Ultrasound-image Guided Versus Doppler Guided Versus Palpation Technique for Arterial Cannulation in Adults

Radial artery cannulation is a common invasive procedure in the operating room, intensive care unit and emergency department. It allows continuous hemodynamic monitoring and repeated arterial blood sampling. Although severe complications are rare, successful radial artery cannulation can be technically challenging, particularly in hypotensive patients and those with vascular disease. Multiple unsuccessful attempts at arterial cannulation increase patient discomfort, delay timely care and may also contribute to adverse events such as arterial spasm or local hematoma.

The radial artery is traditionally located by palpation. A number of techniques to aid radial artery localization have been described. Doppler-assisted radial arterial cannulation was first described in 1976. Several case reports suggest that Doppler can be helpful in patients with difficult arterial access. More recently, ultrasound-guided radial artery cannulation has been described. In a recent meta-analysis of four randomized controlled trials, ultrasound increased the rate of cannulation on the first attempt by 71% compared with palpation. However, two of the studies were of children and all four were small, with 30-152 participants (311 in total), making the generalizability of these results to adult patients uncertain. Furthermore, variation in the training and experience of the operators was evident within one of the studies.

Accordingly, the aim of this study is to compare three different radial arterial cannulation techniques in adult surgical patients when performed by anesthesia residents: Doppler; palpation; and ultrasound. We think that ultrasound would have a higher rate of cannulation on the first attempt compared with other techniques.