Direct vs. Seldinger Technique for Ultrasound-Guided Difficult Radial Access in Cardiac Surgery

February 3, 2026 updated by: DILEK YAZICIOGLU, Diskapi Teaching and Research Hospital

Comparison of the Effectiveness of Ultrasound-Guided Direct and Seldinger Cannulation Techniques in Patients With Anticipated Difficult Radial Artery Cannulation Undergoing Cardiac Surgery

Radial artery cannulation is a routine procedure for invasive hemodynamic monitoring for patients undergoing cardiovascular surgery patients.

Although ultrasound (USG) guidance is known to improve success rates, there is limited data comparing the efficacy of the 'Direct' versus 'Seldinger' techniques specifically in patients with anticipated difficult radial access.

This study aims to compare the effectiveness of USG-guided Direct cannulation and USG-guided Seldinger techniques in adult patients with anticipated difficult radial arterial cannulation.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Study Protocol and Patient Assessment: Data collection and the procedural intervention will be performed in the preoperative period, prior to the induction of anesthesia. All patients will undergo a modified Allen test. The radial artery site will be selected based on the following hierarchy: preferably the non-dominant hand (unless surgical plan dictates otherwise), an arm with no history of coronary angiography, and the side determined to be easiest for cannulation via ultrasound (USG) assessment.

Ultrasound Assessment and Exclusion: A 12 MHz linear ultrasound probe will be used for all assessments and procedures. Before the intervention, a detailed sonographic evaluation of the radial artery will be recorded, including:

  • Artery diameter and wall thickness
  • Lumen continuity and flow velocity
  • Presence of calcification, vessel irregularity, or tortuosity
  • Stenosis (percentage) and plaque characterization (stable/unstable; fibrous/fatty)
  • Presence of hematoma, posterior wall injury, or dissection
  • Skin- mid radial artery distance Patients with significant stenosis where an appropriate arterial segment matching the cannula diameter and length cannot be identified will be excluded from the study, and cannulation will be performed at an alternative site.

Randomization and Positioning: Patients will be randomized into two groups using a computer-generated random number table:

  • Group D (Direct): Cannulation performed using the catheter-over-needle technique.
  • Group S (Seldinger): Cannulation performed using the catheter-over-guide-wire technique.

The patient's arm will be abducted, and the wrist will be extended and fixed over a small support. Standard aseptic preparation and draping will be performed.

Procedural Definitions and Outcome Measures: The procedure will be performed under real-time ultrasound guidance. The following time intervals and metrics will be recorded:

  • Radial artery cannulation time: Defined as the time elapsed from the initial skin contact of the needle/cannula to the appearance of the radial artery pressure waveform
  • Radial artery puncture time: Defined as the time elapsed from the initial skin contact of the needle/cannula to the appearance of blood in the hub Number of puncture: The total number of skin punctures required to achieve successful cannulation.

Number of needle maneuvers: The total number of needle advancements towards the artery

Safety and Follow-up: If arterial cannulation fails, manual compression will be applied to the artery for 5 minutes to prevent hematoma formation. All patients will be monitored for complications (such as hematoma, ischemia, or nerve injury) for 24 hours post-procedure.

Study Type

Interventional

Enrollment (Estimated)

242

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Turkey (Türkiye)
      • Ankara, Turkey (Türkiye), 06170
        • Ankara Etlik City Hospital
        • Contact:
        • Principal Investigator:
          • Dilek ÜNAL, Professor

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Patients aged 18 years or older
  • American Society of Anesthesiologists (ASA) physical status I-IV
  • Patients scheduled for cardiovascular surgery requiring invasive arterial monitoring

Exclusion Criteria:

  • Patients undergoing emergency surgery
  • Coagulation disorders or known coagulopathy
  • Presence of an arteriovenous fistula
  • Patients in shock or hemodynamically instable
  • Patients requiring mechanical circulatory support
  • History of Raynaud's phenomenon
  • Refusal to participate in the study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Other
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Ultrasound-Guided Direct Cannulation Technique
Patients in this group will undergo radial artery cannulation using the ultrasound-guided direct technique.
Procedure: Ultrasound-Guided Direct Cannulation Technique
Radial artery cannulation performed using the direct puncture technique (catheter-over-needle) under real-time ultrasound guidance.
Active Comparator: Ultrasound-Guided Seldinger Cannulation Technique
Patients in this group will undergo radial artery cannulation using the ultrasound-guided Seldinger technique.
Procedure: Ultrasound-Guided Seldinger Cannulation Technique
Radial artery cannulation performed using the Seldinger technique (catheter-over-guide-wire) under real-time ultrasound guidance.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
First-Attempt Cannulation Success Rate
Time Frame: 10 min before anesthesia induction
The proportion of patients in whom radial artery cannulation is successfully performed (verified by the appearance of the arterial pressure waveform on the monitor) with a single skin puncture
10 min before anesthesia induction

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of Cannulation Attempts
Time Frame: 10 min before anesthesia induction
The total number of skin punctures required to achieve successful radial artery cannulation
10 min before anesthesia induction
Radial artery cannulation time
Time Frame: 10 min before anesthesia induction
Total time elapsed from the initial skin contact with the arterial cannula to the visualization of the arterial waveform on the monitor.
10 min before anesthesia induction
Incidence of Procedure-Related Complications
Time Frame: Postoperative 24th hour
Evaluation of adverse events associated with the cannulation procedure, including hematoma, arterial dissection, posterior wall injury, nerve injury, or infection
Postoperative 24th hour

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Diskapi Teaching and Research Hospital

Investigators

  • Principal Investigator: Dilek ÜNAL, Saglik Bilimleri Universitesi

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

March 1, 2026

Primary Completion (Estimated)

September 1, 2026

Study Completion (Estimated)

September 30, 2026

Study Registration Dates

First Submitted

February 3, 2026

First Submitted That Met QC Criteria

February 3, 2026

First Posted (Actual)

February 10, 2026

Study Record Updates

Last Update Posted (Actual)

February 10, 2026

Last Update Submitted That Met QC Criteria

February 3, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • AEŞH-EK-2025-221

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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