Consider the Probe 3: So I've found the effusion, now what?

A 74 y/o F with pmhx of metastatic breast cancer, IDDM, HTN presents after a syncopal episode.  The patient notes that for the past 2-3 days she has been experiencing some lightheadedness and shortness of breath with exertion.  She is presently undergoing chemotherapy (I'd throw in some random chemo drus here, but lets face it, we wouldn't know them anyways...) and radiation.  She notes that she hasn't been eating/drinking very well.  She denies fever, cough, hemoptysis, leg pain/swelling.  She has mild nausea but no abdominal pain.

As you peek up at the monitor, you note that the patient’s HR is ~ 135 and her BP is 88/56.  Her O2 saturation is  99% and the nurse told you that she was afebrile.  Taking a look at this patient, she looks ill-appearing and anxious.  Her extremities are cool to touch.  You quickly decide that Room 33 might not be the best place to manage this patient and that she would be better served in a RESUS station.  As you wheel the patient to RESUS, you are trying to organize a mental game plan. 

You grab a quick accucheck (remembering that your pt is an insulin-dependent diabetic) which comes back normal at 115mg/dL.  You are appropriately concerned about this patient and feel the need to evaluate her for life-threatening pathologies such as pulmonary embolism, cardiac tamponade, pneumothorax, and large malignant pleural effusions.  Wouldn’t it be nice if there were a bedside tool that could help you quickly assess the patient for the aforementioned “can’t miss” diagnoses. 

I think you know where I am going, might be time to…CONSIDER THE PROBE.  I would strongly argue that for a hemodynamically unstable patient, Point-of-care ultrasound should be the initial tool utilized to guide workup in a dyspneic patient.  You help your RESUS nurse get your patient “plugged in” and pull in an ultrasound machine to perform a quick ECHO to guide your decision-making.  You grab a couple quick still images that get you more worried:




https://emedicine.medscape.com/article/80602-overview




Diagnosing a patient with a pericardial effusion is nice, but what value does it serve us as emergency medicine physicians?  In this hypotensive patient with an impressive pericardial effusion at a quick glance, we need to get moving.  GET FLUIDS HANGING (if they aren’t already!) and then start scurrying around to gather a pericardiocentesis kit or (let’s face it) perhaps a Cook County makeshift kit (spinal needles tubing, 3 way stop cock?, get creative…).  Prepare yourself mentally and physically for the prospect that you may need to perform this rare, life-saving procedure!   If you have consultants in-house, GET THEM INVOLVED!  Cardiology should be your first call, but realize that they may want CardioThoracic surgery involved in this case.

You have a page out to cardiology, your equipment for an emergent pericardiocentesis is at the bedside. A 500cc NS bolus is in and the blood pressure improves to 98/60, HR comes down to 120.  You mentally review a recent ultrasound-college presentation on cardiac tamponade and remember how nice it is to be succinct but knowledgeable when communicating with your consultants.  You go back to the bedside and acquire the following echo clips so that you might have a more informed discussion with your consultants. 








Now, to review for a minute.  It doesn’t take too much skill as a bedside sonographer to identify a pericardial effusion.  However, it is much more difficult to assess for tamponade physiology.  Early signs of tamponade physiology include a Dilated IVC with Right Ventricular Diastolic Collapse.  This is easier said then done, especially when considering that these patients are often tachycardic.  Use Apical 4 chamber, Parasternal long or Subxiphoid and take a 5 second clip.  When reviewing these clips, assess the R ventricular free wall during diastole by slowing the clip down to frame by frame progression.  By noting the activity of the mitral (or tricuspid!) valve, you will be able to more easily separate SYSTOLE (Mitral/Tricuspid valves closed) from DIASTOLE (mitral/tricuspid valves open).  One really nice trick is to utilize M-mode in a Parasternal Long View.  Drop the M mode “plane” through the mitral valve (in the same location as we do to calculate an EPSS) and view this plane over time.  You should be more easily able to identify motion of the R ventricular free wall in relation to the mitral valve to assess for diastolic collapse as shown below:




(zoomed)

The Yellow Circle above (familiar from measuring EPSS) illustrates the mitral valve snapping open towards the septal wall (indicating the start of DIASTOLE), while the Blue rectangle shows the R ventricular free wall collapsing inwards—indicating tamponade physiology!

After reviewing your bedside ECHO clips (above), cardiology agrees with your interpretation (R ventricular diastolic collapse indicating cardiac tamponade) and whisks the poatient off to the operating room for a pericardiocentesis with CT surgery prepared to perform a window if the pericardiocentesis fails. 

Take Home Pearls
1)     In a hypotensive and dyspneic patient, always CONSIDER cardiac tamponade in your differential diagnosis and then CONSIDER THE PROBE…

2)     Once you have diagnosed the effusion, use POCUS to assess for IVC dilation with RV free wall collapse during diastole as indicators of tamponade physiology—and a patient that is more likely to require urgent vs emergent pericardiocentesis.

3)     Utilizing M-mode on PSL view may help you to more precisely identify the movement of the RV free wall during Diastole vs Systole.

4)     Once POCUS has identified tamponade physiology, prepare yourself (mentally and physically) to perform a pericardiocentesis while concurrently reaching out to your consultants.

Sources/Links

Nice intro/discussion through Dr. Avila’s 5 min sono: http://5minsono.com/tamp/

Really awesome/in depth videocast from Mike/Matt that delves further into tamponade physiology: http://www.ultrasoundpodcast.com/2013/11/pericardial-tamponade-learn-know-foamed/

Interesting article that highlights the subtelties of accurately diagnosing subacute tamponade: http://www.amjmed.com/article/S0002-9343(13)00391-4/pdf

As always check out Introduction to Bedside Ultrasound Ch: 17 (R Heart Pathology) to review this topic further: https://itunes.apple.com/us/book/introduction-to-bedside-ultrasound/id554196012?mt=11