Ultrasound-Guided Radial Artery Catheterization in a Four-Month-Old Boy

Abstract

Ultrasound-guided radial artery catheterization is increasingly used in pediatric patients because it improves procedural accuracy and may enhance first-pass success in infants and small children with small-caliber arteries. Dynamic needle tip positioning (DNTP), a short-axis out-of-plane ultrasound-guided technique, facilitates repeated identification of the true needle tip during needle advancement and enables precise catheter placement.

This video demonstrates ultrasound-guided radial artery catheterization using the DNTP technique in a 4-month-old, 5.5-kg infant with tetralogy of Fallot undergoing a right-sided systemic-to-pulmonary shunt procedure. Because ipsilateral shunt flow may interfere with accurate arterial pressure monitoring, the left radial artery was selected for cannulation. The video illustrates key technical aspects of DNTP, including stepwise needle and probe advancement to maintain visualization of the true needle tip, as well as practical considerations for minimizing complications. It also emphasizes strict aseptic technique, including maximal sterile barrier precautions, a sterile ultrasound probe cover, and sterile ultrasound gel.

The arterial catheter was successfully placed without immediate complications and functioned appropriately throughout the procedure. This video provides a practical demonstration of DNTP and highlights procedural planning and infection prevention strategies for safe and effective pediatric radial artery catheterization.

Keywords

Infant; radial artery; ultrasonography, interventional; catheterization; infection control. 

Case Overview

Background

Arterial catheterization is an essential procedure in the perioperative management of pediatric patients, enabling continuous blood pressure monitoring and frequent arterial blood sampling. However, radial artery catheterization in children can be technically challenging due to the small vessel size and difficulty of arterial palpation.¹ Repeated unsuccessful attempts may result in hemorrhage or hematoma formation, further complicating subsequent cannulation;² therefore, achieving first-pass success is particularly important.

Ultrasound guidance has increasingly been adopted to improve the success of pediatric arterial catheterization. Among the available techniques, dynamic needle tip positioning (DNTP) enables repeated identification of the true needle tip during advancement and facilitates accurate entry into the vessel lumen.^3,4 A recent network meta-analysis demonstrated that the ultrasound-guided short-axis out-of-plane approach with DNTP was associated with significantly higher first-attempt and overall success rates than those with both conventional palpation and the short-axis out-of-plane approach without DNTP.⁵ The radial artery is generally the preferred site for arterial catheterization in pediatric patients because of its superficial location and ease of stabilization.^6,7 In addition to technical success, strict aseptic technique is essential. Current recommendations support the use of maximal sterile barrier precautions⁸ and, for ultrasound-guided procedures, sterile probe covers and sterile ultrasound gel to minimize the risk of catheter-related infection.⁹

This video demonstrates ultrasound-guided radial artery catheterization in a pediatric patient using the DNTP technique and highlights practical tips for successful cannulation and infection prevention.

Focused History of the Patient

The patient was a 4-month-old male infant weighing 5.5 kg with a diagnosis of tetralogy of Fallot who was scheduled to undergo a systemic-to-pulmonary shunt procedure. Given the need for continuous hemodynamic monitoring and frequent arterial blood gas analysis during cardiac surgery, arterial catheterization was planned after induction of general anesthesia.

Physical Exam

Because a right-sided systemic-to-pulmonary shunt was planned, the left radial artery was selected for arterial catheterization. Placement of an arterial catheter on the shunt side may result in inaccurate arterial pressure monitoring because blood flow is diverted through the systemic-to-pulmonary shunt. Examination of the left upper extremity revealed no local contraindications to radial artery cannulation.

Imaging

Ultrasound examination confirmed the location, patency, and size of the left radial artery before cannulation.

Options for Treatment

Several approaches are available for radial artery catheterization in pediatric patients, including the traditional palpation-guided technique and ultrasound-guided catheterization. Ultrasound-guided catheterization may be performed using either a short-axis out-of-plane approach, including DNTP, or a long-axis in-plane approach.^1,10 In infants and young children, however, the long-axis in-plane approach may be technically challenging because the small vessel size requires precise alignment of both the artery and the needle with the ultrasound beam throughout the procedure.^1,7 When radial artery catheterization is not feasible, alternative sites such as the femoral, posterior tibial, or dorsalis pedis arteries may be considered, depending on the clinical circumstances.¹¹

Rationale for Treatment

Given the patient's young age and small-caliber radial artery, ultrasound-guided catheterization using the DNTP technique was selected to maximize first-pass success and facilitate accurate visualization of the needle tip.

Special Considerations

In infants, excessive transducer pressure can compress the radial artery, obscuring visualization. Gentle probe handling is therefore essential. In addition, the choice of cannulation site should take the planned surgical procedure into account. In this case, the left radial artery was selected because a right-sided systemic-to-pulmonary shunt was planned.

Discussion

This video demonstrates the key technical aspects of DNTP for ultrasound-guided radial artery catheterization in an infant. Using a short-axis out-of-plane approach, the operator repeatedly identifies the true needle tip by alternately advancing the needle and the ultrasound probe in small increments, thereby confirming that the catheter has adequately entered the vessel before cannulation.

Ultrasound-guided radial artery catheterization has become an increasingly important technique in pediatric patients, particularly in infants and young children, in whom palpation-guided catheterization may be technically challenging due to small vessel diameter and weak arterial pulsation. DNTP enables continuous tracking of the true needle tip during advancement and may improve first-pass success while reducing inadvertent posterior wall puncture and unnecessary repeated attempts.³

This case also highlights the importance of individualized procedural planning. Because a right-sided systemic-to-pulmonary shunt was planned, the left radial artery was selected for catheterization to avoid potential inaccuracies in arterial pressure monitoring caused by ipsilateral shunt flow. Accordingly, the choice of arterial access site should be tailored to the planned surgical procedure and the patient's underlying anatomy.

In addition to technical proficiency, meticulous infection prevention is essential during arterial catheter placement. The Centers for Disease Control and Prevention recommend the use of maximal sterile barrier precautions, including a cap, mask, sterile gloves, a fenestrated sterile drape, and an alcohol-based solution containing at least 0.5% chlorhexidine during arterial catheter insertion.⁸ Furthermore, recommendations for percutaneous ultrasound-guided procedures suggest using a sterile probe cover and sterile ultrasound gel.⁹ Taken together, these measures help minimize the risk of catheter-related bloodstream infection while preserving the advantages of real-time ultrasound guidance.

The arterial catheter was successfully placed and functioned appropriately throughout the procedure without immediate cannulation-related complications, including hematoma, distal ischemia, or catheter malfunction. This case demonstrates that ultrasound-guided radial artery cannulation using DNTP can be performed safely and effectively in infants when combined with careful procedural planning, meticulous needle tip visualization, and strict adherence to aseptic technique.

Equipment

• High-frequency linear ultrasound transducer (13–6 MHz)
• Sterile ultrasound probe cover
• Sterile ultrasound gel
• 24-gauge arterial catheter
• Fenestrated sterile drape
• Alcohol-based 1% chlorhexidine antiseptic solution

Disclosures

The author reports no conflicts of interest, financial relationships, funding, sponsorship, equipment support, or other relationships that could be perceived to influence the content of this article.

Statement of Consent

The parent of the patient referred to in this video article provided informed consent for the patient to be filmed and is aware that information and images will be published online.

Acknowledgments

The author thanks the operating room staff and perioperative team for their assistance with patient care and video production.