Endotracheal Tube

Also known as a breathing tube, an endotracheal tube is placed during surgery to deliver oxygen and anesthetic gases in a controlled fashion. It may also be used in gravely ill persons who need the assistance of a ventilator. Rarely, it may cause injury to the posterior part of the larynx, especially when the tube remains in place for many weeks.

Breathing Tube Injury, not Vocal Cord Paralysis

This middle-aged woman was injured severely in an auto accident as a teenager. Recovery involved a long stay in ICU, and ventilation via a breathing (endotracheal) tube for a few weeks prior to tracheotomy. Fifteen years earlier, a posterior commissuroplasty was done by me on the left side.  Severely short of breath before that procedure, she said the improvement was such that she was able to do most activities of daily living remarkably well for many years. While still much better than prior to the posterior commissuroplasty, she has felt a little more limited in the past few years and wants now another similar airway-widening procedure. Speaking voice can easily pass for normal, though she thinks it is occasionally a little rough.
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Aperture is very narrow (1 of 6)

Seen from a distance, during exhalation, the vocal cord aperture is perhaps 30% of normal.

Involuntary inspiratory phonation (2 of 6)

When asked to inspire rapidly, even in this distant view, the vocal cords can be seen to in-draw and vibrate (see blur), creating involuntary inspiratory phonation. Inspiratory phonation time is estimated at 2.5 seconds, rather than the normal 1 second or less.

Divot on left vocal cord (3 of 6)

The shallow “divot” of the left cord (right of photo) is all that remains of what would have been a much deeper divot created at the time of posterior commissuroplasty, 15 years earlier. The dashed line indicates the likely magnitude of laser excision.

Endotracheal tube injury (4 of 6)

The full extent of the original endotracheal tube injury is seen best in this view of the extreme posterior commissure. One can almost see the upper surface of the cricoid cartilage marked with “C” showing also a scar band between arytenoid and cricoid cartilages, especially on the right (at S).

Laser cookie bite (5 of 6)

The posterior commissure during phonation shows the divot on the left cord (right of photo). The dashed line shows the approximate magnitude of the laser “cookie bite” to be created at the time of surgery. But the lighter dotted line is a typical remaining divot after full healing. Interestingly, (as explained by Charles’ Law) if even this small area is added to the size of the glottic aperture while breathing, the patient will notice a significant improvement of exercise tolerance.

Surface scarring in the tracheotomy (6 of 6)

When there is a scar anywhere in the airway, the clinician must make sure there isn’t another causing narrowing. In this case there is no narrowing, but the tracheotomy site shows surface scarring at the arrow.

Breathing Tube Injury may Correlate with Side of Mouth

This person was intubated for 2 weeks due to complications after major surgery.  He was sent for evaluation due to hoarseness, with a diagnosis from elsewhere of vocal cord paralysis.  During the consultation, he described himself as a very quiet person (a “2” on the 7-point talkativeness scale), and living a quiet life.  After the examination below his wife was asked “Was the tube taped to the left corner of his mouth?  Or do you not remember?”  She replied, “Definitely, the left corner.”  This history raises the question:  “Is the diagnosis of paralysis from elsewhere correct, or is the actual diagnosis vocal cord fixation from intubation injury?”
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Vocal cord fixation (1 of 4)

In this mid-range view, the left vocal cord (right of photo) moves laterally for breathing, but the right cord remains at the midline. In contrast to paralysis findings, the right cord does not look particularly atrophied. The margin bowing is somewhat discounted, as this finding is also present on the left cord as it comes to midline. Furthermore, in contrast to paralysis, there is no unusual prominence of ventricle, and the absence of “conus” on the right (left of photo) does not really count, because “conus atrophy” can only be fully evaluated in a lateralized cord position, which is not possible here. Suspicion: This is not paralysis but vocal cord fixation…

Paralysis (2 of 4)

During phonation, both cords meet in a fairly straight line, but the left cord (right of photo) rides higher than the right (left of photo). The absence of the vocal phenomenology of “luffing” even with strong voice elicitation, strongly discounts paralysis in favor of fixation.

Injury from intubation tube (3 of 4)

With a clear view of the posterior commissure, a pressure necrosis “divot” is seen on the right (left of photo) and this is what prompted the question “Was the tube taped to the left corner of his mouth?” The curvature of the tube would be expected to put more pressure on the right posterior cord. Note as well the lack of ventricular prominence that one usually sees with paralysis.

Mismatch of levels (4 of 4)

During sustained phonation, the overlap of left on top of right cord is due to tissue loss and scar contracture in a downward direction of the right arytenoid. The lack of paralysis / atrophy / flaccidity of vibration explains why the patient can recruit loudness to his voice so well. The mismatch of levels explains the mildly rough vocal quality. He is a vocal “underdoer” as described in the introductory paragraph, and may benefit from voice building.

Nuances of Endotracheal Tube Injury Distinguished from Paralysis

This woman with high-risk comorbidities of diabetes and obesity, was in ventilated in ICU more than a month for pulmonary complications of Covid-19 infection. She had an orotracheal tube in place for 3.5 weeks, and then a tracheotomy tube was placed. Now at her first visit a year later, she remains tracheotomy-dependent, and is told she has bilateral vocal cord paralysis (disproven in the photo series).

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Maximum glottic opening (1 of 8)

Is it paralysis, as diagnosed elsewhere? At a fairly distant view, the maximum opening between the vocal cords at any phase of breathing appears to be approximately a 4mm glottic opening.

Undersurface mucosa indraws (2 of 8)

When the patient inspires rapidly with tracheotomy tube plugged, the vocal cord undersurface mucosa indraws (grey bands at dotted lines), further narrowing the glottic chink. One sees a faint suggestion of breathing tube injury (divot) at the arrow. Notably, there is a very low pitched rumbling sound heard that does not come from the glottis.

Phonation (3 of 8)

During phonation, the cords approximate fully, and in fact the voice is remarkably normal-sounding and she even has an excellent upper range.

Posterior commissure divot (4 of 8)

At close range while breathing with trach plugged, the posterior commissure divot subtly visible in Photo 2 is confirmed. A divot in the right posterior cord “always” indicates that the tube was taped to the left corner of the mouth. The patient’s mother confirmed that this was so.

Further evidence of scarring (5 of 8)

Angling farther posteriorly, additional evidence of inter-arytenoid and possible joint capsule injury is seen. Faint dotted lines outline this area. The problem is not bilateral vocal cord paralysis but posterior commissure scarring, tethering the arytenoids together.

View into trachea (6 of 8)

Looking now into the subglottis and trachea, there is narrowing only at trach entry site, accentuated functionally because the membranous trachea (MT) moves in and out with respiratory phase.

Vibration of trachea (7 of 8)

When the patient plugs the trach tube and inspires rapidly, the deep rumbling sound is again heard, and comes from vibration of the membranous trachea indrawing (arrows) and vibrating (zigzag line).

Open trachea beyond the tube (8 of 8)

A view past the tip of the trach tube shows no secondary area of tracheal stenosis.

The plan here is posterior commissuroplasty, followed by placement of a smaller trach tube and a trial of plugging. If plugging is tolerated during the day, she will need a sleep study with it plugged at night, given the tracheomalacia and her obesity.

Breathing Tube Injury—A Rare Complication of Intubation for General Anesthesia

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Inflamed vocal cord (1 of 5)

This patient had severe voice change after intubation for a 2-hour surgical procedure. She says voice was 100% before surgery and she awakened at 15%, a whisper with a bit of voice mixed in. Fortunately, across six weeks she has recovered partially to “70%.” The right cord (left of photo) looks “inflamed.”

Closer view (2 of 5)

At closer range, a little more detail is seen.

Scarring from intubation tube (3 of 5)

Under narrow band light, it appears that there is scarring of that fold likely from a laceration upon insertion of the tube. (She was told intubation was difficult.) A key finding, however: the right vocal process is turned slightly laterally, suggesting weakness of the LCA muscle.

Mucosal Injury (4 of 5)

Under strobe light, closed phase of vibration, it is almost as if there is loss of mucosa upper surface of right cord.

Flaccidity of right vocal cord (5 of 5)

Open phase of vibration shows flaccidity of the right cord, with a much larger lateral excursion / amplitude of open phase on the right (left of photo).

Conclusion: While we try to explain abnormality due to one cause, here, the patient has a mucosal injury and paresis of right TA and LCA muscles, which can also follow intubation. This explains why the initial postop voice was so weak and whispery, and also the rapid partial improvement. This voice will likely continue to improve and be very functional as a speaking voice. Fortunately, this person is not a singer, as clarity especially in upper notes, will likely be remain impaired even after full recovery.

Supraglottic, Glottic, and Subglottic Endotracheal Tube Injury

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Breathing tube injury (1 of 4)

This 20-something individual was premature at birth and intubated for several weeks. Decades later, the evidence of breathing tube injury can be seen. Here, parallel lines outline likely trajectory of tube, taped at right corner of mouth. This fits as well with the left medial arytenoid divot at arrow. Dotted lines indicate aryepiglottic cord margins. Note deficit on right (left of photo) suggesting pressure necrosis from the endotracheal tube.

Aryepiglottic cord defect (2 of 4)

Aryepiglottic cord defect is better seen during phonation. The details of posterior commissure injury are obscured at this distance.

Phonation (3 of 4)

During phonation, low voice, note that the posterior vocal cords cannot come together, (even with cough or breath-holding) due to joint capsule injury from the endotracheal tube. Voice is intractably breathy.

Posterior subglottic thickening (4 of 4)

Posterior subglottic thickening surrounded by dotted lines, indicating a third level of old injury, here with no functional consequence.
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Using Your EARS to Understand Airway Narrowing

A narrowing anywhere in the breathing “pipe” that leads to the lungs causes shortness of breath, typically with harsh inspiratory noise on exertion. Such a narrowing can follow injury, intubation, cancer treatment, auto-immune disorders, etc.

It is possible to gain an immediate understanding of the magnitude of the airway narrowing within minutes by using a simple test “graded” with one’s ears. The severity of the problem can be understood before any examination or X-ray evaluation.

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