veins collapse with compression. When choosing a vein, remember that a vein with a relatively large diameter is more likely to result in successful catheterization. The depth of a vein is not as important as its diameter, but longer IV catheters are needed for veins that lie more than 1 cm from the surface of the skin. Standard IV catheters are 3.2 cm long (Fig. 2). Common sizes range from 24-gauge for newborns to 14-gauge for adult patients with trauma. Angiocatheters that are 6.4 cm long are adequate for cannulating vessels that are a maximum of about 2 cm from the surface of the skin. Specialized catheters may be best for cannulation of deeper veins. 24-gauge