Radial arterial puncture is a commonly performed procedure in emergency departments for arterial blood gas analysis and invasive hemodynamic monitoring. The conventional palpation technique may be associated with prolonged procedure duration and multiple puncture attempts, particularly in patients with weak arterial pulsation or difficult vascular anatomy.

Ultrasound guidance has been proposed as a method to improve procedural success. This randomized controlled trial aimed to compare the static ultrasound-guided technique with the conventional palpation technique for radial arterial puncture in adult emergency department patients.

The primary outcome was puncture duration. Secondary outcomes included first-attempt success rate, total number of attempts, procedure-related complications, and patient pain scores.

Radial arterial puncture is frequently performed in emergency departments for arterial blood gas sampling and invasive arterial pressure monitoring. Although the conventional palpation technique is widely used, procedural failure, prolonged puncture duration, and repeated attempts remain common problems, especially in patients with difficult vascular access.

Ultrasound-guided vascular access techniques have demonstrated improved success rates in several vascular procedures. However, evidence regarding the effectiveness of the static ultrasound-guided method for radial arterial puncture in emergency department settings remains limited.

This prospective randomized controlled trial was conducted in the emergency department of University of Health Sciences, Sisli Hamidiye Etfal Training and Research Hospital. Adult patients requiring radial arterial puncture were randomly assigned to either the static ultrasound-guided group or the conventional palpation group.

In the static ultrasound-guided group, the radial artery location was identified using ultrasonography prior to skin puncture, and the puncture site was marked externally. In the conventional group, arterial puncture was performed using anatomical landmarks and palpation alone.

The primary outcome of the study was puncture duration. Secondary outcomes included first-attempt success, total number of puncture attempts, procedure-related complications, and patient-reported pain scores.

The study aimed to evaluate whether the static ultrasound-guided technique could improve procedural efficiency and success compared with the conventional palpation technique in emergency department practice.

Inclusion Criteria:

• Adult patients aged 18 years and older
• Patients requiring radial arterial puncture in the emergency department
• Patients who provided informed consent

Exclusion Criteria:

• Patients younger than 18 years
• Known vascular abnormalities or previous vascular surgery involving the puncture site
• Local infection or skin lesion at the puncture site
• Hemodynamic instability requiring immediate intervention
• Inability to provide informed consent
• Previous enrollment in the study

Individual participant data are not planned to be shared because of institutional data protection policies and patient confidentiality considerations.