There are a few basic things you are asked to do as a scanner – and one is to work out why a patient is hypotensive. Its straightforward – the patient has low preload, an effusion, poor contractility or is vasodilated. This set of videos and notes helps you see what you should be looking for.
First Assess filling.
The IVC should have plenty of blood in it, but should empty at least a little bit with each cardiac cycle and (if relevant) during inspiration.
This is what the IVC should look like if normal – look for the movement relating to respiration: https://www.youtube.com/watch?v=36EGzB64EWY
If the patient is fluid depleted there will be too little blood entering the heart to give an appropriate stroke volume. This leads to a collapsing IVC: https://www.youtube.com/watch?v=0225pPjxY3A
Filling may not be the problem – and then the patient becomes fluid unresponsive. The IVC will look very full IVC. [the other cause of this is pulmonary hypertension]: https://www.youtube.com/watch?v=ct23oop1eZI
The next step is to Assess Contractility. This is what poor contractility looks like. The LV is best seen for this in the LA view, but apical is also good. The walls come together lethargically. Here are some examples:
(go to 4.21 on the video)https://www.youtube.com/watch?v=RTgkGMLOwSQ
(go to 1.35) https://www.youtube.com/watch?v=2tHrgkrmnQ4
Now look for evidence of vasodilation.
The hallmark of vasodilation is excessive emptying of the LV without adequate blood pressure. Again LA or apical views are best. These videos show that: (go to 6.59 on the video) https://www.youtube.com/watch?v=RTgkGMLOwSQ. Also https://www.youtube.com/watch?v=Hdje3I-emb4
You will have seen this already – but effusion is another cause – cardiac tamponade. Here you are looking for diastolic collapse of RA or RV. The SC view is usually best here, but apical will also work.
People like numbers, and so measuring contraction can help compare different scans. Ejection fraction can be used, but is just a calculation based on fractional shortening, so please record FS. Normal is 35% +. Here is the process, which has to be done in M-Mode of the LA, just above the tips of the MV: https://www.youtube.com/watch?v=WJ6EfMZwr6o&list=PLIioN7ylisU7qS8OB7RE30zvUbuUF6lTl