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Measuring fluid intake and output


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INTAKE AND OUTPUT gauge fluid balance and give valuable information about your patient's condition.

  • Identify whether your patient has undergone surgery or if he has a medical condition or takes medications that can affect fluid intake or loss.
  • Measure and record all intake and output. If you delegate this task, make sure you know the totals and the fluid sources.
  • At least every 8 hours, record the type and amount of all fluids he's received and describe the route as oral, parenteral, rectal, or by enteric tube.
  • Record ice chips as fluid at approximately half their volume.
  • Record the type and amount of all fluids the patient has lost and the route. Describe them as urine, liquid stool, vomitus, tube drainage (including from chest, closed wound drainage, and nasogastric tubes), and any fluid aspirated from a body cavity.
  • Figure. If
    Figure. If:
    irrigating a nasogastric or another tube or the bladder, measure the amount instilled and subtract it from total output.
  • For an accurate measurement, keep toilet paper out of your patient's urine.
  • Figure
    Measure drainage in a calibrated container. Observe it at eye level and take the reading at the bottom of the meniscus.
  • Evaluate patterns and values outside the normal range, keeping in mind the typical 24-hour intake and output. (See Fluid Gains and Losses.)
  • When looking at 8-hour urine output, ask how many times the patient voided, to identify problems. For example, was a total of 300 ml from 2 voids of 150 ml, or from 10 voids of 30 ml each?
  • Regard intake and output holistically because age, diagnosis, medical problem, and type of surgical procedure can affect the amounts. Evaluate trends over 24 to 48 hours.
  • Don't delegate the task of recording intake and output until you're sure the person who's going to do it understands its importance.
  • Don't assess output by amount only. Consider color, color changes, and odor too.
  • Don't use the same graduated container for more than one patient.

Fluid gains and losses

The following are typical 24-hour values for an adult.

Intake 2,600 ml

  • 1,300 ml oral fluids
  • 1,000 ml in food
  • 300 ml in oxidation of food

Output 2,400 to 2,700 ml

  • 1,500 ml urine
  • 200 ml in stool
  • 400 to 600 ml through the skin
  • 300 to 400 ml through respiration


Perry, A., and Potter, P.: Clinical Nursing Skills and Techniques, 4th edition. St. Louis, Mo., Mosby-Year Book, 1998.
    Phipps, W., et al.: Medical-Surgical Nursing, 6th edition. St. Louis, Mo., Mosby-Year Book, 1999.
      © 2002 Lippincott Williams & Wilkins, Inc.