Nurses or other ancillary staff routinely perform the task of acquiring IV access, but at times they are unable to obtain access, which is important for laboratory evaluation or fluid or medicine administration. When this occurs, such as in an obese patient or a patient with IV drug abuse history, the onus falls on the physician to achieve intravenous access.
While several studies have shown increased success rates using ultrasound guidance during the establishment of central venous access, Costantino et al. sought to determine if ultrasound guidance for peripheral IV access in difficult to access patients would have similar results.
The study was designed to prospectively randomize patients who had a history of difficult access—due to obesity, history of intravenous drug use, or chronic medical problems—and had failed at least three attempts at access by a nurse. All patients who had a need for central venous access were excluded, as were pregnant patients, children, and those unable to consent. The patients were allocated to the ultrasonography-guided or the landmark and palpation (control) group based on the presentation to the ED on an odd or even day, respectively. The primary endpoints measured were IV access success rate, time from first percutaneous perforation to successful cannulation, time from request for physician-performed IV access to successful establishment of intravenous access (in order to also take into account time to find and set up the ultrasound machine), number of percutaneous perorations required, patient satisfaction, and complications from intravenous access.
A total of 60 patients were enrolled—39 into the US-guided IV access group, and 21 into the landmark and palpation group. The success rate for the ultrasonographic group was 97%, versus 33% for the control group. Patients undergoing US-guided required less overall time to establish IV access (13 minutes versus 30 minutes). The US-guided group also had less time to successful access from the first percutaneous puncture (4 minutes versus 15 minutes), had fewer percutaneous punctures (1.7 versus 3.7), and had a greater patient satisfaction (8.7 versus 5.7). There were no significant complications reported in either group.
While this study showed ultrasonography is an invaluable tool in aiding the physician in establishing IV access, it is notable that this study did employ a two-operator approach. Castantino et al. addressed this, mentioning a previous study showing no difference in success with US-guided peripheral IV access using either one or two operators. However, although it may not affect overall success of the peripheral IV placement, a single operator approach may or may not prolong the time to achieve access. Another limitation listed in the study was that, although there were three additional “odd” days, a larger than expected group was enrolled into the US-guided IV access group. The authors best explain this as a probable selection bias. In addition, the authors also thought it important to mention that those in the traditional group were allowed to attempt cannulation of the external jugular vein—as that is often what takes place in the “real world”. While this may introduce more bias, it would favor the control group and not the ultrasound group.