What is the risk of aspiration during sedation?

Updated: Nov 06, 2018
  • Author: Arul M Lingappan, MD; Chief Editor: Erik D Schraga, MD  more...
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Periprocedural fasting has historically been a concern for clinicians because of the suspected risk of aspiration. Most of the data are from patients receiving general anesthesia; [30] in these procedures, airway reflexes are lost and, thus, aspiration risk is increased. Aspiration most commonly occurs during intubation and extubation. [30] Thus, while depth of sedation should be a concern, the idea of preprocedural fasting for procedural sedation is controversial and impractical. The current recommendation from the anesthesia community are 2 hours of fasting for clear liquids and 6 hours for solids. [31] However, in an ED, where the flux of patients is constant and very little control of preprocedural fasting times is possible, these recommendations may not be realistic.

To date, one instance of aspiration involving procedural sedation in the ED has been reported, with no adverse events. [32, 33] This can be explained by the following: (1) In order to aspirate, one must vomit and lose protective airway reflexes, and, with the exception of sedation used in rapid-sequence intubation, this combination is unlikely to happen during procedural sedation, and (2) with the exception of nitrous oxide, procedural sedation is not accomplished in the ED using inhalational agents, which are known to be emetogenic.

Given the lack of solid evidence to support periprocedural fasting times, the academic emergency medicine community does not risk-stratify based on a patient's last meal; instead, they advise clinicians to rely on clinical judgment. [30] The procedural sedation guidelines from the American College of Emergency Physicians (ACEP) state that "recent food intake is not a contraindication for administering procedural sedation and analgesia, but should be considered in choosing the timing and target level of sedation." [30]

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