Aortic dissection is easily missed, carries a high mortality and should be on the differential of any patient with shock, abdo pain or chest pain. Contrary to popular belief the entire aorta can be imaged via transthoracic and abdominal ultrasound. Let’s start with some anatomy
Visualised from PLAX view with depth ⬇️ & probe tilted to focus on the root. Tilting superiorly, or moving up a rib space, may help. Examine the AV and look for a dissection flap. Measure the diameter 3-4cm from the AV. The root can also be seen from A5C & A3C views
In Q1 we saw how to measure stroke volume (SV). Q2 helps us manage someone with an inappropriately low SV. Pressors, fluids and inotropes are all treatment options. If If used correctly, they will ↑SV. If not, they won’t, and they may even be harmful.
Measuring VTI before and after each of these interventions will therefore easily show you if they have worked. But can we predict which one is likely to work before we give drugs or a drop of fluid? 1st, let’s go back to some physiology.
@iceman_ex@avkwong Really interesting study. Before I read it I assumed that 'physiological assessment' would be lots of fluid responsiveness assessment and then filling to an unresponsive (pathological) state. In fact a lot of ultrasound was used. And there was no difference in fluid administered
@iceman_ex@avkwong So why did US not help? Echo doesn't tell you whether there is hypovolaemia or not. A hyperdynamic heart is a feature of low venous return which is more often from venoplegia than hypovolaemia. Echo cannot distinguish between these.
@iceman_ex@avkwong Lung US shows if there is pulmonary oedema or not. You have to be significantly fluid overloaded to develop this though and its absence is definitely not a sign to give fluid.
Early in the outbreak it was commonly advised to aim for a -ve fluid balance
More recently a higher than expected occurrence of AKI and RRT has been observed prompting calls for a more liberal fluid strategy.
All these miss the point about the type of fluid being administered
Hypovolaemia (low intravascular volume) should be avoided (AKI and other organ dysfunction).
Hypervolaemia (high intravascular volume) should be avoided (AKI via venous congestion, pulmonary oedema, R heart strain and other organ dysfunction)