#FOAMresus Case from Amand Thind (@Thind888)

So #MedTwitter is truly an incredible forum for case discussion, where you get to exchange with literally some of the best medical minds on the planet who often also happen to be front-line clinicians in the nitty-gritty therapeutic decision-making. Here’s a discussion which I think was great. Recently, Dr. Thind has been generating some great cases and hemodynamic discussions. I thought this one was worth highlighting!
Dr Thind is an internist and currently Critical Care Hospitalist (and upcoming ICU fellow) at the Cleveland Clinic, and tweets out some great #FOAM from @Thind888 on twitter.
Case:
OK, let’s give this a shot. Here’s a ‘hemodynamics special’. Saw this case a couple weeks ago. A lot of decision making was based on educated guesses so it should be a good one for discussion. – 51 yo woman being worked up on the floor for chronic diarrhea, moved to ICU for hypoxia.
Dyspnea progressed over few hours. Vitals significant for tachycardia (140s) and hypotension (MAP in low 60s). On arrival, SBP 60s – improved with fluid bolus. CXR attached. Patient has H/O of pericardial effusion for several months that has been managed conservatively. 
The patient has an official ECHO performed on arrival in ICU (images attached). IVC difficult to assess but about 2cm without collapse. Lung US – diffuse B lines. 
OK so right there a flag goes up for me. A plethoric IVC means something is wrong. Sounds too vague maybe, but you need to find the reason for this, as it likely has therapeutic implications. Let’s see what comes up.
Modifed A5C.
LVOT doppler

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CXR

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Pressing questions –
(i) Is it hydrostatic or increased permeability pulmonary edema?
(ii) Fluids, diuresis, or none?
(iii) Would CPAP help?
(iv) Drain the pericardial effusion?
(v) What about that LVOT doppler? 
Mitral inflow velocities and TDI attached. M-mode through PLAX almost uninterpretable. Lung infiltrates are new so less likely lymphangitic carninomatosis. Note: ScVo2 = 40s. Another Q to ponder on –
(vi) Is tamponade typically associated with hydrostatic pulmonary edema?

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Perhaps this slowed up (0.5x) A3C loop will help with that LVOT doppler!

Great discussion as expected. Lets discuss:
Q4. Is it tamponade? – This is not a slam dunk. Chamber collapse can sometimes be controversial. In these situations I try my best to get MV E-wave variation. I think our tech got a decent signal. But note these are fused E/A waves.
The first thing I look at to screen for tamponade is the IVC. Tamponade is an obstructive form of shock, dependant on the intrapericardial pressure exceeding the right atrial pressure. If it does, unless respiratory efforts are extreme, the IVC should become plethoric. Hence, the absence of such would make the effusion – given the current RA pressure – NOT tamponade. Yet again, another point scored by the IVC for usefulness.
Although I don’t see why we can’t use fused waves for this purpose (couldn’t find anything on it in the literature). Note that in spite of the cardiac motion, the mitral inflow variation is <25% (~23%). It’s close though, and certainly seems to have increased from 3 days ago.

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The cardiologist (understandably) was non-committal and read it as “possible early tamponade”.
Q5. What about LVOT doppler? A good M-mode could not be obtained but the A3C in 6/ shows SAM. The report mentioned “chordal SAM” but I think you can clearly see “valvular SAM” too.
Chordal SAM is SAM of the chordal apparatus (you could see it bumping against the septum in 6/). It is (typically) NOT hemodynamically significant (PMID: 27241937). – When we see mitral SAM, it is important to quantify its hemodynamic effects – with LVOT peak gradient via CW.
In HOCM, DLVOTO is defined by an LVOT gradient of >30; >50 is considered severe. Our patient had a gradient of ~70. Although classically a/w HCM, SAM can be seen in anyone with thick, hypercontractile, underfilled LV. Tachycardia further hampers LV filling (PMID: 27726435).
Mitral SAM is often a/w MR – this acute MR can cause flash pulmonary edema. These patients may actually need fluids (to help with SAM) to fix there hydrostatic pulmonary edema!! (PMID: 20661209). However, our patient only had trace MR (you could see it in 1-2 CD frames).
Working theory (similar to Lars) – Chronic stable pericardial effusion –> diarrhea (pt had 15 BMs the day before the admission) –> reduced venous return –> brought the patient at the verge of low-pressure tamponade (PMID: 16923755) –> further reduction in LV filling  —> reduced stroke volume –> adrenergic drive causing tachycardia and increased inotropy –> all factors culminating in mitral SAM and DLVOTO.
This also explains the low ScVO2. Note – CPAP would further reduce venous return (Q3) so wouldn’t help, may hurt.
Now the most important Qs: why pulmonary edema and what to do about it (Q1 and 2). As tamponade causes impedance to venous return, it is not typically associated with high LAP and hydrostatic pulmonary edema (Q6).
But first, let’s check out another CW tracing. Any thoughts?

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This is a CW beam through LV apex and mitral valve – typically performed to assess mitral inflow and MR velocities and is part of the standard ECHO exam. However, the tracing is not typical for MR (late peaking, dagger shape). Remember, CW does not have depth resolution.

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This is likely mid-cavitay/intra-ventricular obstruction. This is caused by complete mid-systolic obliteration of LV cavity (see PSAX) causing obstruction to the apical systolic flow. Again, seen in hypercontractile, underfilled, thick LV – e.g. sepsis (PMID: 26082197).
Finally – what does the ECHO tell us about LV filling pressures? – E/A ratio: As Lars pointed out, an E/A < 0.8 usually means normal LAP. However, the exception to this is sinus tach. This was shown in a study by none other than Dr. Nagueh (PMID: 9778330). (Also, see image)

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The idea is that when early filling (E) is incomplete due to short diastolic time, the LA remains “full” at the time of the atrial kick – causing higher A velocities. NB: In that paper, E/E’ > 10 had a specificity of 95% for elevated LAP in ST. In our case: E/E’ = 75/5 = 15!

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Potential contributors of high LAP – (i) SAM-associated MR – ‘trace’ in this ECHO but maybe we didn’t catch it. (ii) Tachycardia – E’ is 5 suggestive of delayed relaxation. Tachycardia causes “incomplete relaxation”. (iii) High afterload – high-grade dynamic obstructions.

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So at this point, it’s still contentious but I have my money on hydrostatic pulmonary edema. Will detail our interventions and the remaining course in a bit. …Sorry to make this long but I think it’s worth it!
Now for the home stretch, the remaining course: We realized pericardiocentesis may be required soon but wanted to see if volume helps with (i) Peri-tamponade (ii) Dynamic obstructions. It helped a little – O2 requirements went from 60% HF to 6L NC. BP okay but still tachy.
Day 2: We pushed 2.5 mg metop x2 with concurrent ECHO. LVOT gradient improved from 70s to ~10! (I did not compare mid-cavitary gradient, apologies). Started on 25 bid of PO metop later that night. HR now 90s Day 3: Official ECHO shows improved but persistent gradients.

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Evaluation of tamponade was similar to previous ECHO but E-wave velocity variation now 38% –> elective pericardiocentesis: 550 cc removed. Fluid was transudate We also tapped a small pleural effusion pocket: transudate, cx negative (again goes with hydrostatic pulmonary edema).

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Day 3 (contd): inc metop to 50 Q12H to blunt the gradients.
Day 4 – HR in 80s. ECHO shows no DLVOTO and non-significant mid-cavitary gradient. Oxygenation improved but still not normal. Why?! Check the E-velocity post-pericardiocentesis: it has jumped to 120 with E/A > 1.

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So why is the LAP still high despite no significant dynamic obstruction? – Patients with chronic pericardial effusion may have chronically impaired diastolic filling –> low output –> volume retention (basic CHF physiology). When pericardial restraint suddenly released ––> increased LV preload –> high LAP.
Originally discussed elegantly here: PMID 6877287.
This is especially true if the LV has some baseline dysfunction. Day 5 – We started diuresis! The obvious risk was to precipitate the dynamic obstructions –> metop increased to 50 Q8H.
Day 7: Excellent diuresis (~2-3L negative per day). Hemodynamics stable (SvCO2 normal). Resting HR 60s – 70s. Follow-up ECHO confirmed no dynamic obstructions (see image). Day 8: Finally on room air. Pulmonary infiltrates improved (image). All cx remained negative.

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Some dogmalysis offered by this case – – Fluids (probably) helped the pulmonary edema; CPAP/diuresis may have worsened. – IV metop contraindicated in hypotension? Not in this case – Sometimes you may have to diurese someone who recently had DLVOTO, as discussed above.
This case highlights the cognitive flexibility required to deal with hemodynamic puzzles. One thing I would’ve done different is be more aggressive with metop early on as it made a huge difference with DLVOTO. This was quite a ride. Hope you had fun. Feel free to share! 
Much kudos to the treating team, I think this was excellently managed. As Amand says, cognitive flexibility ias absolutely key in assessing hemodynamics, particularly in the grey zones when multiple processes occur and co-exist. Managing this type of case using a recipe-based approach and without POCUS could have let to a poor outcome. 
Now the POCUS used in this case is on another level. Very impressive and allowing incredible insight and certainly many potentially clinically useful Doppler analysis tips for LVOTO and LAP assessment. 
In the end, I think that there were three pathologies, (a) tamponade physiology, (b) dynamic LVOTO, exacerbated by (c) hypovolemia (diarrhea)  I might have approached this differently, had I seen a truly plethoric IVC. In such a case, one can easily see how tamponade physiology would contribute to LVOTO in two ways by creating intracardiac hypovolemia, hence worsening LVOTO both by decreasing LV preload and by the compensatory tachycardia. My first approach would probably have been to drain the pericardial effusion, and reassessing the hemodynamics afterwards, but correcting the intravascular deficit was necessary.
The other important thing this case re-emphasize is that tamponade is not a static diagnosis but a physiological spectrum. For the same given effusion (read intrapericardial pressure – IPP), it is the RA pressure that will determine whether overt tamponade develops. In this patient, it is very likely that a day earlier, there was no frank tamponade, but that after some diarrheal volume loss, the RAP dropped, and now IPP > RAP.  It is important to know this because if you have an effusion and a fairly full IVC, one needs to be very careful with anything that can drop the RAP, meaning diuretics and vasodilators, because these can easily turn pre-tamponade into overt shock.  And, as this case illustrates so well, you might even end up with LVOTO and pulmonary edema!  Which is one of the myriad reasons one should have a basic POCUS exam in every acutely ill patient. These are things a resucitationist needs to know and prepare for.
cheers and thanks again to Dr. Thind!
Philippe

Wicked Clinical Case: POCUS & Prone save the day! #FOAMed, #FOAMcc, #FOAMer

So I get a call from a colleague in the ED at about 2am, telling me about a 39 yr old woman post-arrest. So I start putting on my boots and warming up the car (it’s January in Montreal folks).  Apparently she had presented earlier in severe acidosis, the diagnosis is unclear, but she apparently got 2 units for an Hb of 49, then went into respiratory failure and got intubated. She arrested about 30 minutes later, cause unknown.

I tell the ICU to prepare a bed but I want to see her in the ED first. Twenty minutes later I put probe to patient and see a full IVC with spontaneous echo contrast. On that I tell the nurse to hold the fluids – there was a bag and tubing and a pump with 100ml/hr on it – and turn into a subxiphoid view to see a normal RV and a hypokinetic LV with some WMAs. She has marked consolidations  in both posterior lung fields and B lines laterally, with small effusions and dynamic air bronchograms (indicating patent airways). At this point she has a HR of about 120, but there is neither perceptible BP (by NIBP) nor saturation. She’s on levophed at 20mcg. She’s about an hour post arrest which was witnessed and brief (<10min to ROSC).

The theories about the arrest are possible hyperkalemia: she was intubated with succinylcholine before the K of 6.1 was back from the lab, and her pre-intubation pH was 7.0, and post-intubation she was only ventilated at 400 x 18, possibly precipitating a drop in pH and a rise in K. Her EKG had some nonspecific signs at this point, but also a poor anterior R wave.

So we head to the ICU, as instrumentation was needed. Cerebral saturation (SctO2) is 42% and ETCO2 is 20mmhg, which reassures me that the BP is probably in the measurable range (normal SctO2 is >60% and varies, but 47% is certainly viable)…  A jugular CVC with continuous ScVo2 and a femoral arterial line goes in:

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So with a BP of 59/44 (ignore the 100/46, not sure whose arm that was on!) I start epinephrine, as the POCUS is similar, as I want some added beta-agonism. ScVO2 matches SctO2 in the 40’s. We get the BP up the the 90-1oo range, the ETCO2 goes to 30, the SctO2 and ScVo2 go up into the high 40’s, which is very reassuring, because with this I know that my epi drip is improving perfusion and NOT over-vasoconstricting. Without looking at a real-time tissue perfusion index of some sort or other, it is nearly impossible to know rapidly whether your therapy is helping or harming (will discuss tissue saturation & resuscitation monitoring in more detail in another post sometime soon).

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So now the sat finally starts to record in the low 60’s. We have a PEEP of 5, so start bringing it up. We hit 16 before the BP starts to drop, and that only gets us to the mid 70’s sat%. She actually squeezes my hand to command.

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At this point I take a few seconds to recap in my mind. I’d spoken to the husband briefly and she had had recurrent episodes of feeling unwell with headache, nausea and diaphoresis, and that had been out for dinner earlier and she felt fine until later in the evening when this came on and eventually brought her to hospital. There was also a notion of hypertension at an ER visit a couple of weeks ago. Her history was otherwise not significant. Nonsmoker.

Pheo? Maybe, but shock?  I repeat the EKG, and now, in I and AVL, there is perhaps a 1mm ST elevation. She’s 39 and essentially dying. Lactate comes back >15, pH 6.9.  I give her a few more amps of NaHCO3. You can see the BP respond to each amp. I decide we need to go to the cath lab and get the cardiologist on call to get on the horn with the interventional team at a nearby hospital with a cath lab and ECMO, which is what I think she needs. Hb comes back at 116, making that initial 49 that prompted 2 PRBCs probably a technical or lab error…very unfortunate. There are no visible signs of significant bleeding.

But back to the patient, because this isn’t really a transferrable case.

Recap: a 39yr old woman in cardiogenic shock AND in severe congestive heart failure exacerbated by fluids and packed red cells, with a PO2 in the 40’s and sat in the 70’s.

So I decide to prone her.

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Along with draining tamponades, this had to be one of the most rapid and rewarding maneuvers I’ve done. There was a scry drop of sat to the 40’s for a few seconds (may have been a technical thing), but then within a few minutes: BP to the 130’s, SctO2 to 59% and sat 100%!

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We dropped the vasopressors, the FiO2, and all breathed a collective sigh of relief. Now for the novices out there, prone ventilation improves VQ mismatch by moving perfusion from diseased, posterior lung fields to now-dependant, relatively healthy, anterior lung fields.

So transfer at this point was in the works. I planned to leave her prone until the last minute. The miraculous effect started to slowly wane within about 30 minutes, with sat and BP creeping down. At the time of transfer, we were back up to 80% FiO2.

So why is this?  Simple enough, this being simple pulmonary edema – rather than consolidated pneumonia – it migrated to dependent areas  relatively quickly. This was confirmed by a quick POCUS check:screen-shot-2017-01-05-at-10-48-06-pmscreen-shot-2017-01-05-at-10-48-26-pm

So in the still shots, you see a pristine “A” profile (normal, no edema) from the patient’s back, and a severe consolidation or “C” profile with ultrasound bronchograms in the antero-lateral (now dependant) chest. Impressive. (for those wanting some POCUS pearls see other posts and here). This is the reverse of her initial POCUS exam.

So we flipped her back and transported her – lights & sirens – the the cath lab, where they were waiting with ECMO cannulae. As an aside, it was quite refreshing to speak to the ICU fellow who spoke POCUS as well as french and english – it’s not usually the case, but I’m glad to see the change. I do believe it to be a direct effect of the influence of my friend and mentor, Dr. Andre Denault, one of the POCUS deities.

So she turned out to have a normal cath and a large adrenal mass. She did well on ECMO, being weaned off it today, and is now alpha-blocked and waiting for surgery, neurologically intact for all intents and purposes. A big thanks to the interventionists and the ICU team at the Montreal Heart Institute. Puts a smile on my face.

 

Take Home Points:

  1. don’t resuscitate without POCUS. I wouldn’t want anyone guessing with my life on the line, would you?
  2. keep pheo in mind as a cause of “acute MI” and shock
  3. if you’re not using some form of realtime monitor of perfusion (continuous CO, SctO2, ETCO2, ScvO2) then all you’ve got is looking at the skin and mentation, so you are essentially flying blind. Lactate and urine output are not realtime in real life.
  4. get ECMO in the house, it’ll come in handy. I’m working on it.

 

Love to hear some comments!

cheers

 

Philippe

 

ps I’ll try to add more ultrasound clips from this case in the next few days.