How do I use ultrasound guidance for subclavian access?

Equipment

• Essential: High-frequency (5–10 MHz) linear transducer, sterile ultrasound probe cover, central venous catheter kit (needle, guidewire, dilator, catheter)
• Optional: Micropuncture kit, power Doppler feature

Positioning and Landmarks

• Position: Patient supine, ideally in Trendelenburg with arms in a neutral or slightly shrugged position to help expose the subclavian/axillary window
• Landmarks/US: Initially place the probe in the sagittal plane over the mid-clavicular area to visualize the clavicle, pleural line, and then slide laterally to identify the axillary vein (transitioning into the subclavian vein as it passes the lateral border of the first rib) ¹²

Analgesia/Sedation

Option	When	Key note
Local anesthetic (e.g., lidocaine)	Prior to needle insertion	Ensure adequate skin and soft tissue anesthesia to minimize patient discomfort
Minimal sedation	If patient is anxious or uncooperative	Use with caution so as not to compromise respiratory drive in critically ill patients

Steps

1. Pre-scan and Preparation:
   Identify the intended access site by scanning over the mid to lateral clavicle. Visualize the clavicle, pleural line, and then the axillary vein with adjacent artery using grayscale and color Doppler to confirm vessel identity ¹².

2. Probe Placement:
   Begin with the probe in a sagittal orientation over the middle third of the clavicle (marker cephalad) to locate key landmarks, then slide laterally until the acoustic shadow of the clavicle clears, revealing the compressible axillary vein ¹.

3. Switch to Long-Axis View:
   Rotate the probe 90° into the long-axis position to align with the targeted vein, ensuring the needle path can be visualized continuously. This helps in keeping track of the needle tip as you advance it ¹³.

4. Needle Insertion:
   Under continuous ultrasound visualization, advanced the needle slowly using an in-plane technique. Watch for the needle tip entering the vein while ensuring it remains in view. Adjust the probe slightly if the needle tip is lost, using incremental “walking the needle” technique.

5. Guidewire and Catheter Placement:
   Once venous return is confirmed, thread the guidewire through the needle. Verify the wire position via ultrasound if possible. Proceed with dilation and catheter placement while maintaining sterile technique ¹².

Post-procedure

• Confirm: Use ultrasound and chest radiography to confirm catheter placement and exclude complications such as pneumothorax
• Aftercare: Secure the line with sutures and appropriate dressing while maintaining sterility
• Re-check: Monitor the patient’s respiratory status and catheter position regularly