Collapsing a lung

[deleted9493]

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My professor in anatomy was talking about the angle of Louis and how endotracheal tubes are measured between it and the mouth. He said that if you cut your tube too long, you're likely to slip it down the right bronchus and subsequently, collapse the opposing lung. Why is this? How does it happen? A related question to that...how close to corina should this tube be and why would it be less effective to just clear the epiglottis...or wouldn't it? Thanks.

 

[UTSouthwestern]

My professor in anatomy was talking about the angle of Louis and how endotracheal tubes are measured between it and the mouth. He said that if you cut your tube too long, you're likely to slip it down the right bronchus and subsequently, collapse the opposing lung. Why is this? How does it happen? A related question to that...how close to corina should this tube be and why would it be less effective to just clear the epiglottis...or wouldn't it? Thanks.

If your endotracheal tube goes down the right main bronchus, the opposite lung will not be ventilated and as it has an open channel along the side of the endotracheal tube to the glottis, it will slowly but surely lose all of the remaining air in the left lung. Without a properly placed ETT 2-3 cm above the carina to provide inspiratory volumes to both the left and right lungs, the left will not be ventilated and will remain collasped and atelectatic.

You must be aware that placing the cuff of the ETT too close to the glottis can cause subglottic tracheal ischemia and or reactive edema and subsequent stenosis.

 

[chillindrdude]

well...the right bronchus is the straighter of the 2 so it more likely to be intubated if you put in the ETT too far down. with regards to the collapse of the opposite lung...my guess is that if the patient is paralyzed and you are only ventilating the right lung (assuming you inadvertently put it down the right mainstem) the left lung would slowly collapse...also assuming you paid no attention to auscultating for breath sounds and an elevated ETCo2....

i verify ETT placement by, auscultating, + etCO2, and feeling for the cuff just above the sternal notch, condensation, etc....

hope that made some semblance of sense. 😉

 

[deleted9493]

That makes good sense. I'm pretty ignorant about most of these things but I find anesthesia to be really interesting...so thanks for the feedback.

 

[jwk]

My professor in anatomy was talking about the angle of Louis and how endotracheal tubes are measured between it and the mouth. He said that if you cut your tube too long, you're likely to slip it down the right bronchus and subsequently, collapse the opposing lung. Why is this? How does it happen? A related question to that...how close to corina should this tube be and why would it be less effective to just clear the epiglottis...or wouldn't it? Thanks.

I haven't cut an endotracheal tube in about 20 years. Anyone else still doing this?

 

[sandman1]

I haven't cut an endotracheal tube in about 20 years. Anyone else still doing this?

I think I have only had to modify an ETT once or twice in an odd situation. If your'e not careful, you can cut the air channel to the cuff, which actually extends slightly distal to the cuff... Been there, done that! 😀

Posting Student: Read up on one-lung ventilation and intra-pulmonary shunts, in Miller or Barash (choose your poison).

It's a good read! 👍

 

[gaslady]

It's carina, not corina. Any air in an unventilated lung will slowly be absorbed by tissues and blood stream, eventually causing that portion to collapse. Without the cuff through the vocal cords you haven't really secured the airway. The cords can spasm (laryngospasm) and close off thereby preventing air movement. Also, the airway isn't protected from possible aspiration of gastric contents. A correctly placed tube can shift once it is placed causing it to be too deep or not far enough. This can be caused by the tube falling further into the mouth, head movement (flexion, extension and side to side) or shifts during patient positioning or movement.

 

[sandman1]

The cuff is not relaible in protecting the airway from gastric aspiration.

 

[HomerSimpson]

I used to cut my tube but it just became kind of redundant. Two ways of determining proper placement of an ETT that I use other than auscultation are: 1) put the tube just past the cords and you can feel for the balloon as you inflate air just below the tracheal cartilage. 2) this method works well with babies you can purposely right mainstem the patient put a pre-cordial or regular stethescope over the left thorax and listen for breath sounds. SLOWLY pull on the tube until you can hear breath sounds bilaterally.

As far as causing lung collapse after right mainstem intubation, I suppose it can happen but probably, it is not that significant. Although the bronchus is open to air, most ett will be able to create a good enough seal to minimize equalization of pressure and eventual collapse of the lung.

Like a previous guy said the chapter on One-lung ventilation is a good read on this sunject in Barash.