Difference between cardiac tamponade and tension pneumothorax

[2mochas]

A speaker for a CCRN review class told us it was a good idea to be able to tell the difference between cardiac tamponade and tension pneumothorax. I am finding conflicting information....anyone know?

[meandragonbrett]

Tell us what you know first of all.

[2mochas]

I know a tension pneumothorax is caused by air getting into the pleural space that cannot escape, usually caused by blunt or penetrating trauma, positive pressure, large TVs, and/or PEEP (also clamped water seal). Caridac tamponade is fluid or blood in the pericardial space, usually also caused by blunt or penetrating injury. I am looking for the differences in symptoms. Both can cause a shift in the mediastinum and both can cause JVD. The differences I came up with are that a tension pneumo causes assymetrical chest excursion, tachypnea and diminished or absent breath sounds on the affected side. Cardiac tamponade can cause a narrowed pulse pressure, a friction rubs, muffled heart sounds and Beck's triad. I think what sets it most apart from a tension pneumo is that there are increased both right and left heart pressures (RAP , PaOp). This is all I could come up with maybe that's all there is...

[akulahawkRN, ADN, RN, EMT-P]

Both will result in lower cardiac output. As to the differences, you may hear friction rubs and you'll possibly see Beck's Triad in Cardiac Tamponade. In a tension pneumo, you may see asymetrical chest excursion, JVD, and so on. I would normally NOT expect to see an actual mediastinal shift in tamponade, though on x-ray, you'll see the medialstinal area become more and more opaque as fluid fills the pericardium. Tracheal Deviation caused by mediastinal shifting in a pneumothorax is a late sign. You'll see the shift on x-ray though.

With a Tension Pneumo, you'll still hear heart sounds pretty well, unlike with tamponade. In a tension pneumo, the affected side will have diminished/absent breath sounds and will likely be hyperresonant to percussion. That's a finding you won't see in tamponade.

Signs that something's wrong with either may be simply start with agitation. Since both will result in decreased cardiac output, you'll start seeing decreased BP and increased JVD with both. Eventually, specific signs will emerge on their own to differentiate them.

Once you've seen a couple classic cases, you won't forget them.

[meandragonbrett]

Cardiac Tamponade can also be associated with a tachy-brady arrhythmia, OP.

[TakeBack]

Cardiac Tamponade can also be associated with a tachy-brady arrhythmia, OP.

By what mechanism?

[TakeBack]

A speaker for a CCRN review class told us it was a good idea to be able to tell the difference between cardiac tamponade and tension pneumothorax. I am finding conflicting information....anyone know?

Both are forms of obstructive shock and result in elevated filling pressures (CVP, PAP) and cardiogenic shock (low CO). They also are seen under similar circumstances (trauma, cardiac surgery, etc)

PTX is far easier to diagnosis by physical exam than tanponade. With true tension you should have absent or severely diminished breath sounds and the things mentioned above (tracheal shift, dyssynchronous chest wall motion). It's pretty obvious and easy to relieve with a needle compression.

Tamponade (in my experience) can lack the hallmark features you read about such as tachycardia or muffled heart tones. Unless the clinical situation makes it obvious (surgery, cath lab procedure, certain traumas), you need a CXR at minumim and echo to rule in/out.

[2mochas]

Sorry to get back to you so late, but thank you!

[2mochas]

Thank you!

[2mochas]

Very helpful, thank you!