The Pre-brief
Critical care echo has taken off in the last couple of decades and has several utilities including diagnostics and hemodynamic monitoring. However, for various reasons, your standard image set may not be reproducible in intensive care, which is where the subcostal view comes into its own.
The Not so Uncommon Critical Care Echo
Patient X had been admitted with sepsis of unclear source and multi-organ failure. He has a background of COPD and obesity. He is currently intubated on PEEP 7.5, PIP 25, Fi02 70% and on two vasopressors in a supine position. You’ve decided your patient would benefit from an echo (who wouldn’t?). You’ve got everything set up, whacked loads of jelly on your probe, and pop it parasternal to get the parasternal long axis. But this is what you get…
Even a big sweep around a rib space above and below yields the same clip. A beautiful A-line profile but not quite what you wanted from an echo. You take the probe off and touch it to make sure it is indeed working in a desperate moment of disbelief – still working. Fine, let’s try the short axis. Unsurprisingly, it yields the same image
Okay, time for the apical 4cH – arguably the hardest echo window.
Hooray, you see something moving! Despite your doubts, this patient does indeed have a heart. Unfortunately, the view is not good enough to say much more beyond that.
So finally you try the subcostal view. To your relief, the patient has an excellent subcostal window…
Let’s rewind. Why was the echo so difficult in this patient?
- The patient was on positive pressure ventilation with high pressures, this expands the lungs creating an air space (ultrasound’s worst enemy) between the probe and the heart
- The patient is obese (no explanation needed there)
- The patient has COPD which causes hyperinflation of the lungs and often pushes the heart down
- The patient was supine and not moved into left lateral decubitus position – although we should be optimizing patient position even in intubated patients, it is much more cumbersome as it requires multiple people to help move the patient
All of these factors combine to give you subpar parasternal and apical views. However, you can probably see that (apart from obesity) none of these other factors affect a subcostal view – in fact, hyperinflation and the subsequent action of the heart getting pushed down will help with your subcostal.
Back to the subcostal…
So you get a beautiful subcostal view. Don’t stop there. There are several adapted subcostal views you can utilise and this is where the subcostal window comes into its own.
From your standard subcostal view, if you rotate the probe so that the orientation marker is pointing towards the patient’s left shoulder (exactly as you would for a parasternal short axis) you will get a subcostal short axis.
From here you can tilt the tail to fan up and down the LV.
By tilting the tail down you can get a subcostal short axis at the AV level with the RV outflow tract in view
You can even get a view similar to the parasternal long axis if you keep rotating the probe with the orientation marker pointing to the right shoulder.
From here if you tilt the tail up you will get the RV inflow view.
Just by doing these few extra maneuvers you have got a more comprehensive set of clips and data with an extended range of Doppler possibilities.
The Debrief
- Echocardiography in critically ill patients is difficult
- Often the subcostal view is the only available view
- Remember to utilize the various different adapted subcostal views which will make up for the rubbish parasternal views
Abbreviation List
COPD – Chronic Obstructive Pulmonary Disease
PEEP – Positive End Expiratory Pressure
PIP – Positive Inspiratory Pressure
4cH- 4 chamber
LV- Left Ventricle
AV- Aortic valve
RV- Right Ventricle
References
- Flower L, Madhivathanan PR, Andorka M, Olusanya O, Roshdy A, Sanfilippo F. Getting the most from the subcostal view: The rescue window for intensivists. J Critical Care 2020 Sep 13;S0883-9441(20)30680-8. (online first) DOI: 10.1016/j.jcrc.2020.09.003.
- Hockstein MA, Haycock K, Wiepking M, Lentz S, Dugar S, Siuba M. Transthoracic Right Heart Echocardiography for the Intensivist. Journal of Intensive Care Medicine. April 2021. doi:10.1177/08850666211003475
