Insulin & Glycemic Targets

• Target 140–180 mg/dL (7.8–10 mmol/L); tight control (80–110) increases hypoglycemia and mortality.
• Protocolized IV insulin infusion in the critically ill; capillary glucose q1h until stable.
• For hypoglycemia <70, give 20–25 g IV dextrose and recheck in 15 min.
• Switch to SC basal-bolus once eating/stable.
• Continue IV insulin until DKA has resolved; start the basal-insulin overlap 1–2 hours before stopping the infusion.

Adjusting the Insulin Infusion

• STEP 1 — Check the current blood glucose (BG) and the hourly rate of change
• BG <70 mg/dL?
• Yes
• Manage as hypoglycemia: 20–25 g IV dextrose, recheck in 15 min, then adjust the infusion per protocol
• Titrate the IV insulin infusion per the locally validated protocol, targeting 140–180 mg/dL; check BG q1h until stable
• In DKA never reduce the insulin infusion below 1 U/h; start SC basal insulin with a 1–2 h overlap before stopping the infusion
• BG stable in target on a low infusion rate, and the patient eating?
• Yes
• Transition to SC basal-bolus insulin with a 1–2 h overlap before discontinuing the infusion
• No
• Continue the infusion; reassess hourly
• Table-driven protocols (e.g., the Yale regimen) vary between institutions — follow the locally validated version

Severe Hypoglycemia in the Critically Ill

• Treat any glucose below 4.0 mmol/L (70 mg/dL) immediately. Below 3.0 mmol/L (54 mg/dL) is clinically significant and below 2.2 mmol/L (40 mg/dL) is an emergency. A sedated or ventilated patient has no warning symptoms at all — the diagnosis is made only by measuring, so measure whenever the neurology is unexplained
• Conscious, cooperative and safe to swallow?
• Yes
• Give 15–20 g of fast-acting oral carbohydrate, recheck at 15 minutes and repeat up to three times, then follow with a longer-acting carbohydrate or the next meal
• No
• Give 100 mL of 20% glucose (or 200 mL of 10%) IV over 10–15 minutes through a reliable line — 50% glucose is sclerosant and is reserved for the arrest situation — or glucagon 1 mg IM if there is no access. Glucagon fails in liver disease, starvation and alcohol excess, where there is no glycogen to mobilise
• Recheck at 10–15 minutes and repeat until glucose is above 4.0 mmol/L, then start a 10% glucose infusion rather than relying on repeated boluses
• Stop or halve the insulin infusion — but do not stop insulin altogether in type 1 diabetes or in DKA. Restart at a lower rate with glucose running alongside, because stopping insulin restarts ketogenesis
• Recurrent or refractory despite treatment?
• Yes
• Think sulfonylurea or long-acting insulin (give octreotide 50–100 µg subcutaneously 6-hourly for sulfonylurea overdose), adrenal insufficiency, liver failure, sepsis, AKI reducing insulin clearance, and the enteral feed that was stopped or interrupted without anyone adjusting the insulin
• Run a 10–20% glucose infusion with hourly glucose measurement until the driver has cleared. Repeated boluses alone will not hold a patient with a long-acting agent on board
• No
• Recheck hourly for 4 hours, document what caused it, and review the whole insulin and feeding prescription before restarting
• A single episode of severe hypoglycaemia is independently associated with higher mortality in critical illness. Target 7.8–10.0 mmol/L — tighter control buys nothing and causes exactly this.