Intravenous math: rate, drip factor, titration

Setup 1 · Pump rate

Rate in milliliters per hour = Total volume in milliliters ÷ Total time in hours. A pump is told a rate, so the answer is a rate. If the stem gives you a bag and a duration and mentions a pump, this is the whole problem.

Setup 2 · Gravity drip

Drops per minute = (Total volume in milliliters × Drop factor in drops per milliliter) ÷ Time in minutes. The drop factor is a property of the tubing set, printed on its package, not something the prescriber orders. Macrodrip sets carry the larger drop factors. A microdrip set is always 60 drops per milliliter.

Setup 3 · Titration

Pump rate in milliliters per hour = (Dose per kilogram per minute × Weight in kilograms × 60 minutes per hour) ÷ Concentration per milliliter in the bag. The minute-to-hour conversion is written into the setup rather than remembered at the end, which is where titration problems are usually lost.

Rounding rules

Drops per minute round to a whole drop, because a fractional drop does not exist. Pump rates follow institutional policy on decimal places. Rounding happens once, at the end, and never in the middle of a multi-step setup.

The infusion safety layer

High-alert infusions run on a pump with dose-error-reduction software, are verified by an independent double check, and are labeled at the insertion site and at the pump. The site is assessed on a schedule. Any pain, swelling, coolness, or leaking stops the infusion first and gets explained second.

Margin notepump answers in milliliters, gravity answers in drops.

Watch outa titrated vasoactive infusion is never adjusted without a parameter in the order to titrate against.

Takeawayidentify the setup first, because each of the three asks for a different unit, and the unit is the answer.

Worked rate problems → BOOK 06 · P7. Titration practice → BOOK 06 · P10.