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Efficacy of Preoperative Ultrasound Assessment of the Radial Artery for Determining the Arterial Cannulation

Efficacy of Preoperative Ultrasound Assessment of the Radial Artery for Determining the Arterial Cannulation (Efficacy of Ultrasound Assessment for the Radial Artery Cannulation)

Ueda Kenichi

Kameda Medical Center

929 Higashimachi, Kamogawashi, Chiba, Japan

ueda.kenichi@kameda.jp

Ueda Kenichi

Kameda Medical Center

929 Higashimachi, Kamogawashi, Chiba, Japan

+81-4-7092-2211

kyamashita508@gmail.com

Recruiting

July. 10, 2026

Interventional

randomized controlled trial

single blind

no treatment control/standard of care control

parallel assignment

other

1. Adult patients scheduled to undergo elective surgery under general anesthesia at our institution, for whom radial arterial line placement is planned for invasive blood pressure monitoring during surgery
2. Patients in whom preoperative ultrasonographic assessment of the radial artery is feasible
3. Patients with a BMI of >16 kg/m2 and <35 kg/m2

1. Patients judged unable to provide sufficient cooperation for preoperative ultrasonographic examination due to impaired consciousness, cognitive decline, delirium, or severe agitation
2. Dialysis patients with an arteriovenous fistula in the forearm
3. Patients with a history of ipsilateral radial artery puncture within the preceding month
4. Patients judged to have factors predictive of difficult puncture based on preoperative ultrasonographic assessment, defined as any of the following:
Depth from the skin to the anterior wall of the radial artery =>4 mm
Radial artery internal diameter <=2.2 mm
Presence of bifurcation, tortuosity, or calcification of the radial artery
5. Patients who did not provide informed consent to participate in the study
6. Patients judged ineligible for any other reason by the principal investigator

Both

Adult patients scheduled to undergo elective surgery under general anesthesia

Preoperative ultrasonographic assessment of the radial artery will be performed at the preoperative outpatient visit or on the day of surgery using an ultrasound device (V scan, GE Healthcare, USA). The radial artery will be evaluated with a high-frequency linear probe in both short-axis and long-axis views, and the following parameters will be measured and assessed. The region of interest will be defined as the distal one-third of the segment between the elbow joint and the proximal wrist crease.
Depth from the skin to the anterior wall of the radial artery (=>4 mm)
Radial artery internal diameter (<=2.2 mm)
Presence or absence of bifurcation, tortuosity, or calcification of the radial artery
Patients found to have no factors predictive of difficult puncture based on the above findings will be eligible for enrollment and randomly allocated in a 1:1 ratio to either the palpation group or the ultrasound-guided puncture group.
Radial artery puncture will be performed by senior anesthesiology residents or board-certified anesthesiologists who were not involved in the preoperative ultrasonographic assessment. To minimize the influence of operator experience, only physicians with experience of 30 or more arterial punctures using each respective method will be assigned, with efforts made to ensure balanced distribution between the two groups. The puncture procedure will be performed according to the allocated method (palpation or ultrasound guidance).
All punctures will be performed using sterile technique with a sterile drape and sterile gloves. Procedures will be carried out under general anesthesia, with puncture initiated when the systolic blood pressure is within 10% below the value recorded at room entry.
A 22-gauge peripheral arterial catheter with an integrated guidewire (BD Insyte A, Becton, Dickinson and Company, USA) or Surshield Surflo II (Terumo Corporation, Tokyo, Japan) will be used for arterial line placement following a standardized technique. The puncture site will be limited to within 2 cm proximal to the proximal wrist crease.

Radial artery, General anesthesia

Ultrasonography, Catheterization Peripheral, Ultrasonography nterventional, Radial Artery

D014463, D002406, D018084, D017534

For the primary outcome, a superiority test will first be performed to assess the difference in time to successful puncture between the palpation group and the ultrasound-guided group. If no statistically significant difference is observed between the two groups, a non-inferiority analysis will be conducted to determine whether the palpation method is non-inferior to the ultrasound-guided method within a clinically acceptable margin. The non-inferiority margin will be set at 30 seconds based on prior studies and clinical plausibility, and non-inferiority will be considered demonstrated if the upper limit of the 95% confidence interval for the between-group difference (palpation method minus ultrasound-guided method) lies below this margin. The primary analysis will be based on the intention-to-treat principle, with a per-protocol analysis performed as a supplementary analysis where necessary.

For secondary outcomes, the following will be recorded and compared between groups: first-attempt success rate, success rate within 5 minutes, number of puncture attempts (defined as one attempt each time the needle is fully withdrawn), need for reinsertion during surgery, rate of conversion to non-invasive blood pressure monitoring, and the occurrence of complications (e.g., hematoma formation, radial nerve injury).

+81-4-7092-2211

June. 08, 2026

Yes

Data will be stored in REDCap. Password-protected OneDrive online storage will be used, with access controls implemented to prevent unauthorized external access.

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