Labs and Lytes 011
Author: Chris Nickson
Reviewer: Owen Roodenburg
Six days ago a 24 year-old male with an isolated severe traumatic brain injury underwent percutaneous dilatational tracheostomy for airway protection and to aid sputum clearance. He no longer requires positive pressure ventilation but still has a tracheostomy tube in place.
You are called to his cubicle because he is having trouble breathing and is starting to desaturate.
You check his ABCs and find:
- tracheostomy tube present
- no airway sounds
- SpO2 88% on FiO2 1.0 via tracheostomy tube
- no chest movement despite apparent respiratory efforts
- HR 120/min and BP 140/90 mmHg
- GCS E3 VT M4 (unchanged over 24 hours)
Q1. What are the possible causes?
In a patient with a tracheostomy, or any type of endotracheal tube, I think of the causes as being related to either ‘man or machine’.
All the usual causes of respiratory distress in a non-tracheostomized patient can occur, but the initial focus should be on the tracheostomy tube.
- displaced tube
- obstructed tube
- patient factors (e.g. pneumothorax)
- equipment (e.g. ventilator if present)
- stacked breaths (e.g. dynamic hyperinflation in a ventilated asthma patient)
The patient has a silent chest that isn’t moving despite apparent respiratory effort. Otherwise, are no immediately identifiable patient factors and he is not on a ventilator.
Q2. What is the first thing you do?
Remove the inner cannula from the tracheostomy tube.
All patients with tracheostomy tubes in ICU (at The Alfred) will have an inner cannula (with rare exceptions). If secretions, blood or a sputum plug has obstructed the inner cannula the problem is immediately solved on removal. This is an easy way to fix life-threatening airway obstruction.
Always do this first.
The inner cannula can usually be easily removed. Depending on the type of tracheostomy tube there may be a ‘pull tag’, others may have a ‘twist to unlock’ mechanism.
Unfortunately, that doesn’t work…
SpO2 has fallen to 86% despite FiO2 1.0 via the tracheostomy tube and a 15L/min non-rebreather mask placed over the patient’s face.
Q3. Now what will you do?
The facemask oxygen is a good idea. However, the patient will only be oxygenated if there is space around the tracheostomy tube – if the tube is cuffed (indicated by the presence of a pilot balloon!) then be sure to deflate the cuff. This may be enough provide oxygenation if the tracheostomy tube is obstructed.
Next, you need to check if the tracheostomy tube itself is obstructed or displaced (i.e. the outer cannula).
Apart from clinical assessment of the neck and tracheostomy site, which may give the game away, this can be done rapidly at the bedside if you:
- check if a suction catheter can pass freely – note that you may be able to pass the catheter in the presence of partial obstruction. Furthermore, suctioning may allow you to clear the obstruction.
- Check the ETCO2 waveform – an absent trace signifies complete obstruction or that the tube is no longer in the airway (or cardiac arrest!)
If there is no imminent emergency, then a chest radiograph may indicate that the tube is displaced or perhaps obstructed by the tube tip abutting the wall of the trachea. However, bronchoscopy is the most useful way to confirm position and patency.
Never delay fixing the problem by waiting for a bronchoscope if the patient is hypoxic and deteriorating!
Today is not your lucky day…
In this case, the suction catheter still doesn’t pass freely and attempts at suctioning haven’t helped.
Now SpO2 has dropped to 80% and there is still no ETCO2 trace.
You really need to sort this out, and fast!
Q4. What will you do now?
Remove the tracheostomy tube.
If it is not working, take it out. In simulations and in real life this can be a difficult act for many doctors to commit to and perform.
If the tube is obstructed or displaced, and the patient is deteriorating, JUST DO IT!
Remember to cover the tracheostomy site during oxygenation and ventilation via the oral route (e.g. apply gauze and gentle pressure).
This patient has not had a laryngectomy, so he should have a patent upper airway (check the patient records if you have time for the intubation grade – but in the deteriorating patent you must proceed regardless). Optimise the airway using head tilt and chin lift, or jaw thrust. Use airway adjuncts as required. Once adequately oxygenated (e.g. assist ventilation via face mask using bag-and-valve), prepare for intubation. Surgical cricothyroidotomy can still be performed if a ‘can’t intubate, can’t ventilate’ situation arises. Ensure the tip of the endotracheal tube passes beyond the tracheostomy site.
Addendum 15 June 2014
The timing of this patient’s original tracheostomy procedure is not stated (intentionally). A reattempt at inserting the tracheostomy tube in the stoma is not recommended within 1 week of the tracheostomy procedure. In an emergency, especially if there are concerns about about the viability of the stoma tract, it is important to not be distracted by the hole in the patient’s neck if the patient has a perfectly good hole between his vocal cords!
The patient now has SpO2 100%.
Whatever you did, it worked!