'Deep' extubation refers to removing the endotracheal tube whilst the patient is still fully anesthetized, i.e. 'deep'.
INDICATIONS
During wake-up from anesthesia the presence of an ET tube in the trachea and the larynx presents an intense stimulus to the patient and invariably causes a cough as well as a gag reflex. In fact, coughing and gagging with the ET tube in-situ are reassuring signs that a patient is 'ready' for extubation, as this indicates the return of normal upper airway reflexes after anesthesia, meaning the patient should be able to protect himself from aspiration once the ET tube is removed. So much so that a cough and gag reflex are one of the three major extubation criteria after general anesthesia.
With 'deep' extubation, the ET tube is removed before wake-up and before the return of upper airway reflexes.
There are no absolute indications for this technique. Most commonly, deep extubation is considered when coughing during wake-up could be detrimental to the patient, e.g. in some cases of intracranial or head and neck surgery.
'Deep' extubation does not guarantee that a patient won't cough during wake-up, but it certainly reduces the risk.
'Deep' extubation for a supraglottic airway device/ laryngeal mask
Many practitioners like to routinely remove a supraglottic airway device/ laryngeal mask 'deep'. The rationale is that the presence of a supraglottic airway during wake-up from anesthesia can trigger laryngospasm, a concern especially in pediatric patients, who generally have more 'lively' upper airway reflexes compared to adults.
TECHNIQUE
The same precautions and conditions apply as for normal extubation with one major exception: The endotracheal tube (or supraglottic airway device) is removed before the return of upper airway reflexes which occurs during wake-up from general anesthesia. In fact, the goal during 'deep' extubation is to have the patient sufficiently anesthetized to suppress any upper airway reflexes such as coughing and gagging.
Make sure you address the following points before proceeding:
- Is your patient a suitable candidate for 'deep' extubation? For example, a patient who required a rapid sequence induction for a "full stomach" or severe GERD should definitely not be extubated 'deep'.
- Consider what airway management was like during induction of anesthesia. Any problems with the airway during induction might resurface during deep extubation.
- Go through your extubation checklist as you would for a 'regular', i.e near-awake extubation.
In particular, identify if your patient belongs to any of the three main groups of patients less suited for 'deep' extubation:
- (Some) patients with difficult airways. This applies mainly to patients in whom maintenance of airway patency during induction was already challenging. Also be hesitant performing 'deep' extubation in patients who had surgery of or near the airway. Maintaining airway patency during wake-up after 'deep' extubation might now be a lot more difficult!
- Obese patients. Obese patients tend to not breath very well unsupported under general anesthesia, i.e. just after 'deep' extubation.
- Patients at risk of aspiration. Presence of material that could be aspirated, e.g. gastric contents, blood in the pharynx, and lack of upper airway reflexes is a potentially unsafe combination in the context of 'deep' extubation.
Here is a suggested sequence for the technique:
1. Clear the airway from secretions
Removing the ET tube 'deep' means the patient is at a high risk of aspiration during the wake-up period. Inspecting and suctioning the upper airway meticulously is therefore even more important before 'deep' compared to 'standard' extubation.
You might want to consider suctioning under direct vision, i.e. under laryngoscopy, to ensure the airway above the ET tube cuff is clear of secretions and blood. This is particularly true in cases where soiling of the upper airway at the end of surgery is likely, e.g. sinus, nasal or oral cavity surgery.
2. Make sure the patient is actually 'deep'
Do not attempt 'deep' extubation when the patient is not sufficiently anesthetized. Removing an endotracheal tube is very stimulating and likely to trigger laryngospasm in patients who are neither awake nor 'deep'. In practice, use at least 1 MAC of volatile agent during deep extubation. There should be no response from the patient to suctioning of the oral cavity and hypopharynx. If there is, the patient is too 'light' for 'deep' extubation.
Laryngoscopy (and suction under direct vision) is also a good way to clinically assess adequate depth of anesthesia just before 'deep' extubation: If there is no patient 'reaction' during laryngoscopy your patient is likely 'deep' enough for removing the ETT.
3. Assess the patients ability to breathe spontaneously without ventilator support
The patient should have an established, more or less 'normal' spontaneous respiratory pattern and rate before 'deep' extubation is attempted. In practice, it is advisable to let the patient breathe spontaneously for a brief period before extubation without mandatory or pressure-augmented ventilator breaths to assess tidal volume and respiratory rate without support. A good approach is to select a pressure support mode and maintain PEEP without pressure support, esentially delivering CPAP during spontaneous breathing.
4. Consider insertion of one or two simple airway adjuncts before extubation
This is most easily done whilst the patient is still intubated. Especially the nasopharyngeal airway is a useful adjunct to maintain airway patency during wake-up and is better tolerated throughout the wake-up phase than an oral airway.
5. Pre-oxygenate
Don't forget to pre-oxygenate as you would for intubation.
6. Extubate
After extubation, turn off anesthetic agents and deliver high-flow oxygen to the breathing circuit.
TIP: It is very common, even for adequately anesthetized patients, to breath-hold for a brief period immediately after 'deep' extubation. Do not rush into administering bag-mask ventilation! Since you have pre-oxygenated your patient, it should be safe to wait at least 40 seconds or so for spontaneous breathing to resume while maintaining airway patency and providing 100% oxygen insufflation.
7. Maintain airway patency
In most patients you will initially require basic airway maneuvers to maintain airway patency. Remember that the patient is still 'deeply' anesthetized just after extubation.
Don't forget to turn off your anesthetic drug administration/ vaporizer!
Constantly re-assess the need for applying the basic airway maneuvers and using simple airway adjuncts by looking for evidence of (partial) airway obstruction, such as stridor, tracheal 'tugging' and a 'see-saw' breathing pattern. As the patient 'lightens' less and less airway support will be needed.
CAUTION: After 'deep' extubation, do not transfer the patient out of the OR or from another environment with monitoring and airway equipment until they are able to maintain their own airway without basic airway maneuvers.