Comparison of Ultrasound-guided Versus Blind Insertion of Radial Artery Catheters.

Arterial catheterization is frequently performed on critically ill patients for invasive blood pressure monitoring and/or frequent blood draws, especially arterial blood gas analysis. The distal part of the radial artery (wrist) is the preferred access site.

The potential complications of the procedure are mostly minor and comprise temporary occlusion of the radial artery (RA), hematoma, local infection or bleeding from the puncture site. Major complications including vessel aneurysm or occlusion with threat to hand viability are rare.

The standard approach to catheterization is "blind" puncture of the RA while locating its pulse by palpation, followed by threading a 20 Gauge (20G) angio-catheter into the vessel. Alternatively ultrasound can be used to locate the vessel and guide needle insertion.

To our knowledge, four prospective randomized trials (PRT)5-8 comparing palpation with ultrasound-guided RA catheterization have been conducted so far and one meta-analysis looked at the pooled data obtained from these. The results showed that ultrasound guidance increased the first-attempt success rate at RA catheterization by 71% compared to palpation. The use of ultrasound also significantly reduced the time to successful catheterization, the number of punctures as well as the amount of catheters required per procedure.

None of the prior randomized trials has been conducted in an ICU setting and in three out of the four studies the arterial lines were placed in patients undergoing elective surgery. The investigators hypothesized that ultrasound could improve first attempt success rate while placing arterial catheters in an ICU setting. Ultrasound may also reduce total time to successful insertion and reduce complications.

The investigators plan to randomize patients to either a palpation technique or ultrasound guided catheter insertion and record the above outcomes.