Jon, great post as always! I do agree with most of it, but would have to caution readers about reading it with the filtered glasses that make people too often take home the message that they want to – usually the path of least resistance (or change). I think your main point and most critical one is that there is no protocol or recipe that should ever be applied to resuscitation, especially single-variable-based resuscitation (eg old school orders like CVP>12 lasix and <12 bolus), and substituting the IVC for CVP won’t help. And from a standpoint of volume-responsiveness, I totally agree, with the understanding that as the IVC gets more plethoric, the percentage of responsive patients will decrease, inevitably, but one cannot predict with certainty whether that one patient will or will not. However, the parallel change is that, as the IVC gets more plethoric, the volume tolerance is likely decreasing as well, so that your benefit to risk ratio is dropping. And of course you can’t recipe that just based on IVC, but should be looking at the site of pathology (eg lung, brain abcess, pancreatitis with ACS, etc…), physical exam, to determine your patient’s volume tolerance. Because we all know that most of that miraculous fluid will end up clogging the interstitium, with consequences ranging from cosmetic to fatal (though usually blamed on the patient being “so sick” in the first place, absolving the clinician from any wrongdoing). So comments like the one previous to mine, stating “give volume and see if the response occurs” are, in my mind, a poor approach. We know from studies that you cannot simply remove the fluid you gave and go back to the start with lasix (glycocalyx damage, etc), and we also know that much of the effect of said fluid administration dissipates in minutes to hours (I’m sure Jon can quote these studies off the top of his head!).
As we have discussed in the past, I think POCUS is much underused as a fluid stop point – most of its use is on the ‘let’s find a cool reason to give.’ I would argue that you should hardly ever give fluid to a full IVC (especially if markers of pathological congestion are present – portal vein pulsatility and all), unless you are dealing with temporarily improving tamponade or tension pneumo, because even if you are volume responsive, you are likely not volume tolerant. This also goes to the point that a single, initial POCUS exam will potentially not have the same impact as a whole POCUS-based management which will use it to reassess congestion status, cardiac function, etc.
Having said all this, the most important part of the SHOC-ED article is, in my mind, their discussion, which is full of all the important reasons why the final conclusion is not `we don’t need to do POCUS in shock,’ which is what I see happening (similarly to the TTM reaction), as they outline the cognitive fallacy of putting on trial a diagnostic tool whilst the therapeutics are not yet clearly established. Those only reading the abstract or conclusion will actually miss the important points of this study which the authors clearly explain.
In particular, the ‘rare’ instances of tamponade or aortic aneurysm or PE in their series would be diluted out by the sepsis, but for those patients, it would matter. As the authors state:
‘one might argue that even a single unanticipated emergency procedure would justify the use of POCUS in critically ill patients.‘
I would have to wholeheartedly agree.