How to Monitor IV Fluid Therapy

Written by richard barker, dvm | 13/05/2017
How to Monitor IV Fluid Therapy
Physicians apply aseptic technique to IV catheter use and fluid therapy. (Monkey Business Images Ltd/Valueline/Getty Images)

Patients receive intravenous fluids, IV fluid therapy, as part of treatment for a variety of medical conditions, primarily in a hospital environment. IV fluid therapy provides for patients' fluid volume needs, and often addresses specific medical needs.

To monitor patients receiving IV fluid therapy, clinicians measure vital signs indicating hydration status and measure specific blood components related to medical needs. Clinicians must replace maintenance and lost fluids while avoiding over-hydration from excessive fluid administration.

Determine fluids needed for adequate patient hydration by calculating the sum of the following: emergency needs for resuscitation; restoration of hydration; maintenance requirements; and ongoing losses.

Measure fluid losses, for example in urine and faeces. Calculate fluid restoration, resuscitation and maintenance requirements, using formulas based on body weight available in references such as "The Merck Manuals." Subtract any fluids the patient ingests from IV fluid needs.

Measure IV fluid volume and type administered and compare with needs. As needs change, for example if vomiting begins, adjust fluids accordingly.

Monitor vital signs and symptoms indicating fluid balance to avoid dehydration or over-hydration. Relevant physical examination results include body weight, gum moisture, skin turgor, heart rate, breathing rate, lung sounds as heard with a stethoscope and observation of tissue swelling around eyes or under the skin.

Heart rate may increase, and body weight, gum moisture and skin turgor, the resiliency of skin after it is pinched, may decrease. Over-hydration, caused by administration of excess IV fluids, may cause swelling of tissue, increased respiratory rate and abnormal lung sounds.

Increase or decrease IV fluid administration rate as need is indicated by these parameters.

In critical-care patients, use blood tests to monitor hydration status and monitor central venous pressure. Blood tests include blood urea nitrogen, urine specific gravity and hematocrit, a measure of red blood cell concentration. Hematocrit, blood urea nitrogen and urine specific gravity may increase during dehydration.

Monitor central venous pressure to avoid dehydration and over-hydration. Central venous pressure is measured with a manometer attached to a catheter placed in a vein near the heart. It may increase during over-hydration and decrease with dehydration.

Monitor specific needs addressed through intravenous fluids for specific conditions.

For example, patients may need calcium and potassium supplementation in pancreatitis cases, and blood tests guide fluid therapy in addressing these needs. A clinician may need to add electrolytes to IV fluids.


Increased body temperature will increase IV fluid needs.


Professionals should direct IV fluid monitoring as errors can lead to serious injury or death.

Tips and warnings

  • Increased body temperature will increase IV fluid needs.
  • Professionals should direct IV fluid monitoring as errors can lead to serious injury or death.

Things you need

  • Stethoscope
  • Blood counting machine
  • Blood gas analyzer
  • Blood chemistry analyzer
  • Refractometer
  • Central venous catheter and manometer

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