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HWN Suggests

For Maintenance Fluids, Reach for Isotonic Saline

Are you still reflexively reaching for hypotonic saline for maintenance hydration? Check the research. Most physicians have been taught to use 0.9 NaCl (normal saline) for boluses, and either dextrose 5% with 0.2 NaCl (D5 quarter-normal) or dextrose 5% with 0.45 NaCl (D5 half-normal) for maintenance. Both 0.2 NaCl and 0.45 NaCl are hypotonic fluids, 0.9 NaCl is considered isotonic.

In February 2003, Michael Moritz and Juan Carlos Ayus published a paper in the journal Pediatrics questioning this approach. They noted that hypotonic maintenance fluids lead to a high incidence of hyponatremia in hospitalized children, including more than 50 reported cases of neurologic morbidity with…

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Featured

 Maintenance Fluids

Most often in the ED, it is done as boluses of isotonic fluids, but some will require maintenance fluids. Seems simple enough… but are we choosing the correct maintenance fluid?

 New Pediatric Intravenous Fluid Guideline

For decades, inpatient fluid management was informed by theory and tradition rather than clinical studies. The arrival of this clinical practice guideline, based on a rigorous review of high-quality evidence, will reassure clinicians already using isotonic maintenance IVFs and should prompt those still using traditional methods to adopt this safer approach.

Articles of Interest

American Academy of Pediatrics Releases New Clinical Guidelines on IV Fluid Use in Children

“Hypotonic fluids have, unfortunately, been the standard of care in pediatrics for more than 50 years, primarily based on tradition and not on science. I introduced the concept of avoiding hypotonic fluids and using isotonic fluids to prevent hyponatremia about 15 years ago. Since then, numerous studies in thousands of children have demonstrated that isotonic fluids decrease the incidence of hyponatremia from greater than 20 percent to less than 5 percent,” says Dr. Moritz.

Calculating Pediatric Maintenance Fluids (4:2:1 Rule)

Pediatrics, calculations, fluids, maintenance, hypotonic, isotonic?!?! These words bring on a new type of stress... Although these calculations are utilized in the hospital/critical care setting, they are fundamental in treating pediatrics in any realm.

Originating in a 1957 study, Malcolm Holliday and William Segar developed an equation for adequate maintenance fluids, hence the Holliday-Segar Rule. What they found was a linear representation between a child’s physiological needs and basal metabolic rate, where a computed average number could be formulated. So what does all this mean? Well, 1kcal burned equals approximately 1ml of water lost. With that, we can calculate fluid requirements based on weight in kilograms, and here is how!

Hypotonic maintenance IV fluids in pediatrics

This article forces us to reassess conventional wisdom in the light of new experimental evidence. Hypotonic maintenance fluids were originally established using a now 60 year old study on the basis of presumed rather than clinically confirmed patient physiology. While this particular systematic review failed to find patient oriented harm associated with hypotonic maintenance fluids it did show an absolute alterations in serum sodium potentially predictive of poor patient outcomes.

Maintenance Fluids Calculations

While originally derived in pediatric patients, this calculator is applicable to any age. Consider using ideal body weight in obese patients. If not calculating based on ideal body weight, use clinical judgment for dosing. A 1-liter bolus may be appropriate for most patients, such as overweight adolescents and adults.

Paediatric Intravenous (IV) Fluid Prescribing

Maintenance fluids are given over 24 hours and calculated by the weight using the Holliday-Segar formula for children >28 days of age, or by weight and age in neonates.

Pediatric Emergency Medicine Fundamentals 2020 Fluids and Electrolytes

Videos from EM:RAP

Pediatric Fluid Management

The Holliday-Segar Method provides a formula for calculating fluid requirements (Holliday-Segar 1957) - contemporary articles support continued use of this method with modifications based on overall health of the child with individualized rates of IV fluids

Pediatric Principles for Pediatric Surgeons - Part I Parenteral Maintenance Fluid Therapy

Selecting [5% dextrose, 0.9% NaCl + 20 mmol/L KCl] solution for maintenance fluid is appropriate for children...

PEM Pearls: Pediatric Sepsis Management – Understanding the Basics

Do NOT stick to strict protocols mandating minimum fluid volumes for sepsis patients. Frequent reassessments and tailoring the volume of fluid resuscitation to each individual patient are better.

Resources

PedsCases

Calculating IV Fluids à STEP 1: Bolus = NS 10-20mL/kg or 5-10mL/kg if worried about myocardial or renal dysfunction. à STEP 2: Calculate deficit= % dehydrated x weight in kg. à STEP 3: Calculate maintenance fluids in mL/hr with 4-2-1 rule. à STEP 4: Calculate Total Fluid Replacement Over 24h = deficit + maintenance – bolus. à STEP 5: Divide volume over 24 hours. à STEP 6: Measure ongoing losses (i.e. vomit, diarrhea, sweat etc.) and replace as needed. à STEP 7: IV Fluid Selection – Typically D5NS +/- 20mEq/L KCl depending on kidney function and electrolytes.