A 47-year-old female patient is in your ICU having had a prolonged wean from mechanical ventilation following severe head and chest injuries sustained in a motor vehicle collision. She has a tracheostomy and has been breathing spontaneously, free from ventilatory support, on an FiO2 of 0.3 via a tracheostomy mask for 24 hours.

Describe how you will assess whether the tracheostomy tube can be safely removed.
 

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College answer

Assessment will involve history, examination and targeted investigations and may involve a trial period with the tracheostomy “capped” or occluded (with the cuff deflated!) to ensure that it can be safely removed.

The tracheostomy can be safely removed if the patient:
•    Has a patent upper airway
•    Has a protected upper airway
•    Can adequately clear her secretions
•    No longer requires mechanical ventilation
 
Patent upper airway
•    History
o    Upper airway trauma
o    Duration of translaryngeal intubation
o    Indication for tracheostomy (was it placed for upper airway obstruction)
o    Known grade of intubation or difficulty with intubation
•    Examination
o    Facial or airway trauma or recent surgery
•    Investigations (if indicated, not routine)
o    Direct or fibreoptic laryngoscopy
o    CT scans if available may offer some information

Protected upper airway
•    History
o    Severity of brain injury
o    Focal brainstem injury
•    Examination
o    Current neurological status
    Level of consciousness
    Lower cranial nerves including cough and gag reflex
•    Investigations
o    Neurological imaging inc CT and MRI
o    Barium swallow or fibreoptic assessment for aspiration

Adequate clearance of secretions

History
o    Injuries that may impair cough
    Spinal cord injury
    Multiple rib fractures with flail segment
    Diaphragmatic injury
    Severe lung trauma
    Recurrent pneumonia or lung abscess
o    Co-morbidity
    Lung disease e.g., bronchietcasis
    Neuromuscular weakness
    Sleep apnoea

Examination
o    Respiratory
    Frequency of suctioning
    Nature and volume of secretions
    Presence of flail segment
o    Neurological assessment
    Peripheral neuromuscular function
    Cough assessment (strength, ability to cough secretions past tube)

Investigation
o    Ultrasound of diaphragm (if problem suspected)
o    Fibreoptic examination of vocal cord function

No requirement for mechanical ventilation
•    History
o    Background and co-morbidities (OSA, smoking, lung or heart disease….)
o    Nature and extent of chest injury and other injuries
o    Requirement for any ongoing surgery
o    Pattern and duration of weaning from ventilation (24hours of spontaneous ventilation would be a minimum for trache removal)

•    Examination
o    Respiratory and cardiovascular examination
o    Tertiary survey

•    Investigations
o    CXR
o    CT chest
o    ABG off ventilation
o    Spirometry

Notes
The answer template is not exhaustive, merely indicative and this level of detail in this template was not required. To pass the candidate needed to demonstrate awareness of the requirement for all of:
1.    Patent upper airway
2.    Ability to clear secretions with a mention of cuff deflation
3.    Adequate level of consciousness
4.    Adequacy of spontaneous ventilation

Examiners Comments:

Superficial approach. Lack of systematic approach to a common procedure done in ICU. Cuff deflation missed most often.
 

Discussion

This college answer has left little room for improvement. One may only try to rearrange the points into something which is not specific to a trauma patient with head and chest injuries, i.e. a more generic approach to anybody with a tracheostomy. One must caution against this formulaic templated approach in the actual exam, as the examiners often complain about how the trainees have not read their carefully worded question text. It would be always important to include case-specific details in one's answer to demonstrate one's engagement with the question.

  • Adequate gas exchange while off mechanical ventilator support:
    • Surviving off the ventilator for at least 24 hours
    • Requiring minimal oxygenation support:
      • "blow over" of humidified gas, i.e. a T-piece trial
      • HME with room air or minimal supplemental oxygen, eg a "Swedish Nose". 
    • No planned procedures in the near future which may require mandatory mechanical ventilation
  • Preconditions for a decannulation trial: 
    • Secretion volume
      • Fewer than 4 suction episodes in the last 24 hours
      • No intercurrent suppurative lung disease
    • Intact airway reflexes
      • Gag reflex present
      • Cough reflex present
    • Intact sensorium
      • Level of consciousness should be high enough to sustain cooperation with physiotherapy and nursing staff in the post-decannulation period
    • Satisfactory muscle power
      • Maximum expiratory peak flow of over 160 L/min with cough
    • If the patient does not meet these preconditions, the cuff deflation trial will need to be delayed
  • Cuff deflation trial 
    • Deflate the tracheostomy cuff
    • Ensure adequate oxygenation and ventilation with the tracheostomy still patent
    • Then, occlude the tracheostomy
    • Observe for 72 hours 
      • If unsuccessful, perform videoendoscopy or CT imaging of the upper airways to determine the cause
    • Test for aspiration during this time (blue dye test)

References

References

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Chadda, Karim, et al. "Physiological effects of decannulation in tracheostomized patients." Intensive care medicine 28.12 (2002): 1761-1767.

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Enrichi, Claudia, et al. "Clinical criteria for tracheostomy decannulation in subjects with acquired brain injury." Respiratory care 62.10 (2017): 1255-1263.

Rumbak, Mark J., et al. "Tracheostomy tube occlusion protocol predicts significant tracheal obstruction to air flow in patients requiring prolonged mechanical ventilation.Critical care medicine 25.3 (1997): 413-417.

Donzelli, Joseph, Susan Brady, and Michele Wesling. "Using Modified Evan's Blue Dye Test to predict aspiration." The Laryngoscope 114.9 (2004): 1680.

Belafsky, Peter C., et al. "The accuracy of the modified Evan's blue dye test in predicting aspiration." The Laryngoscope113.11 (2003): 1969-1972.

Cameron, John L., J. Reynolds, and G. D. Zuidema. "Aspiration in patients with tracheostomies." Surg Gynecol Obstet 136.1 (1973): 68-70.

Shen, K. Robert, and Douglas J. Mathisen. "Management of persistent tracheal stoma." Chest surgery clinics of North America 13.2 (2003): 369-73.

Bach, John R., and Louis R. Saporito. "Indications and criteria for decannulation and transition from invasive to noninvasive long-term ventilatory support." Respiratory care 39.5 (1994): 515.