UK EM Field Notes #6

Cardiac tamponade, pericardiocentesis, aortic dissection + tamponade

Which patients in my ED get pericardial effusions?

I work in an busy East London ED serving a diverse community with a wide range of ethnic and socioeconomic backgrounds. This means our patients can be highly complex (and high acuity). We see some trauma, but are not a major trauma centre. Therefore, it is mostly our TB, cancer, and CKD (ie uraemia) patients who get pericardial effusions. Of course there are rarer causes, but those are the big hitters.

In view of how chronically unwell our patients tend to be, cardiac tamponade should be considered in any patient who presents in respiratory distress or shock.

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Slow build up = big pericardial effusion

Chronic medical patients who develop pericardial effusions (TB, cancer, CKD) … do so slowly. They have chronic pericardial effusions. They can tolerate a large amount of fluid in the pericardial sac before they start to decompensate and tamponade.

You can have quite a dramatic-looking pericardial effusion on POCUS in chronic medical patients without evidence of tamponade. You need to know what to look for (more below).

An MTC will see a lot of penetrating trauma and therefore plenty of traumatic cardiac tamponade – most often from a blade entering the right ventricle. In these cases, there is a sudden build-up of fluid, and not much is needed to before the patient rapidly tamponades.

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POCUS!

“Beck’s triad” – distended neck veins, hypotension, muffled heart sounds – is unreliable. As is electrical alternans on the ECG. NEVER use the absence of Beck’s triad or electrical alternans as a rule out.

It’s the year 2025 - use POCUS (in all severe undifferentiated breathlessness/shock patients).

I won’t describe the technical elements of the scan here. Instead, I’ll signpost you to this this useful video.

Cool detail worth mentioning: tamponade physiology on POCUS (RV diastolic collapse) looks like “a little man bouncing on a trampoline”.

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Pericardiocentesis

This isn’t as intimidating as you think (not that I’ve ever done one... 😳). Ideally, we would get these patients over to tertiary centre so a cardiologist can perform the procedure under controlled conditions. In reality, if the patient is periarrest or indeed has arrested, the procedure needs to happen NOW.

As with all HALO procedures, the decision to perform the procedure is harder thant the procedure itself.

Again, a step-by-step description of the procedure in this forum is not valuable. Check out this video on the procedure.

A few tips:

• Most EDs (in the UK at least) are unlikely to have pericardiocentesis kits in resus. However, we do have central line kits which do the job nicely. Even if we did have pericardiocentesis-specific equipment, I would still recommend using a central line kit because we are familiar with it. Keep it simple… use stuff you know how to.

• Traditionally - before POCUS was a thing - the blind subxiphoid approach was the preferred strategy. This has a high rate of procedural failure and complications (… it involves skewering the liver).

• As you’ll see in the above video, the best approach is probably apical (as long as you can see a decent pocket of effusion to aim for). Use the linear probe as you would do for vascular access. Focus on the effusion and not the traditional cardiac view. Easy.

• If you puncture the heart with your needle don’t panic - it will almost certainly self-seal. However, if you dilate the heart and place your line this is life-threatening. Confirming your guidewire placement before dilation - with multiple ultrasound views - is crucial.

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Aortic dissection & haemopericardium

Aortic tears occur most commonly in the ascending aorta (i.e. Type A aortic dissection). This often results in haemopericardium which is the most common cause of death from aortic dissection.

Interestingly, there is conflicting guidance on this. The Acute Aortic Dissection RCEMLearning module suggests “it is imperative that pericardiocentesis is not performed as a number of case series have demonstrated that rapid decompression of the pericardium can restart fresh bleeding with rapidly fatal consequences”. It cites two outdated papers from 2001 and 1994.

The European Society of Cardiology pericardial diseases guideline published more recently in 2015 states the following: “In the setting of aortic dissection with haemopericardium and suspicion of cardiac tamponade… controlled pericardial drainage of very small amounts of the haemopericardium can be attempted to temporarily stabilise the patient in order to maintain blood pressure at ∼90 mmHg.”

My take:

• Don’t do anything unless they are properly periarrest or in cardiac arrest.

• If indeed they are periarrest/in cardiac arrest… do the pericardiocentesis.

• Drain small volumes paying close attention to haemodynamics.

• They won’t survive unless they are rapidly transferred out for cardiothoracic surgery.

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Cheers all,
Robbie
@robbielloyd.bsky.social