A Case of Endotracheal Tube Obstruction

Normally we view patients who are intubated as being protected in terms of ventilatory support. However, being intubated makes the patient vulnerable to a variety of potential problems. Rapid deterioration of an intubated patient can be a challenging and frightening scenario because the providers must rapidly troubleshoot the causes as well as treat. Here a case of endotracheal tube obstruction and its management is described. Quite a few years ago, I encountered a case well worth discussing. 

The Case

The 30 year old woman was lying on the gurney outside the treatment room. Although she was intubated, the patient was quite cyanotic and it was obvious my colleagues were having difficulty ventilating her. Breath sounds were present and equal but the force required to squeeze the bag was impressive.

The woman had been undergoing a septoplasty, a type of nasal surgery, under conscious sedation combined with local anesthesia when she suddenly lost consciousness. The CRNA monitoring her had intubated immediately. My partner had already treated for bronchospasm even though there was no audible wheezing.

O2 saturation was now 65% and dropping, and worse, the patient was developing a bradycardia of 40. Acute bradycardia in the face of hypoxia is a bad sign that often means impending cardiac arrest. There was a lot of blood in her mouth — drainage from the nasal surgery that had stopped before completion.

I flashed back to a case I had managed years before. My prior patient had suffered from Acute Respiratory Distress Syndrome (ARDS) and had been on the ventilator in the ICU for about a week when she suddenly developed extremely high ventilation pressures. A chest X-ray ruled out pneumothorax. Like the present case, she was intubated but we couldn’t ventilate through the ETT. I removed the endotracheal tube and reintubated the patient awake, describing to her what I as doing rather than sedating her in the face of bradycardia and imminent arrest. After I had reintubated her, we had found the removed ETT was filled with hardened secretions, onion-skinned around the inner surface until barely 1 mm of open channel remained.

Unlike my prior patient, this patient had just been intubated minutes before. I tried suctioning down the tube and couldn’t pass a catheter. The tube didn’t seem kinked and she wasn’t biting the tube.

“Take out the tube and reintubate.” I suggested. My partner hesitated, as well she should have. Taking out a perfectly good endotracheal tube in a patient who you think is about to arrest is not something to be done lightly.

“Take it out. I think it’s plugged.”

My partner grabbed her laryngoscope and under direct vision, extubated and quickly reintubated with a new ETT. Immediately we could ventilate. O2 sat. rose, BP and pulse normalized. She started to wake up.

The ETT we had removed was plugged with an enormous organized blood clot. Apparently our patient had been silently aspirating blood during the procedure, a combination of deep sedation plus topicalization had taken away her cough reflex. The blood clot had caused partial obstruction and an increasing CO2. An acute PCO2 above 70 is sedating and can lead to worsening hypoventilation leading to higher PCO2.

Fortunately, when the first endotracheal tube was passed into the trachea, the clot lodged in the tube. Had it not, we would not removed it with the extubation. It might have continued to obstruct the trachea and perhaps block the carina, making ventilation impossible.

How to Manage Respiratory Deterioration in An Intubate Patient

Time is often of the essence when an intubated patient acutely decompensates. Use of the DOPE mnemonic, as outlined by the Pediatric Advanced Life Support guidelines (1), to troubleshoot acute deterioration in a mechanically ventilated patient, may be helpful. As a reminder:

  • D is for dislodgement of the ETT
  • O is for obstruction of the ETT
  • P is for suspected pneumothorax
  • E is for equipment or operator problem

Whenever ventilation deteriorates in a ventilated patient, always verify breath sounds. Extubation and esophageal intubation can occur at any time.

The risk of barotrauma is real in an intubated patient so always check for pneumothorax. And as an even rarer event, remember that bilateral pneumothorax the breath sounds and can be poor but equal, and the still heart non-displaced. I have seen this myself.

I have also seen a ventilator failure. In this case manual ventilation with an Ambu style bag was successful, proving the endotracheal tube was still positioned and functioning appropriately.

Clearly here we had endotracheal tube obstruction from a clot. Other things that can obstruct your ETT include the patient biting the tube, something that may be hard to see depending n the patient position.  ETT cuff overinflation can cause cuff herniation over or into the ETT opening (2, 3). If you are using a tube without a Murphy Eye, such as some laser tubes or wire reinforced tubes, having the tube up against the carina can also cause obstruction.

If after troubleshooting, you still can’t ventilate through an endotracheal tube, the recommendation is to remove the ETT, manually ventilate the patient with bag-valve-mask, and then reintubate.

Lessons Learned In This Case:

Be lucky.  We were very lucky that the initial intubation forced the clot into the endotracheal tube. While it didn’t help the immediate crisis, this scenario made it easy to remove the clot during extubation. Had the clot been below and outside the tube, blocking the carina, we might never have known.

Be knowledgeable. In this case, it was very helpful that I had faced a similar situation before. Every patient you care for, or that who hear about, adds to your “data base”, and provides the scientific basis for your 6th sense intuition. Listen to it, but always have plan B.

Be imaginative. This is also another instance where a failure of imagination could’ve led to a bad result. After all, the patient had been easily intubated, and the ETT was inspected and properly placed. It would have been easy to assume that the fault lay in something other than the airway.  The problem was that the ETT had been compromised after it was inserted, out of sight but, fortunately, not out of mind.

May The Force Be With You

Christine Whitten

Further Reading

  1. Ralston M, Hazinski M, Zaritsky A, Schexnayder S, Kleinman M. Pediatric advanced life support provider manual. Dallas: American Heart Association; 2006:195.
  2. Johnson KM, Lehman RE. Acute Management of the Obstructed Endotracheal Tube. Respiratory Care August 2012; 57 (8)
  3. Hofstetter C, Scheller B, Hoegl S, Mack MG, Zwissler B, Byhahn C. Cuff overinflation and endotracheal tube obstruction: case report and experimental study. Scand J Trauma Resusc Emerg Med 2010;18(18): 1-5.

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