- a) Describe the ultrasound features that help differentiate the internal jugular vein and the carotid artery? (70% marks)
- b) List the complications of central line insertion. (30% marks)
Answer and interpretation
a) Describe the ultrasound features that help differentiate the internal jugular vein and the carotid artery? (70% marks)
The IJ vein:
- Has an elliptical shape
- Is larger
- More collapsible with modest external surface pressure than the carotid artery (CA), which has
rounder shape, thicker wall, and smaller diameter
- A Valsalva manoeuvre will further augment their diameter
- The IJ vein diameter varies depending on the position and fluid status of the patient and is
particularly useful in hypovolemic patients.
- Adding Doppler, if available, can further distinguish whether the vessel is a vein or an artery. Colour
flow Doppler demonstrates pulsatile blood flow in an artery in either SAX or LAX orientation.
- A lower Nyquist scale is typically required to image lower velocity
venous blood flows. At these reduced settings, venous blood flow is
uniform in colour and present during systole and diastole with laminar
flow, whereas arterial blood flow will alias and be detected
predominantly during systole
(Figure 5) in patients with unidirectional arterial flow (absence of aortic regurgitation).
- A small pulsed-wave Doppler sample volume within the vessel lumen displays a characteristic
- Veins are thin walled and compressible and may have respiratory-related changes in diameter. In
contrast, arteries are thicker walled, not readily compressed by external pressure applied with the ultrasound probe and pulsatile during normal cardiac physiologic conditions.
b) List the complications of central line insertion. (30% marks)
- Air embolus
- Arterial puncture / catheterisation
- Incorrect catheter tip position
- Central vein perforation
- Cardiac arrhythmia
- Embolised, fractured or irretrievable guide wires
- Pass rate: 62%
- Highest mark: 7.3
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.