Thread by @IM_Crit_

ICU stories: 70 yo pt without medical hx but tobacco use (2 ppd x 40 y) was admitted w shortness of breath a wk ago. CXR/chest CT without PE/infiltrate. Was in afib/RVR on admission; placed on heparin & dilt/b-blocker (w some hypotension). Remained dyspneic, at times restless,

“requiring” multiple sedatives, & eventually was brought to the ICU. Intubated for "resp distress" & mental status changes. "Formal" echo, the day of ICU transfer, showed “LVEF 20% w global LV dysfunction”. On the vent 50% - peep 10. BP 110-130/60-70. Lactate < 2.0

Cards follow for "well compensated heart failure". A look w POCUS upon ICU admission:

So: dilated LV/RA/LA. Dilated IVC. Mild pulmonary & systemic venous congestion (I skip the VEXUS clips). Let's take another closer look at heart POCUS:

What is this 👆 in the right atrium?

More importantly, let's focus more in this short axis view (seen from the sub-xiphoid window):

Is there a regional wall motion abnormality (RWMA) or Cards was right when talking about "global LV dysfunction"?

Septum does not look that great, does it? And the opposite wall seems to be squeezing better... 🤷‍♂️
While you collect all this data, the nurse notifies you that the pt has made only 100 cc urine the last 6 hours

Many ways to address this oliguria but let's move forward. A Swan-Ganz was placed. PA pressure 40s/20s, CVP 16. What about the cardiac output? Please take a look at the first 3 "red" CO measurements & the next 3 "green" ones 👇

The first three were re-assuring w an average CI of 2.4. The next three were worrisome w average CI 1.7 (< 2.2 l/min/m2 w support or < 1.8 without support are in the cardiogenic shock territory...). The difference between the first 3 & the last 3 were 5 min. What changed?

Nothing really changed. The saline injections were just repeated & the CO/CI were found to be much lower (please see also the different waveforms in the temperature changes). The CO/CI were close to the ones previously estimated by LVOT & RVOT VTI (not shown)

The Pv-aCO2 gap was 4.2 between SVC and radial artery and 6.6 between PA artery and radial artery. The difference between SvO2 and ScvO2 was 8.5%

The case is still a work in progress but illustrates common scenarios in the ICU:
1. Normal BP does not exclude low cardiac output
2. Normal Pv-aCO2 gap (the magic number is < 6.0) does not exclude low cardiac output

3. CO2 and O2 value discrepancies are very often seen between the SVC and the PA (in other words: between a central line and a Swan-Ganz...)
4. Normal lactate does not rule out low cardiac output
5. All hemodynamic numbers are data points. We have to put the pieces together

6. POCUS skills should (and will) expand beyond the quick look at the basic 4-5 views. Cardiac output estimation & evaluation for regional wall motion abnormalities are very helpful (and not infrequently in disagreement with the "formal" echo; this is fine!)

Thanks for reading!

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Milrinone was added & Lasix 40 mg iv were given (3 liters of urine overnight). CO ⬆️ by 20%. The Pv-aCO2 gap between SVC & radial artery ⬆️ to 7.4 (from 4.2); between PA artery & radial artery ⬇️ to 5.9 (from 6.6). The difference between SvO2 & ScvO2 ⬇️ to 4.3% (from 8.5%) *

The correlation of SvO2/ScvO2/Pv-aCO2 w each other & w CO is imperfect (this was an understatement!). They are affected by so many seemingly unrelated variables (eg, sedation, catheter position etc) that caution is advised when used as resuscitation triggers or end-points

Unpopular opinion: Even though I like and use PAC fairly frequently, there are cases where it behaves like a random number generator (do you remember that we were blaming the uncalibrated CO devices for that?). Or maybe I am not too good in using it & interpreting the data... 🤷‍♂️