Thoracocentesis

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Belleza156

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Can anyone explain the correct placement of the needle to perform thoracocentesis?

There is a disaccord between what uworld, kaplan, and best current medical practice. I just need to know which one to have memorized to my exam.

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2nd intercostal space immediately above the 3rd rib (nerves and vessels run along bottom of ribs) in the midclavicular line.
 
I did a question from the free ones provided by usmle and the answer was above 9th rib in midscapular line. Why do you say 3rd rib? Doesn't the position of the needle at least need to be below the costodiaphragmatic recess?

Only thing I found in Moore is that it needs to be superior to the rib, but high enough to avoid the collateral vessels and nerve.

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Sorry, I'm not thinking very clearly. I'm on my ER rotation and my mind immediately jumped to needle thoracocentesis for a tension pneumo.

I did have an NBME question about a thoracentesis for fluid removal and the 9th rib in the midscapular line sounds right.
 
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Can anyone explain the correct placement of the needle to perform thoracocentesis?

There is a disaccord between what uworld, kaplan, and best current medical practice. I just need to know which one to have memorized to my exam.

Sent from my PC36100 using SDN Mobile

Assuming a non loculated effusion, fluid layers out according to gravity. When you perform a thoracentesis, the patient should be sitting upright, or slightly bent over. Where does all the fluid go? To the bottom. Where's the bottom? Well, the pleural space is further down in back than it is in front, so the "bottom" is the posterior of the back. Now, you dont want to poke diaphragm, and you arent putting in large bore tube (like a thoracostomy, a chest tube), so its just a needle.

Put it in somewhere in the back, mid scapular line, usually lower down (below 6) but not too low (>10). The correct answer is going to be "where the ultrasound shows you fluid." Just remember to go over the rib so as not to poke vessels or nerves of the ribs.
 
I did a question from the free ones provided by usmle and the answer was above 9th rib in midscapular line. Why do you say 3rd rib? Doesn't the position of the needle at least need to be below the costodiaphragmatic recess?

Only thing I found in Moore is that it needs to be superior to the rib, but high enough to avoid the collateral vessels and nerve.

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That question had a patient with dullness to percussion at the 7th rib. The answer was pertinent to the location of the fluid collection, so like the other guy says, you would have to go where the fluid goes (which is down). Of the choices that were listed, above the 9th rib was the only one that fit.
 
I Think I finally have a grasp on where to stick the needle!

Thanks everyone for the responses.

The question didn't specify more than that there was fluid filling up the lower third of the thorax..not really sure what rib that qualifies as. But the only viable answer choices were above the 9gth rib or below the 9th rib. Kaplan and UWorld had me all mixed up because one said to perform between 9-11th rib in the paravertebral line and another said between 10-12th rib in paravertebral line. I assumed paravertebral was close enough to midscapular line and went with below 9th rib because I thought I should be aiming for the 10th rib. I'll just go with the general rule of thumb to not go below the 9th rib and to stay superior to the rib so as to avoid VAN.

I found the pdf version of this year's free question, so for anyone who wanted to see the actual question:

A 25-year-old man is brought to the emergency
department because of a 1-week history of fever
and cough productive of purulent sputum. His
temperature is 38.9°C (102°F), pulse is 110/min,
respirations are 24/min, and blood pressure is
110/70 mm Hg. Crackles, decreased breath
sounds, and decreased fremitus are present in the
right lower lobe. A chest x-ray shows a pleural
effusion over the lower third of the thorax on the
right in the midscapular line. A thoracocentesis
is scheduled. Which of the following locations in
the midscapular line in this patient would be
most appropriate for insertion of the needle
during this procedure?

(A) Above the 2nd rib
(B) Below the 2nd rib
(C) Above the 5th rib
(D) Below the 5th rib
(E) Above the 9th rib
(F) Below the 9th rib
 
(Old thread, but someone is bound to Google this in the future)

I went with "below the 9th rib" for the same reason Belleza had above. In UWorld, they say that the pleural space extends inferiorly to the 12th rib in the paravertebral line and that thoracentesis should be performed between the 9th and 11th ribs accordingly.

Similarly, at the mid-axillary line, UWorld says the pleural space extends inferiorly to the 10th rib and that thoracentesis should be performed between the 7th and 9th ribs.

Based on this, the mid-scapular line should probably require thoracentesis between the 8th and 10th ribs because it's roughly mid-way between the paravertebral and mid-axillary lines.

Now the question is whether it should be done above or below the 9th rib. I believe this question came down to whether one considered the fact that you never stick a needle immediately inferior to any rib (unless you're purposely anesthetizing the intercostal nerve). So the answer has to be above the 9th rib. That both fulfills the 8-10th location and doesn't damage the intercostal VAN.

You answer this question, you either had to A) know straight-up the location of thoracentesis at the mid-scapular line or B) you had to have gone through UWorld, knew mid-scapular should have been a rough average of the paravertebral and mid-axillary, then guessed "above" based on the VAN.
 
I think you guys are making this question a little more difficult than it is.

Always insert the needle above the rib. Never below.

The answer choices don't say "between ribs 8 and 9" or "between ribs 9 and 10", but it sounds like you guys are reading it that way. It simply says above or below 9th rib (as these are the only two possible options; hopefully you wouldn't choose any of the others).
 

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