Comparison of Traditional and Ultrasound-Guided Techniques for Vascular Access in Patients With Difficult Venous Access in Emergency Department.

Peripheral venous cannulation with short peripheral vascular access device, performed by ultrasound technique.

Arterial puncture using a needle and heparinised syringe to extract a sample for arterial blood gas analysis, using the ultrasound-guided technique.

Cannulation of a short peripheral vascular access device using the traditional visualisation and palpation technique.

Arterial puncture using a needle and heparinised syringe to extract an arterial blood sample for arterial gamosetry analysis, performed using the traditional arterial pulse palpation technique.