Inpatient hyperglycaemia and variable-rate insulin — Rapid

Synopsis

Assess inpatient hyperglycaemia systematically and use a variable-rate intravenous insulin infusion only when indicated, monitored and safely linked to nutrition and basal insulin.

First decide whether high glucose represents DKA, HHS, stress hyperglycaemia, steroid effect, feed-related dysglycaemia or known diabetes with inadequate delivery; the correct insulin pathway depends on that diagnosis.
A VRIII adjusts intravenous insulin to the current bedside glucose and is useful when acute illness or inability to eat makes subcutaneous treatment temporarily unreliable.
Do not use the general VRIII chart to treat DKA or HHS; those emergencies require their dedicated fixed-rate protocols, fluids, electrolytes and biochemical endpoints.
The usual JBDS inpatient target on VRIII is 6–10 mmol/L, with 4–12 mmol/L acceptable in many cases and deliberate individualisation for hypoglycaemia risk.
Continue the person’s usual long-acting basal insulin alongside VRIII, especially in type 1 diabetes, unless a diabetes specialist documents a specific alternative.
Prescribe a compatible glucose-containing substrate fluid with insulin and prevent either infusion being interrupted during transfers, imaging, procedures or bag changes.
Check capillary glucose hourly while the infusion runs and use the current local rate table; persistent out-of-range results demand a patient, prescription, pump, cannula and substrate review.
Keep VRIII as short as possible, usually under 24 hours, and plan meal-timed subcutaneous overlap before stopping rather than waiting until the infusion is disconnected.

Key red flags

Insulin-deficient emergency

Vomiting, abdominal pain, ketonaemia, deep breathing or acidosis suggests DKA and must divert the patient from general VRIII to the fixed-rate emergency protocol.

Hyperosmolar phenotype

Extreme glucose, profound dehydration and cognitive change require calculated osmolality and HHS assessment before any routine variable-rate chart is selected.

Infusion failure

Rapid unexplained rise, recurrent low glucose, empty substrate, pump alarm, blocked cannula or discrepant prescription and programmed rate requires immediate bedside system tracing.

Investigation priorities

Bedside glucose profileFirst step

Define severity, timing and relation to meals, feeds, steroids and current insulin delivery.

Management branches

TriageChoose the correct insulin pathway

An inpatient has persistent or severe hyperglycaemia, whether or not diabetes was previously diagnosed.

Assess ABCDE, symptoms, hydration, current diabetes type and treatment, then check ketones, venous acid–base status and osmolality whenever the clinical pattern warrants.
Route DKA, euglycaemic DKA and HHS to their dedicated fixed-rate emergency charts; correct remediable missed doses, nutrition or prescribing errors when a subcutaneous plan remains appropriate.
Select VRIII only for a defined temporary indication such as unreliable oral intake or uncontrolled acute illness, recording target range, review time and planned exit.

Key medicines

Variable-rate intravenous human soluble insulin infusionChoose the hourly rate from the current local JBDS-aligned scale according to bedside glucose and documented insulin sensitivity; never invent a universal rate or use this chart for DKA or HHS.Requires hourly glucose, a checked pump and line, uninterrupted substrate and current potassium assessment. Continue basal insulin, treat low glucose immediately, involve the diabetes team if use extends beyond 24 hours, and reassess any apparent resistance before changing scale.

Intravenous substrate fluid with VRIIIPrescribe the locally approved glucose-containing fluid and rate alongside VRIII, selecting sodium and potassium content from clinical fluid need, renal function and measured electrolytes rather than a generic recipe.Do not allow substrate to finish or disconnect while insulin continues. Avoid fluid or potassium overload in cardiac or renal disease, use a compatible access plan, and review an alternative route when restriction prevents safe standard substrate delivery.

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