How is the infusion concentration found?

Concentration in mg/mL is the drug mass in the bag divided by the bag volume. For example 400 mg in a 250 mL bag is 1.6 mg/mL, or 1600 mcg/mL. The pump rate calculation depends on this value.

How is a weight-based pump rate calculated?

First convert the target to mg/min: target mcg/kg/min times weight in kg, divided by 1000. Then the rate in mL/hr equals that mg/min times 60, divided by the concentration in mg/mL. The tool shows each step.

When do I use mg/hr instead of mcg/kg/min?

Use mg/hr for drugs ordered as a fixed hourly dose, such as some sedatives or heparin. Use mcg/kg/min for weight-titrated vasoactive drugs like noradrenaline or dopamine. The tool supports both modes.

Why does concentration matter so much?

The same target dose needs very different pump rates depending on how concentrated the bag is. Double-concentrated bags halve the mL/hr. Always confirm the bag concentration matches what the pump is programmed to expect to avoid serious dosing errors.

Is this safe to use alone for high-alert drugs?

No. Vasoactive and sedative infusions are high-alert. Verify every calculation against the protocol, the pump's settings, and a second clinician. This tool is an educational double-check and runs entirely in your browser.

Infusion Concentration & Rate Calculator

Continuous infusions of vasoactive and sedative drugs are ordered as a dose (mcg/kg/min or mg/hr) but delivered as a volumetric pump rate (mL/hr). This tool bridges the two by first finding the bag concentration, then the rate that delivers the target dose.

How it works

The bag concentration is mass divided by volume:

concentration (mg/mL) = drug_mg / bag_volume_mL

For a weight-based order:

dose (mg/min) = target_mcg_kg_min * weight_kg / 1000
rate (mL/hr)  = dose_mg_min * 60 / concentration_mg_mL

For a fixed order:

rate (mL/hr) = target_mg_hr / concentration_mg_mL

Example

A bag holds 400 mg of drug in 250 mL, a concentration of 1.6 mg/mL. To deliver 5 mcg/kg/min to a 70 kg patient: dose = 5 × 70 ÷ 1000 = 0.35 mg/min; rate = 0.35 × 60 ÷ 1.6 ≈ 13.1 mL/hr.

Notes

The same target needs a very different rate at a different concentration, so always confirm the bag concentration matches what the pump expects. These are high-alert calculations; verify against the protocol and a second clinician. Everything runs locally in your browser.