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OSCE: actor and procedure stations09 / 22

Cancelling surgery: weekly GLP-1 agonist and a fried breakfastActor: a 45-year-old woman on weekly semaglutide (last dose 3 days ago) for day-case laparoscopic cholecystectomy

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Know this first

  • GLP-1 agonists delay gastric emptying; aspiration risk persists even after standard fasting.
  • Light meal: 6 h; fried or fatty food or meat: 8 h or more; clear fluids: 2 h.
  • Higher risk: weekly dosing, escalation, higher dose, GI symptoms.
  • ASA: hold weekly injections one week before; Kindel: liquid diet for 24 h.
  • Gastric ultrasound or RSI are shared decisions weighed against cancelling.

The patient

Actor: a 45-year-old woman on weekly semaglutide (last dose 3 days ago) for day-case laparoscopic cholecystectomy. She ate a fried-egg breakfast at 7 am; it is now 11 am after a four-hour wait. She feels nauseated and bloated. Her case has been cancelled. Task: explain the cancellation.

The examiner asks

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  1. Open

    How do you open?

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    • I'm speaking to a woman on weekly semaglutide whose gallbladder operation I've cancelled after breakfast. Patient
    • I'm the anaesthetist. I'm sorry you've waited so long. Can I explain why today isn't safe? Communication
    • Can you tell me what you ate this morning, and when?

  2. Explain

    Explain why you are cancelling.

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    • Asleep, food left in the stomach can come back up and get into the lungs. (Communication)
    • A fried breakfast needs eight hours or more to clear; it's been four.
    • Your weekly injection also slows the stomach, and your nausea suggests food is still there.
    • Even fully fasted, people on these injections can still have food in the stomach.
    • I considered scanning your stomach, or a fast way of putting you to sleep; neither makes this worth it.

  3. Respond

    She shouts: 'I took a day off work for this!'

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    • You're right to be angry. You've lost a day and waited hours without news. (Communication)
    • I'm sorry about the wait. That's our failing, not yours.
    • I'd rather cancel than risk a serious lung injury from an operation that can wait.

  4. Respond

    She offers: 'I'll sign something. I'll take the risk.'

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    • I appreciate that, but a signature doesn't make an unsafe anaesthetic safe. (Communication)
    • If this were an emergency, we'd go ahead with extra precautions. It isn't, so we wait.
    • I know that's frustrating. It's your lungs I'm protecting, not a rule for its own sake.

  5. Close

    How do you close?

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    • I'll ask for a priority date and give you written instructions. (Communication)
    • Hold the weekly injection for a week before, agreed with whoever prescribes it.
    • Liquids only for 24 hours before; clear drinks are fine until two hours before.
    • If you want to complain about the wait, patient relations will help you.

Scan · Gastric antrum

Here is your image. Point to and name each structure, then say why it matters.

Curvilinear low-frequency probe parasagittal in the epigastrium under the left liver lobe, supine then right lateral decubitus.

Sagittal epigastric, cranial on the left, anterior at top

Gastric antrum, labels covered, open the image full size
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Gastric antrum, labelled, open the image full size

Labels Liver · gastric antrum · pancreas · SMA superior mesenteric artery · aorta

  • Under the left liver lobe, this round target is the gastric antrum.
  • Deep to it runs the aorta, so I am in the right plane.
  • Empty, the antrum is small and flat; here it is distended.
  • Dark contents mean clear fluid; a hazy, frosted look means solid food.
  • I measure its area on the right side to estimate volume.
  1. Left lobe of liver Acoustic window lying above the antrum
  2. Gastric antrum Round target shape that swells as content increases
  3. Aorta Deep landmark confirming the right plane
  4. Antral contents Clear fluid dark; thick fluid bright; solids ground-glass
  5. Antral area in right lateral position Gives volume; solids or above 1.5 mL/kg means full

Checked against: Barash 9e · Miller 10e

Image: Desai N et al., The pregnant and postpartum stomach (Eur J Anaesthesiol 2026; doi:10.1097/eja.0000000000002320), Fig. 2, CC BY 4.0. Changes: Whole image kept, no crop. Question image: yellow Liver, Gastric antrum (with arrow), Pancreas (with arrow), SMA and Aorta labels covered with boxes; the machine centre line is kept

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Fatal mistakes

  • Proceeding against safety.
  • Arguing back.
  • Blaming the patient.

Checked against: Miller 10e · Practice Guidelines for Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration: Application to Healthy Patients Undergoing Elective Procedures (An Updated Report) (2017) · Multi-society guidance on GLP-1 receptor agonists before procedures (2024)

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Mark Got it only if you said every point. Again brings the case back tomorrow; Got it brings it back in 3, then 7, 14 and 30 days.

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