Peripheral intravenous line insertion is the most commonly performed invasive procedure in the emergency department (ED). The research hypothesis is that a biplane sonographic approach (i.e., an out-of-plane and in-plane view) might be superior to a mono-plane approach (i.e., an out-of-plane or in-plane view) obtaining a peripheral vascular access among difficult patients admitted to the ED

Peripheral intravenous line insertion is the most commonly performed invasive procedure in the emergency department (ED). In some studies, difficult vascular access population was about 33% of evaluated patients and for most of them the "blind" method (i.e., palpation) fails in the line insertion. Ultrasound guidance often increase the success rate among these patients.

Two basic techniques were proposed for sonographic guidance, a transversal or a longitudinal approach to the chosen vessel (i.e., out-of-plane or in-plane view, respectively, "mono-plane" approach).

The availability of hand-held sonographic devices is increasing the number of emergency department were this guidance is used in a difficult vascular access population.

The Butterly iQ+ device is now able to show out-of-plane and in-plane views, simultaneously, the so called bi-plane view.

Aim of this randomized controlled trial is to test if a bi-plane sonographic vision might be able to increase the performance of trained operators in obtaining a peripheral vascular access among difficult patients admitted to the ED.

The present study will be a randomized controlled, 2-arm, nonblinded trial held at the Città della Salute e della Scienza di Torino, University hospital, Turin, Italy.

All healthcare workers already trained in ultrasound-guided vascular access will be considered eligible for the study (i.e., emergency physicians, residents, nurses) after an ad hoc brief (2 hours) training on the study.

This will be a "real world" study, each provider will be free of choosing the device he/she thought appropriate for each patient (in terms of length, gauge, type - peripheral midline will be included in the Italian center).

Using a computerized permuted blocks of random sizes, enrolled patients will be randomized in a 1:1 ratio to be evaluated using either the "standard" ultrasound-guided approach (out-of-place or in-plane view) or the bi-plane view (i.e. out-of-place and in-plane view, simultaneously).

Inclusion Criteria: at least one of the following criteria have to be present along with the need for a peripheral access

• chronic renal disease/ongoing dialysis;
• sickle cell anemia;
• prolonged and/or frequent use of i.v. drugs;
• difficult vascular access (after a first attempt or self-reported);
• previously need for more than one attempts / ultrasound guidance for getting a peripheral vascular access.

Exclusion Criteria:

• no consent to participate in the study.