Intra-operative crises08 / 21

Euglycaemic ketoacidosis after knee replacement61-year-old woman, 92 kg, in recovery 2 hours after an elective knee arthroplasty done under spinal

From memory: the diagnosis and the notes are hidden. Answer each question aloud, then press Show.

Know this first

SGLT2 inhibitors are held for 3–4 days before an operation.
Euglycaemic DKA: glucose under 250 mg/dL, pH under 7.3, bicarbonate under 18, raised ketones.
Fixed insulin at 0.1 units/kg/h waits for K+ over 3.3; give dextrose from the outset if glucose is normal.
Restart the SGLT2 inhibitor only when stable and eating normally.

The patient

61-year-old woman, 92 kg, in recovery 2 hours after an elective knee arthroplasty done under spinal. Type 2 diabetes treated with metformin plus empagliflozin, both continued until yesterday; fasted 16 hours. Now nauseated, breathing fast and deep; glucose 172 mg/dL. Vitals: BP 108/64, HR 108, SpO2 98% on 2 L/min, RR 30, temperature 36.8 °C.

The examiner asks

Answer aloud, then press Show.

Consider
What are you worried about?
Show the answerHide the answer
- A 61-year-old with type 2 diabetes on empagliflozin until yesterday, unwell 2 hours after knee replacement. Patient
- Gliflozins need a 3–4-day break before surgery; she took hers yesterday. Stem trigger
- A 16-hour fast on top of a gliflozin drives starvation-type ketosis.
- Nausea and fast deep breathing with glucose 172 could be euglycaemic ketoacidosis. Disease
- Her near-normal glucose doesn't exclude it; I test for it directly.
Prepare
How do you confirm it?
Show the answerHide the answer
- Blood gas now: I'm looking for pH under 7.3 and bicarbonate under 18. (Disease)
- Blood ketones and the anion gap; a raised gap with ketones makes the diagnosis.
- Her glucose of 172 is under 250, so this would be the euglycaemic form.
- Potassium, sodium, creatinine and lactate on the same sample.
- I look for a trigger beyond the drug, such as infection or ischaemia.
Crisis
Gas: pH 7.08, bicarbonate 9 mEq/L, ketones 5.8 mmol/L, glucose 170 mg/dL, K+ 3.1 mEq/L. What do you do?
Show the answerHide the answer
- Severe euglycaemic DKA from empagliflozin: treat now, in a monitored bed. (Crisis)
- Potassium first: at 3.1, insulin waits until it's above 3.3.
- Potassium 10–40 mEq/h when urine flows; above 10 mEq/h she needs a continuous ECG.
- Saline 1–2 L over 1–2 hours, then guided by her pressure and urine.
- Then an insulin infusion, 0.1 units/kg/h without titrating, to shut down ketone production.
- Dextrose from the start, because her glucose is already normal.
- No bicarbonate; it's only considered below pH 6.9.
Plan
Where does she go, and when does the drug restart?
Show the answerHide the answer
- HDU with the diabetes team; insulin and dextrose continue until her ketones clear. (After surgery)
- Hourly glucose and ketones, and potassium every few hours.
- Empagliflozin restarts only when she's stable and eating normally.
- Metformin can resume as she eats; recent data don't link it to lactic acidosis.
- Our pre-op pathway is fixed so gliflozins stop 3–4 days before elective surgery.

Fatal mistakes

Excluding ketoacidosis because her glucose is normal.
Starting insulin with her potassium at 3.1.
Insulin without dextrose at her normal glucose.

Checked against: AHA/ACC 2024 · Miller 10e · Barash 9e

Report a problem with this case

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.