Aspiration risk under anaesthesia (revision 12)
Old revision·19:11, 30 Apr 2025·RetinopathyRex
| Aspiration risk under anaesthesiaPerioperative | |
|---|---|
| Mechanism of concern | Delayed gastric emptying |
| Assessment tool | Gastric ultrasound |
| Evidence base | Case reports and imaging series |
| Topic infobox · conventions | |
Delayed gastric emptying produced by GLP-1 receptor agonists has raised concern that residual gastric contents may persist beyond conventional preoperative fasting periods, with a corresponding risk of pulmonary aspiration during anaesthesia.[1]
The evidence is largely case reports and imaging series showing residual gastric contents on ultrasound after standard fasting in people taking these agents, rather than trials demonstrating an increased aspiration rate. Aspiration is rare enough that a randomised demonstration is impractical.[1]
Professional guidance has been issued and revised more than once, moving from broad recommendations to withhold treatment before procedures towards a more individualised assessment. This article describes the position; it is not medical advice.[2]
The mechanism and its magnitude
[edit]The gastric-emptying delay is largest during escalation and with short-acting agents, and attenuates with continued exposure to a long-acting agonist.[3] A person established on a weekly agent for months has a smaller delay than one in the first weeks of treatment.[4]
Gastric ultrasound can assess residual content directly and has been used both to demonstrate the phenomenon and, in practice, to guide individual decisions. It measures the thing of interest rather than a proxy, which is its advantage over any rule based on the drug alone.[1]
The relationship between residual content and aspiration is not one-to-one. Aspiration requires content, regurgitation and failure of airway protection, and content alone is a necessary rather than a sufficient condition.[1]
How guidance has developed
[edit]Early guidance suggested withholding weekly agents for a period before elective procedures and daily agents on the day. Subsequent statements moderated this, noting the absence of outcome evidence, the harm of interrupting treatment, and the availability of individualised assessment.[1]
| Consideration | Direction |
|---|---|
| Recent escalation or dose increase | Higher concern |
| Established on stable dose for months | Lower concern |
| Symptoms of delayed emptying | Higher concern |
| Ultrasound showing empty stomach | Assessment rather than inference |
| Urgency of the procedure | Weighs against delay |
The table describes factors named in published guidance. It is not a protocol, and decisions of this kind belong to the clinicians involved.[2]
See also
- Gastric emptying
- Adverse effects of GLP-1 receptor agonists
- GLP-1 receptor agonist
- Dose escalation schedule
References
- ^ a b c d e Joshi GP, Abdelmalak BB, Weigel WA, et al. "American Society of Anesthesiologists consensus-based guidance on preoperative management of patients on glucagon-like peptide-1 receptor agonists." (2023).
- ^ a b American Diabetes Association. "Standards of Care in Diabetes." Diabetes Care 47(Suppl 1) (2024).
- ^ Marathe CS, Rayner CK, Jones KL, Horowitz M. "Relationships between gastric emptying, postprandial glycemia, and incretin hormones." Diabetes Care 36(5):1396–1405 (2013). PMID 23613599.
- ^ Drucker DJ. "Mechanisms of action and therapeutic application of glucagon-like peptide-1." Cell Metabolism 27(4):740–756 (2018). PMID 29617641.