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IV fluids & electrolytes

Prescribing intravenous fluids for surgical patients: what bag, how much, how fast.

Written and clinically reviewed by , consultant minimally invasive and bariatric surgeon, Al-Makassed Hospital, Jerusalem, and Assistant Professor of Surgery, Al-Quds University. Last updated .

Almost every surgical inpatient has a drip, and most fluid errors are made by the most junior doctor at night. This topic brings together the Intravenous Fluids book, the calculator and the OSCE stations, so you can learn the rules and then practise them.

Three questions before every bag

  • Resuscitation, maintenance or replacement? Each needs a different fluid, volume and rate.
  • What are the sodium and potassium today? Look before you prescribe, not after.
  • What is the fluid balance? Read the chart and the weight, not just yesterday’s prescription.

In this topic

Start here

Free bookIntravenous Fluids71 pages: resuscitation, maintenance, replacement and the fluid balance chart.CalculatorIV fluids calculatorMaintenance, drip rates, Parkland, sodium correction and potassium.

Practise

OSCE stationMaintenance intravenous fluidsWrite the prescription, then check the model answer.OSCE stationFluid balance chartRead the chart the way the examiner will.

Where fluids meet other topics

GuideSaline and the acid–base balanceWhy large volumes of 0.9% saline cause a hyperchloraemic acidosis.GuideHypercalcaemic crisisFluids first, and why furosemide is the wrong reflex.GuidePersistent vomitingThe hypochloraemic alkalosis, and the fluid that corrects it.

Test yourself: Champion

5 rapid-recall questions on this topic, thirty seconds each.

Play this topic →
8Test yourself: Surgical nutrition MCQs
Single-best-answer questions with answers, explanations and references.Start →

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