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Purpose and principlesIndications, selection and cautionsAssessment before treatmentTreatment approachRegimens, contraindications and interactionsComplications, monitoring and follow-upSpecial situationsCommon pitfallsQuestionsSources
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Inpatient hyperglycaemia and variable-rate insulin

Endocrinology and metabolism · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

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Time-critical presentation

Hyperglycaemia with ketones, acidosis, marked hyperosmolality, shock, vomiting or altered consciousness is not routine ward dysglycaemia: assess for DKA or HHS and use its fixed-rate emergency pathway. During VRIII, glucose below 4.0 mmol/L, interruption of insulin or substrate, severe potassium disturbance or clinical deterioration requires immediate treatment, pump and line checks, and urgent senior review.

Purpose and principles

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

Inpatient hyperglycaemia may predate admission or arise from infection, surgery, myocardial injury, glucocorticoids, enteral nutrition, reduced activity, omitted medicines or previously unrecognised diabetes. It is associated with infection, delayed healing, osmotic symptoms and longer admission, yet overly aggressive correction creates hypoglycaemia, falls, arrhythmia and neurological harm. Diagnosis, nutrition and trajectory should therefore guide treatment, not an isolated reading.

VRIII delivers short-acting insulin through a pump at a rate chosen from repeated capillary glucose. Because it has a short biological tail, it is controllable during rapidly changing illness but vulnerable to interruption and prescribing error. A separate substrate infusion provides carbohydrate, fluid and often potassium according to the local chart, while basal subcutaneous insulin protects continuity and makes later transition safer.

VRIII is a bridge, not a complete diabetes plan. Each prescription needs an indication, target, sensitivity scale, fluid choice, electrolyte plan, monitoring frequency, hypoglycaemia treatment and stop strategy. Complex type 1 diabetes, pregnancy, renal replacement therapy, parenteral or enteral feeding, high-dose steroids, severe insulin resistance and prolonged use should involve the inpatient diabetes team and the relevant specialist protocol.

Indications, selection and cautions

Stress hyperglycaemia

Acutely raised glucose may reflect counter-regulatory illness in someone without known diabetes, but still requires HbA1c-based follow-up and exclusion of a hyperglycaemic emergency.

Insulin-deficient emergencyRed flag

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 phenotypeRed flag

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

Nutrition mismatch

Unexpected glucose change around missed meals, vomiting, enteral-feed interruption, parenteral nutrition or procedures often signals a delivery problem rather than a need for repeated arbitrary corrections.

Steroid pattern

Once-daily morning glucocorticoid commonly drives afternoon and evening hyperglycaemia, while multiple or long-acting doses produce a different profile requiring matched treatment.

Infusion failureRed flag

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

Assessment before treatment

  1. 01
    Bedside glucose profileFirst step
    Why
    Define severity, timing and relation to meals, feeds, steroids and current insulin delivery.
    Interpretation and limitations
    Use repeated values rather than one result; rapid rise in type 1 diabetes or illness warrants ketones, while recurrent lows demand immediate regimen and intake review.
  2. 02
    Blood ketones and venous gas when indicated
    Why
    Exclude DKA or euglycaemic DKA before labelling the problem routine inpatient hyperglycaemia.
    Interpretation and limitations
    Significant ketonaemia with acidosis invokes fixed-rate DKA care; modest glucose does not reassure when SGLT2 exposure or insulin interruption is present.
  3. 03
    Electrolytes, creatinine and fluid assessment
    Why
    Guide substrate composition, identify acute kidney injury and prevent unsafe potassium or volume delivery.
    Interpretation and limitations
    Declining renal clearance may reduce insulin requirement and raise hypoglycaemia risk; potassium and fluid prescriptions must use measured values and the local chart.
  4. 04
    HbA1c
    Why
    Distinguish likely chronic dysglycaemia from acute stress and support a post-discharge diagnostic or treatment plan.
    Interpretation and limitations
    Interpret cautiously after transfusion, anaemia, haemoglobinopathy or advanced kidney disease; a non-diabetes-range result does not make current severe stress hyperglycaemia irrelevant.

Treatment approach

01TriageChoose the correct insulin pathwayFirst stepAn inpatient has persistent or severe hyperglycaemia, whether or not diabetes was previously diagnosed.+
  1. 1Assess ABCDE, symptoms, hydration, current diabetes type and treatment, then check ketones, venous acid–base status and osmolality whenever the clinical pattern warrants.
  2. 2Route 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.
  3. 3Select VRIII only for a defined temporary indication such as unreliable oral intake or uncontrolled acute illness, recording target range, review time and planned exit.
02RunDeliver VRIII as a linked systemA clinician has confirmed that variable-rate intravenous insulin is the appropriate temporary treatment.+
  1. 1Prescribe insulin on the approved chart with the appropriate sensitivity scale, continue established long-acting basal insulin and reconcile which prandial or non-insulin medicines are being held.

Regimens, contraindications and interactions

Provides rapidly adjustable insulin during temporary acute illness or unreliable intake when subcutaneous absorption and meal matching are unsuitable.

Variable-rate intravenous human soluble insulin infusion

Choose 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.

Supplies carbohydrate to limit catabolism and hypoglycaemia while supporting required fluid and electrolyte delivery during intravenous insulin treatment.

Intravenous substrate fluid with VRIII

Prescribe 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.

Complications, monitoring and follow-up

  • Record capillary glucose every hour from initiation until VRIII stops, including during theatre, imaging, ward transfer and out-of-hours periods when missed checks are most likely.
  • Review the programmed insulin rate against the signed prescription and actual glucose at every adjustment, bag change and nursing handover, with independent checks required by local policy.
  • Measure serum potassium and renal function at least daily and more often when abnormal, unstable or receiving replacement; electrolyte risk can change quickly as insulin drives potassium intracellularly.
  • Assess cumulative substrate fluid, urine output, oedema and respiratory status, particularly in frailty, acute kidney injury or heart failure where the standard bag rate may be unsuitable.
  • Document meals, vomiting, enteral or parenteral feed, glucocorticoid dose and interruptions so glucose variation can be linked to physiology rather than managed reactively.
  • After stopping, check glucose at one hour and at least four-hourly for 24 hours, confirming that the discharge regimen, education and primary-care communication reflect inpatient changes.

Special situations

VRIII is not FRIII

Variable-rate treatment reacts to glucose in general inpatient care; fixed-rate emergency insulin targets ketogenesis or defined HHS physiology and cannot be substituted casually.

Basal insulin is the bridge

Continuing long-acting insulin reduces rebound hyperglycaemia after infusion and protects people with type 1 diabetes from an abrupt absence of insulin.

Substrate and insulin travel together

A pump may keep running when a fluid bag empties or during transfer, so safe systems make both infusions visible and jointly handed over.

Timing reveals steroid effect

A daytime glucose rise after morning glucocorticoid often responds better to matched subcutaneous strategy than prolonged nonspecific intravenous insulin once stable.

The exit is prescribed early

Writing a stop criterion and anticipated subcutaneous regimen when VRIII starts prevents avoidable overnight continuation and insulin-free gaps.

New hyperglycaemia needs ownership

Stress dysglycaemia may resolve before discharge yet predicts future diabetes risk; record HbA1c interpretation and assign repeat testing rather than losing follow-up.

Common pitfalls

  1. 01

    Putting a ketotic acidotic patient on the general VRIII chart because it is readily available, without activating the DKA fixed-rate and fluid protocol.

  2. 02

    Stopping basal insulin when VRIII begins in a person with type 1 diabetes, leaving no background protection if the infusion is interrupted.

  3. 03

    Running insulin after the substrate bag finishes during transport or imaging and failing to recognise the system failure until severe hypoglycaemia occurs.

  4. 04

    Responding to every high reading by moving off the approved scale without checking cannula patency, pump programming, feed, steroids, ketones or worsening sepsis.

  5. 05

    Continuing VRIII for several days because no one has documented oral-intake recovery, a subcutaneous regimen or responsibility for the transition.

  6. 06

    Stopping the infusion between meals without timed subcutaneous insulin overlap, then discovering rebound hyperglycaemia or ketonaemia hours later.

Practice

Two practice questions

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Question 1 of 2
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Endocrinology and metabolismOriginal SBA

Choosing fixed versus variable rate

A patient with type 1 diabetes has glucose 17 mmol/L, blood ketones 4.6 mmol/L and venous pH 7.21. Which insulin approach is most appropriate?

Choose one answer, then submit
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Sources and review status5 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • JBDS 09 VRIII in medical inpatientsOfficial indications, target range, infusion setup, monitoring, basal insulin and transition guidance.
  • JBDS 01 inpatient hypoglycaemiaRescue treatment and infusion-restart safeguards when glucose falls below 4 mmol/L.
  • Centre for Perioperative Care diabetes guidelineRoyal College-supported perioperative assessment, medication, intravenous insulin and transfer principles.
  • NICE NG17 type 1 diabetes recommendationsInsulin continuity, inpatient safety and long-term education context.
  • NICE NG28 type 2 diabetes recommendationsIndividualised glucose targets and post-admission treatment planning for type 2 diabetes.

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateComplete draft

Key points

  • 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.
  • 05
    Prescription, pump and nutrition reconciliation
    Why
    Confirm that intended insulin, substrate, feed and subcutaneous basal treatment have actually reached the patient.
    Interpretation and limitations
    Trace bag label, pump rate, tubing, cannula, fluid balance, meal or feed timing and administration record; discrepancies explain many apparent resistance or sensitivity changes.
  • 06
    Precipitant assessment
    Why
    Identify infection, infarction, glucocorticoid exposure, pancreatic disease or omitted home treatment.
    Interpretation and limitations
    Treat the underlying illness and anticipate how its resolution changes insulin need; falling steroid dose, recovering sepsis or resumed nutrition can rapidly alter the safe rate.
  • 2Prescribe compatible substrate fluid and potassium from current electrolytes, ensuring dedicated access, labelled lines and a transfer plan that prevents accidental disconnection.
  • 3Measure capillary glucose hourly, adjust only by the authorised table and review the patient, pump, cannula, substrate and underlying illness when readings remain outside the intended range.
    • 03CorrectRespond to instability on infusionGlucose is below 4 mmol/L, repeatedly above target, rapidly changing or inconsistent with the programmed rate.+
    1. 1For hypoglycaemia, pause active insulin, give rescue treatment appropriate to swallow and consciousness, check substrate delivery and monitor until safely corrected under the hypoglycaemia chart.
    2. 2For persistent high glucose, reassess for ketones and new illness, confirm prescription, scale, pump, bag, tubing and access, and obtain senior diabetes advice rather than making off-chart jumps.
    3. 3Recheck potassium, renal function, feed and steroid timing, then document the cause and revised monitoring plan at the next clinical and nursing handover.
    04StopTransition at a mealThe acute indication has resolved, the person can eat and drink, and a suitable subcutaneous regimen is agreed.+
    1. 1Plan cessation for a mealtime, ensure basal insulin has continued and give the appropriate rapid-acting or mixed subcutaneous dose with food according to the individual regimen.
    2. 2For rapid-acting mealtime insulin, the JBDS general approach stops VRIII about 30 minutes after the subcutaneous dose; follow the exact local overlap rule for the chosen insulin.
    3. 3Check glucose one hour after stopping and at least four-hourly for 24 hours under the guideline, with an explicit restart or adjustment route if control deteriorates.
    Clinical stateAwaiting review
    JurisdictionUnited Kingdom