VA-BC Ultrasound Guidance 4 — Questions and Answers
Question 1: A nurse notices that the ultrasound image shows a 'dirty shadow' artifact below a hyperechoic structure during vessel scanning. This artifact most likely indicates:
- A patent vein with laminar flow
- Air or gas in the tissue
- A calcified vessel wall or foreign body (Correct answer)
- Posterior acoustic enhancement
Correct answer: A calcified vessel wall or foreign body
A clean acoustic shadow behind a hyperechoic structure suggests calcification or a dense foreign body, while a 'dirty shadow' is more associated with gas/air.
Question 2: The catheter-to-vein ratio for PICC placement, assessed via ultrasound, should ideally not exceed:
- 25%
- 33% (Correct answer)
- 50%
- 66%
Correct answer: 33%
A catheter-to-vein ratio of ≤33% is recommended to minimize thrombosis risk by allowing adequate blood flow around the catheter.
Question 3: Which technique uses ultrasound to inject saline around a nerve or vessel to create a tissue plane before catheter insertion?
- Hydrodissection (Correct answer)
- Hydrolocalization
- Hydraulic compression
- Acoustic coupling
Correct answer: Hydrodissection
Hydrodissection uses saline injected under ultrasound guidance to separate tissue planes, potentially displacing nerves or other structures before needle advancement.
Question 4: When using M-mode ultrasound to assess vessel pulsatility during vascular access assessment, what does a flat, non-pulsatile waveform most likely represent?
- A normal artery
- A patent peripheral vein (Correct answer)
- Complete arterial occlusion
- Cardiac arrhythmia artifact
Correct answer: A patent peripheral vein
Veins display flat, non-pulsatile waveforms on M-mode, while arteries show cyclical pulsatile waveforms corresponding to cardiac contractions.
Question 5: A patient has a history of multiple previous PIVs and difficult access. Ultrasound reveals the cephalic vein is patent but located 2.8 cm deep. The best catheter choice is:
- Standard 1.16-inch PIV catheter
- Ultrasound-guided PICC
- Ultrasound-guided long peripheral catheter (LPC) (Correct answer)
- Implanted port
Correct answer: Ultrasound-guided long peripheral catheter (LPC)
A long peripheral catheter (LPC/extended dwell catheter) is appropriate for deep peripheral veins too superficial for PICC criteria but inaccessible with standard PIV length.
Question 6: During real-time ultrasound guidance, the nurse sees the needle tip enter the vein lumen but cannot advance the guidewire. Which action should be performed FIRST?
- Apply firm pressure and force the wire
- Reposition the arm and reassess needle angle under ultrasound (Correct answer)
- Remove the needle and attempt the contralateral arm
- Increase ultrasound frequency to improve visualization
Correct answer: Reposition the arm and reassess needle angle under ultrasound
Repositioning the arm and reassessing needle angle under live ultrasound can correct minor angulation issues that prevent smooth guidewire advancement.
Question 7: Which ultrasound finding during post-insertion assessment best confirms that a PICC is NOT in the axillary or subclavian vein during an arm-based placement?
- Absence of the catheter echo in the IJV on ultrasound (Correct answer)
- Presence of triphasic waveform on Doppler in the axillary vein
- Color Doppler showing flow in the basilic vein
- Probe compression causing vessel collapse
Correct answer: Absence of the catheter echo in the IJV on ultrasound
Scanning the IJV on ultrasound and finding no catheter echo confirms the PICC did not malposition into the internal jugular vein from the subclavian junction.
VA-BC Ultrasound Guidance 4
A nurse notices that the ultrasound image shows a 'dirty shadow' artifact below a hyperechoic structure during vessel scanning.
This artifact most likely indicates: