List the potential adverse effects of endotracheal intubation, and briefly outline how they can be minimised.

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College Answer

The answers provided by the candidates were very disappointing. Endotracheal intubation is so fundamental to Intensive Care practice that a high standard was expected in this question to obtain a pass mark. A list of the major complications and some suggestions regarding prevention were required. Very few candidates included myocardial ischemia, elevation of ICP, the potential for spinal cord injury in the presence of an unstable spine, or even failed intubation. Few candidates listed pre-oxygenation as potentially helpful in preventing hypoxia.

Potential adverse effects included:

Hypoxia, Failed intubation, Oesophageal intubation, Endobronchial intubation, Aspiration, Bronchospasm, Structural damage (including Cord injury/False passage), Foreign body aspiration, Bacteraemia, Hypertension/tachycardia/arrhythmias/myocardial ischaemia, Raised ICP, Hypotension/exacerbation of shock state, Other drug side-effects, Sputum retention / pneumonia, Sub-glottic stenosis, Tracheo-oesophageal fistula.

Discussion

The candidate, who is preparing for their fellowship, does not need to hear how disappointing the college finds the previous candidates. Even among the genre of college feedback, which is notoriously unhelpful, such comments are especially pointless. Must we open a window on this? Sure, not one of the candidates achieved the "high standard" which the examiners considered a pass mark. But some might say that the candidates, all being senior ICU staff, by definition have a superlative understanding of intubation, and that the question was worded in such a profoundly stupid manner that this knowledge did not have a chance to spill out onto the answer booklet. 

Perhaps one might have asked:

"What are the acute physiological consequences of a successful endotracheal intubation? How might these impact adversely on the critically ill patient?

What might be the adverse consequences of a failed intubation attempt?

"Describe some steps which might be taken to protect the patient from these consequences."

"You may tabulate your answer."

Complication

Preventative measure

Failure of intubation

Oesophageal intubation

  • Visual confirmation of ETT position
  • Capnometry
  • Auscultation of the chest

Right main bronchus intubation

  • auscultation of both lungs
  • chest Xray
  • Bronchoscopic confirmation

Broncospasm

  • Pre-intubation nebulised salbutamol or adrenaline

Hypoxia

  • Pre-oxygenation
  • Continuous pulse oximetry

Aspiration

  • Cricoid pressure (debatable)
  • Aspiration of stomach contents by NG tube
  • Fasting the patient in preparation
  • Careful bag-mask ventilation to prevent gastric inflation
  • Alternatively: do not bag-mask ventilate (RSI)

Pneumothorax and tension pneumothorax

  • Use of moderation in bag-mask ventilation volumes
  • Post-intubation CXR

Cuff leak

  • Select a size-appropriate tube

Myocardial ischaemia

  • Use of opiate analgesics as part of intubation drug cocktail to prevent the sympathetic response to laryngoscopy
  • Anaesthtising the vocal cords

Spinal injury

  • Correctly identify patients at risk of spinal injury, and use of inline stabilisation
  • Fiberoptic bronchoscopy

Increased intracranial pressure

  • Use of opiate analgesics as part of intubation drug cocktail to prevent the sympathetic response to laryngoscopy
  • Hyperventilation with bag to decrease CO2 post intubation

Increased intraocular pressure

  • Use of opiate analgesics as part of intubation drug cocktail to prevent the sympathetic response to laryngoscopy
  • Anaesthtising the vocal cords

Structural damage:

-lips
-teeth
-tongue

  • Skilled practitioner
  • Limit the number of attempts by unskilled practitioners
  • Videolaryngoscopy
  • Avoid the use of stylet or bougie
  • Ensure the tip of the stylet is well within the ETT when it is advanced (i.e. not sticking out past the end of the ETT)

References

Griesdale, Donald EG, et al. "Complications of endotracheal intubation in the critically ill." Intensive care medicine 34.10 (2008): 1835-1842.

Rashkin, Mitchell C., and Tern Davis. "Acute complications of endotracheal intubation. Relationship to reintubation, route, urgency, and duration." CHEST Journal 89.2 (1986): 165-167.

Divatia, J. V., and K. Bhowmick. "Complications of endotracheal intubation and other airway management procedures." Indian J Anaesth 49.4 (2005): 308-18.