Aspiration as a Complication of Failed Intubation
Aspiration is classified as a moderate complication related to the intubation procedure but is not considered part of the definition of failed intubation itself. 1
Understanding Failed Intubation vs. Complications
Failed intubation in the intensive care setting is specifically defined as requiring two or more attempts at endotracheal intubation 1. This is distinct from the complications that may occur during or as a result of intubation attempts.
According to the 2017 Anaesthesia guidelines, complications of intubation are categorized as either:
- Severe complications: Severe hypoxemia, severe collapse, cardiac arrest, death
- Moderate complications: Difficult intubation, arrhythmia, oesophageal intubation, aspiration, agitation, dental injury 1
The Relationship Between Failed Intubation and Aspiration
While aspiration is not part of the definition of failed intubation, there is an important relationship between them:
- Failed intubation increases the risk of aspiration occurring
- When intubation is difficult, the incidence of all complications, including aspiration, increases 1
- In emergency settings, the risk of regurgitation or vomiting is greater, making aspiration more likely during repeated intubation attempts 1
Clinical Implications for Airway Management
Understanding this distinction has important clinical implications:
In rapid sequence induction: The Difficult Airway Society guidelines specifically note that after failed intubation attempts in rapid sequence induction, Plan B (secondary intubation techniques) is omitted precisely because "the risk of regurgitation or vomiting is greater than in the elective patient, so that the risk of aspiration during further attempts at tracheal intubation is higher" 1
In ICU settings: The risk of aspiration is particularly high due to emergency conditions, with aspiration listed as one of the life-threatening complications that may occur in 20-50% of ICU intubations 1
During CICO situations: When "can't intubate, can't oxygenate" situations develop, aspiration risk increases further, requiring rapid progression to front-of-neck airway access 1
Risk Factors and Prevention
Several factors increase the risk of both failed intubation and aspiration:
- Obesity and pregnancy (decreased functional residual capacity)
- Emergency settings
- Critically ill patients
- Presence of blood or vomitus in the airway
- Multiple intubation attempts
To minimize these risks:
- Use the MACOCHA score to predict difficult intubation 1
- Limit intubation attempts to a maximum of two in high-risk settings 1
- Consider early release of cricoid pressure if difficulties are encountered 1
- Ensure adequate preparation, positioning, and pre-oxygenation
- Have suction immediately available
Conclusion
While aspiration is a recognized complication that can occur during or after failed intubation attempts, it is not part of the definition of failed intubation itself. Failed intubation refers specifically to the inability to place an endotracheal tube after multiple attempts, while aspiration is one of several potential complications that may result from this situation.
Understanding this distinction is crucial for proper airway management protocols and for recognizing when to transition to alternative airway techniques to prevent life-threatening complications like aspiration.