Thread by @Manoj_Wickram

So what does a #POCUS guided fluid assessment look like? #tweetorial #askpocus @IMPOCUSFocus @DRsonosRD @KalagaraHari @SonoSerious @tsquaredmd @jaffa_md @nick_wroe @EM_RESUS @coreultrasound @kyliebaker888

Let’s start of the with the lungs! Normal dry lungs are represented by an A line profile. These are horizontal lines that are equidistant from each other and are reverberations artefacts of the pleural line.

B lines are vertical artefacts arising from the pleural propagating all the way down. When widespread and bilateral can be an indication of interstitial/alveolar oedema.

Bilateral pleural lines can also be present in disease process like ARDS. Close inspection of the pleural line can try and differentiate these. Pure fluid overload will have a nice thin pleural line (left) whereas ARDS typically has an irregular pleural line (right)

Ultrasound is more sensitive than CXR to detect pulmonary oedema.

Additionally lung bases can be visualised to pick up pleural effusions. Ultrasound is (you guessed it) more sensitive for pleural effusions compared to CXR.

That’s lungs. Let’s move onto the abdomen briefly. Look for free fluid within the abdomen indicating ascites which might be secondary to a fluid overloaded state such as heart failure. A pretty obvious example here!

Let’s move onto the heart. There are so many things you can look at/measure in the heart when focussing on fluid status.

Let’s start with visual assessments. Visual assessment of LV contractility gives us an idea of LV function and presence of heart failure. Normal vs severely impaired below.

A hyperdynamic LV could be indicative that the patient is hypovolaemic - all it really tells is is there a reduced preload (due to hypovolaemia OR vasodilation). Don’t pour fluids in just because you see this. Use the rest of your clinical and POCUS exam.

The same applies for looking at the RV. A massive dilated and impaired RV might prompt you to put down that bag of Hartmann’s!

Some fancier stuff. You can work out surrogate pulmonary artery pressures using TR jet and the modified Bernoulli equation.

https://twitter.com/wilkinsonjonny/status/1367877706956832768

You can also use echo to calculate stroke volume using LVOT and VTI. Here is an excellent talk on how to do and use this!

https://twitter.com/katiewiskar/status/1367586233258405889

Let’s move on to the IVC. Something that can definitely be used as a stand alone test for fluid status assessment.... well no. Nothing is that good. The IVC gets a lot of stick but it gives great information - we just need to interpret it right.

The IVC moves with respiration with changes in intrathroacic pressure. The level it moves can be indicative of how ‘full’ the vessel is

IVC collapsibility can be affected by many things such as respiratory effort and positive pressure ventilation.

A plethoric IVC with no respiratory variation likely represents venous congestion. A nice example here

https://twitter.com/Stronysono/status/916518508732801024

A small IVC that collapses fully likely represents an underfilled patient.

VEXUS discussion has already begun since we’ve mentioned IVC. Get a view of the portal vein, hepatic vein and (if you can) renal vein and whack some PW Doppler on it! The subsequent waveforms give an idea of venous congestion.

https://twitter.com/argaizr/status/1228427055253139456

VEXUS is gaining a huge amount of traction recently. Follow the experts for up to date information and tips @ThinkingCC @ArgaizR @NephroP @Wilkinsonjonny @icmteaching

So that just about covers most of it (I think). Multisystem POCUS in addition to history and clinical exam gives us very useful data points for fluid assessment and monitoring different organs and their response to fluid resuscitation/deresucitation. Hope you found it useful!