Anesthesiology APPLIED Exam › Endocrine, renal, hepatic and metabolic

Diabetic ketoacidosis

Endocrine, renal, hepatic and metabolic·~4 min read· Physician-reviewed✓ Sourced · 2

Stem

A 26-year-old man, 70 kg, with type 1 diabetes is booked for urgent laparoscopic appendectomy after two days of abdominal pain and vomiting. Heart rate is 118 and blood pressure 98/60. Glucose is 486 mg/dL, venous pH 7.12, bicarbonate 9 mmol/L, beta-hydroxybutyrate 6.1 mmol/L, potassium 5.4 mmol/L and sodium 131 mmol/L. CT shows a non-perforated, inflamed appendix.

Question

Do you take him to the operating room now, and how will you manage him?

Ideal answer

HeadlineDiabetic ketoacidosis: beta-hydroxybutyrate above 3, pH 7.12.¹ Not straight to theatre: a few hours of resuscitation and antibiotics first.

Tell the surgeon: resuscitate first, hard stop for peritonitis, because DKA itself causes pain and vomiting, the appendix is intact, and induction while hypovolemic and acidotic risks collapse.
Isotonic saline or balanced crystalloid, 500 to 1,000 mL per hour for 2 to 4 hours,¹ because volume comes before insulin.
Fixed-rate insulin 0.1 units/kg/h, 7 units an hour, since potassium 5.4 is above 3.5.¹
Potassium below 5.0; dextrose below 250, aiming for 4 to 5, so insulin keeps clearing ketones; no bicarbonate above pH 7.0.¹
In the OR: infusion continues, rapid sequence for ileus, arterial line if acidosis persists, ventilation matching his compensation.

Watch for: hourly glucose; electrolytes and gas every 1–2 hours.

Breaking down the answer

The 2024 criteria — glucose ≥200 mg/dL or known diabetes, ketones (beta-hydroxybutyrate ≥3.0 mmol/L), and pH <7.3 and/or bicarbonate <18; the anion gap is no longer a first-line criterion.¹
Timing is the judgment call — resuscitate first unless source control cannot wait. Changes if: perforation or ischemic bowel.
Potassium gates insulin — insulin drives potassium into cells; below 3.5 I give potassium at 10 mmol/h and hold insulin.¹
The target is ketones — not glucose; dextrose 5–10% lets me continue the infusion, rather than stopping it when glucose normalizes.¹
Why ventilation matters — a patient breathing off a severe metabolic acidosis decompensates if I ventilate him to a normal PaCO2 after induction.
When it is over — beta-hydroxybutyrate below 0.6 plus venous pH ≥7.3 or bicarbonate ≥18.¹

Follow-up question

The appendix perforates and he goes to the OR two hours later. Forty minutes into the case, the arterial gas shows potassium 3.1 mmol/L, glucose 238 mg/dL and pH 7.21. The ECG shows flattened T waves. What do you do?

Follow-up answer

HeadlineInsulin- and fluid-driven hypokalemia: total-body potassium was low despite a normal starting level. It is now my priority, and I say so.

It can cause arrhythmias and weakness that will matter at extubation. I give potassium through a central or secure large line and, following the consensus rule for potassium below 3.5, pause the insulin until it is back above 3.5.¹ I add dextrose because glucose is under 250, so insulin can restart without hypoglycemia.¹ I check magnesium and phosphate, watch the ECG, avoid hyperventilating him below his compensation, and recheck a gas every 30–60 minutes until potassium is stable.

Pitfalls that cost points

Rushing a non-perforated appendix to the OR before any resuscitation.
Giving bicarbonate at pH 7.12.

Rapid-fire

Q: When does he transition to subcutaneous insulin? A: After resolution, with basal insulin given at least 1 to 2 hours before the infusion stops.¹

Q: Which drug class causes euglycemic DKA? A: SGLT2 inhibitors; the 2024 criteria allow known diabetes in place of a glucose threshold to capture it.¹

Q: How long before surgery are SGLT2 inhibitors stopped? A: At least 3 days for canagliflozin, dapagliflozin and empagliflozin, 4 days for ertugliflozin.²

Q: What insulin rate is used in hyperosmolar hyperglycemic state? A: 0.05 units/kg/h.¹

Q: When do you give smaller fluid boluses? A: In older adults and patients with heart or kidney failure, for example 250 mL at a time.¹

Numbers to know

Item	Value
DKA diagnosis	Glucose ≥200 or known DM; BHB ≥3.0; pH <7.3 and/or HCO3 <18¹
Initial fluid	500–1,000 mL/h for 2–4 h¹
Insulin infusion	0.1 units/kg/h (7 units/h at 70 kg)¹
Hold insulin	K <3.5 mmol/L¹
Add dextrose	Glucose <250 mg/dL¹
Bicarbonate	Consider only if pH <7.0¹
Resolution	BHB <0.6 plus pH ≥7.3 or HCO3 ≥18¹

Sources

1.Hyperglycemic crises in adults: a look at the 2024 consensus report · Cleveland Clinic Journal of Medicine, 2025 · ccjm.orgSummarizes the 2024 ADA/EASD/JBDS/AACE/DTS hyperglycemic crises consensus report.
2.FDA Approves Safety Labeling Changes to SGLT2 Inhibitors · Drug Topics (FDA labeling change, March 2020), 2020 · drugtopics.com

Facts on this page were checked against these sources on Oct 15, 2026. Guidelines change; confirm doses against current institutional protocols.