Perioperative Management of Diabetic Medications and Diabetes Mellitus

CreatedJanuary 22, 2024

Last UpdateFebruary 18, 2026

Annelise Kerr, Jo Moore, Ross Hanrahan

Pre-Operative HbA1c Targets

HbA1c should be measured < 3 months (preferably 4-6 weeks) prior to elective surgery.
Refer to endocrinologist when HbA1c is ≥ 9% or when there is hypoglycaemia unawareness.
Target HbA1c < 9% prior to elective surgery.
- Patients with HbA1c > 9% have poorer outcomes and the ADS-ANZCA Guidelines recommend delaying elective surgery to obtain better glycaemic control.
- This delay may be 1-2 weeks in urgent surgery settings, or 3 months in less urgent settings.

Screening of Patients Without Known Diabetes

Up to 30% of patients may have undiagnosed diabetes
> 12mmol/L
Perioperative planning should proceed as if patient has diabetes

Planned Surgery	Undiagnosed Diabetic Screening
Major	HbA1c
Minor	Random BGL

Perioperative Diabetic Medication Management

Oral Antihyglycaemic Medication Management

Class	Examples	Day Prior to Surgery	Day of Surgery
Sulphonylureas	gliclazide (diamicron) glipizide (glucotrol) glimepride (amaryl) glyburide (glynase)	Continue as Usual	Withhold
Alpha-glucosidase Inhibitors	Acarbose
DPP-IV Inhibitors	linagliprin (Trajenta) sitagliptin (Januvia) alogliptin (Nesina) saxagliprin (Onglyzna) vildagliptin (Galvus)
Thiazolidinediones	rosiglitazone (Avandia) pioglitazone (Actos)
Biguanides	metformin metformin + sinagliptin (Janumet)
SGLT2is	dapagliflozin (Forxiga) empagliflozin (Jardiance) rrtugliflozin (Steglatro) dapagliflozin + metformin (Xigduo)	Major Surgery / Colonoscopy Cease 2 days prior + day of surgery last dose day -3 Day Surgery / Gastroscopy Cease Day of Surgery
GLP-1 Analogues	semaglutide (Ozempic) liraglutide (Saxenda)	Continue As Usual Follow 24-hour Fasting Guideline Clear Fluids Only Day Prior Water Only on DOS NBM 2 hours pre-op

-                                        Day Prior to Surgery
+                                        Day of Surgery
-                                        Continue as Usual
+                                        Withhold
-                                        Day Prior to Surgery
+                                        Day of Surgery
-                                        Continue as Usual
+                                        Withhold
-                                        Day Prior to Surgery
+                                        Day of Surgery
-                                        Continue as Usual
+                                        Withhold
-                                        Day Prior to Surgery
+                                        Day of Surgery
-                                        Continue as Usual
+                                        Withhold
-                                        Day Prior to Surgery
+                                        Day of Surgery
-                                        Continue as Usual
+                                        Withhold
-                                        Day Prior to Surgery
+                                        Day of Surgery
-                                        Major Surgery / Colonoscopy
Cease 2 days prior + day of surgery
last dose day -3

Day Surgery / Gastroscopy
Cease Day of Surgery
+                                        Withhold
-                                        Day Prior to Surgery
+                                        Day of Surgery

SGLT2i: Sodium-glucose cotransporter 2, DPP-IV: Dipeptidyl peptidase IV, GLP-1: glucagon-like peptide
* Major surgery: surgical cases requiring > 1 night of hospitalisation post-operatively
* Minor surgery: all day surgical cases and extended day surgery cases that require 1 night in hospital

Insulin Management

Type
Basal Insulin Only Insulin glargine • Lantus • Optisulin • Tuojeo • Semglee Insulin determir • Levemir
AM List	PM List
No dose change*	No dose change*

Basal Bolus Regime Basal • Insulin glargine • Insulin detemir Bolus • Ultrarapid: Aspart-FiAsh •Rapid: humalog, novorapid, apidra • Short: actrapid, Humulin R
AM List	PM List
Withhold bolus insulin Keep basal dose unchanged*	Give 50% morning bolus insulin with light breakfast. Omit lunch time dose Keep basal dose unchanged*

Pre-Mixed (intermediate + short/rapid) • Novomix 30 • Mixtard 30/70 • Humalog mix 25
AM List	PM List
Give 50% usual dose	Give 50% usual dose

Co-Formulated (ultra-long + rapid) • Ryzodeg 70/30
AM List	PM List
Delay morning dose until lunch / evening if eating and drinking	Give 50% usual morning dose Omit lunch time dose

Intermediate +/- Rapid Acting • Protaphane • Humulin
AM List	PM List
Calculate total dose of all insulin for morning + lunch. Give 50% of the total insulin dose as intermediate actng in the morning. (e.g. if on 20U protaphane + 8U Novorapid give 14U protaphane and no novorapid)

Type	Examples	AM List	PM List
Basal Insulin Only	Insulin glargine • Lantus • Optisulin • Tuojeo • Semglee Insulin determir • Levemir	No dose change*	No dose change*
Basal Bolus Regime	Basal • Insulin glargine • Insulin detemir Bolus • Ultrarapid: Aspart-FiAsh •Rapid: humalog, novorapid, apidra • Short: actrapid, Humulin R	Withhold bolus insulin Keep basal dose unchanged*	Give 50% morning bolus insulin with light breakfast. Omit lunch time dose Keep basal dose unchanged*
Pre-Mixed (intermediate + short/rapid)	• Novomix 30 • Mixtard 30/70 • Humalog mix 25	Give 50% usual dose	Give 50% usual dose
Co-Formulated (ultra-long + rapid)	• Ryzodeg 70/30	Delay morning dose until lunch / evening if eating and drinking	Give 50% usual morning dose Omit lunch time dose
Intermediate +/- Rapid Acting	• Protaphane • Humulin	Calculate total dose of all insulin for morning + lunch. Give 50% of the total insulin dose as intermediate actng in the morning. (e.g. if on 20U protaphane + 8U Novorapid give 14U protaphane and no novorapid)

* Reduce basal insulin dose by 20% if recent overnight hypoglycaemia

Available Forms of Insulin in Australia

Types of Insulin
Brand name	Type
Mealtime or prandial insulins
Ultra rapid-acting Onset in 5–10 minutes, peak at 30 minutes, duration for 3.5–4 hours
FiAsp	Faster insulin aspart
Rapid-acting Onset in 15–20 minutes, peak at one hour, duration for 3.5–4.5 hours
Humalog	Insulin lispro
NovoRapid	Insulin aspart
Apidra	Insulin glulisine
Short-acting Onset in ~1 hour, peak at two to five hours, duration for six to eight hours
Actrapid	Neutral
Humulin R	Neutral
Basal insulins
Intermediate-acting
Humulin NPH	Isophane
Protaphane	Isophane
Levemir	Insulin detemir Onset in three to four hours, peak at three to eight hours, duration for 20–24 hours
Optisulin	Insulin glargine (U100) Onset in one to two hours, flat, duration for 18–24 hours
Semglee
Toujeo	Insulin glargine (U300) Onset in one to two hours, flat, duration for 24–36 hours
Premixed insulins
Humalog Mix 25	Lispro 25%/lispro protamine 75% Onset in 15–20 minutes, peak at one hour, duration for 14–24 hours
Humalog Mix 50	Lispro 50%/lispro protamine 50% Onset in 15–20 minutes, peak at one hour, duration for 14–24 hours
NovoMix 30	Insulin aspart 30%/insulin aspart protamine 70% Onset in 15–20 minutes, peak at one hour, duration for 14–24 hours
Humulin 30/70	Neutral 30%/isophane 70% Onset in one to two hours, peak at two to five hours, duration for 12–18 hours
Mixtard 30/70
Mixtard 50/50	Neutral 50%/isophane 50% Onset in one to two hours, peak at two to five hours, duration for 12–18 hours
Ryzodeg 70/30	Insulin degludec 70% and insulin aspart 30% Onset in 5–20 minutes, peak at one hour, duration for 36–48 hours

Bowel Prep

Monitor BSL q2h
Withhold SGLT2is 2 days pre-procedure plus day of procedure
Patients on Insulin Receiving Bowel Preparation Need Changes to Insulin Management

Type	Morning of Bowel Prep	Evening of Bowel Prep
Basal Bolus	Withhold Rapid Acting Continue Long Acting	Withhold Rapid Acting Give 50% Long Acting
Intermediate +/- Rapid Acting	Calculate Total Morning Dose and Give 50% as Intermediate Acting Withhold Rapid Acting
Pre-Mixed Insulin	Give 50% Usual Dose
Co-Formulated Insulin	Give 50% Usual Dose

Insulin Pump Management

Day Prior to Procedure	Day of Surgery	Post Op
Perform a line and set change 24 hours before surgery and record all BGL checks to ensure pump is functioning normally. The insertion site should be moved to a site distant from surgical site.	If planned eating + drinking post op: • Contnue basal infusion via pump introp • If HbA1c <6.5% or if fastng BSL < 5mmol/L set a temporary basal rate of 80% basal intraop. If nil by mouth post op: • Cease pump • Commence insulin-glucose infusion intraop.	Continue at Usual Rates

SGLT2i Management

BSL and ketones should be checked on admission
Ketones > 1mmol/L should have an urgent VBG to measure base excess
euDKR is diagnosed if base excess is < -5mol and ketones > 1mmol/L

Ketones	Base Excess	Comments
<1	> -5	No Ketosis and No Metabolic Acidosis • Consider proceeding with day surgery • Hourly monitoring of blood ketones during the procedure and 2 hourly following the procedure until eating and drinking normal or discharged. • Where blood gas analysis is not available proceed only if added risk is consistent with goals of care. • More extensive surgery: Consider goals of care and collaboration with endocrinology and critical care. • Perioperative insulin and glucose infusion may reduce risk.
>1	> -5	Ketosis Without Metabolic Acidosis • Seek endocrinology or general medicine advice. Ketosis without acidosis may reflect starvation, particularly individuals with HbA1c < 9% (< 75mmol/mol). • Consider proceeding, but with perioperative insulin and glucose infusion to reduce risk of ketoacicosis.
>1	< -5	Ketosis With Metabolic Acidosis • Postpone non-urgent surgery. • Escalate care with Endocrinology and Critical Care. • URGENT surgery to proceed with insulin and glucose infusion and ketone monitoring with guidance from endocrinology and/or critical care.
Footnote: Blood gas analysis is recommended to assess for presence of metabolic acidosis. Where blood gas analysis is not readily available and the ketones are > 1.0mmol/L, the procedure should not be performed.

GLP-1 Analogues

Cessation of GLP1 analogues is not recommended
If any of these agents have been taken within 4 half lives (typically 4 weeks) the patient should be considered at risk of delayed gastric emptying.
See ADS / ANZCA Guideline here
See Patient Information Handout here

Time Until Procedure	Allowed Oral Intake
Minimum 24 hours before procedure	Clear Fluids Only. (See patient hand out for details)
6 hours before procedure	Water only. Up to 125ml/hr
2 hours before procedure	Nil by Mouth

Bedside gastric ultrasound and IV erythromycin may have a role as outline below.

Clinical Practice Recommendations regarding patients taking GLP-1 receptor agonists and dual GLP-1/GIP receptor co-agonists prior to anaesthesia or sedation for surgical and endoscopic procedures (April 2025) Source

PeriOperative Management

Pre-Operative

Monitor BSL hourly when fasting
Treat hypoglycaemia and hyperglycaemia as per below

Intra-Operative

Monitor BSL hourly
Consider treating hyperglycaemia when BSL > 10mmol/L with subcutaneous insulin
Consider commencing variable rate insulin infusion (VRII) when BSL > 12mmol/L
Blood gas and ketones should be measured when BSL > 15mmol/L to check for ketoacidosis

Fluid management

Isotonic solutions: 0.9% saline, Hartmanns, Plasmalyte can be used for hydration
Glucose containing solutions should only be used for the treatment of hypoglycaemia or when using an insulin infusion.

Antiemetics

Dexamethasone: where possible it is recommended to use other antiemetics due to glucocorticoid induced hyperglycaemia.

Suggested algorithm for intra-operative hyperglycaemia from the ADS-ANZCA Perioperative Diabetes and Hyperglycaemic Guidelines (adult)¹

Post-Operative

Monitor BSL hourly until patient leaves PACU

If BSL has been stable, monitoring can be decreased to Q2H for type 1 diabetics, and Q2-4H for type 2 diabetics.

Restart usual medications when eating and drinking.

Exceptions:
- Metformin: Patents with CKD 3B / eGFR < 45: recommence when renal functon returned to baseline.
- SGLT2i
  - Major surgery: Withhold for at least 2 days
  - Minor surgery: Recommence day after surgery
  - Should only be recommenced once eating full diet.

Hyperglycaemia and Hypoglycaemia Management

Hyperglycaemia Management

Hyperglycaemia should be treated when BSL >12mmol/L
Repeat correctional insulin should not usually be administered within 3 hours of each other.
E.g. if a patient is on a total of 50 units of insulin per day the ISF = 2, ie, One unit of insulin is anticipated to lower the BSL by 2mmol/L.

Type I Diabetes

Determine correctional insulin doses based on patients’ usual insulin sensitvity factor (ISF)
ISF is an approximate amount by which 1 unit of insulin will lower the BSL (in mmol/L)
Estimating initial ISF for insulin treated patients: ISF = 100/ total daily insulin dose.
E.g. if a patient is on a total of 50 units of insulin per day the ISF = 2, ie, One unit of insulin is anticipated to lower the BSL by 2mmol/L.

Insulin Correction Dose

Insulin Sensitivity ≈ ¹⁰⁰ ⁄ _TDD

In the absence of known TDD, a rough estimate of TDD can be made from:

TDD ≈ Body Weight (kg) x ¹ ⁄ ₂

Be conscious of risk of ‘insulin stacking‘. A single rapid acting insulin dose may last 3-5 hours, and repeat insulin doses in that interval may risk over correction.

Type II and Other Forms of Diabetes

If >100kg, give 6 units Q3hr until BSL < 12mmol/L
If 55-100kg, give 4 units Q3hr until BSL < 12mmol/L
If < 55kg, give 2 units Q4hr until BSL <12mmol/L

Hypoglycaemia Management

BSL < 4.0mmol/L should be avoided
Treatment to avoid hypoglycaemia should begin when BSL < 5.0mmol/L

BSL targets:
- General: 5-10 mmol/L
- Pregnancy: 5.0 ± 1.0 mmol/L
- Emergency surgery with poor glycaemic control: 10.0 ± 2.5 mmol/L
- Known hypoglycaemia unawareness: 10.0 ± 2.5 mmol/L
Treatment of hypoglycaemia
- If >2 hours prior to surgery: clear apple juice
- If < 2 hours prior to surgery: 25-50ml 50% glucose

Flowchart for management of hypoglycaemic from Canberra Health Sercices Guideline: Diabetes Management: Including hypoglycaemia, IV insulin infusions and insulin pumos (Adults only). 2021²

³ ⁴ ⁵ ⁶ ⁷

Variable Rate Insulin Infusions

Criteria to cease (all must be met)
- There is no evidence of diabetic ketoacidosis
- Tolerating 50% of normal oral intake/ commenced enteral feeds/ TPN
- Usual diabetes therapies have been resumed
- Management plan for glycaemic control has been implemented
Time to cease
- Ideally cease afer breakfast, with a dose of oral anti-hyperglycaemic medication having been given before breakfast.

Crisis

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Perioperative Medication Management

Investigations

Calculators

Cardiology

Complications

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Useful Links

Pre-Operative HbA1c Targets

Screening of Patients Without Known Diabetes

Perioperative Diabetic Medication Management