Pneumothorax

[You'reCrazy]

Just had a question on pneumothorax, I remember Goljan explained tension v spontaneous but looking at First Aid p. 433 I just got confused (since it doesnt explain the difference at all. Can someone who is a pro at pulmonary explain pneumothorax to me (i searched the internet and kaplan books but I can't find a good explanation).

Ok what I am asking is, what is happening with trachea(tension pneumo-away from lesion and diaphragm down, spontaneous pneumo - toward the lesion and diaphragm up), resonance( up in both right?), fremitus (really confused about this), and breath sounds. And what crepitus has to do with all of thiss too. Sorry for being so long winded (its been a bad day). would love some help. thanks

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[Tired]

Just had a question on pneumothorax, I remember Goljan explained tension v spontaneous but looking at First Aid p. 433 I just got confused (since it doesnt explain the difference at all. Can someone who is a pro at pulmonary explain pneumothorax to me (i searched the internet and kaplan books but I can't find a good explanation).

Ok what I am asking is, what is happening with trachea(tension pneumo-away from lesion and diaphragm down, spontaneous pneumo - toward the lesion and diaphragm up), resonance( up in both right?), fremitus (really confused about this), and breath sounds. And what crepitus has to do with all of thiss too. Sorry for being so long winded (its been a bad day). would love some help. thanks

I'll take a stab.

The issue is pressure in the thoracic cavity.

In a tension pneumo, air goes in but doesn't come out (one-way valve). Thus the pressure on the affected side is higher than the normal side, causing the unaffected side to be compressed, and the trachea (the midline marker) to be pushed towards the unaffected side.

In a spontaneous pneumothorax, the lung collapses, but there is no air trapping in the thoracic cavity, resulting in normal or relatively decreased pressure in the affected side. Thus the trachea is pulled towards the affected side, or stays midline, depending on the severity of the collapse.

(I've seen probably 2 dozen spontaneous pneumothoraces, and none of them had tracheal deviation)

Yes, resonance should be increased on the affected side in both cases. Breath sounds should be decreased in both cases. Fremitus is decreased in both cases because air conducts sound less efficiently than fluid does.

 

[Army DOC DO]

hope this helps, this is directly from goljans Audio on this topic>
Tension Pneumo: means you have a penetrating trauma, like a knife fight,gun shot, you get a flap and as you breath (diaphram goes down increasing negative intrathoracic pressure) air comes into the plueral cavity but can't go back through the flap, it seals itself building up intra thoracic pressure, and this causes the trachea to deaviate away from the affected side and the diaphram to be depressed on that side and stay down. and compression atelectasis occurs
Spontaneous Pneumo: from a ruptured bleb, get a hole that has no flap, and thus communicates with the atm through the lung and out the trachea etc. and you loose theability to draw negative intrathoracic pressure, and this causes some or all of the lung to colapse and you get trachea to deviate to that side, and the diaphram elevates because there is No "pressure" of air filled lungs pressing down on the diaphram. (lung does not ventilate on that side very well, loss of negative intrathoracice pressure to draw air into the lung.
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[ginger60]

The above posters pretty much said everything, but I can tell you how I altered the chart in FA (I have the 2006 edition) so that it was more complete and agreed with Goljan. The row that says pneumothorax corresponds to spontaneous pneumothorax, and the entries in the rest of the row is correct (decreased bs, hyperresonant, no fremitus) except the trachea deviates ipsilateral to the lesion and the ipsilateral diaphragm moves up in spontaneous pneumothorax (FA didn't mention the diaphragm, and incorrectly said the trachea deviates away from the side of the lesion). I created a new row for tension pneumothorax, with decreased bs, hyperresonance, no fremitus, tracheal deviation contralateral to lesion, and ipsilateral diaphragm moves down. Hope that helps.

 

[You'reCrazy]

thanks you guys, and nice idea on changing the table on first aid

 

[imnestea]

Great job explaining this!

sorry to revive an old thread, but where does atelectasis fit into all this?

 

[Jamiu22]

Great job explaining this!

sorry to revive an old thread, but where does atelectasis fit into all this?

I don't think atelectasis fits into pneumothorax since it's a different pathology...pneumothorax typically deals with air in the pleural space while atelectasis deals with air not being able to get into the alveolar space

.....and think of it this way... you have the alveolar collapsing pressure = 2T/r (this is the force that wants to keep your alveolar closed - and where T is the surface tension and r is the alveolar radius)... so when you get chest trauma or prolonged acute lung injury, you tend to get reduced surfactant production... the job of surfactant is to reduce surface tension T... so now the patient will have a high T... hence high collapsing pressure... hence your alveolar wants to stay collapsed - and it's hard to re-inflate with normal breathing.... and that my friend is atelectasis.

 

[imnestea]

I don't think atelectasis fits into pneumothorax since it's a different pathology...pneumothorax typically deals with air in the pleural space while atelectasis deals with air not being able to get into the alveolar space

.....and think of it this way... you have the alveolar collapsing pressure = 2T/r (this is the force that wants to keep your alveolar closed - and where T is the surface tension and r is the alveolar radius)... so when you get chest trauma or prolonged acute lung injury, you tend to get reduced surfactant production... the job of surfactant is to reduce surface tension T... so now the patient will have a high T... hence high collapsing pressure... hence your alveolar wants to stay collapsed - and it's hard to re-inflate with normal breathing.... and that my friend is atelectasis.

How is what you explained different from a spontaneous pneumothorax where there is no air trapping in the thoracic cavity (i.e. from a ruptured bleb.)

 

[Jamiu22]

How is what you explained different from a spontaneous pneumothorax where there is no air trapping in the thoracic cavity (i.e. from a ruptured bleb.)

ha... I think I see where you are coming from.. in that the end outcome is similar i.e. your lungs would like to collapse in both scenarios.. in the case of spontaneous pneumothorax, look at the lungs like concentric balloons and the space between them (intrapleural space) has a negative pressure (vacuum)... so with ruptured subpleural bleb, you lose this negative pressure .. hence the whole lung doesn't want to stay inflated.

While in the case of atelectasis, the negative intrapleural pressure is maintained, but rather the lack of surfactant makes it difficult for the alveolar to open once they collapse on expiration.

So while they look somewhat alike on explanation, the pathophys are different and the treatment are also different - in tension pneumothorax, you would typically insert a chest tube to normalize this pressure again... while in the case of ateletasis (or ARDS), you would tend to place the patient on a breathing machine with PEEP therapy (this just maintains a little more pressure in the lungs when the patient breathes out so that the lung doesn't completely collapse). Hope this help.s