Ultrasound Guided Catheter Length Survivability

Overview

In patients with difficult IV access, ultrasound-guided catheter insertion is a preferred technique. However, many peripheral catheters fail and must be replaced, adding extra pain and difficulty for the patient, and requiring more healthcare provider time to maintain. In preliminary studies, we determined that catheters which extend further into the vein have a smaller failure rate. This study will compare two lengths of catheters to see if the longer catheters have better survival in a population of patients who have difficult IV access. Patients will be randomized to receive a standard length or extra-long venous catheter, which will be monitored daily for functionality during the patient's hospital course.

Patients with poor intravenous (IV) access present a daily challenge to emergency department (ED) practitioners. Placement of an ultrasound (US)-guided peripheral IV catheter in this patient population is a viable and safe option. Ultrasound-guided IVs are often the last recourse for IV access before resorting to more invasive procedures in patients with difficult access. Successful cannulation with US-guided IV occurs in more than 90% of cases compared with 25-35% with traditional IV placement in patients with difficult vascular access. Once cannulated, however, the failure rate of IV catheters placed under ultrasound guidance is concerning compared with traditional blind IV placement. Overall failure rates after successful IV cannulation for US-guided IVs is 45-56% when compared to traditional IV placement which is 19-25%. Because failure rate is high, it is important to approach insertions methodically to improve survival rates. A variable that may alter the survival of US-guided IVs that has not been studied is the length of catheter that resides in the vein. Currently the general accepted rule is that an "adequate" amount of the catheter should be in the vein to avoid failure of the catheter. Our preliminary data focused on defining this relationship. In our study, 100% of catheters failed in which less than 30% of the catheter was placed within the vein and no failures in those IVs in which at least 65% of the catheter was in the vein. This study was performed by the PI at Beaumont this past year and is published in Emergency Medicine Journal. This study is a prospective randomized controlled study of catheter longevity comparing a 4.78 cm (1.88 in) catheter to a longer 6.35 cm (2.5 in) catheter. Subjects will consist of a convenience sample of patients with difficult IV access presenting to the Beaumont Hospitals emergency department that require US-guided IV access. Standard of care is defined as use of a readily available 1.88 inch IV catheter that is used daily by emergency department personnel. Following consent, patients will be randomized to the control arm using the standard 4.78 cm catheter, or the experimental arm using a 6.35 cm catheter. All catheters are 20 gauge in diameter. After patient enrollment, the insertion tech, nurse or physician who has been credentialed in ultrasound-guided vascular access will place catheters in study subjects. Staff are expected to attempt a minimum of 3 attempts before enlisting another provider for help. After initial assessment, follow-up functionality of the catheter will be assessed every 24 hours by the research team as long as the patient is hospitalized, up to 30 days. Function of the catheter will be assessed daily by research staff. Function is defined by a catheter's ability to draw back 5 ml of blood, flush with 5 ml normal saline without resistance, or if IV fluids or medication are continually infusing through the IV. Other data variables collected include: patient pertinent medical history, vitals, age, sex, cannulation success or failure, vein diameter, length of catheter in vein as well as % length of the catheter in the vein, angle of insertion, number of venous access attempts, time to IV insertion (tourniquet to tegaderm), location of IV insertion, medications infused or use for ionic contrast injection for computed tomography.