What insulin rate does this use?

It uses the JBDS fixed-rate intravenous insulin infusion of 0.1 units per kilogram per hour, made up as 50 units of soluble insulin in 50 mL of 0.9% sodium chloride. The displayed rate in mL/hour equals the units/hour because the mixture is 1 unit per mL.

How is the first litre handled if blood pressure is low?

If the systolic blood pressure is below 90 mmHg the protocol gives a 500 mL bolus of 0.9% sodium chloride over 10 to 15 minutes, repeated if needed, before starting the timed replacement bags. The tool flags this and starts the timed schedule afterwards.

Why does potassium depend on the serum level?

Insulin drives potassium into cells and can cause dangerous hypokalaemia. The protocol adds 40 mmol potassium chloride per litre when serum potassium is 3.5 to 5.5 mmol/L, no potassium above 5.5, and senior review with more aggressive replacement below 3.5.

Does this replace clinical judgement?

No. It reproduces the standard adult JBDS schedule for a typical case. Pregnancy, young adults, heart or kidney failure, and very high or low presentations need senior input and individualised fluid rates, which this tool does not model.

When should the fluid bags be slowed?

The staged schedule front-loads fluid then slows as the deficit is corrected. Caution and slower rates apply in the elderly, in pregnancy, and where there is a risk of cerebral oedema or fluid overload, so reassess clinically at each bag change.

DKA IV Fluid Regime Calculator

Diabetic ketoacidosis is treated with prompt fluid resuscitation, a fixed-rate insulin infusion, and careful potassium replacement. This calculator reproduces the standard adult schedule used across UK acute units so you can read the insulin rate, the staged saline volumes, and the potassium addition for a given patient at a glance.

How it works

The regime has three parts that run together:

Insulin   = 0.1 units/kg/hour, made as 50 units in 50 mL 0.9% NaCl
            (so mL/hour = units/hour)
Fluids    = 0.9% sodium chloride in timed bags:
            1 L over 1 h, 1 L over 2 h, 1 L over 2 h, 1 L over 4 h,
            1 L over 4 h, 1 L over 6 h
            (if systolic BP < 90 mmHg: give 500 mL bolus first)
Potassium = serum K > 5.5  -> none
            serum K 3.5-5.5 -> 40 mmol KCl per litre
            serum K < 3.5   -> senior review, >40 mmol/L needed

The insulin mixture is deliberately one unit per millilitre, so a pump rate in millilitres per hour reads the same as the units-per-hour dose.

Example and notes

An 80 kg patient with a systolic blood pressure of 110 mmHg and a serum potassium of 4.2 mmol/L receives an 8 units/hour fixed-rate insulin infusion, the timed litre bags of 0.9% sodium chloride, and 40 mmol of potassium chloride added to each litre from the second bag onward. Always recheck potassium hourly at first, watch for cerebral oedema in younger patients, and slow the fluids for frail or cardiac patients. This tool is a bedside aid, not a substitute for the full protocol or senior review.