Single Lumen Midline Catheter vs Ultrasound Guided Peripheral IV as Performed by Bedside Emergency Department Registered Nurses

Intravenous (IV) access is one of the most frequently performed procedures in emergency medicine and serves as the foundation for many aspects of acute patient care. Reliable vascular access is necessary for laboratory testing, administration of medications and intravenous fluids, contrast-enhanced imaging, blood product transfusion, and other diagnostic and therapeutic interventions. Failure to obtain timely IV access may delay treatment and contribute to prolonged emergency department (ED) length of stay. Difficult intravenous access (DIVA) has been identified as an independent predictor of delayed care and prolonged ED length of stay, making it an important operational and patient safety concern in emergency medicine. Previous studies have suggested that approximately 10% of ED patients have DIVA, while observational data from Albany Medical Center have demonstrated similar rates. Patients with DIVA frequently require multiple attempts at vascular access, which may increase patient discomfort, disrupt clinical workflow, and increase healthcare resource utilization.

Numerous vascular access devices (VADs) are available to manage patients with DIVA. These devices differ in catheter length, insertion technique, location within the vascular system, expected dwell time, and clinical indications. Unlike inpatient settings, where guidance exists for selecting appropriate vascular access devices, there are currently no widely accepted recommendations for vascular access device selection in emergency department patients. Consequently, clinicians often rely on individual experience, local practice patterns, and device availability when selecting a vascular access strategy.

Ultrasound-guided peripheral intravenous catheters are commonly used when traditional landmark-based IV insertion is unsuccessful. Previous investigations have demonstrated that catheter length influences device survival. Shorter catheters placed into deeper veins under ultrasound guidance are associated with shorter dwell times and earlier failure. Prior studies have demonstrated that ultrasound-guided long peripheral IV catheters may fail within hours of insertion and that increasing catheter length may improve catheter survival. These findings suggest that catheter design and insertion technique may play important roles in determining catheter performance.

Single-lumen midline catheters (SLMCs) have emerged as an alternative vascular access device for patients who require intermediate-duration intravenous therapy. Midline catheters are inserted into peripheral veins of the upper extremity and terminate within the axillary venous system. Unlike central venous catheters, midline catheters remain entirely within the peripheral venous system while offering a longer catheter length than traditional peripheral IV catheters. Most midline catheters are inserted under ultrasound guidance and frequently incorporate modified or accelerated Seldinger techniques that may facilitate successful cannulation of deeper veins.

Several characteristics make SLMCs attractive for the management of patients with DIVA. First, previous studies have suggested that midline catheters have substantially longer dwell times than peripheral IV catheters. Published investigations have reported average dwell times of approximately 16 days for midline catheters compared with approximately 5 days for peripheral IV catheters. Second, midline catheters may provide more durable vascular access throughout a patient's hospitalization. Previous studies have demonstrated that many patients who receive a midline catheter do not require any additional vascular access devices during the remainder of their hospital stay. These findings suggest that midline catheters may reduce the need for repeated vascular access procedures after initial insertion. However, relatively little evidence exists regarding the use of these devices in emergency department populations.

Investigators at Albany Medical Center have conducted multiple studies evaluating advanced vascular access in emergency department patients. An ongoing observational study examining vascular access patterns in ED patients demonstrated that patients requiring advanced vascular access devices were generally older, had greater illness severity, and were more likely to arrive by ambulance. A pilot study evaluating procedural characteristics of advanced vascular access devices demonstrated differences in procedural duration and catheter dwell time among ultrasound-guided peripheral IV catheters, single-lumen midline catheters, and central venous catheters. Additional simulation-based work has been performed to characterize procedural workflows, identify procedural micro-skills, and develop standardized training strategies for advanced vascular access procedures. These investigations have provided important preliminary data regarding procedural performance and training requirements.

The most relevant preliminary data informing the current study originate from an ongoing randomized controlled trial comparing SLMCs and ultrasound-guided long peripheral IV catheters in ED patients with DIVA. Preliminary analyses have demonstrated significantly longer catheter dwell times among patients receiving SLMCs. Furthermore, patients randomized to SLMCs experienced higher rates of vascular access remaining functional until completion of care and lower rates of catheter removal because of dislodgement, occlusion, or infiltration. These findings suggest that SLMCs may provide more reliable vascular access for patients with DIVA.

Despite these encouraging findings, an important limitation of previous studies is the identity of the proceduralist. Existing studies evaluating SLMCs have generally involved emergency physicians, advanced practice providers, dedicated vascular access teams, or specialized vascular access nurses. In many emergency departments, however, bedside registered nurses are responsible for obtaining vascular access. As a result, the generalizability of previous findings remains uncertain. Demonstrating favorable outcomes in a controlled environment involving specialized operators does not necessarily establish that similar outcomes can be achieved when the procedure is performed by clinicians who provide routine bedside care in a busy emergency department.

The current study was designed to address this implementation gap by evaluating the performance of SLMCs and ultrasound-guided long peripheral IV catheters when inserted by trained bedside emergency department nurses. Rather than evaluating the technical performance of the devices alone, the study examines whether a model of nurse-performed ultrasound-guided midline catheter insertion can be successfully integrated into routine emergency department practice. This distinction is important because bedside nurses perform most vascular access procedures in many emergency departments and may represent the clinicians most likely to adopt this technique if it proves to be effective.

This prospective, randomized clinical trial will compare ultrasound-guided SLMCs and ultrasound-guided long peripheral IV catheters among adult emergency department patients with DIVA. Both devices will be inserted by bedside emergency department nurses who have undergone standardized training in ultrasound-guided vascular access techniques. The study will evaluate device performance across multiple domains, including procedural success, safety, catheter functionality, durability, and patient-centered outcomes. Additional exploratory analyses will examine the relationships among vessel characteristics, catheter position within the target vessel, and vascular access outcomes.

The investigators hypothesize that ultrasound-guided SLMCs inserted by trained bedside emergency department nurses will demonstrate procedural success rates that are not inferior to ultrasound-guided long peripheral IV catheters while providing improved catheter durability and higher rates of completion of care. If these hypotheses are confirmed, the findings may support broader implementation of nurse-performed ultrasound-guided midline catheter insertion in emergency departments and may contribute to the development of future recommendations for vascular access device selection in patients with difficult intravenous access.

This study may also provide insight into how emergency departments can expand advanced vascular access capabilities while minimizing repeated IV insertion attempts and improving the patient experience. Ultimately, the results may help define the role of bedside emergency department nurses in the delivery of advanced vascular access and identify strategies to improve the care of patients with difficult intravenous access.